UDK 550.344.4(26I.26)"633" Documenta Praehistorica XXXV (2008) The catastrophic final flooding of Doggerland by the Storegga Slide tsunami Bernhard Weninger1, Rick Schulting2, Marcel Bradtmöller3, Lee Clare1, Mark Collard4, Kevan Edinborough4, Johanna Hilpert1, Olaf Jöris5, Marcel Niekus6, Eelco J. Rohling7, Bernd Wagner8 1 Universität zu Köln, Institut für Ur- und Frühgeschichte, Radiocarbon Laboratory, Köln, D, b.weninger@uni-koeln.de< 2 School of Archaeology, University of Oxford, Oxford, UK< 3 Neanderthal Museum, Mettmann, D< 4 Laboratory of Human Evolutionary Studies, Dpt. of Archaeology, Simon Fraser University, Burnaby, CDN< 5 Römisch Germanisches Zentralmuseum Mainz, D< 6 Groningen Institute of Archaeology, Groningen, NL< 7 School of Ocean and Earth Science, National Oceanography Centre, Southampton, UK< 8 Universität zu Köln, Institut für Geologie und Mineralogie, Köln, D ABSTRACT - Around 8200 calBP, large parts of the now submerged North Sea continental shelf ('Dog- gerland') were catastrophically flooded by the Storegga Slide tsunami, one of the largest tsunamis known for the Holocene, which was generated on the Norwegian coastal margin by a submarine landslide. In the present paper, we derive a precise calendric date for the Storegga Slide tsunami, use this date for reconstruction of contemporary coastlines in the North Sea in relation to rapidly rising sea-levels, and discuss the potential effects of the tsunami on the contemporaneous Mesolithic popula- tion. One main result of this study is an unexpectedly high tsunami impact assigned to the western regions of Jutland. IZVLEČEK - Okoli 8200 calBP je velik del danes potopljenega severnomorskega kontinentalnega pasu (Doggerland) v katastrofalni poplavi prekril cunami. To je eden največjih holocenskih cunamijev, ki ga je povzročil podmorski plaz na norveški obali (Storegga Slide). V članku predstavljamo natančne datume za cunami Storegga Slide in jih uporabimo pri rekonstrukciji takratnih obal Severnega mor- ja, v času naglega dviganja morske gladine. Dotaknemo se tudi možnih posledic cunamija za mezo- litske populacije. Glavni rezultat študije je nepričakovano močan vpliv cunamija na zahodni del Jut- landa. KEY WORDS - Mesolithic; Doggerland; Storegga Slide tsunami Introduction The hypothesis that a major tsunami was generated by an underwater slide off the west coast of Norway was first proposed by Svendsen (1985) and further elaborated in a large number of studies (e.g. Bonde- vik 2003; Bondevik et al. 1997; 2003; 2005; 2006; Dawson et al. 1988; 1990; 1993; Grauert et al. 2001; Haflidason et al. 2005; Long et al. 1989; Smith et al. 1985; 2004). As a result of detailed fieldwork (e.g. Bondevik et al. 1997; 2003; 2005; Smith et al. 2004), followed by comprehensive modelling studies (Har- bitz 1992; Bondevik et al. 2005), a comparatively large number of deposits on the coasts of Norway and eastern Scotland can now be safely attributed to the Second Storegga Slide tsunami. The generation of the tsunami apparently involved some 2400- 3200km3 of material that spread across the North Atlantic sea floor, altogether covering an area of around 95 000km2 (Haflidason et al. 2005) - that is about the size of Scotland. Bryn et al. (2005) sug- gest the cause of the Storegga slide was a strong earthquake in the North Atlantic, but further inves- tigations are necessary to substantiate this hypothe- sis. Due to the large slide/slump volume and exten- sive reworking, the direct dating of the slide sedi- ments is no easy matter. Comprehensive analysis of a long (more than 50 14C-ages) series of AMS-radio- carbon ages for stratified basal post-slide sediments, processed on purposely chosen monospecific planc- tonic foraminifera (Neogloboquadrina pachyderma and Globigerina bulloides) to reduce the risk of re- working, give an (averaged) direct date for the main slide of 7250 ± 250 14C yrs BP (Haflidason et al. 2005). Traces of the corresponding Second Storegga Slide tsunami have been identified in many regions of the North Atlantic, with the best-studied locations on the coast of Norway and eastern Scotland. On the Nor- wegian coast, at locations directly opposite to the sub-marine landslide region, the tsunami had a ma- ximum runup of 10-12m. Further north, a runup of 6-7m is reconstructed. On the eastern coast of Scot- land typical runup heights exceed 3-5m (Smith et al. 2004). Storegga deposits are also known from the Faroes (Grauert et al. 2001) and the Shetland Islands, where runup exceeds 20m (Bondevik et al. 2005). Recent studies show that the tsunami proba- bly even reached the east coast of Greenland (Wag- ner et al. 2007). This would agree with modelling studies (Bondevik et al. 2005), according to which the wave front would have crossed the North Atlan- tic within 3 hours, with maximal elevation on the open ocean of 3m. The size of these waves, and their spread over such a large area, indicate that most of the volume of the slide was involved in the genera- tion of the tsunami (Bondevik et al. 2005). On the Norwegian coast, the arrival of the first wave would have been associated with a major water withdra- wal, corresponding to a predicted initial sea-level drop of 20m. The model also predicts that multiple waves should occur. This is confirmed for deposits probably laid down by the Storegga slide tsunami on the east coast of Greenland, where the grain-size composition, biogeochemical and macrofossil data indicate that the Loon Lake basin was inundated by at least four waves (Wagner et al. 2007). The effects of the tsunami on other North Sea coasts - and no- tably on Mesolithic Doggerland (Coles 1998) - have not yet been modelled. As a starting point for our studies towards the potential effects of the Storegga Slide tsunami in the southern North Sea, we assume that runup in this region is likely to have been around 3m (pers. comm. Bondevik 2007). Tsunami deposits The accurate dating of the Storegga Slide Tsunami represents a major challenge to established radiocar- bon methodology. As already recognised by Bonde- vik et al. (2006), the accurate radiocarbon dating of palaeotsunamis is problematic for three reasons: (1) erosion of the underlying strata, (2) redeposition of organic material within the tsunami deposit, and (3) redeposition of organic matter following the tsunami event. Due to the importance of these issues for ra- diocarbon dating, we begin with a brief description of the tsunami deposits under study on the coasts of Norway and Great Britain. Norway In Norway, the Storegga Slide tsunami deposits are typically recognised as a distinct layer of sand in peat outcrops, with an underlying and often sharply erod- ed surface (Bondevik et al. 1997; 2003). Similar ob- servations have been made all along the eastern coast of Scotland, where the inferred tsunami depo- sits are readily recognised by a recurring sand layer within raised estuarine sediments that pass into peat in a landward direction (Dawson et al. 1993). This sand layer, both in Norway and Scotland (see be- low), contains a variety of chaotically redeposited organic materials, including twigs and bark. These are the samples, typically described as deriving from 'within the tsunami layer', that were carefully selec- ted during field-work. When short-lived (annual growth) dating material (e.g. twigs, bark) is avail- able, this is the preferred material submitted for ra- diocarbon dating, in contrast to peat samples, which are expected to have an in-built 'older' age due to peat growth processes. Along the Norwegian coast, as observed at higher levels, the tsunami inundated a number of fresh-wa- ter bodies, again leaving behind a characteristic sand layer. These deposits contain redeposited lake mud, rip-up clasts, and churned up marine fossils. This sand layer has many of the characteristic properties known from modern tsunami deposits. In particular, the observations made for the Storegga Slide tsuna- mi are consistent with the modern observation that tsunamis are commonly associated with at least two waves, with the second wave arriving within minu- tes, but even up to a few hours after the first, depen- ding on distance to the source (Bondevik et al. 2005). Regarding the geological situation in Norway, the first wave typically appears to have eroded the peat surface, producing huge amounts of rip-up peat clasts, which were then chaotically redeposited along with other organic remains, during the backwash. The second wave then appears to have buried these ma- terials in a layer of sand (Bondevik et al. 1997). In order to accurately measure the runup heights for the Storegga tsunami, Bondevik et al. (2005) devel- oped a novel method for runup reconstruction, which is applicable to the large number of tsunami depo- sits known from the Norwegian coast. The method is to map the precise heights of the tsunami deposits in a series of increasingly higher lake basins, until the maximum height is reached. By this method, it appears that the waves inundated the coastal lakes up to 10-12m above contemporary sea-level, but failed to reach lakes at a height of 13m (Bondevik et al. 2005). Similar to the Shetland islands, as de- scribed below, the reconstructed maximal runup depends strongly on the established local contempo- rary sea-level, but in this case that level is well con- strained (to within 1m), due to previous studies of Glacial uplift for the Fennoscandian ice-shield. According to Bondevik et al. (2003), the tsunami de- posits in Norway were sampled for radiocarbon da- ting by the careful selection of short-lived plant ma- crofossils. Such samples are available both from peat outcrops, as well as lakes. From the peat deposits, the ages judged most reliable were obtained on seeds found immediately below the sand layer. Fur- ther sampling emphasis is on leaves and seeds from lake mud just above the tsunami deposit. In one case, a radiocarbon age was obtained on a stick immedi- ately above the sand layer. Following critical sam- ple selection, Bondevik et al. (1997) propose that the tsunami most likely dates to c. 7300 14C-BP. This age is supported by Bondevik et al. (2003), who give a calibrated age value of c. 8150 calBP. Scotland Geological observations probably relating to the Sto- regga tsunami are also available for the east coast of Scotland, where a conspicuous sand layer is recog- nised at numerous localities (Dawson et al. 1988; 1993; Smith et al. 2004). According to Dawson et al. (1990), this sand layer was deposited by a major tsu- nami believed to have overwhelmed a Mesolithic occupation at Inverness, and it may also have flooded other Scottish archaeological sites, e.g. at Morton. Ballantyne (2004) urges interpretational caution, however, since localised storm events would have had equally catastrophic effects, particularly during a period of rapidly rising sea-levels. The sand layer is not found on the west coast of Scotland. This would be indicative of a tsunami coming from the east. Britain A useful review of all the currently known sites in the United Kingdom with evidence of the Storegga Slide tsunami is given by Smith et al. (2004). These authors demonstrate that the tsunami affected a much larger coastal area than previously described, with the total length of the inundated coastline reaching more than 600km along eastern Scotland. In addition to giving information on the altitude, distribution, stratigraphi- cal context, and microfossil characteristics of the de- posits, it is shown by detailed particle size analysis that the majority of tsunami sand deposits have a marked fining-upwards characteristic. This is impor- tant, because it gives information pertaining to the dynamics of the wave at different heights. Since sedi- mentation is only possible when the suspended sand particles are released, the implication is that the tsu- nami runup is likely to have exceeded the measured maximal height of the sand layer by several metres (Smith et al. 2004, with references). This study is of further interest, since the authors invest some effort in discussing the taphonomic properties of the dated samples, in search of a useful dating strategy. According to Smith et al. (2004), based on a total of 47 radiocarbon dates from the United Kingdom, the tsunami event took place sometime around 7100 14C-BP (7900 calBP). This estimate seems about 200 years later than that from Norway (Bondevik et al. 1997; 2003), but this 'offset' likely results from the different dating approaches in the Norwegian and British studies. In their i4C-analysis, which is of special interest to us for the purposes of comparison, Smith et al. (2004) describe and classify the UK i4C-dates accor- ding to whether the samples have a 'transgressive' or 'regressive' overlap with the tsunami sand layer. The idea is that it might be possible to produce a sta- tistical 'sandwich' date for the tsunami, when large numbers of such paired dates are analysed. As men- tioned by Smith et al. (2004), this approach could be problematic, since the derived dates from the con- tact zone might turn out too young, if there is a delay in peat growth on the sand layer, following the tsu- nami. To further analyse the UK dates, and notably to compare the results of applying different descrip- tive approaches to the tsunami deposits, we have adopted the database of Smith et al. (2004) essen- tially unchanged (Appendix, Tab. 8). England (Howiek case study) Further south, deposits that have been attributed to the Storegga tsunami have been identified in the vicinity of the Mesolithic site at Howiek, situated in Northumberland on the east coast of England (Bo- omer et al. 2007). For these deposits a set of 14C- ages is available (Tab. 1). It is important to note that these 14C-ages are not from the Mesolithic coastal cliff- top site at Howick (Waddington 2007), but from a core, approximately 800cm long core (HEX02 11007) taken from riverine sediment in the immediate vici- nity of the site (Boomer et al. 2007). The stratigra- phic situation in core HEX02 11007 is highly com- plex. According to the detailed description by Bo- omer et al. (2007), core HEX02 11007 contains a 30cm layer of coarse sands and sandstone pebbles, which is distinctly defined at a depth of around 750- 705cm. Due to a lack of samples, no 14C-dates are available from this layer. Terrestrial samples from immediately below this layer have ages ranging be- tween 8.2 and 10 ka i4C-BP. They do not contribute to the present discussion. Hazelnut shells from the immediately overlying deposits have supplied a date of 7269 ± 39 14C-BP (Oxa-11833) at a depth of 685- 684cm, and a statistically identical date of 7308 ± 40 i4C-BP (OxA-11858) at 683cm depth. In the strati- graphy 53cm higher, there follows a slightly youn- ger date from a hazel twig (0xA-11860: 7160 ± 40 BP), and further dates around 7 ka i4C-BP are ob- tained at depths up to 580cm. According to Boomer et al. (2007), the sand layer at 750-705cm may be related to the Storegga tsunami. It appears as a dis- tinct and 'chaotic' clastic unit, within an otherwise uniform and fine-grained riverine sediment. Although quite different from the tsunami deposits along the Scottish coast, the geological context of this layer is indicative of an extremely high-energy event. Although we can follow the authors in relating this layer to the Storegga tsunami, we are not convinced of the proposed age of 8350 calBP for the event, which was derived by Bayesian linear regression analysis of the sample stratigraphy at heights above the sand layer. As an alternative approach, further described below in the context of a model we have developed for radiocarbon dating of chaotic tsunami deposits, we propose simply to take the two (statistically identical) dates closest to the clastic unit (Oxa- 11833 and OxA-11858), calculate their weighted average, and use the age value as a close terminus ante quem for the tsunami event. This weighted average (7308 ± 28 i4C-BP: 8110 ± 50 calBP) corresponds closely to the date of 7300 14C-BP (8150 calBP) proposed by Bondevik et al. (1997) and Bondevik et al. (2003), but disagrees significantly with the result of 8350 calBP obtained by Boomer et al. (2007). If the Boomer et al. (2007) estimate is correct, then the dating discrepancy poses the question of whether both studies are addressing the same event, and notably whether the event ob- served at Howick indeed represents the Storegga Slide tsunami. Boomer et al. (2007) mention that the clear identification of tsunami deposits at Howick requires further fieldwork, but do not comment on the issue of why there should be a large (200 yr) dis- crepancy between the ages of the Storegga Slide tsu- nami at Howick and on the Norwegian coast. In con- trast, our simpler and more straightforward ap- proach to dating the event in Howick would suggest that the deposits at Howick are of exactly the same age (within confidence limits) as the Storegga event deposits in Norway. Radiocarbon dating model for tsunami depo- sits The difficulties encountered when radiocarbon dat- ing palaeotsunamis, when based on peat stratigra- phies with intercalated tsunami deposits, can be seen as a chain of interrelated problems: (i) the tsunami wave(s) will have cut away an undefined amount of peat, such that (ii) the deposits remaining in-situ ('below the tsunami) after the waves have passed may be of any age, ranging from decades to hundreds of years older than the event of interest. Next, (iii) reworking the highly mobile deposits will cause the majority of samples found within the tsunami la- Lab Code 14C-Age [BP] S13C [%o PDB] Material Core Depth [cm] Calendric Age [calBP] (68%) Oxa-12952 6988 ± 37 -26,5 hazelnut shell 580 7840 ± 60 Oxa-12953 7^7 ± 39 -26,1 hazelnut shell 580 7940± 40 OxA-12954 7075± 37 -30,7 sliver of wood bark 583 7910 ± 40 OxA-11859 7174 ± 35 -26,4 carbonised wood 627 7990 ± 30 OxA-11860 7160 ± 40 -27,3 hazel twig 630 7980 ± 30 OxA-11858 7308 ± 40 -25,6 hazelnut shell 683 8110 ± 50 OxA-11833 7269 ± 39 -24,9 hazelnut shell 684-685 8090 ± 60 Tsunami - - poorly sorted, coarse clastic unit 7°5-75° - Tab. 1. Selected Radiocarbon Ages from Howick, Core HEX0211007 ^Boomer et al. 2007). yer to have dates totally unrelated to the tsunami event, and (iv) due to the good conservation of or- ganic substances in peat deposits, the 'short-lived' samples (e.g. leaves, seed) found within the tsuna- mi layer' may originate from older layers, Finally, (v) due to the differential sedimentation of the re- worked materials (peat, sand, rocks, twigs, leaves, seeds) many of the plant materials taken from layers above the tsunami may not be younger, as per- haps expected, but rather again represent older sam- ples, since these (twigs, leaves, seeds) would have the longest floatation times. That these expected ef- fects may indeed be effective for the deposits under study in Norway, England and Greenland is shown in Figure 1. We omit discussion of the four irrelevant samples that are catalogued as deriving from below the tsu- nami' (Fig. 1). The following group of samples de- signated as taken from 'directly below' the tsunami show the expected wide spread of ages, with an over- all range of 9300-8180 calBP. Interestingly, the samples from within the tsunami sand show the same overall spread in age, but this group ends with an enhanced cluster of dates, centred on the time-window 8200-8000 calBP, which give the ap- pearance of a sharply defined age cut-off. We have shaded the corresponding region range (8000-8200 calBP) in Figure 1, and have also extracted the cor- N=12 s_J Transgressive Contact N=14° r Regressive Contact p Howick .... .... „.. .... ..... g - Above Tsunami N=2™ "" "" "" < \ Directly Above Tsunami N=27 Within Tsunami Sand .... .... .,„ .... .... „- "A Directly Below Tsunami N=4™ "" Below Tsunami = Sea- Level Southern North Sea [m NN] (Behre 2003) 9000 [cal BP] Fig. 1. Calibrated radiocarbon ages for tsunami deposits from Norway, East Greenland, and Britain, arranged according to descriptive taphono- mic terms (Below Tsunami, Directly Below Tsunami, Within Tsunami Sand, Directly Above Tsunami, Above Tsunami, Transgressive Contact, Regressive Contact). Due to chaotic reworking of tsunami deposits tempo- ral relations such as 'older' or 'younger' do not correctly describe the sam- ple sequence (cf. text). The applied descriptive terms allow for this situa- tion and support visual identification of meaningful tsunami samples (cf. text). We conclude the Storegga Slide tsunami dates between 8200 and 8000 calBP (vertical shading, cf. Fig. 2). responding time-windows for all groups, for further analysis. As it turns out, all samples belonging to this time-window and selected from the group 'within the tsunami sand' were processed on short-lived samples (moss, twigs, bark cf. Tab. 2). The next 'younger' group (Fig. 1) taken from di- rectly above the tsunami contains only two sam- ples, one of which is a churned up and redeposited shell from Loon Lake (East Greenland), dating to 8800 ± 120 calBP (KIA-27661: 7925 ± 45 14C-BP). The second date in this group is also older than ex- pected. The multi-group sequence continues with an exceptionally large ('default') group of widely sprea- ding dates on samples taken from 'above the tsu- nami'. We note that this group contains just as many dates 'younger' than the tsunami, as dates that are clearly 'older'. The following set of dates from Howick Core HEX02 11007 (Fig. 1) contains the two short-lived dates on hazelnut, already discussed above (OxA-11833: 7269 ± 39; OxA-11858: 7308 ± 40 14C-BP). Both dates, and especially their weighted average of 7308 ± 28 14C-BP (8110 ± 50 calBP), have a central position within the shaded time-window of the Storegga Slide tsunami. As discussed above, these samples were taken from immediately above the pos- sible tsunami sands. The position of these two sam- ples within the overall tsunami group sequence now simultaneously confirms the identification of these sands as laid down by the Sto- regga tsunami, and refutes the date of 8350 calBP deri- ved from Bayesian stratigra- phic analysis (Boomer et al. 2007). Finally, as shown in Figure 1, the classification of 14C- dates from eastern Scot- land (Smith et al. 2004) according to the descriptive stratigraphic terms 'Regres- sive Contact' and 'Transgres- sive Contact' with the tsuna- mi sand layer does not allow the required clear distinction between samples contempora- neous with the tsunami, and other (older or younger) sam- ples, as was already recogni- sed by the authors (Smith et al. 2004). At this point of the discus- sion, we have two weighted 14C-age averages at our dispo- sal, both directly dating the tsunami event, that is (i) 7298 ± 26 14C-BP for N = 10 selected short-lived sam- ples from N = 5 different sites in Norway (Tab. 2), and (ii) 7308 ± 28 14C-BP for two selected samples from Howick in England (Tab. 3). There is a strong agreement between these two va- lues and calculation of the weighted average for the two combined ages (7298 ± 26 14C-BP and 7308 ± 28 14C-BP) finally gives 7308 ± 19 14C-BP. A statistical Chi-Square test gives 95% probability that the ob- served spread in the overall underlying data (total N = 12 ages on short-lived samples from N = 6 diffe- rent sites in 2 countries; cf Tab. 3) can be explained by random effects in the 14C-measurement procedu- res. To allow for possible differences in interlaboratory calibration, as well as for advisable caution in subse- quent interpretation we raise the calculated error from ±19 14C-BP to ±30 14C-BP. This measure is neither necessary nor indicated by the given data; we simply wish to remain on the safe side of the ra- diocarbon-based chronological world of chance. As a final measure, again only taken for convenience, in all following discussions we base our argumenta- tion on the rounded value 7300 ± 30 i4C-BP (8110 ± 100 calBP, p = 95%). In conclusion, although we have not been able to de- monstrate the existence of a reliable (single sample) dating method for Storegga Slide deposits, the 'best' sampling (and classification) method appears to be the careful selection of short-lived macro-samples from within the tsunami sands. By comparing the spread of calibrated median values for sample groups classified by different field criteria (Fig. 1), we can show that a well-defined 'cut-off age exists, for short- lived samples taken from the tsunami sands. These results corroborate and highlight the sampling stra- tegy of Bondevik et al. (2006), which advocates the AMS radiocarbon dating of green (chlorophyll-rich) moss stems. Palaeogeographic boundary conditions Due to rising sea-levels in the 9th millennium calBP, the exact timing of the Storegga Slide tsunami rela- tive to contemporaneous sea-levels in the North Sea is of major importance for the reconstruction of the tsunami-'s environmental impact. At this time the North Sea region was experiencing a phase of most rapid early Holocene sea-level change (Lambeck 1995; Shennan et al. 2000; Behre 2003), in combi- nation with equally significant glacio- and hydro-iso- static land-level changes, e.g. tilting of Scotland and Norway (Lambeck 1995; Dawson and Smith 1997; Gyllencreutz 2005b). To further complicate matters, due to rapidly rising sea-levels during the 9th millen- nium, more and more sections of Doggerland - a now submerged land-area situated between Britain and the continent (Coles 1998) - were becoming submerged. Allowance also has to be made for the tidal regime at the time. To facilitate study of the environmental impact of the Storegga Slide tsunami in the southern parts of Doggerland (where we expect the highest density of Mesolithic occupation, see below), we can now rely on a highly accurate date for the tsunami event at our disposal: 7300 ± 30 i4C-BP (95%-confidence), or 8100 ± 100 calBP (95%-confidence). The importance of using an appropriate regional sea-level value in any investigation of the impact of the Storegga slide tsunami is exemplified by data from the Shetland Islands. There, the tsunami appears to have invaded Lab Code 14C-Age 1BC- PDB Material Country Site Position Latitude Long. Reference Tua-1350 7315 ± 70 -22,9 Moss Norway Audalsvatnet within Tsunami 63,8314 9,8289 Bondevik et al. 1997 Tua-834 6970 ± 175 -26 Twig Norway Gorrtjonna I within Tsunami 63,8264 9,8308 Bondevik et al. 1997 Tua-1269 7445 ± 65 -29,5 Twig Norway Gorrtjonna I within Tsunami 63,8264 9,8308 Bondevik et al. 1997 Tua-1122 7175 ± 75 -30,7 Twig Norway Klingrevatnet within Tsunami 62,4424 6,2324 Bondevik et al. 1997 Tua-831 7240 ± 70 -27,7 Twig Norway Kvennavatnet within Tsunami 63,8347 9,8225 Bondevik et al. 1997 Tua-984 7200 ± 80 -26,1 Twig Norway Kvennavatnet within Tsunami 63,8347 9,8225 Bondevik et al. 1997 T-10597 7230 ±105 -26,1 Twig Norway Ratvikvatnet within Tsunami 62,4619 6,2242 Bondevik et al. 1997 Tua-861 7250 ± 75 -26,1 Bark Norway Skolemyra within Tsunami 62,3331 5,6486 Bondevik et al. 1997 Tua-524 7365 ± 90 -26,1 Twig Norway Skolemyra within Tsunami 62,3331 5,6486 Bondevik et al. 1997 Tua-860 7435 ± 75 -26,1 Bark Norway Skolemyra within Tsunami 62,3331 5,6486 Bondevik et al. 1997 Tab. 2. Subgroup of 14C-Ages for Samples taken from 'Within the Tsunami Deposit', with ages 8000- 8200 calBP (cf. Fig. 1). Weighted Average: 7298 ± 2614C-BP (8110 ± 50 calBP). Tab. 3. Subgroup of 14C-Ages on Samples taken from 'Directly Above the Tsunami Deposit', from Howiek (Great Britain) (cf. Fig. 1). Weighted Average: 7308 ± 28 14C-BP (8110 ± 50 calBP). Lab Code 14C-Age 13C- PDB Material Country Site Position Latitude Longitude Reference Oxa-11833 7269 ± 39 -24.9 hazelnut England Howick directly above 55,4403 -1,5917 Boomer et al. 2007 Oxa-11858 7308 ± 40 -25,6 hazelnut England Howick directly above 55,4403 -1,5917 Boomer et al. 2007 coastal lakes and have run up peaty hillsides to a maximum height of 9.2m above the present high tide level (Bondevik et al. 2005). However, around 7300 14C-BP, sea levels around the Shetland Islands and the Faroes stood at 10-15m below the present level (Lambeck 1995), so that the reconstructed run- up height in reality must have been within a range around 19-25m above the sea level of that time. Within confidence limits, this would be the largest runup reconstructed anywhere for the Storrega Slide tsunami (Bondevik et al. 2005). Regarding sea-level and tsunami impacts on our study region - Doggerland (Coles 19988) - a number of geological and geomorphological boundary condi- tions must be taken into consideration. Foremost is the rapid rise of sea-levels in the early Holocene. For example, in the southern North Sea (a region with minimal isostasy), sea-level rise between 9000 calBP and 7000 calBP amounts to an average value of 1.25m/100 yrs (Behre 2003). In addition, several superimposed geomorphological and climatic pro- cesses (with their own time-scales) have contributed and complicated the sea-level changes during the in- terval of interest (Tab. 4). The timing of the Storegga Slide On the basis of comprehensive submarine geomor- phological studies off the coast of Norway, a series of more than 50 14C-AMS-ages on monospecific plancto- nic foraminifera from stratified basal post-slide sedi- ments give a direct date (weighted average) for the expected timing of the Storegga Slide emplacement of 7250 ± 250 14C yrs BP (Haflidason et al. 2005), in close agreement with our summary estimate for the Storegga tsunami of about 7300 14C yrs BP (this paper). In Figure 2 this 14C-date is shown along with the early Holocene sea-level curve for the southern North Sea (Behre 2003), and the stable oxygen iso- tope record from the Greenland GISP2 ice core (Gro- otes et al. 1993). Two key observations can be made from Figure 2. Firstly, the broad picture of sea-level rise, as shown in Figure 2 (lower box), is one of a comparatively ra- pid rise between 10 ka calBP and 6 ka calBP, follo- wed by a significant slowing in the following millen- nia. The slow rise in recent millennia (since 5000 calBP) is accompanied by minor oscillations (for dis- cussion, see Bungenstock 2006). According to Behre (2003; 2007), the sea-level curve for the southern North Sea is to some extent representative of global sea-level rises. In the southern North Sea, isostatic effects are not observed, and tectonic movements are so weak as to be irrelevant (the situation be- comes more complex when Scotland and north Jut- land are considered, as these areas were subject to isostatic uplift). The correlation of the 14C-age for the Storegga Slide and Tsunami with this sea-level curve (Fig. 2) shows that the Storegga Slide occurred at a time when the sea level in the southern North Sea stood at about 17m higher than the present level. Secondly, Figure 2 suggests that the Storegga Slide occurred during the period of the well-known '8200 calBP' climate event. The implications of this obser- vation will be studied further below. Key Event or Process Duration Affected Region Date Reference Abrupt Drainage of Lake Agassiz Months North Atlantic 8470 ± 300 calBP Barber et al. 1998 Rapid rise in global sea-level by 0.2-0.5 m Months Global ~ 8200 calBP Bauer et al. 2004 Reduced North Atlantic Deep Water Formation Two Centuries Global 8247-8086 calBP Thomas et al. 2007 Storegga Slide Tsunami Hours North Sea ~ 8150 calBP Bondevik 1997 Eustatic/isostatic Sea Level Rise Millenia Northwest Europe Continuous Lambeck 1995 Slow Flooding of Doggerland Centuries North Sea ~ 8000 calBP Behre 2003 Slow Final Flooding of Doggerland Centuries North Sea ~ 7000 14C-BP Shennan et al. 2000 Rapid Final Flooding of Doggerland Hours North Sea 8100 ± 100 calBP this paper Tab. 4. Key events, processes, time scales, dates, and geographic regions. The timing of the Storegga Slide tsunami In the following, we present further refinements to the temporal correlation of the Storegga Slide tsu- nami with contemporary sea-levels, and consider in detail the potential correlation of the tsunami with the 8200 calBP climate event. These arguments make use of CalPal-software (Weninger et al. 2003; Wenin- ger and Jöris 2004), and the main results are displa- yed in Figure 3. Figure 3 shows in high resolution the tree-ring cali- brated radiocarbon date for the tsunami (7300 ± 30 14C-BP, 95%) in comparison with the Greenland 518Oice ice-core data obtained from the GISP2-dril- ling (Grootes et al. 1993). The 518Oice-GISP2 data, as shown in Figure 3, are shifted 40 years younger, in comparison to the age values published by Grootes et al. (1993). This shift is obtained by visual compa- risons between different climate proxies undertaken to achieve a precise and absolute (tree-ring synchro- nised) reference time interval for the North Atlantic 8200 climate event sensu strictu (i.e. the Hudson Bay outflow) (Weninger et al. 2006). The 40-year shift of the GISP2 age model is supported by the re- cent recount of Greenland Ice Core ages in the Holo- cene (GICC05 age model) (Vinther et al. 2006), as well as by dedicated high-resolution studies of the 8200 calBP climate event by Thomas et al. (2007). Following Barber et al. (1997), the sequence of events associated with the '8200 calBP' event is as follows: during deglaciation, a remnant ice mass blocked the northward drainage of the large glacial lakes Agas- siz and Ojibway, which previously discharged south- eastward over sills into the St Lawrence river. Around 8500 calBP (8470±300 calBP according to Barber et al. 1997), the ice dam collapsed, allowing the lakes to drain swiftly northwards into the Labrador Sea. The release of an estimated 1.6 x 1014 m3 of fresh- water (Teller et al. 2002) from the proglacial lakes through the Hudson Strait would have substantially weakened deep water formation in the North Atlan- tic (e.g., LeGrande 2006). Temperatures in the North Atlantic region decreased abruptly, with subsequent recovery over the following 200 years or so (e.g. Le- Grande et al. 2006; Thomas et al. 2007). In central Greenland the surface air temperature dropped by 3-6°C (e.g. Johnsen et al. 2001), and perhaps up to 7.4°C (Leuenberger et al. 1999). A reduction in air temperature of this magnitude is likely to be linked with drier conditions and stronger winds over the North Atlantic and the surrounding land (Alley et al. 1997; Bauer et al. 2004; LeGrande 2006). The freshwater release estimates are of importance for the present studies, since this water would lead to an abrupt rise of global-mean sea level. The esti- mates range from about 0.25 to 0.5m, with time- scales of the release thought to be in the order of se- veral months to a year (e.g. Bauer et al. 2004; Le- Grande 2006). Clearly, the exact timing of these events is of crucial importance to socio-environmental studies on the Mesolithic in north-western Europe, just as it is on Fig. 2. Overview. Tree- Ring Age Calibration of 14C-Age for Storegga Slide 7250 ± 250 BP (Haflidason et al. 2005) shown in context of Early Holocene Sea-Le- vel Rise in the Southern North Sea (Behre 2003) and Stable Oxygen Iso- tope Signature in Green- land Ice-Core GISP2 (Grootes et al. 1993). Calibration Data: Rei- mer et al. (2004). Cali- bration Methods: Wenin- ger and Jöris (2004). wider archaeological scales (cf. Weninger et al. 2006; Clare et al. this volume). However, the situa- tion is complicated, since we now recognise that the '8200 calBP event' (sensu strictu: Hudson Bay out- flow) is superimposed on a wider period of cooling, dating to c. 8600-8000 calBP (Rohling and Pälike 2005). Given the lack of sufficient temporal resolu- tion, the signatures of actually quite different clima- tic and environmental processes are unfortunately quite often compounded into one 'default' signal cal- led the '8200 calBP' event. However, the complexity of rapid climate change during this period is be- coming clearer now, on the basis of dedicated high- resolution studies. Of special interest to our study, the temporal structure of the '8200 calBP' cooling event has been studied in great detail by Thomas et al. (2007), who conclude that the event had an over- all duration of 220 ± 2 years and a central, 4-year- long spike at 8222 calBP, during which Greenland ice surface temperatures dropped by up to 13 ± 2 °C (for comparison: cooling during the Younger Dryas amounts to approx. 15 °C). We make use of these re- Fig. 3. Tree-ring calibration of the derived 14C-age (7300 ± 30 14C-BP, 95%) for the Storegga Slide tsunami (upper box) in comparison with GISP-Sl8O- data showing the '8200 calBP' cooling event and contempo- rary sea levels in the southern North sea (lower box). The GISP-Sl8O-data have been shift- ed 40 yr younger, in compari- son to age values published by Grootes et al. (1993), according to results by Weninger et al. (2006), which agree with re- cent age revisions of the Green- land Ice-Core Age Model (Vin- ther et al. 2006) and with dedi- cated high-resolution studies of the event by Thomas et al. (2007). The shaded age interval 8000-8200 calBP shows that the Storegga Slide occurred during the Middle/Late phase of the North Atlantic 8200 calBP co- oling. The derived tree-ring ca- librated 14C-age of 8100 ± 100 calBP (95%) for the tsunami corresponds to a reading of -17 ± 2 m on the sea-level curve for the southern North Sea of Behre (2003). Tree-ring 14C-age calibration data (± 1 a error bars) by Reimer et al. (2004). sults in evaluating the temporal relation between the 8200 calBP climate event and the Storegga Slide tsunami, as follows. Figure 3 illustrates that the Storegga Slide tsunami occurred, with 95% confidence, at some time during the interval 8200-8000 calBP. We can state this is surely within the period of reduced North Atlantic Deep Water (NADW) formation and attendant cir- cum-Atlantic cooling (8247-8086 calBP, according to Thomas et al. 2007). Dating constraints are also sufficient to state that it is unlikely that the tsunami occurred near the onset of the 8200 calBP climate event, or, in other words, the Storegga Slide was not synchronous with the Hudson Bay flood, but post- dated it. Consequently, the tsunami appears to have impacted the southern North Sea at some time dur- ing the course of the 8200 calBP climate event. Fur- ther precision is impeded by the fact that the tsu- nami's 14C-age of 7300 ± 30 14C-BP (95%) falls into a flat region of the tree-ring calibration curve (Fig. 3). Given that reduced North Atlantic Deep Water (NADW) formation may cause changes in the carbon cycle that may lead to such so-called radiocarbon plateaux in the calibration curve (as modelled for the Younger Dryas, Hughen et al. 2006), this provi- des extra corroboration for the suggestion that the Storegga Slide occurred at some time within the 8200 calBP climate event. To conclude, the Storegga tsunami event occurred within one to two centuries after the global sea-level jump of 0.25-0.5m that was associated with the Hudson Bay flood. This juxtapo- sition would have helped to increase the flooding impact of the tsunami in low-lying coastal regions. Palaeogeographical reconstructions: key sta- ges and events The large continental shelf between Britain, Norway, and the NW-European coast which is commonly known as 'Doggerland' (Coles 1998) is now comple- tely submerged under the North Sea, but was subae- rially exposed at the beginning of the Holocene. In addition, a considerable area of land was exposed off the west coast of Jutland. Due to eustatic sea-le- vel changes, combined with glacio- and hydro-isosta- tic land-level changes, the former land areas were in- creasingly submerged during the course of the Early Holocene. Key stages in the development of Dog- gerland, according to reconstructions by Lambeck (1995), Shennan et al. (2000) and Behre (2003), in- clude (i) the gradual evolution of a large tidal em- bayment between eastern England and Dogger Bank before 9 ka calBP (9-8 ka 14C-BP); (ii) the develop- ment of Dogger Bank as an island at high tide 8-7 ka 14C-BP; and (iii) the final disconnection of Eng- land from the continent by c. 8.0 ka calBP (7-6 ka 14C-BP). Prior to its complete flooding around 8000 calBP, Doggerland formed a wide, undulating plain containing a complex meandering river system, with associated channels and lakes (Gaffney et al. 2007). Although there is general consensus that Doggerland was completely submerged by c. 8000 calBP, diffe- rent authors give alternative palaeogeographic re- constructions for the history of Doggerland (Dix et al. 2008). Corresponding to the quite general lack of archaeological and palaeo-environmental data from the submerged areas, contemporary research puts the focus on the timing of selected major (key) events. An example is shown in Table 5, where Gyllencreutz (2005a) has collated published ages for the opening of the English Channel. Note that, according to the ages given in Table 5, the English Channel was most likely open at the time of the Storegga Slide Tsunami - although this may have been a fairly recent development which had taken place just a few hundred years previously. Summaries such as Table 5 would imply that the existence of the key event 'Opening of the English Channel' is not open to question, but that its age is. However, there is a higher level of complexity. It is important to recognise not only that intensive re- search may result in different apparent dates for the same (or similar) events, but also that the illustrated approach relies on an underlying assumption that an event (e.g. the flooding of Doggerland) is actually well-described by the dates. There is a strong empha- sis in contemporary studies on dating key events as a widespread method to describe the history of Dog- gerland. Lambeck (1995) argues that the English Channel was established as an open marine water- way by about 7500 14C-yrs BP (8600 calBP). Accor- ding to Shennan et al. (2000), at this time Dogger Bank was still an island at high tide, while the chan- nel separating northern Norfolk from mainland Eu- rope was 5-10m deep. At the same time, wide inter- tidal areas and saltmarsh lowlands are predicted for areas to the east of Norfolk (Shennan et al. 2000). During these centuries, according to Behre (2003; 2005), the sea level in the southern North Sea rose at the enormous rate of more than im per century. The southern North Sea had become fully marine by 7000 14C-yrs BP (7840 calBP) (Lambeck 1995). Very similar results, with the focus on the timing of the 'fully marine' North Sea, were reported by Shennan et al. (2000). Recent work has taken an entirely different approach to reconstructing the history of Doggerland, building on the unique oppor- tunities offered by 3D seismic analysis of submerged North Sea sediments, as made available by petroleum-exploration compa- nies {Fitch et al. 2005; Gaffney et al. 2007). The available data demonstrate the existence 14C-Age [ka 14C-BP] Calendric Age [ka calBP] Reference 8 9.° - 8.7 Nordberg 1991 7.6 8.5 Conradsen and Heier-Nielsen 1995 7.7 8.6 Jiang et al. 1997 8 - 7 9.° - 7.7 Björklund et al. 1985 8 - 7 9.° - 7.7 Lambeck 1995 8.7 - 8.3 9.7 - 9.3 Jelgersma 1979 Tab. 5. A Key Event in the History of Doggerland: The En- glish Channel Opening (compilation by Gyllencreutz 2005a). in the submerged North Sea of complex meandering river systems, with major and secondary channel belts, tunnel valleys, possible estuarine or intertidal settings, sand banks, and lakes, as revealed at high vertical and horizontal resolution at different depths, times, and stratigraphic settings, for the Early Holo- cene deposits (Fitch et al. 2005; Gaffney et al. 2007). However, before integrating the bathymetric and 3D seismic data, we must await additional information, especially concerning the precise timing of the diffe- rent stratigraphic settings. As was stated by Coles (1998), there remains the 'intriguing' question of whether the sediments in the southern North Sea show signs of impact by the Storegga Slide tsunami. An explorative bathymetric 3D digital elevation model for Doggerland With this question in mind, and wishing to evaluate the potential environmental and social impact of the tsunami, we have undertaken further explorative studies to assess the impacted coastlines, with the re- sults shown in Figure 4. These results are based on (i) the derived date for the tsunami event of 7300 ± 30 i4C-BP (8100 ± 100 calBP; 95%) (cf Fig. 1), (ii) the hypothetical sea-level height of -17 ± 2m (95%) NN for the southern North Sea at this time (cf. Fig. 3), but extended to cover bathymetric depths of -17 ± 5m (see below), and (iii) the palaeo-coastlines at this time, as interpolated from the reconstructions of Shennan et al. (2000) and Behre (2003). In detail, our reconstruction of the impacted areas as shown in Figure 4 is based on the following data and methods. From the different coastlines, defined by these authors for different stages in the develop- ment of Doggerland, we first selected coastlines da- ting as closely as possible to the tsunami event. As shown above, these coastlines are typically defined for 'key events', between which we must now inter- polate. For the tsunami age of 7300 ± 30 14C-BP (8100 ± 100 calBP) there are two such (closest) coastlines, which give us an event-sandwich: firstly, the coast-line defined c. 200 i4C-yrs before the tsu- nami event (Shennan et al. 2000.Fig.5d: 7500 i4C- BP) and, secondly, the coastline c. 200 i4C-yrs after the tsunami (Shennan et al. 2000.Fig.5d: 7000 i4C- BP). Although very similar coastlines can be read from the palaeo-geographic reconstructions of Dog- gerland given by Behre (2003), we decided to base our reconstructions on Shennan et al. (2000), if only for the simple reason that the coastlines in this pub- lication are defined using uncalibrated 14C-ages of 7500 and 7000 i4C-BP, which simplifies our visual interpolation for the nearly exactly intermediate va- lue of 7300 i4C-BP. The first step in map construction, then, was to digi- tize the coastlines from the colour graphs of Shen- nan et al. (2000) for 7500 14C-BP and 7000 14C-BP. They are shown as thin lines in Figure 4. They are used as a basic reference for the coasts of Dogger- land 'before' and 'after' the tsunami event. Note that we do not imply that the tsunami was responsible for reshaping the Doggerland coasts. The adopted coastlines were then projected as shapefiles onto a map of the North Sea based on a 3D digital eleva- tion model using unedited SRTM (Shuttle Radar To- pography Mission) data. Since this data is unedited, it contains occasional voids, gaps, or streaks, where the terrain lay in the radar beam's shadow or in areas of extremely low radar backscatter where an elevation solution could not be found. Such streaks are evident in Figure 4 for the SRTM30 tile we use, which is named w020n90 by the USGS (United Sta- tes Geological Survey 2008). This tile has a horizon- tal grid spacing of 30 arc seconds (approximately 1 kilometre). The data is expressed in geographic co- ordinates (latitude/longitude) and is referenced to the World Geodetic Survey (WGS) system of 1984 (WGS84). We used Globalmapper (www.globalmap per.com) to construct the map. The next step was to find an interpolation between these two coastlines that would be representative of the coastline at 7300 i4C-BP, the time of the Storeg- ga Slide tsunami. Rather than applying a direct inter- polation between the two given coastlines, we ap- plied an explorative method, based on the calcula- tion of a set of bathymetric contours using the SRTM- data, at intervals of 1m between -30m and -10m. These contours were projected onto the same map as previously used for the two coastline shapefiles derived from Shennan et al. (2000) for ages 'before' and 'after' the tsunami. As shown in Figure 4 using an appropriate colour ramp to show areas poten- tially 'above' and 'below' the contemporary sea-level, it was possible to approximate the coastlines of Shen- nan et al. (2000) for Dogger Bank solely based on SRTM 1m bathymetric contours. The final step was to colour shade the interpolated areas according to their bathymetric depth, in relation to the two refe- rence coastlines derived from the studies of Shen- nan et al. (2000). It is encouraging that quite similar reconstructions are obtained from the maps of Dog- gerland, as published by Behre (2003), for the time- window under study. We emphasise that the preci- sion and accuracy of the maps obtained by this pro- Fig. 4. Hypothetical regions with major impact by the Storegga Slide tsunami. Ocean colour shading is based on SRTM bathymetric data (United States Geological Survey 2008; cf. text). Major individual hypo- thetical tsunami impact areas, represented by the SRTM-bathymetric depth interval -17 ± 5 m, are sha- ded red. Due to applied reconstruction and specific colour shading approach, red shaded areas represent lowlying 'run-in' areas. These are not identical to potentially even more dangerous 'run-up' areas (cf. text). Thin brown lines represent digitized palaeogeographic coastlines according to Shennan et al. (2000), but slightly changed to allow for minor differences vs the reconstructions given by Behre (2003). Together, these two coastlines approximate Doggerland some 20014C-yrs 'before' and 'after' the tsunami event. For simplicity, the Doggerbank 'island' is only shown for the date c. 750014C-BP. Whether this 'is- land' was really subaerial, or not, at the time of the tsunami, cannot be decided with given data. cedure is not limited to that of the palaeo-coastlines used in their calibration. Although these are extre- mely useful for orientation purposes, they do not enter the final reconstruction (Fig. 4). Instead, assu- ming the correlation between the derived date for the tsunami and the contemporaneous sea-level is accepted, we recognise as a major limiting factor our lack of knowledge concerning the post-tsunami sedi- mentational processes that surely occurred in the regions under study. One main result of this study is the (unexpectedly) high tsunami impact assigned to the western regions of Jutland, and in particular to the northern coasts of Jutland opposite Norway (Fig. 4). Due to the given combination of shallow flats and steep coastal channels, these coasts are es- pecially vulnerable to the different kinds of destru- ctive energy contained in the tsunami (see below). Tsunami physics and palaeogeographic impact scenarios A detailed description of tsunami impacts on coastal lowlands is beyond the scope of the present paper, and we suffice with a brief recapitulation of the ge- neral physical principles underlying a tsunami im- pact, following Dawson (2008). We interpret those processes within the context of the configuration of the palaeo-landscapes under study in the southern North Sea. The impacts of a tsunami depend most strongly on coastal shape. For steep coastlines, such as the fjords and estuaries of East Scotland, the physical effects are best expressed in terms of runup, which is de- fined as the maximum height reached by the head of the tsunami wave. However, on the more gently inclined coastlines, mud-flats, salt-marshes and gen- tly rolling plains of Mesolithic Doggerland, it would be more appropriate to take the maximum width of the inundated zone (or 'run-in') as a measure of the scale of the energetic impact. For such gently inclined areas, the extent of the inundated area is limited not by the maximum height of the wave, but by frictio- nal forces, drag and turbulence, as the wave advan- ces and retreats over the more or less rough surface. In such settings, a tsunami initially appears more like an unusually extensive flood, rather than a giant wave. The water body first develops its huge destru- ctive potential at the moment the wave breaks. This can already occur at some distance from the coast, as shown by eyewitness accounts on Flores Island of the 1992 Indonesian tsunami (Shi and Smith 2003). On Flores Island, already along a comparatively short coastline of some 100km, runup heights varied most- ly between 1.5 and 4m, but runup reached as high as 26m at one location (Riangkrok), due to local underwater bathymetry and coastline configuration (Shi and Smith 2003). The extent of the (catastrophically) flooded area fur- ther depends strongly on local vegetation (e.g. sand, grass, peat, schrubs, trees) and local topography (e.g. sandbanks, slopes, smaller and larger water channels). As documented for the 1992 Indonesian tsunami, this combination of major 'runin' and lo- cally extreme 'runup effects could also be expected for the Storegga Slide tsunami in the southern North Sea, and here most likely in the fjords of Jutland, or in the tunnel valleys found by 3D-seismic surveying in Late Holocene Doggerland (Fitch et al. 2005). In search of these areas, a closer look at Figure 4 re- veals that quite a number of the red areas indeed put focus on such coastal sections (recognisable by the bending-in of the red areas), where underwater bathymetry would magnify the incoming waves. This differential vulnerability of palaeo-coastlines is clearly an important topic (e.g. Shi and Smith 2003), although beyond the scope of the present paper. We are confident that, allowing for such effects, the hy- pothetical tsunami 'run-in' impact map (Fig. 4) sup- ports a conservative assessment of potential tsunami 'danger zones'. As a final topic to address, due their long wave- lengths in deep water, tsunamis will refract around large obstacles, such as islands. Hence, depending strongly on the sea level of the time, the Storegga Slide tsunami may either have dissipated its ener- gy on the northern side of the Dogger Bank, if this region was indeed an island with a height above around 5-10m, or - if the Dogger Bank was sub- merged already - the tsunami may have reached the coasts of Belgium, the Netherlands and North Ger- many. Based on the reconstruction shown in Figure 4, and in view of all the data entered, interpolations, literature, and methods, this latter scenario seems the most probable. As shown below, this conclusion is further corroborated by available 14C-ages mea- sured on finds dredged up from the southern North Sea. Radiocarbon data from the southern North Sea Numerous Pleistocene and Holocene faunal remains have been dredged up from the southern North Sea, particularly in recent years (Mol et al. 2006; 2008), including worked bone and antler implements, some of which have been directly dated to the Early Meso- lithic (Tab. 6), while other finds can be assigned to this period typologically. Even more dramatic evi- dence has emerged in the form of human skeletal re- mains dredged from many kilometres offshore and directly dated to the Early Mesolithic (Glimmerveen et al. 2004; Mol et al. 2008) (Tab. 6). Abundant faunal remains and artefacts have also been found close to shore in the Netherlands (Louwe Kooijmans 1971; Verhart 2005) and both inshore and offshore along the west coast of Jutland (Fischer 2004.Fig. 3.3). Although surely not the last word, since it is impos- sible to generalize from the present small (but beau- tiful) database of finds from the North Sea (cf. Glim- merveen et al. 2004; Mol et al. 2008), we need but a quick look at the available 14C-ages to conclude that these do not provide evidence for habitation of Doggerland, at ages younger than c. 8000 14C-BP. For completeness, we must comment on the refer- ence to 'Andersen (pers comm) given by Coles (1999.57) and repeated by Behre (2003.41), as well as by Behre (2005.210), concerning a worked bone dredged from Dogger Bank dating to '6050 calBC' (Coles 1999.57) resp. '6050 v.Chr.' (Behre 2003.41; 2005.210). This date was long suspect to the present authors, since it seemed to indicate a very late final flooding of Dogger Bank, perhaps even synchronous with the Storegga Slide tsunami. If validated, this date would have directly falsified our reconstruction (Fig. 4), at least give reason to assume a much larger Doggerland at this time. However, the date itself does not survive critical scrutiny. According to Soren Andersen (pers comm to B.W., 15th April 2008), it is simply misquoted. Mesolithic palaeodemography Since the pioneering studies of Coles (1998), it is be- yond credence that Doggerland was an inhabited landscape during the Late Palaeolithic and earlier Mesolithic periods. In terms of estimating the impact of the Storegga slide event on contemporary human populations, results will depend strongly on the extent of the area impacted, the severity of the tsu- nami over this area, and the density and distribution of human settlement (Fig. 5). Average population densities for Mesolithic northwest Europe, based largely on ethnographic analogy, have been estima- ted on the order of 0.05 to 0.10 person/km2 (Binford 2001; Constandse-Westermann and Newell 1989; Rozoy 1978). However, the population would not have been evenly distributed over Doggerland, and we can propose with some confidence that coastal, lacustrine and riverine areas would have experi- enced substantially higher population densities (Fi- scher 1997; Paludan-Müller 1978), perhaps to the order of 0.50 to 1.0 person/km2 (cf. Schulting in press), while areas further inland (away from re- sources) would have been relatively sparsely popu- lated. There exists some stable isotope and archaeo- logical evidence in support of these notions (Schul- ting in press; Schulting and Richards 2001). Since it is precisely the coastal and near-shore rive- rine areas (the latter because of a funnelling effect up coastal river valleys) that would have been most affected by the Storegga tsunami, there may have been considerable impact on the contemporary po- pulation. For example, one of the most notable geo- Location Species Element Lab no. 14C-BP Calendric Age [calBP] (68%) References Leman & Owen C elaphus antler harpoon OxA-1950 11740±150 13640±200 (4) S Bight, North Sea Bos primigenius? decorated metapodial GrA-28364 11560±50 13460±80 (3) S Bight, North Sea A alces worked antler GrA-27206 9910±50 11350±90 (3) S Bight, North Sea H sapiens mandibula GrA-23205 9870±70 11330±100 (2) 52°io' N, 02°49' E H sapiens cranium UtC-3750 9640±400 11110±620 (1) S Bight, North Sea A alces worked antler GrA-37004 9520±50 10880±150 (3) S Bight, North Sea Sus scrofa humerus UtC-7886 9450±70 10790±180 (2) S Bight, North Sea H sapiens humerus GrA-27188 9140±50 10320±70 (3) S Bight, North Sea H sapiens humerus GrA-30733 9080±50 10250±40 (3) S Bight, North Sea H sapiens humerus GrA-31287 9°35±4° 10210±30 (3) S Bight, North Sea H sapiens humerus GrA-35949 9005±45 10140±90 (3) 52°22' N, 03°06' E C elaphus 1st phalanx GrA-20256 8820±60 9920±i60 (2) Eurogeul C capreolus worked antler? GrA-33949 8405±45 9420±60 (3) 53°00' N, 02°54' E H sapiens mandible GrA-11642 8370±50 9390±70 (2) 52°27' N, 02°55' E C elaphus 2nd phalanx GrA-20353 8350±50 9370±70 (2) S Bight, North Sea H sapiens cranium UtC-624 8340±130 9300±150 (2) S Bight, North Sea A alces worked antler? GrA-30731 8240±45 9220±80 (3) S Bight, North Sea H sapiens humerus GrA-27205 8i80±45 9140±90 (3) Eurogeul C elaphus modified antler GrA-22999 8070±50 8950±110 (2) Eurogeul A alces antler GrA-23201 7970±60 8830±120 (2) Tab. 6. Final Upper Palaeolithic and Mesolithic dates on human and faunal remains dredged from the North Sea. Sources: 1 - Erdbrink and Tacoma 1997; 2 - Glimmerveen et al. 2004; 3 - Mol et al. 2008; 4 - Gillespie et al. 1984. According to Glimmerveen (pers. commj most of the finds from the Southern Bight originate southwest of the Brown Bank and have the following approximate coordinates: 52°34' N, 02°35'5" E. Calibrated using CalPal (http://www.calpal.de). morphological features in a recent 3D-seismic map- ping exercise of the southern North Sea is the pres- ence of a central lake known as the 'Outer Silver Pit' (Gaffney et al. 2007). Briggs et al. (2007) interpret two elongate ridges within the Pit as sand banks that formed in an estuarine environment during the Early Holocene transgression, inferring from this the presence of strong tidal currents in the north-facing estuary. Following Donovan (1975), these tidal cur- rents may have been in part responsible for the for- mation of the Outer Silver Pit depression itself. Si- milar estuarine features are well-known from the sea floor in the Danish archipelago, where they sup- port numerous Mesolithic settlements (Fischer 2004). They would have, (i) attracted a concentration of Mesolithic settlements (Fischer 1997; 2004) and (ii), been heavily impacted by a channelling of energy during the impact of the Storegga tsunami. Fig. 5. Early Holocenepalaeogeography of the Northwest European continental shelf ('Doggerland') and geographic distribution of 14C-dated Mesolithic sites in Northwest Europe for the time-window 7600-7000 14C-BP. Palaeogeographic coastlines according to Shennan et al. (2000) and Behre (2003), with colour shading on the base of SRTM bathymetric data (cf. text). Radiocarbon-dated Mesolithic sites according to Weninger et al. in press) shown as black dots. Red dots indicate sites with radiocarbon-dated tsunami de- posits (cf. Appendix, Tab.8). Area of the submarine Storegga Slide digitized and georeferenced according to Bondevik et al. (2003) shown red. Modelled wave for the Storegga tsunami taken from Bondevik et al. (2005), adapted and projected onto the map graphically, with no vertical scaling. The modelled tsunami wave has a height of 3 m on the open ocean (Bondevik et al. 2005) and is likely to have reached the south- ern North Sea with this height (Bondevik, pers. comm. 2007) Table 7 presents various possible scenarios for the number of indivi- duals affected by the Storegga tsu- nami, based on the 'danger areas' shown in red in Figure 4. As a first approximation, and assuming that half of the area under threat was se- verely impacted, it can be suggested that some 700 to 3000 individuals were affected. This number is suffi- ciently large to have potentially re- sulted in the extinction of a number of local bands, or possibly even a regional dialectical tribe (cf. Newell etal. 1990.table 13). This does not necessarily imply that all were killed immediately, although given the likely rapidity and scale of the event, a significant number of people would almost certainly have been caught and drowned by the inexorably rising waters, while many others would have been displaced. Nor would the consequences be limited to the wave's im- mediate impact, as productive coastal areas could have been devastated, shellfish beds destroyed and covered by sands, together with any fixed fishing fa- cilities, well-attested for the Late Mesolithic Erteb0lle period (Pedersen 1997), but also known from the early Kongemose (c. 8300 calBP) in Denmark (Fi- scher 2004). Moreover, depending on the time of year that the wave hit, any stored foods meant to last over the winter may also have been lost (cf. Spi- kins 2008), with subsequent starvation among sur- vivors. Indeed, macrofossil analysis of fish bone and twigs from deposits in Norway has shown that the tsunami probably occurred during late autumn (Bon- devik et al. 1997). It is conceivable, particularly in the context of continuing rising sea-levels at this time, that the final abandonment of the remaining remnants of Doggerland as a place of permanent ha- bitation by Mesolithic populations was brought about by the Storegga tsunami. Thus, both the immediate and longer-term affects of this event, in terms of population redistribution and social memory would have been considerable, al- though it remains difficult to provide more specific details at this stage (cf. Coles 1998; Waddington 2007; Ward et al. 2006). One clear effect of the final separation of Britain and the continent is a strong impression of insularity in the former, seen most clearly in the absence in Britain of the trapeze arma- tures that dominate later Mesolithic microlith indus- tries on the adjacent continent from c. 8500 calBP (Jacobi 1976). Incidentally, this date is consistent with some of the more recent estimates given by palaeo-environmental researchers for the formation area (km2) Population density (person/km2) 0.05 0.10 0.50 1.00 Total area under threat 13 600 680 1360 6800 13 600 1/2 area 6800 340 680 3400 6800 1/4 area 3400 170 340 1700 3400 Tab. 7. Estimated population sizes in the study area affected by the Storegga tsunami at various population densities. The most likely scenario may be a population density of 0.10 to 0.50 per- son/km2 over an impacted area of some 6800km2, affecting some 700 to 3000 people, both directly and indirectly (see text). of the English Channel (see Tab. 5), and could even be interpreted as providing independent corrobora- tion. while the process thus appears to have already been well underway, the Storegga tsunami may have finally severed any remaining (e.g. tidal) link be- tween England and the continent. Discussion and conclusions We have assembled a large amount of 14C-radiomet- ric evidence for the Storegga Slide and its attendant tsunami, ranging from Norway to the British Isles. We find that the Storegga Slide tsunami event is re- liably and accurately dated to 7300 ± 30 14C-BP (p = 95%) [8100 ± 100 calBP]. We then combined this with published palaeogeographic reconstructions for the now submerged Northwest European continental shelf known as 'Doggerland' (Coles 1998; Behre 2003) and regional sea-level records for the southern North Sea (Behre 2003) to evaluate the potential en- vironmental and social impact of the tsunami in the Doggerland region. During the time-interval 8200- 8000 calBP, the coastal lowlands of North Germany and the Netherlands were being steadily inundated by rising sea-levels due to a combination of eustatic and isostatic processes (amounting to a rise of 1.25m per century, Behre 2003). In addition, there would have been an abrupt 0.25-0.5m sea-level jump at around 8300 calBP, marking the sea-level effects of the catastrophic meltwater release from Lake Agas- siz that triggered the so-called '8200 calBP' cold event around the Atlantic (e.g. LeGrande 2006; Clare et al., this issue). Simply stated, due to this coinci- dence, it may have been unusually cold and windy on the remaining coasts of Doggerland. In the Netherlands (especially the northern part of the country, i.e. north of the Rhine), at the time of the Storegga Slide tsunami, and again essentially simultaneous with the 8200 calBP climate event, the number of available 14C-dates is very low when com- pared to the earlier and final part of the Mesolithic. This temporal patterning seems to correspond with a shift in emphasis of settlement location towards the central and western part of the area (Niekus 2006). However, the process of a drop in the num- ber of dates begins c. 300 years earlier than the tsunami, and c. 200 years earlier than the North At- lantic 8200 calBP cold event, and at present we see no causal relation between these natural processes and the drop in the number of dates. Furthermore, according to Raemaekers and Niekus (in press), it would be better to interpret the observed patterns as a demise in i4C dates in the higher areas, instead of a true shift in occupation, especially since there are several major biasing factors that should be taken into account when discussing spatio-temporal patterning in the northern Netherlands (discussed in more detail in Niekus 2006). It seems most likely, however, that the Mesolithic population in the area were reacting to the steadily rising ground-water le- vels at this time (Niekus 2006). Similar population relocation - in reaction to the loss of vital hunting and fishing grounds - may also be expected for the steadily sinking Doggerland. Un- fortunately, due to major syn-sedimentary processes in the southern North Sea (Fitch et al. 2004; Gaf- fney et al. 2007; Dix et al. 2008) it is not yet possi- ble to reliably reconstruct the ancient topography of Mesolithic Doggerland itself solely on the base of mo- dern bathymetric data, let alone reconstruct the exact coastlines for the time-window of 8200-8000 calBP. By comparing two alternative scenarios, based on 'highest possible' and 'lowest possible' sea levels (ra- ted at -17 ± 5 m asl) that are contemporary with the derived date for the tsunami (8100 ± 100 calBP, 95% confidence) according to the sea-level curve of Behre (2003) for the southern North Sea, we conclude that the Storegga Slide tsunami would have had a cata- strophic impact on the contemporary coastal Mesoli- thic population. One main result of this study is the high tsunami impact assigned to the western regions of Jutland, and in particular to the northern coasts, where Storegga Slide deposits may be expected, de- pending on locality, with strong postglacial isostatic working against rapid sea-level rise (Fischer 2004). Following the Storegga Slide tsunami, it appears, Bri- tain finally became separated from the continent and, in cultural terms, the Mesolithic there goes its own way. -ACKNOWLEDGEMENTS- This study makes use of high-resolution 3D-digital sa- tellite data from the SRTM (Shuttle Radar Topogra- phy) mission, flown in February 2000. This data is freely available for scientific research. We would like to express our sincere thanks to everyone involved in data accumulation, processing, and distribution. Jan Glimmerveen (The Hague, Netherlands) is personally thanked for providing 14C-dates on finds from the North-Sea. We extend our personal thanks to Bryony Coles (Exeter, Great Britain), S0ren Andersen (H0j- bjerg, Denmark), Stein Bondevik (Bergen, Norway), and Martin Street (Neuwied, Germany) for helpful information. REFERENCES ALLEY R. B., MAYEWSKI P. A., SOWERS M., STUIVER M., TAYLOR K. C., CLARK P. U. 1997. Holocene climate insta- bility: A prominent, widespread event 8200 yr ago. Geo- logy 25(6): 483- 486. BALLANTYNE C. K. 2004. After the Ice: Paraglacial and Postglacial Evolution of the Physical Environment of Scot- land, 20,000 to 5000 BP. In A. Saville (ed.), Mesolithic Scotland and its Neighbours. The Early Holocene Prehi- story of Scotland, its British and Irish Context, and some Northern European Perspectives. Society of Antiquaries of Scotland. Edinburgh: 27-53. BAUER E., GANOPOLSK A., MONTOYA M. 2004. Simula- tion of the cold climate event 8200 years ago by melt- water outburst from Lake Agassiz. Paleoceanography 19. BARBER D. C., DYKE A., HILLAIRE-MARCEL C., JENNINGS A. E., ANDREWS J. T., KERWIN M. W., BILODEAU G., McNE- ELY R., SOUTHON J., MOREHEAD M. D., GAGNON J.-M. 1997. Forcing of the cold event of 8,200 years ago by cata- strophic drainage of Laurentide lakes. Nature 400:344- 348. BEHRE K.-E. 2003. Eine neue Meeresspiegelkurve für die südliche Nordsee. Transgressionen und Regressionen in den letzten 10.000 Jahren. In E. Strahl, F. Bungenstock, J. Ey, S. Wolters, R. Kiepe, L. Spath (eds.), Probleme der Küstenforschung im südlichen Nordseegebiet. (Nieder- sächsisches Institut für historische Küstenforschung), Iseensee Verlag. Oldenburg: 9-63. 2005. Die Einengung des neolithischen Lebensraumes in Nordwestdeutschland durch klimabedingte Fakto- ren: Meeresspiegelanstieg und grossflächige Ausbrei- tung von Mooren. In D. Gronenborn (ed.), Climate Va- riability and Culture Change in Neolithic Societies of Central Europe, 6700-2200 cal BC. RGZM-Tagungen Band 1. Verlag des Römisch-Germanischen Zentralmu- seums Mainz. Mainz: 209-220. 2007. A new Holocene sea-level curve for the southern North Sea. Boreas 36: 82-102. BINFORD L. R. 2001. Constructing Frames of Reference. University of California Press. Berkeley. BJÖRKLUND K. R., BJ0RNSTAD H., ERLENKEUSER H., HEN- NINGSMOEN K. E., H0EG H. I., JOHNSEN K., MANUM S. B., MIKKELSEN N., NAGY J., PEDERSTAD K., QVALE G., ROSEN- QVIST I. T., SALBU B., SCHOENHARTING G., STABELL B., THIEDE J., THRONDSEN I., WASSMAN P., WERNER F. 1985. Evolution of the upper Quaternary depositional environ- ment in the Skagerrak: A synthesis. Norsk Geologisk Tids- skrift 65:139-149. BONDEVIK S. 2003. Storegga tsunami sand in peat below the Tapes beach ridge at Har0y, western Norway, and its possible relation to an early Stone Age settlement. Boreas 32: 476-483. BONDEVIK S., SVENDSEN J. I., JOHNSEN G., MANGERUD J., KALAND P. E. 1997. The Storegga tsunami along the Nor- wegian coast, its age and runup. Boreas 26:29-53. BONDEVIK S., MANGERUD J., DAWSON S., DAWSON A., LOHNE 0. 2003. Record-breaking Height for 8000-Year- Old Tsunami in the North Atlantic. EOS Trans. AGU 84 (31): 289-300. BONDEVIK S., L0VHOLT F., HARBITZ C., MANGERUD J., DAWSON A., SVENDSEN J. I. 2005. The Storegga Slide tsu- nami - comparing field observations with numerical ob- servations. Marine and Petroleum Geology 22:195-208. BONDEVIK S., LOYHOLT F., HARBITZ C., STORMO S., SKJERDAL G. 2006. The Storegga Slide Tsunami - Depo- sits, Run-up Heights and Radiocarbon Dating of the 8000- Year-Old Tsunami in the North Atlantic. Eos Trans. AGU 87(52), Fall Meet. Suppl., Abstract 0S34C-01. BOOMER I., WADDINGTON C., STEVENSON T., HAMILTON D. 2007. Holocene coastal change and geoarchaeology at Howick, Northumberland, UK. The Holocene 17 (1): 89- 104. BRIGGS K., THOMSON K., GAFFNEY V. 2007. A geomor- phological investigation of submerged depositional fea- tures within the Outer Silver Pit, southern North Sea. In V. Gaffney, K. Thomson, S. Fitch (eds.), Mapping Dogger- land: the Mesolithic Landscapes of the Southern North Sea. Archaeopress. Oxford: 43-59. BRYN P., BERG K., FORSBERG C. F., SOLHEIM A., KVAL- STAD T. J. 2005. Explaining the Storegga Slide. Marine and Petroleum. Geology 22:11-19. BUNGENSTOCK F. 2006. Der holozäne Meeresspiegelan- stieg südlich der ostfriesischen Insel Langeoog, südliche Nordsee - hochfrequente Meeresspiegelbewegungen wäh- rend der letzten 6000 Jahre. PhD-Thesis. Mathematisch- Naturwissenschaftliche Fakultät der Rheinischen Friedrich- Wilhelms-Universität Bonn. Available online: http://hss. ulb.uni-bonn.de/diss_online COLES B. J. 1998. 'Doggerland': a speculative survey. Proc. Prehist. Society 64: 45-81. COLES B. 1999. Doggerland's loss and the Neolithic. In B. Coles, J. Coles, M. Schou Jorgensen (eds.), Bog Bodies, Sacred Sites and Wetland Archaeology. WARP (Wetland Archaeology Research Project) Occasional Paper 12. De- partment of Archaeology, University of Exeter. Exeter: 51-57. CONRADSEN K., HEIER-NIELSEN S. 1995. Holocene pale- oceanography and paleoenvironments of the Skagerrak- Kattegatt, Scandinavia. Paleoceanography 10:810-813. CONSTANDSE-WESTERMANN T. S., NEWELL R. R. 1989. So- cial and biological aspects of the Western European Meso- lithic population structure: a comparison with the demo- graphy of North American Indians. In C. Bonsall (ed.), The Mesolithic in Europe. Edinburgh University Press. Edinburgh: 106-115. DAWSON S., SMITH D. E. 1997. Holocene relative sea-level changes on the margin of a glacio-isostatically uplifted area: an example from northern Caithness, Scotland. The Holocene 7 (1): 59-77. DAWSON A. G., LONG D., SMITH D. E. 1988: The Storegga Slides: evidence from eastern Scotland for a possible tsu- nami. Marine Geology 82:271-276. DAWSON A. G., SMITH D. E., LONG D. 1990. Evidence for a tsunami from a Mesolithic site in Inverness, Scotland. Journal of Archaeological Science 17 (6): 509-512. DAWSON A. G., LONG D., SMITH D. E., SHI S., FOSTER I. D. L. 1993. Tsunamis in the Norwegian Sea and North Sea caused by the Storegga submarine landslides. In S. Tinti (ed.), Tsunamis in the World. Kluwer Academic Publi- shers. The Netherlands: 228. DAWSON A. 2008. The Tsunami Risk Project, on-line: www.nerc-bas.ac.uk/tsunami-risks/html/Phy3Impact. htm. DIX J., QUINN R., WESTLEY K. 2008. A Re-assessment of the Archaeological Potential of Continental Shelves. Final Report. Department of Archaeology, University of South- ampton, available on-line: http://www.arch.soton.ac.uk/ Research/Aggregates/shelve-report.htm. DONOVAN D. T. 1975. The geology and origin of the Sil- ver Pit and other closed basins in the North Sea. Proce- edings of the Yorkshire Geological Society 39:267-293. EDINBOROUGH K. 2004. Evolution of Bow Arrow Tech- nology. Unpubl. PhD thesis: University College London. ERDBRINK D. P. B., TACOMA J. 1997. Une calotte humaine datee au 14C du basin sud de la mer du Nord. L'Anthropo- lgie 100:541-545. FISCHER A. 1997. People and the sea - settlement and fi- shing along the Mesolithic coast. In L. Pedersen, A. Fi- scher, B. Aaby (eds.), The Danish Storebwlt Since the Ice Age. A/S Storebffilt Fixed Link, Kalundborg Museum, Natio- nal Forest and Nature Agency and the National Museum of Denmark. Copenhagen: 63-77. 2004. Submerged Stone Age - Danish examples and North Sea potential. In N. C. Flemming (ed.), Subma- rine prehistoric archaeology of the North Sea. Council for British Archaeology. York: 23-36. FITCH S., THOMSON K., GAFFNEY V. 2005. Late Pleisto- cene and Holocene depositional systems and the palaeo- geography of the Dogger Bank, North Sea. Quaternary Research 64:185-196. GAFFNEY V., THOMSON K., FITCH S. (eds.) 2007. Mapping Doggerland: the Mesolithic Landscapes of the Southern North Sea. Archaeopress. Oxford. GILLESPIE R., GOWLETT J. A. J., HALL E. T., HEDGES R. E. M. 1984. Radiocarbon measurements by accelerator mass spectrometry: an early selection of dates. Archaeometry 26: 15-20. GLIMMERVEEN J., MOL D., POST K., REUMER J. W. F., van der PLICHT H., van GEEL B., van REENEN G., PALS J. P. 2004. The North Sea project. The first palaeontological, palynological and archaeological results. In N. C. Flem- ming (ed.), Submarine Prehistoric Archaeology of the North Sea. Council for British Archaeology Research Re- port 141: 21-36. GRAUERT M. S., BJÖRCK S., BONDEVIK S. 2001. Storegga tsunami deposits in a coastal lake on Suduroy, the Faroe Islands. Boreas 30:263-271. GROOTES P. M., STUIVER M., WHITE J. W. C., JOHNSEN S., JOUZEL J. 1993. Comparison of Oxygen Isotope Records from the GISP2 and GRIP Greenland Ice Core. Nature 366:552-554. GYLLENCREUTZ R. 2005a. Holocene and Latest Glacial Paleoceanography in the North-Eastern Skagerrak. Med- delanden frän Stockholms Universitets Institution för Geo- loggi Och Geokemi No. 322. Available on-line: http://www. gyllencreutz.se/references.html 2005b. Late Glacial and Holocene paleoceanography in the Skagerrak from high-resolution grain size records. Palaegeography, Palaeoclimatology, Palaeoecology 222: 344-369. HAFLIDASON H., LIEN R., SEJRUP H. P., FORSBERG C. F., BRYN P. 2005. The dating and morphometry of the Sto- regga Slide. Marine and Petroleum Geology: 123-136. HARBITZ C. B. 1992. Model simulation of tsunamis gene- rated by the Storegga Slides. Marine Geology 105:1-21. HUGHEN K., SOUTHON J., LEHMAN S., BERTRAND C., TURNBULL J. 2006. Marine-derived 14C calibration and activity record for the past 50,000 years updated from the Cariaco Basin. Quaternary Science Reviews 25:3216- 3227. doi:10.1016/j.quascirev.2006.03.014. JACOBI R. M. 1976. Britain inside and outside Mesolithic Europe. Proceedings of the Prehistoric Society 42: 67- 84. JELGERSMA S. 1979. Sea-level changes in the North Sea basin. In E. Oerle, R. T. E. Shüttenhelm, A. J. Wiggers (eds.), The Quaternary history of the North Sea. Symposia Uni- versitatis Upsaliensis Annum Quingentesimum Celebran- tis 2: 233-248. JIANG H., BJÖRCK S., KNUDSEN K. L. 1997. A palaeoclima- tic and palaeoceanographic record of the last 1100014C years from the Skagerrak-Kattega. JOHNSEN S. J., DAHL-JENSEN D., GUNDESTRUP N., STEF- FENSEN J. P., CLAUSEN H. B., MILLER H., MASSON-DUL- MEOTTE V., SVEINBJ0RNDOTTIR A. E., WHITE J. 2001. Oxygen isotope and palaeotemperature records from six Greenland ice-core stations: Camp Century, Dye-3, GRIP, GISP2, Renland and NorthGRIP. Journal Quaternary Sci- ence 16 (4): 299-307. KLITGAARD-KRISTENSEN D., SEJRUP H. P., HAFLIDASON H., JOHNSEN S., SPURK M. 1998. A regional 8200 cal. yr BP cooling event in northwest Europe, induced by final stages of the Laurentide ice-sheet deglaciation? Journal of Quaternary Science 13 (2): 165-169. LAMBECK K. 1995. Late Devensian and Holocene shore- lines of the British Isles and North Sea from models of glacio-hydro-isostatic rebound. Journal of the Geological Society 152: 437-448. LeGRANDE A. N. 2006. The Climate Imprint on the Oxy- gen Isotopic Composition of Water: Observations, Pro- xies, and Coupled Isotopic Model Simulations. Ph.D. the- sis. Columbia University. LEUENBERGER M., LANG C., SCHWANDER J. 1999. Delta 15N measurements as a calibration tool for the paleother- mometer and gas-ice age differences: A case study for the 8200 B.P event on GRIP ice. Journal of Geophysical Re- search 104 (22): 163-170. LONG D., SMITH D. E., DAWSON A. G. 1989. A Holocene tsunami deposit in eastern Scotland. Journal of Quater- nary Science 4: 61-66. LOUWE KOOIJMANS L. P. 1971. Mesolithic bone and antler implements from the North Sea and from the Netherlands. Berichten Rijksdienst voor het Oudheidkundig Bode- monderzoek 20-21:27-73. MOL D., POST K., REUMER J. W. F., van der PLICHT J., de VOS J. 2006. The Eurogeul-first report of the palaeonto- logical, palynological and archaeological investigations of this part of the North Sea. Quaternary International 142- 143: 178-85. MOL D., GLIMMERVEEN J., POST K., van der PLICHT H., van GEEL B. 2008. Kleine encyclopedie van het leven in het Pleistoceen. Mammoeten, neushoorns en andere die- ren van de Noordzeebodem. Veen Magazines. Diemen. NEWELL R. R., CONSTANDSE-WESTERMANN T. S., van der SANDEN W. A. B., van GIJN A. 1990. An inquiry into the ethnic resolution of Mesolithic regional groups. The study of their decorative ornaments in time and space. Brill. Leyden. NIEKUS M. J. L. Th. 2006. A geographically referenced 14C database for the Mesolithic and the early phase of the Swifterbant culture in the Northern Netherlands. Palaeo- historia 47/48: 41-99. NORDBERG K. 1991. Oceanography in the Kattegat and Skagerrak over the past 8000 years. Paleoceanography 4: 461-484. PALUDAN-MÜLLER C. 1978. High Atlantic food gathering in north-western Zealand: ecological conditions and spa- tial representation. Studies in Scandinavian Prehistory and Early History 1:120-57. PEDERSEN L. 1997. They put fences in the sea. In L. Pe- dersen, A. Fischer, B. Aaby (eds.), The Danish Storebwlt Since the Ice Age. Copenhagen: 124-143. RAEMAEKERS D. C. M., NIEKUS M. J. L. Th. in press. Deve- lopments in Dutch Late Mesolithic: landscape, site location, subsistence and the introduction of pottery. In Ph. Crom- be, M. van Strydonck, J. Sergant, M. Bats, M. Boudin (eds.), Proceedings of the international congress "Chronology and Evolution in the Mesolithic of NW Europe", Brus- sels, May 30 till June 1 2007, Cambridge Scholar Publi- shing. REIMER P. J., BAILLIE M. G. L., BARD E., BAYLISS A., BECK J. W., BERTRAND C. J. H., BLACKWELL P. G., BUCK C. E., BURR G. S., CUTLER K. B., DAMON R. L., EDWARDS R. L., FAIRBANKS R. G., FRIEDRICH M., GUILDERSON T. P., HOGG A. G., HUGHEN K. A., KROMER B., McCORMAC F. G., MANNING S. W., RAMSEY C. B., REIMER R. W. REMME- LE S., SOUTHON J. R., STUIVER M., TALAMO S., TAYLOR F. W., van der PLICHT J., WEYHENMEYER C. E. 2004. IntCal04 Terrestrial radiocarbon age calibration, 26 - 0 ka BP. Ra- diocarbon 46:1029-1058. ROHLING E. J., PÄLICKE H. 2006. Centennial-scale climate cooling with a sudden cold event around 8,200 years ago. Nature 434:975-979. ROZOY J.-G. 1978. Les Derniers Chasseurs. L'Epipaleoli- thique en France et en Belgique. Essai de Synthese. Bul- letin de la Societe Archeologique Champenoise. Charle- ville. SCHULTING R. J., RICHARDS M. P. 2001. Dating women and becoming farmers: new palaeodietary and AMS data from the Breton Mesolithic cemeteries of Teviec and Hoe- dic. Journal of Anthropological Archaeology 20: 314- 344. SCHULTING R. J. in press. Worm's Head, Caldey Island (south Wales, UK) and the question of Mesolithic territo- ries. In S. B. McCartan, R. J. Schulting, G. Warren, P. C. Woodman (eds.), The Proceedings of the 7th Mesolithic in Europe Conference. Oxbow. Oxford. SHENNAN I., LAMBECK K., FLATHER R., HORTON B., Mc- ARTHUR J., INNES J., LLOYD J., RUTHERFORD M., WING- FIELD R. 2000. Modelling western North Sea palaeogeo- graphies and tidal changes during the Holocene. In I. Shennan, J. Andrews (eds), Holocene Land-Ocean Inter- action and Environmental Change around the North Sea. Geological Society, London, Special Publications 166: 299-319. SHI S., SMITH D. E. 2003. Coastal Tsunami geomorpholo- gical impacts and sedimentation processes: Case studies of modern and prehistorical events. Lecture held at the International Conference on Estuaries and Coasts Novem- ber 9-11, 2003, Hangzhou, China. Available online: http:// www.irtces.org/pdf-hekou/021.pdf SMITH D. E., CULLINGFORD R. A., HAGGART B. A. 1985. A major coastal flood during the Holocene in eastern Scot- land. Eiszeitalter und Gegenwart 35:109-118. SMITH D. E., SHI S., CULLINGFORD R., DAWSON A., DAW- SON S., FIRTH C., FOSTER I., FRETWELL P., HAGGART B., HOLLOWAY L., LONG D. 2004. The Holocene Storegga Slidse tsunami in the United Kingdom. Quaternary Sci- ence Reviews 23: 2291-2311. SPIKINS P. A. 2007. Mesolithic Europe: glimpses of another world. In G. Bailey, P. A. Spikins (eds.), Mesolithic Europe. Cambridge University Press. Cambridge: 1-17. SVENDSEN J. L. l985. Standforskyvning pa Sunnm0re. Bio- og litostratigrafske undersokelser pa Gursk0y, Lein0y og Bergs0y. Thesis, University of Bergen, 142 pp. [Cited in Bondevik et al. 1997]. TELLER J. T., LEVINGTON D. W., MANN J. D. 2002. Fresh- water outbursts to the oceans from glacial Lake Agassiz and their role in climate change during the last deglacia- tion. Quaternary Science Reviews 21: 879-887. TELLER J. T., MURTY T., NIRUPAMA N., CHITTIBABU P., BAIRD W. F. 2005. Possible Tsunami in the Labrador Sea related to the Drainage of Glacial Lake Agassiz ~8400 years B.P. Science of Tsunami Hazards 23 (3): 3-16. THOMAS E. R., WOLFF E. W., MULVANEY R., STEFFENSEN J. P., JOHNSEN S. J., ARROWSMITH C., WHITE J. W. C., VAUGHN B., POPP T. 2007. The 8.2 kyr event from Green- land ice cores. Quaternary Science Reviews 26(1-2): 70-81. UNITED STATES GEOLOGICAL SURVEY 2008. Data from http://edc.usgs.gov/products/elevation/gtopo30/gtopo30. html VERHART L. 2005. A drowned land. Mesolithic from the North Sea floor. In L. P. Louwe Kooijmans, P. W. van den Broeke, H. Fokkens, A. L. van Gijn (eds.), The Prehistory of the Netherlands. Amsterdam University Press. Amster- dam: 157-160. VINTHER B. M., CLAUSEN H. B., JOHNSEN S. J., RASMUS- SEN S. O., ANDERSEN K. K., BUCHARDT S. L., DAHL-JENSEN D., SEIERSTAD I. K., SIGGAARD-ANDERSEN M.-L., STEFFEN- SEN J. P., SVENSSON A. M., OLSEN J., HEINEMEIER J. 2006. A synchronized dating of three Greenland ice cores throu- ghout the Holocene. Journal of Geophysical Research. doi:10.1029/2005JD006921. WADDINGTON C. (ed.) 2007. Mesolithic Settlement in the North Sea Basin: A Case Study from Howick, North- East England. Oxbow and English Heritage. Oxford. WAGNER B., BENNIKE O., KLUG M., CREMER H. 2007. First indication of Storegga tsunami deposits from East Green- land. Journal of Quaternary Science 22 (4): 321-325. WARD I., PIERS L., LILLIE M. 2006. The dating of Dogger- land - post-glacial geochronology of the southern North Sea. Environmental Archaeology 11 (2): 207-218. WENINGER B. 1986. High-precision calibration of archaeo- logical radiocarbon dates. Acta Interdisciplinaria Archaeol IV: 11-53. 1995. Stratified 14C Dates and Ceramic Chronologies. Case Studies for the Early Bronze Age at Troy (Turkey) and Ezero (Bulgaria). Radiocarbon 37 (2): 443-456. WENINGER B., JÖRIS O., DANZEGLOCKE U. 2003. Climate Archaeology with Fortran. Fortran Source Volume 19,1. Spring 2003. Lahey Computer Systems Inc. WENINGER B., JÖRIS O. 2004. Glacial Radiocarbon Cali- bration. The CalPal Program. In T. Higham, C. Bronk Ram- sey, C. Owen (eds.), Radiocarbon and Archaeology. Fourth International Symposium. Oxford, 2002. Oxford University School of Archaeology Monograph 62: 9-15. WENINGER B., ALRAM-STERN E., BAUER E., CLARE L., DANZEGLOCKE U., JÖRIS O., KUBATZKI C., ROLLEFSON G., TODOROVA H., van ANDEL T. 2006. Climate forcing due to the 8200 cal yr BP event observed at Early Neoli- thic sites in the eastern Mediterranean. Quaternary Inter- national 66: 401-420. WENINGER B., EDINBOROUGH K., BRADTMÖLLER M., COLLARD M., CROMBE P., DANZEGLOCKE U., HOLST D., JÖRIS O., NIEKUS M., SHENNON S., SCHULTING R. in press. A Radiocarbon Database for the Mesolithic and Early Neo- lithic in Northwest Europe. In Ph. Crombe, M. Van Stry- donck, J. Sergant, M. Bats, M. Boudin (eds.), Proceedings of the international congress "Chronology and Evolu- tion in the Mesolithic of NWEurope", Brussels, May 30 till June 1 2007. Cambridge Scholar Publishing. Appendix Tab. 8. Radiocarbon dates for the Storegga Slide tsunami Age conventions In the present paper all ages are given in tree-ring calibrated calendric years [calBP] before present (0 calBP = AD 1950). Calibrated 14C-ages are obtained using the software CalPal (www.calpal.de), with methods described in Weninger (1986) and procedures described in Weninger and Jöris (2004), using the tree-ring data set INTCAL04 (Reimer et al. 2004). Conventional 14C-ages are given on the 14C-scale with units [14C-BP]. To avoid misunderstanding, in the text we provide ages on both time scales. An example is: T-11707A: 7020 ± 90 14C-BP (7840 ± 90 calBP) with laboratory code T-11707A. In this case the conventional i4C-age is 7020 ± 90 14C-BP. The corresponding tree-ring calibrated calendric age is 7840 ± 90 calBP. A database contain- ing the 14C-ages for the Storegga Slide tsunami, as collated from published studies and used here (Tab. 8). Note that this database does not show the tree-ring calibrated ages for individual dates. For the purposes of the present paper, these values are superfluous. The age-calibrated results based on these dates are shown in the graphs and tables. References: Abbreviations (1) Bondevik et al. 1997; (2) Boomer et al. 2007; (3) Wagner et al. 2007; (4) Smith et al. 2004 Position: Abbreviations Position e.g. 'Above Tsunami': in relation to Storegga sand deposit, as defined in reference. (R) = Regressive Contact (defined by Smith et al. 2004). (T) = Transgressive Contact (defined by Smith et al. 2004). Lab Code 14C-Age 13C- PDB Material Country Site Position Latitude Long. Reference Tua-522 7080 ± 80 -26,1 Twig Norway Almesstadmyra above Tsunami 62,2175 5,6675 (1) T-11707A 7020 ± 90 -29,6 Gyttja Norway Auretjorn above Tsunami 60,9564 4,8147 (1) T-11606A 7320 ± 140 -29,8 Gyttja Norway Auretjorn above Tsunami 60,9564 4,8147 (1) T-10599A 6865 ±105 -30,7 Gyttja Norway Endrevatnet above Tsunami 62,4331 6,2708 (1) T-10598A 7105 ± 135 -30,6 Gyttja Norway Endrevatnet above Tsunami 62,4331 6,2708 (1) T-4162 7490 ± 90 -32,1 Gyttja Norway Endrevatnet above Tsunami 62,4331 6,2708 (1) T-10592A 7500 ± 80 -25,2 Gyttja Norway Froystadmyra above Tsunami 62,3253 5,6764 (1) T-10593A 7615 ± 150 -26 Gyttja Norway Froystadmyra above Tsunami 62,3253 5,6764 (1) T-11708A 7475 ± 110 -2 9,9 Gyttja Norway Forlandsvatnet above Tsunami 60,8906 4,8442 (1) T-11249A 7605 ±105 -29,8 Gyttja Norway Gorrtjonna I above Tsunami 63,8264 9,8308 (1) T-11244A 7100 ± 125 -29,8 Gyttja Norway Kvennavatnet above Tsunami 63,8347 9,8225 (1) T-12013A 7570 ± 90 -30 Gyttja Norway Kvennavatnet above Tsunami 63,8347 9,8225 (1) T-10595A 6550 ± 100 -2 9,9 Gyttja Norway Ratvikvatnet above Tsunami 62,4619 6,2242 (1) T-10594A 7430 ± 95 -2 9,5 Gyttja Norway Ratvikvatnet above Tsunami 62,4619 6,2242 (1) T-10590A 7130 ± 95 -30,6 Gyttja Norway Skolemyra above Tsunami 62,3331 5,6486 (1) T-10591A 7205 ± 90 -30,2 Gyttja Norway Skolemyra above Tsunami 62,3331 5,6486 (1) T-11278A 6575 ± 110 -30,4 Gyttja Norway Skolemyra above Tsunami 62,3331 5,6486 (1) T-11277A 6890 ± 65 -30,7 Gyttja Norway Skolemyra above Tsunami 62,3331 5,6486 (1) T-11276A 7045 ± 70 -30,1 Gyttja Norway Skolemyra above Tsunami 62,3331 5,6486 (1) T-11245A 7610 ± 100 -29,4 Gyttja Norway Skolemyra above Tsunami 62,3331 5,6486 (1) Tua-862A 7850 ± 85 -27,7 Gyttja Norway Skolemyra above Tsunami 62,3331 5,6486 (1) T-11282A 5695 ± 100 -30,6 Gyttja Norway Asetjorn above Tsunami 60,9056 4,8797 (1) T-11281A 6406 ± 85 -30,2 Gyttja Norway Asetjorn above Tsunami 60,9056 4,8797 (1) T-11280A 6995 ± 110 -30,7 Gyttja Norway Asetjorn above Tsunami 60,9056 4,8797 (1) Lab Code 14C-Age 13C- PDB Material Country Site Position Latitude Long. Reference T-12260A 7180 ± 95 -30,8 Gyttja Norway Asetjorn above Tsunami 60,9056 4,8797 (1) T-11202A 7230 ±105 -31.1 Gyttja Norway Asetjorn above Tsunami 60,9056 4,8797 (1) Tua-1350 7315 ± 70 -22,9 Moss Norway Audalsvatnet with n Tsunami 63,8314 9,8289 (1) T-11705A 8090 ± 120 -28,5 Detritus Norway Auretjorn with n Tsunami 60,9564 4,8147 (1) Tua-523 7655 ± 85 -26,1 Twig Norway Froystadmyra with n Tsunami 62,3253 5,6764 (1) T-11246A 7985 ± 115 -24,8 Detritus Norway Froystadmyra with n Tsunami 62,3253 5,6764 (1) T-4967A 8480 ±160 -27,8 Detritus Norway Froystadmyra with n Tsunami 62,3253 5,6764 (1) T-11710A 8040 ±160 -30,5 Detritus Norway Forlandsvatnet with n Tsunami 60,8906 4,8442 (1) Tua-834 6970 ± 175 -26 Twig Norway Gorrtjonna I with n Tsunami 63,8264 9,8308 (1) Tua-835 7930 ± 65 -26,1 Twig Norway Gorrtjonna I with n Tsunami 63,8264 9,8308 (1) Tua-1269 7445 ± 65 -29,5 Twig Norway Gorrtjonna I with n Tsunami 63,8264 9,8308 (1) Tua-1122 7175 ± 75 -30,7 Twig Norway Klingrevatnet with n Tsunami 62,4424 6,2324 (1) Tua-833 8285 ±185 -27,7 Calluna Norway Kulturmyra with n Tsunami 62,3319 5,6553 (1) TUa-831 7240 ± 70 -27,7 Twig Norway Kvennavatnet with n Tsunami 63,8347 9,8225 (1) TUA-984 7200 ± 80 -26,1 twig Norway Kvennavatnet with n Tsunami 63,8347 9,8225 (1) TUa-832 8405 ± 70 1 Shell Norway Kvennavatnet with n Tsunami 63,8347 9,8225 (1) TUa-859 10780 ± 95 1 Shell Norway Kvennavatnet with n Tsunami 63,8347 9,8225 (1) T-10597 7230 ±105 -26,1 Twig Norway Ratvikvatnet with n Tsunami 62,4619 6,2242 (1) T-10596 7610 ± 70 -26,1 Wood Norway Ratvikvatnet with n Tsunami 62,4619 6,2242 (1) TUa-861 7250 ± 75 -26,1 Bark Norway Skolemyra with n Tsunami 62,3331 5,6486 (1) TUa-524 7365 ± 90 -26,1 Twig Norway Skolemyra with n Tsunami 62,3331 5,6486 (1) TUa-860 7435 ± 75 -26,1 Bark Norway Skolemyra with n Tsunami 62,3331 5,6486 (1) T-11275A 8315 ± 110 -24,9 Detritus Norway Skolemyra with n Tsunami 62,3331 5,6486 (1) TUa-858 7765 ± 80 -26,1 Twig Norway Skolemyra with n Tsunami 62,3331 5,6486 (1) T-11279A 7915 ± 70 -30,4 Detritus Norway Asetjorn with n Tsunami 60,9056 4,8797 (1) TUa-864 8045 ± 75 -26,1 Twig Norway Asetjorn with n Tsunami 60,9056 4,8797 (1) TUa-863 8350 ± 80 -26,1 Twig Norway Asetjorn with n Tsunami 60,9056 4,8797 (1) T-11704A 7320 ± 80 -29,9 Gyttja Norway Auretjorn directly below 60,9564 4,8147 (1) T-11247A 9020 ± 155 -26,1 Gyttja Norway Froystadmyra directly below 62,3253 5,6764 (1) T-11709A 7985 ±150 -29,5 Gyttja Norway Forlandsvatnet directly below 60,8906 4,8442 (1) T-11250A 7680 ± 70 -32,5 Gyttja Norway Gorrtjonna I directly below 63,8264 9,8308 (1) T-11837A 8340 ± 115 -29,7 Gyttja Norway Kulturmyra directly below 62,3319 5,6553 (1) TUa-1270 7350 ± 80 -22,3 Moss Norway Kvennavatnet directly below 63,8347 9,8225 (1) T-11201A 7805 ± 115 -29,6 Gyttja Norway Asetjorn directly below 60,9056 4,8797 (1) Oxa-11833 7269 ± 39 -24,9 Hazelnut England Howick directly above 55,4403 -1,5917 (2) Oxa-11858 7308 ± 40 -25,6 Hazelnut England Howick directly above 55,4403 -1,5917 (2) OxA-11860 7160 ± 40 -27,3 Twig England Howick above Tsunami 55,4403 -1,5917 (2) OxA-11859 7174 ± 35 -26,4 Wood England Howick above Tsunami 55,4403 -1,5917 (2) OxA-12954 7075 ± 37 -30,7 Bark England Howick above Tsunami 55,4403 -1,5917 (2) OxA-12953 7117 ± 39 -26,1 Hazelnut England Howick above Tsunami 55,4403 -1,5917 (2) OxA-12952 6988 ± 37 -26,5 Hazelnut England Howick above Tsunami 55,4403 -1,5917 (2) KIA-24754 6735 ± 40 0,41 Shell Greenland Loon Lake above Tsunami 72,8839 -22,1342 (3) KIA-27660 7720 ±45 -0,77 Shell Greenland Loon Lake above Tsunami 72,8839 -22,1342 (3) KIA-27661 7925 ± 45 0,85 Shell Greenland Loon Lake directly above 72,8839 -22,1342 (3) KIA-27662 7640 ± 45 1,68 Shell Greenland Loon Lake within Tsunami 72,8839 -22,1342 (3) KIA-27663 7515 ± 45 1,54 Shell Greenland Loon Lake directly below 72,8839 -22,1342 (3) KIA-27664 7820 ± 45 0,37 Shell Greenland Loon Lake under Tsunami 72,8839 -22,1342 (3) KIA-27665 7555 ± 45 0,56 Shell Greenland Loon Lake under Tsunami 72,8839 -22,1342 (3) KIA-24755 7625 ± 60 -5,95 Shell Greenland Loon Lake under Tsunami 72,8839 -22,1342 (3) SRR 4902 7215 ± 60 -27.4 Peat Shetland Burragarth R 60,7134 -0,949 (4) Lab Code 14C-Age 13C- PDB Material Country Site Position Latitude Long. Reference Beta169274 6840 ± 40 -25.0 Peat Shetland Norwick R 60,807 -0,8196 (4) SRR 1793 5130 ± 50 n.d Wood Shetland Garth's Voe above Tsunami 60,4371 -1,2746 (4) SRR 1794 7870 ± 50 n.d Wood Shetland Garth's Voe below Tsunami 60,4371 -1,2746 (4) SRR 3839 5315 ± 45 -28.8 Peat Shetland Garth's Voe R 60,4371 -1,2746 (4) SRR 3838 5765 ± 45 -27.8 Peat Shetland Garth's Voe T 60,4371 -1,2746 (4) SRR 3841 3815 ± 45 -28.5 Peat Shetland Scatsta Voe R 60,4367 -1,275 (4) SRR 3840 5700 ± 45 -28.5 Peat Shetland Scatsta Voe T 60,4367 -1,275 (4) n.d 7025 ± 60 n.d. Wood Shetland Sullom Voe R 60,5132 -1,3641 (4) n.d. 7120 ± 60 n.d. Seeds Shetland Sullom Voe T 60,5132 -1,3641 (4) n.d. 7320 ± 70 n.d, Twig Shetland Garth Loch within Tsunami 60,2647 -1,1536 (4) n.d. 7220 ± 70 n.d. Seeds,LeavesShetland Garth Loch directly above 60,2647 -1,1536 (4) Beta105030 7290 ± 50 -31.4 Peat Scotland Strath Halladale R 58,5375 -3,9062 (4) Beta105031 7590 ± 50 -30.5 Peat Scotland Strath Halladale T 58,5375 -3,9062 (4) Beta 89710 7070 ± 80 -27.9 Peat Scotland Wick River R 58,4533 -3,1283 (4) Beta 89709 7210 ± 80 -27.6 Peat Scotland Wick River T 58,4533 -3,1283 (4) Beta89706 7170 ± 80 -28.4 Peat Scotland Wick River R 58,4533 -3,1283 (4) Beta89707 7140 ± 90 -29.4 Peat Scotland Wick River T 58,4533 -3,1283 (4) Beta89712 7810 ± 70 -28.4 Peat Scotland Wick River T 58,4533 -3,1283 (4) SRR 3791 6580 ± 55 -29.0 Peat Scotland Smithy House R 57,9654 -4,0095 (4) SRR 3792 6980 ± 65 -29.0 Peat Scotland Smithy House R 57,9654 -4,0095 (4) SRR 3694 6930 ± 55 -27.6 Peat Scotland Creich R 57,8682 -4,2781 (4) SRR 3693 6950 ± 55 -28.9 Peat Scotland Creich T 57,8682 -4,2781 (4) SRR 3787 5190 ± 65 -27.5 Peat Scotland Dounie R 57,8456 -4,1971 (4) SRR 3790 7120 ± 45 -27.7 Peat Scotland Dounie T 57,8456 -4,1971 (4) BIRM 1126 7270 ± 90 -21.6 Peat Scotland Moniack R 57,463 -4,4312 (4) BIRM 1127 7430 ±170 -21.1 Peat Scotland Moniack T 57,463 -4,4312 (4) GU 1377 7080 ± 85 -25.5 Charcoal Scotland Castle St.Inverness T 57,6754 -4,5994 (4) SRR 5478 6905 ± 55 -27.3 Peat Scotland Water of Philorth R 57,6672 -1,976 (4) SRR 5479 7395 ± 45 -29.2 Peat Scotland Water of Philorth T 57,6672 -1,976 (4) SRR 5473 6995 ± 45 -28.1 Peat Scotland Water of Philorth R 57,6672 -1,976 (4) SRR 5474 7215 ± 45 -28.9 Peat Scotland Water of Philorth T 57,6672 -1,976 (4) SRR 1565 6850 ±140 -26.0 Peat Scotland Waterside RŽT 57,3284 -1,9904 (4) SRR 4717 7135 ± 45 -28.1 Peat Scotland Tarty Burn R 57,3342 -2,0292 (4) SRR 4718 7400 ± 45 -28.4 Peat Scotland Tarty Burn T 57,3342 -2,0292 (4) SRR 2119 6850 ± 75 -28.8 Peat Scotland Puggieston R 56,7315 -2,493 (4) SRR 2120 7120 ± 75 -27.4 Peat Scotland Puggieston T 56,7315 -2,493 (4) BIRM 867 6880 ± 110 -26.8 Peat Scotland Fullerton R 56,694 -2,5319 (4) BIRM 823 7140 ± 120 -26.8 Peat Scotland Fullerton T 56,694 -2,5319 (4) Beta92235 7070 ±130 -28.9 Peat Scotland Maryton R 56,6993 -2,5166 (4) Beta92236 7420 ± 120 -28.8 Peat Scotland Maryton T 56,6993 -2,5166 (4) n.d. 7605 ± 130 n.d. Peat Scotland Silver Moss T 56,4905 -2,8852 (4) SRR 1333 7050 ±100 -28.1 Peat Scotland Silver Moss R 56,4905 -2,8852 (4) SRR 1334 7555 ± 110 -23.6 Peat Scotland Silver Moss T 56,4905 -2,8852 (4) SRR1603 6870 ± 50 -26.6 Peat ScotlandOver Easter Offerance T 56,1375 -4,2909 (4) SRR 1431 7490 ± 70 -28.1 Gyttja Scotland Lochhouses R 56,0305 -2,6167 (4) SRR 1430 7450 ± 60 -29.1 Gyttja Scotland Lochhouses T 56,0305 -2,6167 (4) SRR 3912 7315 ± 70 -30.0 Gyttja Scotland Lochhouses R 56,0305 -2,6167 (4) SRR 3913 7590 ± 60 -30.0 Gyttja Scotland Lochhouses T 56,0305 -2,6167 (4) AA 25596 6700 ± 60 -28.2 Peat Scotland Broomhouse Farm R 55,6992 -1,9395 (4) AA 25601 7165 ± 60 -29.0 Peat Scotland Broomhouse Farm T 55,6992 -1,9395 (4) 24 back to contents