© Author(s) 2018. CC Atribution 4.0 LicenseGEOLOGIJA 61/1, 49-71, Ljubljana 2018 https://doi.org/10.5474/geologija.2018.004 Lower Jurassic succession at the site of potential Roman quarry Staje near Ig (central Slovenia) Spodnjejurske plasti na območju morebitnega rimskega kamnoloma Staje pri Igu Boštjan ROŽIČ1, Luka GALE1,2, Rok BRAJKOVIĆ2, Tomislav POPIT1 & Petra ŽVAB ROŽIČ1 1University of Ljubljana, Faculty of Natural Sciences and Engineering, Department for Geology, Privoz 11, SI-1000 Ljubljana, Slovenia; 2Geological Survey of Slovenia, Dimičeva ul. 14, SI-1000 Ljubljana, Slovenia e-mail: bostjan.rozic@ntf.uni-lj.si, luka.gale@ntf-lj.si, rok.brajkovic@geo-zs.si, tomi.popit@ntf.uni-lj.si, petra.zvab@ntf.uni-lj.si. Prejeto / Received 22. 3. 2018; Sprejeto / Accepted 19. 6. 2018; Objavljeno na spletu / Published online 20. 7. 2018 Keywords: Lower Jurassic, Sinemurian, Dinaric Carbonate Platform, neptunian dyke, microfacies, Roman quarry Ključne besede: spodnja jura, sinemurij, Dinarska karbonatna platfroma, neptunski dajk, mikrofacies, rimski kamnolom Abstract Several locations along the southern margin of the Ljubljana Moor have been proposed as sites of antique Roman quarries, but except for the site in the village of Podpeč, no detailed sedimentological investigations, which would reveal the spectrum of available natural stone, have yet been made. This paper presents a section logged at the potential Roman quarry from the small valley southeast of the village of Staje near Ig. The section is composed of Sinemurian strata dominated by micritic limestone with dissolution voids and bioclastic limestone, mostly wackestone with mollusks. Other facies are rare aggregate-grain/ooidal calcarenite, lumachella, limestone microbreccia, and stromatolitic limestone. Altogether, 21 microfacies types are described. Facies association points to sedimentation in restricted and open marine lagoon repeatedly subjected to emersion, rarely high-energy conditions or events. Previously unrecorded on the Dinaric Carbonate Platform in this area are neptunian dykes that occur as fractures partially filled by calcite cement and partially by intra/bioclastic packstone containing upper Jurassic microfossils. These could potentially serve as a diagnostic feature for recognizing artefacts made from stone quarried at Staje. Izvleček Do sedaj je bilo vzdolž južnih obronkov Ljubljanskega barja predlaganih nekaj lokacij kot domnevno rimskih kamnolomov, vendar nobena izmed teh, razen Podpeči, ni bila detajlno sedimentološko raziskana. Spekter dostopnega naravnega kamna tako ostaja dokaj slabo poznan. V tem prispevku predstavljamo profil, ki je bil posnet na območju morebitnega rimskega kamnoloma v majhni dolini jugovzhodno od vasi Staje pri Igu. Profil sestavljajo spodnjejurske, natančneje sinemurijske plasti, v katerih prevladujejo mikritni apnenci z dvema generacijama korozijskih votlinic in bioklastični apnenci, večinoma tipa wackestone z mehkužci. Ostali faciesi so redki kalkareniti z agregatnimi zrni ali ooidi, lumakela in apnenčeva mikrobreča. V raziskanem zaporedju izdvajamo 21 mikrofaciesnih tipov. Faciesna združba kaže na sedimentacijo v zaprti in občasno odprtomorski laguni, ki je bila podvržena ponavljajočim se okopnitvam, redko pa tudi višjeenergijskim razmeram ali dogodkom. Raziskane plasti ustrezajo predhodno opisanemu spodnjejurskemu zaporedju širšega območja, ki kaže postopno odpiranje iz hettangijskega medplimskega sedimentacijskega okolja v pliensbachijsko razgibano laguno. Pomemben element profila Staje so tudi neptunski dajki, ki do sedaj niso bili poznani v kamninah Dinarske karbonatne platfrome tega območja. Pojavljajo se v obliki razpok, zapolnjenih deloma s kalcitnim cementom, deloma pa s sedimentom tipa intra/bioklastični packstone, ki vsebuje zgornjejurske fosile. Le ti bi kot specifična značilnost lahko služili pri razločevanju artefaktov narejenih iz naravnega kamna pridobljenega iz območja Staj. 50 Boštjan ROŽIČ, Luka GALE, Rok BRAJKOVIĆ, Tomislav POPIT & Petra ŽVAB ROŽIČ Introduction The large alluvial fan of the Iška River at the southern outskirts of the Ljubljana Moor has been populated since pre-history (Velušček, 2004, 2010). During the first centuries AD the settlements from the Iška alluvial fan supplied the evolving colony of Emona (Šašel Kos, 2009) and left rich archaeological evidence, including numerous se- pulchral monuments (roman tombstones) (Šašel, 1959; Ragolič, 2016; Veranič & Repanšek, 2016). At Marof near Ig, the archaeological site was discovered in the year 2014, which included a pit with stone monuments from the Roman period (Ragolič, 2016). The majority of these monuments are made of limestone, for which a local origin has been presumed (Žvab Rožič et al., 2016). Proof of Roman use of natural stone comes to us from de- pictions on stone monuments (stelae), which indi- cate that the Roman-era inhabitants of the Ig area were involved in quarrying, forestry, and metal- working (Šašel, 1959). Ramovš (in Šašel Kos, 1997) mentions four locations of possible quarries from the Roman period along the southern outskirts of the Ljubljana Moor: Sveta Ana, Podpeč, Staje and Skopačnik (listed moving from west to east). The only proven roman quarry is that known in the village of Podpeč (Ramovš, 2000; Djurić & Rižnar, 2017), because during the archaeological excava- tions by B. Djurić in 2017 remains of Roman-age architecture were found inside the quarry (Djurić, pers.comm.). In this locality grey, dark grey and almost black Pliensbachian limestone with abun- dant ooids and bioclasts is exposed (Buser & De- beljek, 1995; Gale, 2014, 2015; Kramar et al., 2015). However, as pointed out already by Žvab Rožič and co-workers (2016), facies of analysed artefacts from Marof differ from the Podpeč limestone. Nor does it correspond to the Lower Triassic lime- stone of the potential ancient quarry near the Sko- pačnik farm that was described by Mušič (1990). Until now, there was no detailed lithological data from the other two sites (Sveta Ana and Staje) of potential ancient quarries. This paper is the result of geological research of the Lower Jurassic succession from the village of Staje, i.e. the proposed site of the Roman quarry that was located closest to the above-mentioned Marof archeological site (cf. Ramovš - in Šašel Kos, 1997). We provide a detailed sedimentologic and biostratigraphic description of the limestone succession from the Staje section from the site where the ancient quarry was most likely situat- ed. This data will serve as the basis for compar- ison with stone artefacts recovered at Marof and other archaeological sites located close by. Geological setting The studied succession is located on the north- ern edge of the Krim-Mokrec Mountain Range and structurally belongs to the Hrušica Nappe of the External Dinarides (fig. 1) (Placer, 1999; 2008). The main structures of the area are NW- SE oriented strike-slip faults (Buser et al., 1967; Buser, 1968). During the Mesozoic this area be- longed to the northern part of the Dinaric (Adri- atic) Carbonate Platform; thus, Upper Triassic to Middle Jurassic carbonates prevail (fig. 1). The Upper Triassic begins with a thin succession of coarse-crystalline (“cordevolian”) dolomite, part of which could be Middle Triassic in age (Cel- arc, 2004, 2008). It is followed by a thick peritid- al Norian-Rhaetian Main Dolomite Formation. The Lower Jurassic part is dominated by micritic and bioclastic limestones that alternate with oo- idal limestone. In the Pliensbachian part of this succession, lithiotid bivalves occur (Buser & De- beljak, 1995; Debeljak & Buser, 1997; Gale 2014, 2015), whereas the Toarcian part is marked by thin-bedded micritic limestone (Dozet, 2009). The Middle Jurassic is composed almost exclusively of ooidal limestone (Miler & Pavšič, 2008). Jurassic limestones are often replaced by dolomite (Bus- er et al., 1967, Buser, 1968; Miler & Pavšič, 2008). In addition to the described carbonates, Paleo- zoic clastics and Early Triassic carbonate-clas- tic succession outcrops to the east of the studied area (Buser, 1968; Mušič, 1990). To the north the described units are covered by Quaternary allu- vial fan coarse-clastic sediments, which further north interfinger with lacustrine and marsh de- posits (Buser et al., 1967, Buser, 1968). Methods The micro-location of the potential Roman quarry was determined using a combination of fieldwork observations and analysis of the digital elevation model based on detailed 1 × 1m Lidar data. In the selected area a detailed sedimento- logical section (almost 40 m at 1:50 scale) was logged and densely sampled. Logging included measurements of structural elements (orientation and dip of fractures, veins, neptunian dykes). A total of 58 samples were selected; from these, 62 thin-sections were made for microfacies and biostratigraphic analysis. Names of the sample correspond to the stratimetric position of the logged section (sample 7.1 was taken at the 7.1th m of the section). The size of the ooids and aggre- gate grains, and the number of ooid laminae were measured in at least 30 grains in each thin-sec- tion dominated by these grains. 51Lower Jurassic succession at the site of potential Roman quarry Staje near Ig (central Slovenia) Micro-location of the potential Roman quarry The hilly area south of the village of Staje is composed of Lower Jurassic limestone and sub- ordinate dolomite (fig. 2). This karstic terrain is dominated by dolines and passes into the rela- tively flat Iška River alluvial fan. On the transi- tional belt (including the area of Staje and other villages) between the hills and flatland, the grav- el-sand sediments also cover geomorphological depressions within outcropping base-rock, such as valleys and larger dolines. Anthropogenic al- Fig. 1.a) Location of the studied section (boxed area is enlarged to the right). b) Macrotectonic subdivision of Slovenia (af- ter Placer, 1999) with marked position of geological map below. c) Simplified geological map of the southern outskirts of the Ljubljana Moor (compiled from Buser et al., 1967 and Buser, 1968). The star marks the location of the studied section. 52 Boštjan ROŽIČ, Luka GALE, Rok BRAJKOVIĆ, Tomislav POPIT & Petra ŽVAB ROŽIČ Fig. 2. Geomorphological map of the area of Staje and Marof with marked positions of the logged section (potential roman quarry), “Stari dedec” Roman monument and Marof arheological site. 53Lower Jurassic succession at the site of potential Roman quarry Staje near Ig (central Slovenia) terations of the bedrock can be recognized in the area of the villages of Staje and Ig, on the Pungrt hill, where the Ig Castle is situated, and at the SW flank of the flat valley that runs from the vil- lage of Staje in the SE direction (figs. 3a, b). The latter shows a straight escarpment, which is in stark contrast to the NE flank of the same val- ley, which is defined by soft karstic lines (some are probably dolines filled by gravel and sand de- posits). The escarpment on the SW flank of valley is a subvertical rock-wall stretching up to 6 m in height. Fractures run parallel to the massive wall surface, whereas rock debris is accumulated at the base of the wall. As already mentioned by Vuga (2000a, b), this might be the site of ancient extraction of stone blocks that was positioned along the local Ro- man road that ran SE-ward. The same author proposes that the extraction site was owned by a family of stonecutters that carved the Roman stele (known as “Stari dedec”) into the massive limestone block that stands at the entrance to the same valley; figs. 2, 3a). If this hypothesis is true, the extraction of blocks was likely facilitated by the above-mentioned sub-vertical fractures. In- terestingly, it looks is if the road-cut of the po- tential Roman road (located in the lower right corner of the fig. 2) follows the same fracture zone. On the walls of the road-cut we noticed in- dices of dextral strike slip movement. Although the described features point to rock-cutting activities during the Roman peri- od in the Staje area, more precise archaeological research is needed, because rock-extraction and road-construction could easily be of later origin. For example, lime production is reported from the Staje area (Dozet, 2014). Description of the Staje section With the Staje section 39.4 stratigraphic me- ters of Lower Jurassic carbonates were logged. The tentative productive part (main escarpment) of the presumed Roman quarry starts at 4.3 m and ends at 11 m of the section (Fig. 3b). It is pos- sible that there is a minor fault at the base of the escarpment (fig. 4). Fig. 3. a) ”Stari dedec” Roman stela carved into the massive limestone outcrop at the entrance to the valley with potential roman quarry. b) Limestone escarpment at SW bank of the valley that could be of anthropogenic origin. c) Reddish sediment infill of large dissolution void (5. m of the section). d) Bioclastic rudstone deposited above erosional surface (just above 20. m of the section). 54 Boštjan ROŽIČ, Luka GALE, Rok BRAJKOVIĆ, Tomislav POPIT & Petra ŽVAB ROŽIČ Fig. 4. Staje section with position of microfacies types, time-diagnostic foraminifers and nature of deformation at particular interval of the section (presented as spherical projection; equal-area projection, lower hemisphere and compiled in circular histogram of fracture strike directions). 55Lower Jurassic succession at the site of potential Roman quarry Staje near Ig (central Slovenia) The predominant facies are grey to dark grey micritic and bioclastic limestones, representing most of the thick beds, including the massive wall of the potential Roman quarry. Micritic limestone (F1) is characterized by small fenestrae. Also present are large dissolution cavities filled with cement and/or reddish, rarely greenish sediment (fig. 3c). Bioclastic limestone (F2) locally contains large (cm-sized) bivalves and subordinate gas- tropods. A single solitary coral was also spotted. The matrix between large fossils is micritic lime- stone, locally calcarenite. Besides fragments of mollusks, some beds are rich in other bioclasts: for example, the bed at the 20th m of the section also contains abundant dasycladacean algae. The third facies is grey, thin- to medium-bedded cal- carenite (F3) that also occurs in thin lenses with- in the micritic and bioclastic facies. It is present at the base of the section (from the 2nd to 4th m), becomes more common in the middle part (15th to 20th m) and also occurs in the upper part of the section (28th to 29th and at 35th m). The next facies type could be described as lumachella (F4) as bioclasts (gastropods, bivalves and dasycladacean algae) are accumulated in a bed at the 20.5th m of the section that shows scour-like depressions at the base (fig. 3d). A thin lens (channel) of limestone microbreccia (F5) was spotted at the 6.3th m of the section within mic- ritic limestone. At the base of the section a thin stromatolite bed (F6) is present (no thin section was made from this facies). Neptunian dykes are present in the form of fractures filled by calcite and sediment. Microfacies of the Staje section The greatest diversity of microfacies was found within micritic limestone, as it is also the most common facies. Mudstone (F1A) appears in a sin- gle thin-section. The most common is fenestral mudstone/wackestone (F1B). Apart from spo- radic ostracods, it is very poor in fossils. Dissolu- tion voids are usually of two generations. Earlier, smaller (mm-sized) and usually geopetally filled birds-eyes fenestrae. These are followed by larg- er dissolution cavities, filled with sediment and/ or cement (Figs. 5a-c). The following microfacies types are generally similar to the previous one (F1B), but have specific characteristics. In fenes- tral laminated mudstone (F1C) dense, curly lam- inae are visible. Fenestral mudstone with clus- ters of small circular grains (F1D) shows intense dissolution and microsparite fields that contain small circular microsparite grains (Figs. 5d. e). Disintegrated laminated mudstone (F1E) is com- posed of intraclasts that originated from disinte- gration of laminated mudstone (fig. 5f). The following five microfacies are macroscop- ically defined as micritic limestone, but show transitional characteristics. Fenestral mudstone with large gastropods (F1F) is mudstone that contains rare larger gastropods and already rep- resents transition to bioclastic limestone (fig. 6a). Fenestral pelletal packstone (F1G) and Parallel and low-angle cross-laminated pelletal pack/ grainstone (F1H) are packstones composed of small pellets. The first is non-laminated with two generations of dissolution voids (equal to F1B) (fig. 6b). The second is laminated packstone with fenestrae present only occasionally in the form of small, lamination-parallel birds-eyes (Figs. 6c, d). Bioturbated intraclastic/pelletal wackestone (F1I) is wackestone that contains sand-size grains of the same type as encountered in calcarenite (fig. 6e). Fenestral wackestone with coated grains (oncoids) (F1J) also shows transitional charac- teristics to the bioclastic limestone. It generally corresponds to previously described microfacies, but additionally contains large, coated bioclasts (fig. 6f), sometimes in the form of well-developed oncoids. Bioclastic limestone occurs in form of five mi- crofacies. The first is Bioclastic wackestone with or without large mollusks (F2A). Large fossils, when present, are cm-sized (fig. 7a). In some thin sections, the density of large fossils is high and the microfacies is better described as molluskan floatstone (F2B) (figs. 7b, c). Two other microfa- cies types are found within this group. They both have large bioclasts (mostly mollusks), but the matrix between them is grain-supported (figs. 7d, e), in the form of either (partly washed) pack- stone (intraclastic, ooidal, pelletal partly-washed packstone with large bivalves and intraclasts – F2C) or grainstone (intraclastic, ooidal, pelletal grainstone with large mollusks and intraclasts – F2D). The last microfacies, dasycladacean & molluskan pack/floatstone (F2E) is transitional to ooidal calcarenite, because it contains ooidal, partly-washed packstone as a matrix and large mollusks and dasycladacean algae (fig. 7f). Calcarenite can be divided into two subgroups according to its composition. In the first, aggre- gate grains prevail among the constituents (figs. 8a-c). These microfacies types are either poor- ly sorted, partly-washed packstone that locally contain large bioclasts (partly washed packstone with aggregate grains - F3B) or well sorted grain- stone (grainstone with aggregate grains - F3A). The second subgroup is dominated by ooids (fig. 56 Boštjan ROŽIČ, Luka GALE, Rok BRAJKOVIĆ, Tomislav POPIT & Petra ŽVAB ROŽIČ Fig. 5. Microfacies of micritic limestone. 57Lower Jurassic succession at the site of potential Roman quarry Staje near Ig (central Slovenia) 8d), mainly in the form of ooidal grainstone and subordinate packstone (F3C). One thin section is ooidal packstone with fenestrae (F3D) that shows an intense dissolution of matrix between ooids (fig. 8e). The last two (micro) facies types appear as coarse-grained accumulations at only two levels (figs. 8f, g). Lumachella is described as dasycla- dacean & molluskan rudstone (F4A) because it consists almost exclusively of large (cm-sized) gastropods, bivalves and dasycladacean algae (fig. 8f). Limestone microbreccia, named litho- clastic floatstone (F4A), is composed of diverse, angular lithoclasts and comes from a thin lens (?channel) within micritic limestone (fig. 8g). For a detailed description of microfacies see Table 1. Biostratigraphy of the Staje section The foraminiferal assemblage within the in- vestigated succession (fig. 9) is characterized by Pseudopfenderina butterlini (Brun), Mesoen- dothyra sp., Everticyclammina praevirguliana Fugagnoli and ?Lituolipora termieri (Hotting- er). The uncertainties in the structure of the wall and the type of aperture prevent us from reliably determining the latter species. The stratigraph- ic range of P. butterlini is from late Sinemurian to Pliensbachian (BouDagher-Fadel & Bosence, 2007; Velić, 2007). Due to the absence of lithiot- id bivalves and Orbitopsella in the section, we suggest Sinemurian age for the studied succes- sion. Mesoendothyra sp. likewise makes its first appearance in Sinemurian (Velić, 2007), where- as E. praevirguliana possibly appears already in the latest Hettangian (Velić, 2007) or during the Sinemurian (BouDagher-Fadel & Bosence, 2007). Other associated foraminiferal species, all with long stratigraphic ranges or not considered to be reliable biostratigraphic fossils, are Duotaxis metula Kristan, Siphovalvulina ex gr. gibralta- rensis BouDagher-Fadel et al., Siphovalvulina colomi BouDagher-Fadel et al. vel Siphovalvuli- na variabilis Septfontaine, Earlandia dunningto- ni (Elliot), Involutina farinacciae Brönnimann & Koehn-Zaninetti, ?Trocholina umbo (Frentzen), Ammobaculites sp., Reophax sp., Textulariidae, undetermined miliolid and lagenid foraminifers. Neptunian dykes and other structural elements Neptunian dykes occur in the form of thick extensional fractures with a NW-SE strike and dipping generally perpendicular to the bedding of the host-rock, but other directions are also present. Infilling of fractures vary from: A) com- pletely sediment-filled fractures, B) sediment fill that follows the first generation of cements (usually with crystal growth perpendicular to fracture margin), C) geopetally filled fractures (often after the first generation of cement), and D) fractures filled with calcite and fragments of host-rock. The thick, calcite-filled veins probably belong to the same extensional event. The combi- nations and vertical alternation of the described subtypes (including thick veins) can be visible in the same thin-section (fig. 10a). Sediment of neptunian dykes varies from calcisiltite to medium-grained calcarenite; oc- casionally it even alternates irregularly or in laminae within the same dyke (figs. 10b-d). Most information comes from the dyke at 6.4 m of the section that is filled with coarse calcarenite (Fig. 10d). It is well-sorted medium-grained packstone composed predominantly of bioclasts, intraclasts, pellets and subordinate small, superficial ooids. Among the bioclasts echinoderm fragments pre- vail. Others are foraminifers, Tubiphytes-like grains, fragmented bivalves and fragments of dasycladacean algae. Part of the sparitic grains could also originate from the disintegration of early cements. Fig. 5. Microfacies of micritic limestone a) Fenestral wackestone with large void filled by several generations of cement and sediment. Arrows indicate margins betwe- en large cavity and host rock. Circle (right side of micrograph) envelops birds-eyes void filled geopetally with ostracod-bea- ring calcisiltite and drusy-mosaic calcite (mf-type F1B, sample 14.1). b) Field of small fenestrae (some geopetally infilled) that are divided by a network of thin micritic walls (mf-type F1B, sample 0.5). c) Geopetal infill of stromatactis with two generations of cement and intermediate sediment infill with calcisiltite. In boxed area an ostracod from calcisiltite is enlarged (mf-type F1B, sample 21.6). d) Fenestral mudstone with clusters of small circular grains (enlarged in fig. 1e). Early fenestrae tend to form in micrite betwe- en these clusters. Later generations of dissolution voids (filled with calcisiltite) are larger and do not follow the preceding texture (mf-type F1D, sample 25.5). e) Enlarged cluster with small oval microsparitic grains that may be produced through early diagenetic bacterial-induced cementation (mf-type F1D, sample 25.5). f) Disintegrated laminated mudstone. Downwards, intraclasts tend to decrease in size and oval, mm-sized grains (?pisoids) start to occur between them (mf-type F1E, sample 26.55). 58 Boštjan ROŽIČ, Luka GALE, Rok BRAJKOVIĆ, Tomislav POPIT & Petra ŽVAB ROŽIČ Fig. 6. Transitional microfacies from micritic to other microfacies. a) Mudstone with gastropod shell involved in formation of fenestrae (mf-type F1F, sample 1.9). b) Pelletal packstone with fenestrae filled by dense micrite, dissolved again and geopetally refilled. The enlarged box shows that the host-rock is composed of densely packed tiny pellets (mf-type F1G, sample 1.0). c) Pelletal packstone with fenestrae occurring mostly in distinct laminae (enlarged in Fig. 6d). Fracture is filled with latest Jurassic sediment (neptunian dyke); arrows indicate minor displacement (mf-type F1H, sample 32.2). d) Birds-eyes laminae within pelletal packstone (enlargement of boxed area from Fig. 6c) (mf-type F1H, sample 32.2). e) Intraclasts and pellets concentrated in burrow inside wackestone that contains equal grains (mf-type F1I, sample 16.3). f) Coated bioclasts within fenestral wackestone; arrow indicates Thaumatoporella sp. (mf-type F1J, sample 3.1). 59Lower Jurassic succession at the site of potential Roman quarry Staje near Ig (central Slovenia) Fig. 7. Microfacies of bioclastic limestone. a) Bioclastic wackestone with large recrystallized bivalve. Small circular grain (enlarged in boxed area) could be gyrogonites (mf-type F2A, sample 27.4). b) Gastropods and bivalves as main cm-sized grains in floatstone (boxed area enlarged in Fig. 7c) (mf-type F2B, sample 35.1). c) Complex pattern of poly-generation dissolution and subsequent infilling of bioclastic floatstone as a result of repeatable su- baerial exposure (enlargement of boxed area from Fig. 7b) (mf-type F2B, sample 35.1). d) Gastropod and bivalve within generally finer partly-washed packstone (mf-type F2C, sample 18.2). e) Large fossils (bivalves, brachiopod, dasycladacean algae) and intraclasts inside intra/bioclastic and ooidal grainstone. Arrow indicates microbial crusts on completely dissolved and geopetally infilled grain, probably bivalve in origin (mf-type F2D, sample 26.35). f) Dasycladacean algae and large gastropod inside ooidal and intraclastic partly-washed packstone (mf-type F2E, sample 19.8). 60 Boštjan ROŽIČ, Luka GALE, Rok BRAJKOVIĆ, Tomislav POPIT & Petra ŽVAB ROŽIČ Fig. 8. Microfacies of calcarenite, lumachella and litoclastic microbreccia. a) Hardground with irregular surface ending with encrusting organisms (boxed are enlarged in Fig. 8b) and overlain by partly-washed packstone with aggregate grains and large bioclasts, mainly bivalves and dasycladacean algae (mf-type F3A, sample 28.95). b) Encrusting organism at the surface of the hardground and structure below bivalve shells (enlarged from boxed area in fig. 8a) (mf-type F3A, sample 28.95). c) Grainstone composed of aggregate grains and ooids (mf-type F3B, sample 15.4). d) Laminae of pelletal packstone within ooidal grainstone (mf-type F3C, sample 2.3). e) Ooidal packstone with dissolution voids often selective to matrix. Cements are fibrous-rim, drusy-mosaic and possibly stalactitic (white arrows) and micritic meniscus (black arrows) cements. The latter could also represent the remains of an undissolved matrix that remained close to contacts of dissolution-resistant ooids (mf-type F3D, sample 34.8). e) Recrystallized dasycladacean algae and mollusks inside rudstone (mf-type F4A, sample 20.5). f) Diverse lithoclasts that form a floatstone matrix. Note that the margins of lithoclasts are highly irregular, which points to very short transport. Some also show burrows at margins (mf-type F5A, sample 6.3). 61Lower Jurassic succession at the site of potential Roman quarry Staje near Ig (central Slovenia) Fig. 9. Foraminifers from the logged Staje succession. a-b: Everticyclammina praevirguliana Fugagnoli. Thin sections 4.1 and 18.2, respectively. c: Pseudopfenderina butterlini (Brun). Thin section 3.3. d-g: Mesoendothyra sp. 4: Thin section 18.2. 5: Thin section 5.3. 6: Thin section 4.5. 7: Thin section 34.55. h-m: ?Lituolipora termieri (Hottinger). 8-10: Thin section 37.55. 11: Thin section 28.25. 12: Thin section 18.2. 13: Thin section 5.3. n: Undetermined Lituolida. Note canaliculate wall structure. Thin section 7.1. o: Involutina farinacciae Brönnimann & Koehn-Zaninetti. Thin section 15.9. p: ?Quinqueloculina sp. Thin section 5.4. Infill of neptunian dyke. r: Siphovalvulina ex gr. gibraltarensis BouDagher-Fadel, Rose, Bosence & Lord. Thin section 25.9. 62 Boštjan ROŽIČ, Luka GALE, Rok BRAJKOVIĆ, Tomislav POPIT & Petra ŽVAB ROŽIČ Fa cie s M icr of ac ie s De sc rip tio n F1 – Micritic limestone F1 A – M ud st on e Sa m pl e 22 .8 Co m po sit io n: M icr ite st ro ng ly p re do m in at es . V er y ra re a re sm al l, ov al sp ar iti c g ra in s ( bi oc la st s) . Di ag en es is: C on ta in s d en se n et w or k of th in ca lci te v ei ns . SM F / e nv iro nm en t: SM F2 3 / S up ra -in te rt id al , r es tr ict ed la go on . F1 B - F en es tr al m ud /w ac ke st on e Sa m pl es 0 .5 , 1 .0 , 1. 5, 4 .8 , 5 .4 , 7 .6 , 10 .5 , 1 3. 9, 1 4. 1, 15 .8 , 2 1. 6, 2 5. 7, 26 .8 5, 3 6. 3, Co m po sit io n: M icr ite co nt ai ns ra re p el le ts a nd sm al l b io cla st s ( fig . 5 a) : p re do m in an tly o st ra co ds , v er y ra re sm al l b iv al ve s a nd g as tr op od s. F en es tr ae a re sm al l ( m m -s ize d) a nd ir re gu la r, ra re ly of st ro m at ac tis ty pe o r o va l s ha pe d (fi g. 5 c) . I nf ill in gs sh ow g eo pe ta l s tr uc tu re s: m icr ite /c al cis ilt ite (l am in at ed , c an co nt ai n os tr ac od s) is a t t he b ot to m , w hi le th e to p is fil le d w ith m os ai c ca lci te . S om e fe ne st ra e (o f s tr om at ac tis ty pe ) c on ta in is op ac ho us fi br ou s r im ce m en ts th at ca n po st - o r p re -d at e ca lci sil tit e fil l. So m e sm al l-s ca le fe ne st ra e in sa m pl e 0. 5 ar e gr ou pe d in la rg er fi el ds a nd d iv id ed b y ve ry th in , u nd ul at ed m icr ite fi lm s, th us fo rm in g an ir re gu la r, ge op et al ly fi lle d m es h (fi g. 5 b) . L ar ge (c m - siz ed ) d iss ol ut io n vo id s l oc al ly p os t-d at e fe ne st ra e. T he y ar e irr eg ul ar , m os tly fi lle d by is op ac ho us fi br ou s o r d ru sy -m os ai c c em en ts . S om e ar e fil le d w ith m ud st on e w ith o st ra co ds . La rg e vo id in sa m pl e 14 .1 sh ow s c om pl ex m ul ti- ge ne ra tio n fil lin g w ith p el oi da l/i nt ra cla st ic/ oo id al p ac ks to ne th at e ith er g ra de s o r s ha rp ly p as se s t o m ud st on e. O ld er fi lli ng s e xh ib it pa rt ia l di ss ol ut io n (fi g. 5 a) . Di ag en es is: Lo ca lly , m icr ite is re cr ys ta lli ze d to m icr os pa rit e. P re se nt a re st yl ol ite s a nd d en se n et w or k of th in , o cc as io na lly th ick er ca lci te v ei ns . S om e fra ct ur es in sa m pl es 4 .8 a nd 5 .4 a re fi lle d by y ou ng er se di m en t ( ne pt un ia n dy ke s) . S am pl e 4. 8 sh ow s d isp er se d do lo m ite cr ys ta ls clo se to a nd in sid e of n ep tu ni an d yk e. SM F / e nv iro nm en t: SM F2 1 / S up ra -in te rt id al , r es tr ict ed la go on ; r ep ea ta bl e pe rio ds o f p os t-d ep os iti on al su ba er ia l e xp os ur e. F1 C - F en es tr al la m in at ed m ud st on e Sa m pl es 6 .4 , 2 4. 7 Co m po sit io n: Ir re gu la r l am in ae o f d en se , a ph an iti c m icr ite w ith ra re o st ra co ds a lte rn at e w ith m icr os pa rit e w ith b ird s- ey es fe ne st ra e of v ar io us si ze s. Ap ha ni tic m icr ite m ay la te ra lly p as s i nt o pe lle ta l m icr ite . F en es tr ae a re fi lle d by m os ai c c al cit e ce m en t. Di ag en es is: T hi n ca lci te v ei ns ru n in v ar io us d ire ct io ns . S am pl e 24 .7 h as th ick er ca lci te v ei ns o rie nt ed su b pa ra lle l t o la m in ae . L am in at ed m ud st on e in sa m pl e 6. 4 sh ow s a lm os t c om pl et e do lo m iti za tio n: d ol om ite is sl ig ht ly re dd ish ; d en se m icr iti c l am in ae re m ai n pa rt ly p re se rv ed in ir re gu la r f ie ld s. SM F / e nv iro nm en t: ?S M F 19 / Su pr a- in te rt id al , r es tr ict ed la go on . F1 D - F en es tr al m ud st on e w ith clu st er s o f s m al l cir cu la r g ra in s Sa m pl e 25 .5 Co m po sit io n: M icr ite co nt ai ns h ig hl y irr eg ul ar – ca ul ifl ow er -li ke b od ie s o f m icr os pa rit e w ith a bu nd an t s m al l c irc ul ar g ra in s ( so m et im es sp ar ite , s om et im es w ith sp ar iti c r im a nd m icr iti c c or e) (fi gs . 5 d, e ). Th es e bo di es co ul d or ig in at e du rin g ea rly d ia ge ne tic (? ba ct er ia l-i nd uc ed ) c em en ta tio n. M icr ite sh ow s c om pa ct io n al on g th e m ar gi ns w ith m icr os pa rit e. It ca n co nt ai n ve ry ra re os tr ac od s. Fe ne st ra e ca n be b ird s- ey es o r v er y irr eg ul ar a nd te nd to a pp ea r s el ec tiv el y in m icr ite b et w ee n th e m icr os pa rit e bo di es . L ar ge r h av e co m pl et e or g eo pe ta l f ill in g w ith ca lci sil tit e. U pp er p ar ts of p ar tly fi lle d fe ne st ra e of te n sh ow tw o ge ne ra tio ns o f c em en ta tio n. F irs t-f or m ed is th e iso pa ch ou s r im ce m en t ( ca n be fo llo w ed b y se co nd g en er at io n of ca lci sil tit e fil l). T he se co nd ce m en t is dr us y- m os ai c c al cit e. La rg e (c m -s ize d) d iss ol ut io n vo id s ( yo un ge r t ha n fe ne st ra e) a re ir re gu la r, fil le d by m ud /w ac ke st on e w ith v er y sm al l p el le ts . I nf ill se di m en t c an co nt ai n la st g en er at io n of sm al l b ird s- ey es fi lle d w ith d ru sy -m os ai c c al cit e. Di ag en es is: P yr ite o cc ur s a lo ng th e st yl ol ite s o r i n fo rm o f r ar e fra m bo id al p yr ite w ith in th e se di m en t SM F / e nv iro nm en t: SM F2 1 / S up ra -in te rt id al , r es tr ict ed la go on ; r ep ea tin g pe rio ds o f s ub ae ria l e xp os ur e. F1 E - Di sin te gr at ed la m in at ed m ud st on e Sa m pl e 26 .5 5 Co m po sit io n: La rg e (c m -s ize d) in tr ac la st s o f d en se la m in at ed m ud st on e th at sh ow p ar tly fi tt ed fa br ics a re su nk in to u nd er ly in g m icr ite (f ig . 5 f). D ow nw ar ds , i nt ra cla st s a re p ro gr es siv el y sm al le r a nd m or e ro un de d. S m al l, ge op et al ly fi lle d bi rd s- ey es fe ne st ra e oc cu r i ns id e an d be tw ee n in tr ac la st s. Th e m icr ite in th e lo w er p ar t o f t he th in -s ec tio n co nt ai ns ra re co at ed g ra in s ( ?p iso id s) a nd a fo ra m in ife r. Fe w co at ed g ra in s o cc ur a lso in m at rix b et w ee n th e in tr ac la st s. Di ag en es is: T hi n ca lci te v ei ns ru n in v ar io us d ire ct io ns . P yr ite o cc ur s a lo ng st yl ol ite s a nd sm al l d iss ol ut io n se am s w ith in m icr ite . SM F / e nv iro nm en t: ?S M F2 4 / R es tr ict ed la go on . F1 F - F en es tr al m ud st on e w ith la rg e ga st ro po ds Sa m pl e 1. 9 Co m po sit io n: V er y ra re sm al l b io cla st s ( re co gn iza bl e ar e bi va lv e fra gm en ts ), an d up to a fe w m m la rg e ga st ro po ds , w hi ch ca n ha ve g eo pe ta l i nf ill in g (fi g. 6 a) . Tw o ki nd s o f d iss ol ut io n vo id s a re p re se nt : -s m al le r f en es tr ae : t he se u su al ly co nt ai n ge op et al in fil l w ith m icr ite /c al cis ilt ite a nd d ru sy -m os ai c c al cit e. S om e ha ve th in ca lci te ri m th at fo rm ed p rio r t o se di m en t i nf ill . D iss ol ut io n oc ca sio na lly in clu de s t he w al ls of g as tr op od sh el ls an d al so th e pr im ar y m icr ite in fil l o f s he ll- ca vi tie s. -la rg e (c m -s ize d) ir re gu la r d iss ol ut io n vo id s i nf ill ed w ith la rg e m icr ite in tr ac la st s ( or ig in at in g fro m co lla ps e of th e vo id ro of ) a nd ca lci sil tit e, o cc as io na lly w ith p el le ts . Di ag en es is: N et w or k of th in ca lci te v ei ns th at ru n in v ar io us d ire ct io ns . O th er fe at ur es a re st yl ol ite s a nd ra re fr am bo id al p yr ite . SM F / e nv iro nm en t: Be tw ee n SM F2 1 an d SM F1 2 / L ag oo n (re st ric te d) ; r ep ea tin g pe rio ds o f s ub ae ria l e xp os ur e. F1 G - F en es tr al pe lle ta l p ac ks to ne Sa m pl e 1. 0 Co m po sit io n: P el le ts a re sm al l a nd d en se ly p ac ke d. S m al l b io cla st ic fra gm en ts a re p re se nt b ut ra re . T hr ee ty pe s o f d iss ol ut io n vo id s c an b e re co gn ize d (fi g. 6 b) : -s m al l f en es tr ae fi lle d w ith d ru sy -m os ai c c al cit e, -la rg e cm -s ize d irr eg ul ar d iss ol ut io n vo id s f ill ed w ith m icr ite co nt ai ni ng ra re o st ra co ds a nd sm al l b io cla st ic fra gm en ts , -s m al l f en es tr ae o cc ur rin g so le ly in sid e or a t u pp er m ar gi ns o f m icr ite in fil ls of la rg e vo id s; th es e fe ne st ra e sh ow g eo pe ta l i nf ill w ith ca lci sil tit e an d dr us y- m os ai c c al cit e. Di ag en es is: N et w or k of th in ca lci te v ei ns th at ru n in v ar io us d ire ct io ns . S ty lo lit es o cc ur . SM F / e nv iro nm en t: Be tw ee n SM F1 6- NO NL AM IN AT ED a nd S M F2 1 / R es tr ict ed la go on ; r ep ea tin g pe rio ds o f s ub ae ria l e xp os ur e. T ab le 1 . M ic ro fa ci es t y p es o f th e S ta je s ec ti on . S ta n d a rd M ic ro fa ci es t y p es ( S M F ) a re s u m m a ri ze d a ft er F lü ge l (2 00 4) . P le a se n ot e th at f en es tr ae a re c on si d er ed a s ge n er a ll y sy n se d im en - ta ry a n d a re d es cr ib ed w it h in t h e co m p o si ti on ( in cl u d in g in fi ll s ed im en t a n d c em en ts ) of t h e p a rt ic u la r m ic ro fa ci es t y p e. 63Lower Jurassic succession at the site of potential Roman quarry Staje near Ig (central Slovenia) F1 H - P ar al le l a nd lo w -a ng le cr os s la m in at ed p el le ta l pa ck /g ra in st on e Sa m pl es 1 1. 8, 12 .7 , 3 0. 45 , 3 2. 2 Co m po sit io n: P el le ts p re do m in at e. S ub or di na te a re sm al l b io cla st ic fra gm en ts (m os tly u nr ec og ni za bl e, so m e fra gm en te d sh el ls, e ch in od er m s a nd fo ra m in ife rs ). So m e la m in ae h av e gr ai ns to ne te xt ur e. T he y co nt ai n la rg er g ra in s, in clu di ng su pe rfi cia l o oi ds a nd co rt oi ds . Sa m pl e 32 .2 co nt ai ns e lo ng at ed fe ne st ra e (b ird s- ey es ) t ha t r ep la ce ce rt ai n be dd in g- pa ra lle l l am in ae o r a re (m or e ra re ly ) c ur ve d. In fil l i s d ru sy -m os ai c c al cit e (fi gs . 6 c, d ). Di ag en es is: N et w or k of th in ca lci te v ei ns th at ru n in v ar io us d ire ct io ns . S ty lo lit es a re ra re . S am pl es 1 1. 8 an d 12 .7 h av e la rg e co ar se -c ry st al lin e ca lci te v ei ns . S am pl e 32 .2 h as la rg e fra ct ur es , pa rt ly fi lle d by co ar se -c ry st al lin e ca lci te a nd su bs eq ue nt se di m en t, w hi ch is a lte rn at in g w ith le ve ls of ca lci sil tit e an d bi o/ in tr ac la st ic fin e- gr ai ne d pa ck st on e. SM F / e nv iro nm en t: SM F1 6- LA M IN AT ED ; s am pl e 32 .2 h as ch ar ac te ris tic s a lso o f S M F 21 / Re st ric te d la go on . F1 I - B io tu rb at ed in tr ac la st ic/ pe lle ta l w ac ke st on e Sa m pl e 16 .3 Co m po sit io n: T he a m ou nt o f g ra in s i s v ar ia bl e, m os tly d ue to b io tu rb at io n (F ig . 6 e) a nd a lso b ed di ng -p ar al le l l am in at io n. Gr ai ns a re re pr es en te d by in tr ac la st s, pe lo id s a nd p el le ts , r ar e m icr iti ze d oo id s, an d ve ry ra re b io cla st s ( ec hi no de rm p la te s, bi va lv e sh el ls an d sm al l g as tr op od s) . R ar e fe ne st ra e oc cu r i n fo rm of sm al l i rr eg ul ar v oi ds o r l ar ge r s tr om at ac tis ; b ot h ar e fil le d w ith d ru sy -m os ai c c em en t. Di ag en es is: N et w or k of th in ca lci te v ei ns th at ru n in v ar io us d ire ct io ns . S am pl e co nt ai ns la rg e fra ct ur es th at a re p ar tly fi lle d by co ar se -c ry st al lin e ca lci te a nd p ar tly b y ca lci sil tit e (? ne pt un ia n dy ke ) SM F / e nv iro nm en t: ?S M F2 4 / S tr uc tu ra l i nv er sio n: lo w e ne rg y (la go on al ) m ud w ith g ra in s f ro m e nv iro nm en t o f h ig he r e ne rg y (in tr ac la st s, oo id s) . F1 J - F en es tr al w ac ke st on e w ith co at ed g ra in s (o nc oi ds ) Sa m pl es 3 .1 , 7 .1 , 17 .5 , 1 7. 6 Co m po sit io n: M ai n co ns tit ue nt s a re fo ra m in ife r, in tr ac la st s a nd a gg re ga te g ra in s ( sim pl e lu m ps co m po se d of fe w , u p to 0 .5 m m la rg e oo id s a nd in tr ac la st s) . Q ua nt ity o f i nd iv id ua l co ns tit ue nt s v ar ie s s ig ni fic an tly b et w ee n th e th in -s ec tio ns (l um ps a re d om in at ed in sa m pl e 17 .5 , f or am in ife rs in sa m pl es 3 .1 a nd 7 .1 ). Ot he r g ra in s a re o oi ds (s am pl e 17 .5 ) a nd d iv er se b io cla st s: bi va lv es , o st ra co ds , d as yc la da ce an a lg ae (s am pl e 3. 1) , o va l T ub ip hy te s- lik e gr ai ns (s am pl e 3. 1, 7 .1 ), Th au m at op or el la sp . ( sa m pl e 3. 1, 7 .1 , 1 7. 6) , e ch in od er m p la te s a nd sp in es . S am pl e 17 .6 h as cm -s ize d bi va lv e, th at w as d iss ol ve d, g eo pe ta lly fi lle d w ith ca lci sil tit e w ith p el oi ds a nd la rg e- cr ys ta lli ne d ru sy -m os ai c c al ci te . M at rix o cc as io na lly re ve al s a co m po sit io n of sm al l, de ns el y pa ck ed p el le ts . Co at ed g ra in s h av e bi oc la st ic co re (F ig . 6 f; bi va lv es , d as yc la da ce as ). So m e ar e w el l d ev el op ed (r ou nd ed ) o nc oi ds , o th er s h av e th in co at in gs a nd m im ic th e or ig in al sh ap e of a co re . C oa tin gs a re m os tly b y fil am en to us m at s ( so m et im es w ith cl ea rly v isi bl e fil am en ts ), bu t e nc ru st in g fo ra m in ife rs a lso o cc ur . Fe ne st ra e ar e pr es en t a nd a re g eo pe ta lly fi lle d w ith ca lci sil tit e/ m icr ite a nd d ru sy -m os ai c c al cit e. Sa m pl es 7 .1 a nd 1 7. 5 sh ow b io tu rb at io n. Di ag en es is: N et w or k of th in ca lci te v ei ns th at ru n in v ar io us d ire ct io ns . S ty lo lit es o cc ur . SM F / e nv iro nm en t: SM F 8- 9 an d SM F 22 / Op en -m ar in e la go on cl os e to m or e re st ric te d en vi ro nm en t; su ba er ia l e xp os ur e. F2 – Bioclastic limestone F2 A – Bi oc la st ic w ac ke st on e w ith or w ith ou t l ar ge m ol lu sk s Sa m pl es 3 .3 , 5 .3 , 27 .4 Co m po sit io n: B io cla st s a re b iv al ve s, ga st ro po ds , f or am in ife rs , o st ra co ds a nd sm al l u nr ec og ni za bl e de tr itu s. In sa m pl e 27 .4 e ch in od er m sp in es a re p re se nt . T he re a re si m ila r, bu t p ol y- cr ys ta lli ne o va l g ra in s w ith ra di al ly d ist rib ut ed ri m o f s m al l c irc ul ar ca vi tie s. Th ey re se m bl e gy ro go ni te s o r s m al l d as yc la da ce an a lg ae (F ig . 7 a) , b ut sh ow n o ce nt ra l c av ity . O th er g ra in s a re pe lle ts a nd in sa m pl e 3. 3 al so in tr ac la st s. Sa m pl es 3 .3 a nd 2 7. 4 co nt ai n ra re la rg e bi va lv es a nd sa m pl e 27 .4 a lso a la rg e ga st ro po d. Sa m pl e 3. 3 ha s b ur ro w s f ill ed b y pe lle ta l p ac ks to ne a nd sp ar ite . F en es tr ae a re p re se nt a nd a re g eo pe ta lly fi lle d w ith ca lci sil tit e an d dr us y- m os ai c c al cit e. In sa m pl e 3. 3 th ey o cc ur in b ur ro w s. La rg e bi va lv es w er e di ss ol ve d an d re pl ac ed b y dr us y- m os ai c c al cit e, in ca se o f s am pl e 37 .4 m ol ds w er e fir st li ne d by th in ri m -c em en t. Di ag en es is: N et w or k of th in ca lci te v ei ns th at ru n in v ar io us d ire ct io ns . T hi ck fr ac tu re s a re fi lle d m os tly b y dr us y- m os ai c c al cit e, b ut in sa m pl e 27 .4 th e fra ct ur e (n ep tu ni an d yk e) h as g eo pe ta l fil l w ith ca lci sil tit e, sh ow in g di ffe re nt o rie nt at io n th an in fe ne st ra e (fi g. 1 0c ). St yl ol ite s a re p re se nt a nd sa m pl e 27 .4 h as ra re fr am bo id al p yr ite SM F / e nv iro nm en t: SM F8 a nd S M F9 / Op en -m ar in e la go on w ith su ba er ia l e xp os ur e. F2 B – M ol lu sk an flo at st on e Sa m pl es 1 .4 , 3 5. 1, 37 .4 Co m po sit io n: La rg e (c m -s ize d) m ol lu sk s f lo at in b io cla st ic w ac ke st on e m at rix (f ig . 7 b) . S am pl e 1. 4 co nt ai ns th ick -s he lle d bi va lv es . I n sa m pl es 3 5. 1 an d 37 .4 , g as tr op od s a nd m ed iu m -th ick sh el ls of b iv al ve s p re do m in at e, b ut sa m pl e 37 .4 co nt ai ns fr ag m en te d th ick -s he lle d bi va lv e w ith m ul ti- la ye re d pr ism at ic te xt ur e. B io cla st s i n m at rix a re sm al l ( m m -s ize d) , f re qu en tly fra gm en te d bi va lv es , g as tr op od s, os tr ac od s a nd fo ra m in ife rs . S am pl e 35 .1 co nt ai ns d as yc la da ce an a lg ae a nd 3 7. 4 cr in oi ds . I nt ra cla st s a nd su bo rd in at e m icr iti ze d oo id s w er e lo ca lly o bs er ve d. Al l s am pl es sh ow in te ns e di ss ol ut io n: -m os t i nt en se d iss ol ut io n at ta ck ed la rg e bi oc la st s, an d pl ac es w ith la rg es t co nc en tr at io n of fo ss ils , d iss ol ut io n of te n de vi at es fr om sh el ls to su rr ou nd in g m at rix , -is ol at ed fe ne st ra e w ith in th e m at rix a re ra re . M ul tip le g en er at io ns o f i nf ill ca n be se en in v oi ds : -th e fir st g en er at io n is th in ri m -c em en ts (n ot o bs er ve d in sa m pl e 37 .4 ), -th e se co nd is a g eo pe ta l i nf ill b y ca lci sil tit e (in sa m pl e 35 .1 w ith o st ra co ds a nd 3 7. 4 w ith sm al l i nt ra cla st s/ pe lle ts ), -in sa m pl e 35 .1 , i t i s f ol lo w ed b y th e se co nd g en er at io n of th in ri m -c em en t ( so m e pa rt s s ho w e ve n m or e co m pl ex a lte rn at io n of ri m ce m en ts a nd se di m en t i nf ill s; fig s. 7b , c ). -la rg e- cr ys ta lli ne , i so pa ch ou s r im (o fte n bl ad ed ) o r d ru sy -m os ai c c em en t, -m at rix in sa m pl e 35 .1 sh ow s d en se n et w or k of ir re gu la r t hi n fra ct ur es fi lle d w ith ca lci te , w hi ch w e at tr ib ut e to th e de sic ca tio n. Di ag en es is: N et w or k of th in ca lci te v ei ns th at ru n in v ar io us d ire ct io ns . S ty lo lit es o cc ur . S am pl e 1. 4 ha s w id e fra ct ur e pa rt ly fi lle d w ith la rg e ca lci te (o cc as io na lly b la de d) a nd su bs eq ue nt se di m en t: ve ry -fi ne p ac ks to ne w ith p el le ts o r c al cis ilt ite (i t c ou ld e ith er b e ne pt un ia n dy ke o r c oa rs er sy ns ed im en tr y in fil l o f l ar ge r d iss ol ut io n vo id ). In sa m pl e 35 .1 is m m -s ize fi el d of p yr ite . Sa m pl e 37 .4 h as sy st em o f b ro w n- co lo ur ed (? py rit e) ca rb on at e ve in s. SM F / e nv iro nm en t: SM F8 / Op en -m ar in e la go on w ith a t l ea st o ne lo ng er p er io d of su ba er ia l e xp os ur e. 64 Boštjan ROŽIČ, Luka GALE, Rok BRAJKOVIĆ, Tomislav POPIT & Petra ŽVAB ROŽIČ F2 C – In tr ac la st ic, oo id al , p el le ta l pa rt ly -w as he d pa ck st on e w ith la rg e bi va lv es a nd in tr ac la st s Sa m pl es 4 .5 , 6 .9 , 14 .9 , 1 8. 2, 2 5. 9, 34 ,5 5, 3 8. 7 Co m po sit io n: T he co m m on es t g ra in s a re in tr ac la st s, oo id s ( m os tly m icr iti siz ed ), an d pe lle ts . O th er su bo rd in at e gr ai ns a re co rt oi ds a nd b io cla st s: fo ra m in ife rs , s m al l a nd m os tly fr ag m en te d bi va lv es , e ch in od er m s ( sa m pl e 6. 9) , T ub ip hy te s– lik e fo ss ils , c al cim icr ob es (s am pl e 4. 5) . La rg e (fe w -m m si ze d) g ra in s f lo at w ith in th e pa ck st on e m at rix a nd a re m os tly b iv al ve s a nd in tr ac la st s. Su bo rd in at e ar e ga st ro po ds (F ig . 7 d; sa m pl es 1 4. 9, 1 8. 2, 2 5. 9) a nd b ra ch io po ds (s am pl es 25 .9 , 3 4. 55 ). La rg e bi oc la st s t en d to b e co m pl et el y re cr ys ta lli ze d. In tr ac la st s r ev ea l p rim ar y st ru ct ur e of m ud st on e or w ac ke st on e w ith o st ra co ds , f ra gm en te d bi va lv es , a nd o th er sm al l bi od et rit us . S am pl e 4. 5 ha s l ar ge in tr ac la st o f p el le ta l a nd o oi da l p ac ks to ne w ith m icr iti c r im . Sa m pl e 6. 9 is pa rt ly w as he d- ou t p ac ks to ne , c om po se d m os tly o f i nt ra cla st s a nd p el le ts , a nd co nt ai ns fe ne st ra e. Di ag en es is: N et w or k of th in ca lci te v ei ns th at ru n in v ar io us d ire ct io ns . T hi ck fr ac tu re s a re fi lle d m os tly b y dr us y- m os ai c c al cit e; in sa m pl e 4. 5 al so ca lci sil tit e (n ep tu ni an d yk e) . S om e th ick , ca lci tic v ei ns in sa m pl e 4. 5 ar e un us ua lly cu rv ed . I n sa m pl e 34 .5 5, o ne th ick v ei n is br ow n co lo re d an d co nt ai ns p yr ite . S ty lo lit es w er e no tic ed a nd sm al l d isp er se d py rit e oc cu rs in sa m pl es 2 5. 9 an d 34 .5 5. SM F / e nv iro nm en t: ?S M F8 -1 8, cl os e to S M F1 1 / O pe n- m ar in e, lo w - e ne rg y la go on ; s ub ae ria l e xp os ur e. F2 D – In tr ac la st ic, oo id al , p el le ta l gr ai ns to ne w ith la rg e m ol lu sk s an d in tr ac la st s Sa m pl es 4 .1 , 26 .3 5, 2 8. 25 , 37 .5 5 Co m po sit io n: B im od al g ra in -s ize (f ig . 7 e) . S m al l g ra in s a re in tr ac la st s a nd p el le ts , s ub or di na te a re o oi ds (o fte n su pe rfi cia l a nd /o r m icr iti ze d) , c or to id s ( m os tly fr om b iv al ve fr ag m en ts ) a nd fo ra m in ife rs . R ar e ar e ec hi no de rm s a nd T ub ip hy te s– lik e fo ss ils . I n sa m pl e 4. 1 ag gr eg at e gr ai ns (l um ps ) w er e al so o bs er ve d. La rg e gr ai ns a re p re do m in an tly b iv al ve s ( th ick to m ed iu m sh el le d) a nd g as tr op od s, bu t b ra ch io po ds a nd d as yc la da ce an a lg ae a re a lso p re se nt . M os t s am pl es (4 .1 , 2 6. 35 , 3 7. 55 ) h av e al so la rg e, w el l r ou nd ed m ud st on e in tr ac la st s, w hi ch in sa m pl e 4. 1 te nd to b e do lo m iti ze d. La rg e gr ai ns te nd to h av e en do lit hi c m ar gi ns o r o ve rg ro w th s o f c al cim icr ob es (f ila m en ts a re st ill v isi bl e) o r e nc ru st in g fo ra m in ife rs . S he lls a re re cr ys ta lli ze d or w er e di ss ol ve d an d fil le d w ith ce m en t. In sa m pl e 26 .3 5, o ne su ch fo ss il ha s g eo pe ta l i nf ill w ith ca lci sil tit e, a th in ri m -c em en t a nd su bs eq ue nt d ru sy -m os ai c c em en t. Sa m e gr ai ns h av e th in ca lci m icr ob ia l o ve rg ro w th . B el lo w la rg e sh el ls sh el te r p or es a re co m m on . T hi n m icr iti ze d su rfa ce (? ha rd gr ou nd le ve l) w as o bs er ve d in sa m pl e 28 .2 5. S am pl e 26 .3 5 ha s f ew fe ne st ra e in lo ca l v er y- fin e gr ai n/ pa ck st on e th at oc cu rs b el lo w sh el te r s tr uc tu re . F en es tr ae a re li ne d w ith th in ri m -c em en t a nd fi lle d w ith d ru sy -m os ai c c em en t. Di ag en es is: N et w or k of th in ca lci te v ei ns th at ru n in v ar io us d ire ct io ns , b ut th ick er ca lci te v ei ns a lso o cc ur . S am pl e 26 .3 5 ha s p yr ite co nc en tr at ed in so m e m icr iti c g ra in s ( pa rt icu la rly in la rg er in tr ac la st s) . S am pl e 4. 1 ha s s el ec tiv e do lo m iti sa tio n of m icr iti c g ra in s, pa rt icu la rly th e la rg e in tr ac la st s. Sa m pl e 37 .5 5 ha s s ty lo lit es w ith a dj ac en t m in or d ol om iti sa tio n. SM F / e nv iro nm en t: ?S M F8 -1 0 / H ig h- en er gy e nv iro nm en t ( or e ve nt ) w ith in o pe n- m ar in e la go on . S am pl e 26 .3 5 sh ow s s ub ae ria l e xp os ur e. F2 E – Da sy cla da ce an & m ol lu sk an pa ck /f lo at st on e Sa m pl e 19 .8 (s ev er al th in se ct io ns ) Co m po sit io n: La rg e gr ai ns a re d as yc la da ce an a lg ae , b iv al ve s a nd g as tr op od s ( fig . 7 f). R ar e ar e cm -s ize d m ud /w ac ke st on e in tr ac la st s w ith p el le ts a nd sm al l b io de tr itu s. M at rix b et w ee n la rg e fo ss ils is p ar tly -w as he d pa ck st on e co m po se d of o oi ds (m os tly m icr iti ze d) a nd p el le ts , s ub or di na te a re fo ra m in ife ra , c or to id s, in tr ac la st s a nd u nr ec og ni za bl e bi od et rit us . Ra re a re sm al le r b iv al ve s, fra gm en te d da sy cla da ce as , T ub ip hy te s- li ke g ra in s, ec hi no de rm p la te s. Fe ne st ra e ar e m m -s ize d an d hi gh ly ir re gu la r. Th ey a re fi lle d w ith th in is op ac ho us ri m ce m en t f ol lo w ed b y dr us y- m os ai c c em en t. Th e sa m e ce m en ts a re o bs er ve d in m ol lu sk s, pa rt icu la rly th e w al ls of g as tr op od sh el ls. Di ag en es is: N et w or k of th in ca lci te v ei ns th at ru n in v ar io us d ire ct io ns , b ut o ne d ire ct io n pr ev ai ls (o ne o f t he se v ei ns is th ick er ). O ne th in -s ec tio n ex hi bi ts h ig hl y irr eg ul ar “v ei n” th at co ul d be la rg er , e lo ng at ed d iss ol ut io n vo id . P yr ite ra re ly o cc ur s i n di sp er se d fra m bo id s o r s m al l c lu st er s. SM F / e nv iro nm en t: SM F1 8 / O pe n- m ar in e, cl os e to o oi da l s ho al s; su ba er ia l e xp os ur e. F3 - Calcarenite F3 A – Pa rt ly w as he d pa ck st on e w ith ag gr eg at e gr ai ns Sa m pl es 2 8. 95 , 29 .1 , 2 9. 2 Co m po sit io n: T he m ai n co m po ne nt s a re a gg re ga te g ra in s ( fig . 8 a) . I n sa m pl e 28 .9 5, th ei r a ve ra ge si ze is fr om 1 .4 6 to 1 .6 9 m m , w ith la rg es t b ei ng a fe w m ill im et re s l on g. T he y ar e lu m ps co m po se d of se ve ra l m ed iu m -s ize d gr ai ns , m os tly o oi ds , b ut p el le ts , i nt ra cla st s a nd b io cla st s a lso o cc ur . Ot he r r ar e, sa nd -s ize g ra in s a re o oi ds (m os tly m icr iti ze d) , i nt ra cla st s a nd b io cla st s ( of te n w ith m icr ob ia l c ru st s) : b iv al ve s, da sy cla da ce an a lg ae (f ra gm en ts o f l ar ge sp ec im en s a nd sm al l w ho le sp ec im en s) , r ar e cr in oi ds , g as tr op od s a nd sm al l f or am in ife rs . T in y pe lle ts o cc ur in m at rix . La rg e fo ss ils o cc ur in sa m pl es 2 8. 95 a nd 2 9. 2; th es e ar e bi va lv es , d as yc la da ce an a lg ae a nd ra re r g as tr op od s. Bi va lv es o fte n fo rm sh el te r t ex tu re . T he y ha ve e nd ol ith ic m ar gi ns a nd so m et im es al so th in m icr ob ia l o ve rg ro w th s. In sa m pl e 28 .9 5, b el ow th e he re in d es cr ib ed m icr of ac ie s t he re is a la te ra lly d isc on tin uo us h ar dg ro un d (F ig . 8 a) . T he h ar dg ro un d fo rm ed o n m icr of ac ie s c or re sp on di ng to sa m pl e 16 .3 (b io tu rb at ed in tr a/ pe l w ac ke st on e) . T ow ar ds th e m ar gi ns (v er tic al a nd la te ra l) it be co m es m icr iti c, w ith v isi bl e irr eg ul ar la m in ae (? m icr ob ia l m at s) . A t t he h ar dg ro un d ed ge th er e is an en cr us tin g fo ss il (fi g. 8 b) . Sa m pl e 29 .2 h as fe ne st ra e w ith sh ap es a dj us tin g to th e m ar gi ns o f l ar ge r g ra in s ( di ss ol ve d is m at rix w ith p el le ts ). Th es e vo id s t og et he r w ith sh el te r t ex tu re s a nd fo ss il ca vi tie s a re in fil le d ge op et al ly b y ca lci sil tit e, ra di ax ia l f ib ro us a nd su bs eq ue nt d ru sy -m os ai c c em en t. Di ag en es is: N et w or k of th in ca lci te v ei ns th at ru n in v ar io us d ire ct io ns , b ut th ick er ca lci te v ei ns a lso o cc ur . S ty lo lit es a nd d isp er se d fra m bo id al p yr ite (m os tly in m icr iti c g ra in s a nd m at rix ) oc cu r. Ce m en ts in g ra in st on e pa rt s a re th in fi br ou s r im -c em en ts (d iff er fr om th os e fil lin g th e la rg er v oi ds ) a nd d ru sy -m os ai c c al cit e. SM F / e nv iro nm en t: SM F 17 / Op en m ar in e la go on e st ab lis he d af te r t he ce ss at io n of se di m en ta tio n an d fo rm at io n of a gi ta te d se a- flo or (h ar dg ro nd ). Sa m pl e 29 .2 sh ow s s ub ae ria l e xp os ur e. F3 B – Gr ai ns to ne w ith a gg re ga te gr ai ns Sa m pl e 15 .4 Co m po sit io n: T he m ai n co m po ne nt s a re a gg re ga te g ra in s, oo id s a nd p el le ts (f ig . 8 c) . A ve ra ge si ze o f a gg re ga te g ra in s i s 1 .5 5 m m ; t he se a re lu m ps co m po se d of n um er ou s f in e- to m ed iu m - gr ai ne d oo id s ( ra di al a nd ta ng en tia l) an d pe lle ts . A ve ra ge si ze o f o oi ds is 0 .3 7 m m ; t he y ha ve fi ve la m in ae ; t he n uc le us :c or te x r at io is 4 2: 58 . O th er g ra in s a re b io cla st s ( so m et im es w ith m icr ob ia l c ru st s) : b iv al ve s, da sy cla da ce an a lg ae , c or to id s a nd ra re e ch in od er m s a nd fo ra m in ife rs . Di ag en es is: C em en ts a re th in fi br ou s r im -c em en t a nd su bs eq ue nt d ru sy -m os ai c c al cit e ce m en t. Ne tw or k of th in ca lci te v ei ns th at ru n in v ar io us d ire ct io ns , b ut th ick er ca lci te v ei ns a lso o cc ur . SM F / e nv iro nm en t: SM F 17 / Hi gh -e ne rg y en vi ro nm en t w ith in o pe n m ar in e la go on (c lo se to sa nd y sh oa ls) . 65Lower Jurassic succession at the site of potential Roman quarry Staje near Ig (central Slovenia) F3 C – Oo id al gr ai ns to ne , su bo rd in at e pa ck st on e Sa m pl es 2 .3 , 19 ,8 sp 1, 2 7. 85 , 34 .7 Co m po sit io n: T he m ai n co m po ne nt s a re o oi ds a nd p el le ts . P el le ts a re sm al l, sh ow in g bi m od al si ze d ist rib ut io n an d co nc en tr at ed in g en er al ly th in ne r l am in ae (f ig . 8 d) . T yp e an d siz e of o oi ds va rie s f ro m 0 .3 7 to 0 .7 9 m m . T he y ha ve b et w ee n fo ur a nd si x l am in ae , a nd th e nu cle us :c or te x r at io a ro un d 44 :5 6. T he y ar e pr ed om in an tly ta ng en tia l a nd m icr iti ze d, in sa m pl e 34 .7 ra di al oo id s a lso o cc ur . Ot he r g ra in s a re b io cla st s, m ai nl y fo ra m in ife rs , b ut fr ag m en te d bi va lv es , e ch in od er m s a nd d as yc la da ce an a lg ae a lso o cc ur . S po ra di c a re T ub yp hi te s- li ke g ra in s, sm al l g as tr op od s a nd co rt oi ds , ag gr eg at e gr ai ns , i nt ra cla st s a nd g as tr op od s. Di ag en es is: C em en ts a re th in fi br ou s r im -c em en t a nd su bs eq ue nt d ru sy -m os ai c c em en t. Sa m pl e 2. 3 co nt ai ns v er y sp or ad ic do lo m ite rh om bo ed er s i n m icr iti ze d oo id s. Ne tw or k of th in ca lci te ve in s t ha t r un in v ar io us d ire ct io ns . S am pl e 34 .7 h as a lso n et w or k of th ick ca lci te v ei ns . S ty lo lit es a nd d isp er se d fra m bo id al p yr ite a re ra re . SM F / e nv iro nm en t: SM F1 5 / S an dy sh oa ls, cl os e to th e op en m ar in e la go on . F3 D – Oo id al pa ck st on e w ith fe ne st ae Sa m pl e 34 .8 Co m po sit io n: T he m ai n co m po ne nt s a re m os tly ra di al o oi ds , b ut ta ng en tia l a nd sm al l s up er fic ia l o oi ds a lso o cc ur (f ig . 8 e) . T he y ha ve a ve ra ge si ze o f 0 .4 8 m m a nd h av e six la m in ae . T he ra tio nu cle us :c or te x i s 4 1: 59 . O th er g ra in s a re p el le ts , r ar e sm al l f or am in ife rs . I t c on ta in s a lso ra re la rg e bi oc la st s: bi va lv es , g as tr op od , m m -s ize d da sy cla da ce an a lg ae a nd p ar tly re cr ys ta lli ze d ca lci m icr ob es . Fe ne st ra e ar e of m ill im et er si ze . O oi ds sh ow so m e di ss ol ut io n at th ei r m ar gi ns . F en es tr ae a nd in te rg ra nu la r s pa ce s a re fi lle d w ith th in ri m ce m en t a nd d ru sy -m os ai c c al cit e ce m en t. M en isc us ce m en t o cc ur s a s p en da nt m icr ite (i t c ou ld a lso b e m at rix w hi ch e sc ap ed d iss ol ut io n) . M icr os ta la ct iti c s pa r c em en t a lso o cc ur s ( be ca us e or ie nt at io ns a re in v ar io us d ire ct io ns , s om e of th es e ce m en ts co ul d al so b e m en isc us b rid gi ng ce m en t). Di ag en es is: N et w or k of th in ca lci te v ei ns th at ru n in v ar io us d ire ct io ns . S om e ve in s a re a b it th ick er , o ne o f t he se sh ow s p ar tia l i nf ill w ith ca lci sil tit e (n ep tu ni an d yk e) . P yr ite o cc ur s i n up to 1 m m la rg e fie ld s o r a s d isp er se d fra m bo id s. SM F / e nv iro nm en t: ?S M F1 5 / S tr uc tu ra l i nv er sio n: g ra in s f ro m h ig h- en er gy e nv iro nm en t ( oo id al sh oa ls) re se di m en te d in to q ui et e nv iro nm en t ( la go on ); su ba er ia l e xp os ur e. F4 - Lumachella F4 A – Da sy cla da ce an & m ol lu sk an ru ds to ne Sa m pl e 20 .5 Co m po sit io n: G ra in s a re a lm os t e xc lu siv el y cm -s ize d bi va lv es a nd g as to po ds , a nd m m -s ize d da sy cla da ce an a lg ae (f ig . 8 f). C m -s ize d w ac ke st on e in tr ac la st w ith fr ag m en te d bi va lv es a nd ec hi no de rm s w as d et ec te d (th es e gr ai ns re se m bl e th os e fro m 1 9. 8) . B io cla st s a re st ro ng ly re cr ys ta lli ze d, so m e ha ve th in m icr ob ia l c ru st s. M ol lu sk s w er e pr ob ab ly d iss ol ve d an d fil le d w ith ce m en ts . S om e ce nt ra l c av iti es (m ed ul la ) o f d as yc la da n al ga e co nt ai n pe lle ts a nd sm al l o oi ds o r i nt ra cla st s. Ra re sm al l g ra in s a re o oi ds a nd in tr ac la st s. Di ag en es is: In te rg ra nu la r p or es a re fi lle d w ith ra di ax ia l r im -c em en ts fo llo w ed b y dr us y- m os ai c c em en ts . L ar ge d iss ol ut io n vo id is ir re gu la r a nd fi lle d w ith d ru sy -m os ai c c em en t. Ca lci te v ei ns ar e ra re a nd th in . SM F / e nv iro nm en t: SM F1 4 / L ag -d ep os it w ith in o r c lo se to o pe n m ar in e la go on ; s ub ae ria l e xp os ur e F5 - Limestone microbreccia F5 A – Lit oc la st ic flo at st on e Sa m pl e 6. 3 Co m po sit io n: M m - t o cm -s ize d lit oc la st s w ith in w ac ke st on e m at rix w ith p el le ts a nd b io cla st s ( fig . 8 g) : s m al l o st ra co ds , e ch in od er m s, sm al l b iv al ve s, ov al sp ar iti c g ra in s ( pr ob ab ly b io cla st s) . Lit ho cla st s a re a ng ul ar (s om e ev en sh ow b or in gs ) a nd d iv er se : A ) m ud /w ac ke st on e, so m et im es w ith v isi bl e pe lle ts , s m al l u nr ec og ni sa bl e bi od et rit us , a nd u nd et er m in ed o va l s pa rit ic gr ai ns ; so m e ar e sm al l, an gu la r a nd e lo ng at ed (c ou ld b e m ud ch ip s) , B ) p el le ta l g ra in /p ac ks to ne , a nd C ) o oi da l g ra in st on e w ith m ed iu m -g ra in ed ta ng en tia l a nd le ss fr eq ue nt ra di al o oi ds , r ar e pe lle ts , in tr ac la st s, an d ag gr eg at e gr ai ns . Di ag en es is: So m e m ud st on e lit ho cla st s s ho w d isp er se d do lo m iti c r ho m bo ed er s. N et w or k of th in ca lci te v ei ns th at ru n in v ar io us d ire ct io ns . SM F / e nv iro nm en t: SM F 24 / St or m d ep os it w ith in ti da l f la t o r r ed ep os ite d in to re st ric te d la go on . 66 Boštjan ROŽIČ, Luka GALE, Rok BRAJKOVIĆ, Tomislav POPIT & Petra ŽVAB ROŽIČ In the sample at 5.3 m of the section, the an- gle between the primary geopetal orientation and those of the neptunian dykes can reach up to 69° (fig. 10c), and in the sample from 1.4 m of the sec- tion a difference of 33° was measured (fig. 10b). From the laminations in the sample at 32.2 m of the section, the maximum difference in angle is 57°. The neptunian dykes from the sample at 4.8 m of the section show complex evolution (fig. 10a). The first generation of dykes is irregular and filled with early generations of cement and sub- sequent very fine calcisiltite. The second genera- tion cuts through the first filling of the dykes. It is represented by a thin cement layer, followed by very fine calcisiltite. Infill of the first two gen- erations shows mostly dispersed dolomite crys- tals similar to those observed in the host-rock. It could point to an older (maybe even Lower Ju- rassic) opening of the dykes, but dolomitization could also be selective to the lithology (dolomite is more abundant in micrite and very fine calcis- iltite). In the third phase, new fractures formed or the old fractures re-activated. This generation of dykes is filled primarily by coarse-crystalline calcite and sporadic fine calcisiltite, followed by a deposition of generally coarser sediment within the cracks. This sediment can be further divided into first-settled sediment, consisting of calcis- iltite that contains fine-grained packstone lami- nae and shows some plastic deformation, whereas the youngest sediment is fine-grained packstone, and is in composition very similar to the sedi- ment infill of the neptunian dyke from the sample at 6.4 m of the section. Foraminifera ?Quinqueloculina sp. and dasy- cladacean algae Clypeina jurassica Favre (det. by R. Radoićić; fig. 10d) were found in the intra-bio- clastic packstone filling of the neptunian dykes. The latter indicates infiltrated sediment of Up- per Jurassic age (Chiocchini et al., 1994; Senow- bari-Daryan et al., 1994). Other structures are fractures and veins, but we emphasize that the fractures observed in the weathered rock largely follow the orientation of a particular vein-cluster. Most fractures and veins are oriented in an approximate N-S stike (fig. 3). Other veins run in the NW-SE direction. The most common veins are also the thickest, and could be extensional fractures originating from the latest Jurassic tectonic movements, but they lack the sediment infill. The azimuth and dip of the main wall of the potential Roman quarry is 60/75, and the rock behind the wall is fractured in the same direction. Other calcite veins are generally thinner and strike in various direc- tions (commonly W-E and NE-SW) and cross cut the neptunian dykes. The azimuth and dip of the beds is constant, with small variations around 220/40. Discussion Sedimentary environment: The lower Low- er Jurassic (Sinemurian) succession of the Sta- je section shows characteristics of the platform interior. The first of the dominating facies, mi- critic limestone, is characterized by fenestrae (birds-eyes). This facies deposited in a shallow subtidal environment such as a restricted lagoon with frequent subaerial exposure. A stromato- lite bed, probably also laminated mudstone and limestone microbreccia, deposited in intertidal environment (tidal flats). The second dominating facies, bioclastic limestone, is of variable texture and shows a rich fossil assemblage. It was sed- imented in an open-marine lagoon. The transi- tion to a restricted lagoon is marked by fenestral wackestone that contains oncoids and pelletal pack/grainstone (laminated and fenestral sub- types). The lagoon was occasionally subjected to more agitated conditions (storms) as evidenced by grainstone with large bioclasts and particu- larly by a lumachella bed. A more agitated yet still lagoon environment can also be implied for the grain/packstone composed predominantly of aggregate grains, and ooidal grain/packstone as well. The latter was deposited at the transition to the ooid shoals. Correlation: In recent years, several sections were studied within the Lower Jurassic beds that outcrop along the southern margin of the Ljubljana Moor (Gale, 2014, 2015; Gale & Kele- men 2017). The Staje section correlates well with the Sinemurian Preserje, Tomišelj, Jezero and Zalopate sections, in which the authors describe a gradual opening up of lagoonal sedimentary environments as documented by the increasing presence of bioclastic and later also ooidal lime- stones (Gale & Kelemen, 2017). The same sedi- mentary trend continues upwards into Pliensba- chian “Podpeč limestone” (microfacies described in detail by Gale, 2015) in which grain-supported facies (pack/grain/rudstone) become even more frequent or even dominate the succession (Buser & Debeljak, 1995; Debeljak & Buser, 1997; Gale, 2014, 2015; Kramar et al., 2015). Sedimentation of the “Podpeč limestone” took place in the lagoon close to ooid shoals that characterized the mar- gin of the Dinaric Carbonate Platform during the 67Lower Jurassic succession at the site of potential Roman quarry Staje near Ig (central Slovenia) Fig. 10. Microfacies of neptunian dykes. a) A complex pattern of neptunian dykes. Older dykes are irregular and filled first with cement (1a) and later by fine sediment (1b). The younger phase forms straight, wide-opened fractures filled with thin cement (2a), followed by calcisiltite (2b). The third generation re-opens fractures of previous generations and opens new. It was first filled with coarse-crystalline cement (3a) and small amount of calcisiltite (3b). The last generation re-opens old fractures that fill with sediment, presumably in two generations: the older (4a) shows sliding (indicated by arrows) that occurred during the final opening and refilling (4b) of the fracture (sample 4.8). b) Difference of 33° in geopetal infilling of dissolved bivalve shell and fenestrae (white arrows) and those of neptunian dykes (black arrow) (sample 1.4). c) Difference of 69° in geopetal infilling of fenestrae (white arrows) and those of neptunian dykes (black arrows) (sample 5.3). d) Composition of neptunian dyke: intraclasts, small superficial ooids, pellets, echinoderm plates and other bioclasts with latest Jurassic Clypeina jurassica Favre (arrows) (sample 5.4). 68 Boštjan ROŽIČ, Luka GALE, Rok BRAJKOVIĆ, Tomislav POPIT & Petra ŽVAB ROŽIČ Lower Jurassic (Buser & Debeljak, 1995). A sim- ilar Lower Jurassic succession is also described from the Kovk section in western Slovenia (Črne & Goričan, 2008) and can be recognized in the lithostratigraphic subdivision that was proposed by Dozet and Strohmenger (2000) and Dozet (2009). Neptunian dykes: The neptunian dykes from the Staje section show a rather complex relation- ship between cement and sediment infills, which points to a pulsating opening of the fractures. The nature of infill during each pulse is related to the connection of the fractures to the surface. Cements were closing the fractures during peri- ods of poor connection with the surface or during emersion. Sediment infilled the fractures during the well-established connection of the fractures with the sea bottom. Although these opening pulses could originate during several chronologi- cally distant extensional phases, we propose that these fractures formed inside a relatively short time during the Late Jurassic. This is suggested by (A) Clypeina jurassica Favre determined in the sediment of the neptunian dykes, (B) the sim- ilar sediment infill of different pulses and (C) a soft deformation inside the older sediment cov- ered by younger sediment. The neptunian dykes of the Staje section are connected to the middle Late Jurassic tecton- ic phase that is well expressed on the Dinaric Carbonate Platform. It is seen as a widespread emersion that terminated the growth of the vast barrier reef and is documented in the form of bauxites and horizons of polymict breccias (Bus- er, 1989; Strohmenger & Dozet, 1990; Dozet, 1994; Dozet et al.,1996; Turnšek, 1997; Vlahović et al., 2005; Buser & Dozet, 2009). The breccia is polygenetic, and is interpreted as karst breccia or talus breccia originating along scarps and is followed by shallow water limestones character- ised by Clypeina jurassica Favre (Strohmenger & Dozet, 1990; Buser & Dozet, 2009). Reports of neptunian dykes within the Jurassic strata of the Dinaric Carbonate Platform are rare (Otoničar, 2015; Žibret, 2015). On the contrary, they are well known from the northerly Julian Carbonate Plat- form located today in the Southern Alps (Babić, 1981; Buser, 1996). One of these extensional phases was dated as upper Late Jurassic (Šmuc, 2005; Črne et al., 2007). The Lower Jurassic beds are covered in the Krim-Mokrec Mountain Range by a succession of Middle Jurassic ooidal limestone strata some sev- eral hundred meters thick, followed in the wid- er region by Upper Jurassic reefal limestone and subsequent lagoonal limestones with Clypeina jurassica (Turnšek 1997; Miler & Pavšič, 2008; Buser & Dozet, 2009). The connection of the frac- tures within Lower Jurassic strata to the upper Upper Jurassic surface/sea bottom is therefore somewhat problematic, especially as no large- scale neptunian dykes have yet been detected within the younger strata. A possible solution arises out of the fact that in the wider surround- ings of the Staje area only Lower Jurassic beds outcrop (fig. 1). It is possible that the investigated succession originated already in marginal parts of the platform that are otherwise known to con- tain a large-scale (Middle) Jurassic gap (Buser & Dozet, 2009; Otoničar, 2015). A specific succes- sion, where the latest Jurassic strata lies directly on Lower Jurassic lagoonal limestones, was re- cently described in the Avče area in western Slo- venia, which represents one of the northernmost (marginal) Jurassic outcrops of the Dinaric Car- bonate Platform (Kovač, 2016). Natural stone: In the case the Roman quarry existed in the selected location near the village of Staje, the stonecutting products that would have come from the quarry would have been composed predominantly of micritic limestone in microfa- cies, mostly as fossil-poor mudstone or wacke- stone with two (or more) distinct generations of dissolution voids (F1B microfacies type). Some voids are filled with reddish sediment. This facies could contain parts (laminae, lenses, pockets…) of other facies, such as bioclastic limestone, cal- carenite or microbreccia (lithoclastic rudstone). Another possible facies would be bioclastic lime- stone in the form of various microfacies, but partly-washed packstone with large mollusks is most common (F2C microfacies type). Calcaren- ites composed either of ooids or aggregate grains are subordinate and occur in generally thinner beds. Their use is less probable, but could be con- sidered more probable in view of their character- istics that make them suitable for stone-cutting. Our field observations show that similar natural stones would have been obtained also from oth- er potential quarries of the wider Staje (Ig) area, as the composition of the succession is monoto- nous. A thin-section made from the massive out- crop with the “Stari dedec” stela at the entrance of the valley confirms our proposition. It shows that the outcrop is a fenestral (birds-eyes) mud- stone (F1B microfacies type). On the margin of the thin section it passes with a sharp, curved contact into intraclastic/pelletal dense wacke- stone/partly-washed packstone, which generally 69Lower Jurassic succession at the site of potential Roman quarry Staje near Ig (central Slovenia) corresponds to our F1I microfacies type, but ad- ditionally contains some anomuran pellets. The later grains were not detected from the Staje sec- tion, but are reported from other, Lower Jurassic sections (Gale, 2015) located close by. This helps explain the fact that, despite dense sampling, it is not possible to describe all the microfacies that can be extracted from the studied section, and other varieties can be expected within the frame of the studied sedimentary environment. Similar natural stones could have been ac- quired also from quarries of the Podutik area, lo- cated just north of Ljubljana. This natural stone is known as “gliničan” and was likely quarried already in Roman times (Ramovš, 1990; in Šašel- Kos, 1997). The Lower Jurassic limestone of the Podutik area represents a time and facies equiva- lent of the succession studied in the Staje section (Novak, 2003; Vodnik, 2016; Vodnik et al., 2017). Those characteristics that might distinguish the sites may consist in the Late Jurassic neptunian dykes that were detected in the “main wall” of the potential Roman quarry near Staje. Such fea- tures were not described from the Podutik area, but reddish and greenish colored veins, i.e. po- tential neptunian dykes, are reported (Ramovš, 1990; Novak, 2003; Vodnik, 2016, Vodnik et al., 2017), and study of their microfacies would be welcomed in the future. Conclusions Geomorphological study and field observations indicate that the Roman quarry in the Staje area could potentially be located in the valley running SE of the village. The section logged across the wall at the SW bank of the valley shows that the studied succession is composed of micritic lime- stone, subordinate bioclastic limestone and rare calcarenite and limestone microbreccia. Most common microfacies are mud/wackestone with several generations of dissolutions voids (often with geopetal fill) and partly-washed packstone with large mollusks. Calcarenite is pack/grain- stone, dominated either by aggregate grains or ooids. The sedimentary environment was restricted to an open marine lagoon with repeating subae- rial exposure. High-energy events, which are in- dicated by sandy facies (ooidal pack/grainstone, aggregate grains pack/grainstone, bioclastic grainstone) and lumachella (bioclastic rudstone), occasionally interrupted the “quiet” lagoonal conditions. The studied section is Sinemurian in age and fits well within the Hettangian to Pliens- bachian opening of the sedimentary environment from intertidal flats to a differentiated lagoon from the previously described northern part of the Dinaric Carbonate Platform. The section is characterized by neptunian dykes that reveal a pulsating opening of the frac- tures but which were presumably formed with- in a relatively short time in the Late Jurassic, as evidenced by Clypeina jurassica Favre deter- mined in the sediment fill. The neptunian dykes could be distinguishing characteristics of the Staje succession, allowing for a distinction from the potential Roman quarry site in Podutik, just north of Ljubljana, that represents a time and facies equivalent succession. However, an addi- tional study of the reddish and green-coloured “veins” that are reported from the Podutik site are needed to confirm our proposal. Acknowledgment This research was financially supported by the Slovenian Research Agency (research core funding No. P1-0195(B) and No. P1-0011). We sincerely thank Rajka Radojčić for determination of Clypeina jurassi- ca Favre. 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