GEOLOGIJA 49/2, 243–251, Ljubljana 2006 The origin of volcanic rock fragments in Upper Pliocene Grad Member of the Mura Formation, North-Eastern Slovenia Izvor klastov vulkanskih kamnin v zgornjepliocenskem Gra{kem ~lenu Murske formacije v severovzhodni Sloveniji Polona KRALJ Geolo{ki zavod Slovenije, Dimi~eva 14, SI-1109 Ljubljana Key words: basaltic rocks, volcaniclastic sediments, Pannonian Basin, Mura Formation, Grad Member Upper Pliocene, Slovenia Klju~ne besede: bazaltne kamnine, vulkanoklasti~ni sedimenti, Panonski bazen, Murska formacija, Gra{ki ~len, zgornji pliocen, Slovenija Abstract Fresh-water, coarse-grained and detritus-dominated Mura Formation in NorthEastern Slovenia includes pyroclastic and volcaniclastic deposits originating from Upper Pliocene volcanic activity of basaltic geochemical character. Although localized in occurrence at the hamlet Grad, these pyroclastic and volcaniclastic sediments form a distinctive depositional unit, for which the term “Grad Member” is proposed and introduced in this paper. In the Grad area no lavas or cinder cones are preserved, and the origin of volcaniclastic fragments still uncertain. For this reason, chemical composition of basaltic rock fragments from the Grad Member volcaniclastics has been studied and compared with basaltic rocks from the neighboring locations at Klöch, Kindsberg, Dölling and Neuhaus. The Grad Member pyroclastic and volcaniclastic deposits seem to be fed from the same source which is different from the occurrences in Austria. That supports the idea about the existence of a local volcanic centre in the present Grad area. The old volcanic edifices were possibly destroyed by the late-stage hydrovolcanic eruptions, and pyroclastic and volcaniclastic deposits subjected to constant reworking by fluvial currents in a dynamic sedimentary environment of alluvial fan and braided river systems. Kratka vsebina Sladkovodna Murska Formacija, katero grade predvsem debelozrnati sedimenti, vklju-~uje piroklastite in vulkanoklastite, ki izvirajo iz zgornjepliocenskega vulkanskega delovanja bazaltnega zna~aja. ^eprav se pojavljajo ti sedimenti na zelo omejenem prostoru v okolici zaselka Grad, predstavljajo zna~ilno sedimentacijsko enoto, za katero je v tem prispevku predlagano in prvi~ uporabljeno ime Gra{ki ~len Murske formacije. V okolici Grada do sedaj {e niso bile najdene lave ali sto‘ci vulkanskega pepela in bomb skorje, zato ostaja izvor bazaltnih klastov v vulkanoklastitih Gra{kega ~lena {e vedno nerazjasnjen. V ta namen smo preiskali in primerjali kemi~no sestavo odlomkov bazalt-nih kamnin iz vulkanoklastitov Gra{kega ~lena in bazaltnih kamnin iz bli‘njih lokacij na Klöchu, Kindsbergu, Döllingu in Neuhausu. Ugotovili smo, da so bazaltni klasti iz Gra{kega ~lena po sestavi med seboj podobni, vendar se od avsrijskih nahajali{~ zna~ilno razlikujejo. To potrjuje domnevo, da je na podro~ju Grada obstajal samostojen vulkanski center, ~eprav danes ni ve~ ohranjenih lavinih tokov ter sto‘cev vulkanskega pepela in bomb skorje. Starej{e vulkanske oblike so najverjetneje poru{ile hidrovulkanske eksplozije v kasnem obdobju vulkanskega delovanja. Piroklasti~ni in vulkanoklasti~ni sedimenti pa so bili podvr‘eni nenehni presedimentaciji v dinami~nem okolju aluvialnega vr{aja in prepletenih rek. 244 Polona Kralj Introduction Fresh-water, coarse-grained and detritus-dominated Mura Formation in NorthEastern Slovenia includes pyroclastic and volcaniclastic deposits originating from Upper Pliocene volcanic activity of basaltic geochemical character. Although localized in occurrence at the hamlet Grad, these py-roclastic and volcaniclastic sediments form a distinctive depositional unit, for which the term “Grad Member” is proposed and introduced in this paper. Upper Pliocene Grad Member consists of pyroclastic, syn-eruptive resedimented vol-caniclastic and mixed volcaniclastic-fluvial deposits. Their formation is closely related to continental alkali basaltic volcanism which was active about 3 million years ago in the area of the present medieval castle and the surrounding hamlet Grad in Gori~ko, NorthEastern Slovenia. The volcanism forms a part of a broader volcanic province encompassing South Styrian Basin (Pöschl, 1991; Winkler, 1927; Poulditis, 1981; Pould-itis & Scharbert, 1986) and Little Hungarian Plain (Martin & Németh, 2004), and developed as a consequence of post-collisional extension of the south-western realm of the Pannonian Basin. At the present, no lavas are preserved in the Grad area, but only their fragmented remains (Plate 1 – Fig. 1) in volcaniclastic debris flow deposits. For this reason, doubts have been posed again recently about the existence of local volcanic centre in the Figure 1. Simplified geological map of Gori~ko (after Pleni~ar, 1970) Slika 1. Poenostavljena geolo{ka karta Gori~kega (po Pleni~arju, 1970) The origin of volcanic rock fragments in Upper Pliocene Grad Member of the Mura Formation,... 245 Grad area (Martin & Németh, 2004). Close proximity – about 10 km - of large lava flows on the crest of the South Burgenland Swell and in the neighboring Styrian Basin in Austria - at Stradner Kogel, Klöch, Kindsberg, Dölling and Neuhaus, supported a possibility that some of them might have been an additional source of volcaniclastic debris at Grad. The present contribution deals with detailed chemical composition of potential rock occurrences in Austria, and lava fragments in the Grad Member volca-niclastic rocks in order to characterize the source and consider possible paleotransport directions for volcaniclastic rock fragments of the Grad Member. Geological setting outline North-easternmost Slovenian territory (Fig. 1) is a hilly country that forms a part of the Mura Basin – the south-easternmost extending of the Pannonian Basin. The Mura Basin is filled with clastic, and to minor extent carbonate sediments, that range in age from Neogene to Quaternary. The Mura Basin consists of two depressions – northerly positioned southwest – northeast trending Radgona depression, and nearly west-east trending Ljutomer depression. They are separated by the Murska Sobota Swell (Kiso-var, 1979). The Radgona depression is separated from the neighboring Styrian Basin in the north by the South Burgenland Swell (Tollmann, 1986; Oberhauser, 1980). The basement of the Mura Basin mainly consists of Paleozoic metamorphic and clastic sedimentary formations; only in the deepest parts of depressions, Mesozoic carbonates are preserved. Tertiary sediments were deposited in a marine environment during Karpatian, Badenian and Sarmatian stage (Rijavec et al., 1985). Except for Bad-enian, they are developed as clastics – clays, marls, silts and sands. During Pannonian, brackish conditions prevailed. Lower Pannonian sediments are silts and marls characterised by the occurrence of ostracods. They are overlain by the beds with Paradacna abichi mollus-cans, termed the »Abichi beds« (Pleni~ar, 1968). Overlying Lower Pliocene – Pontian sediemnts are mainly limnic, and consist of quartz sands, sandy silts and clayey silts. These deposits are regarded as »the freshwater equivalent of the Rhomboidea beds« (Pleni~ar, 1968). Middle Pliocene deposits overlie discordantly Pontian beds and are developed as sands and gravels. Fluvial sedimentation that started with Middle Pliocene persisted during Upper Pliocene and Quaternary. Sarmatian sediments are united in the Murska Sobota Formation, Pannonian and Lower Pontian in the Lendava Formation, and Upper Pontian and Quaternary in the Mura Formation ([imon, 1966). During Pliocene, volcanic activity of basaltic composition occurred in the Styr-ian Basin and in the northern margins of the Radgona depression. On the crest of the South Burgenland Swell large lava flows occur (Fig. 2). Towards the north, maars, tuff rings and tuff cones are more common in occurrence. Strongly differentiated and alkalies-rich varieties include nephelinites, basanites, nepheline basanites, thrachy-basalts and alkali basalts. Peridotite and/or lherzolite xenoliths are common and indicate the origin of magmas and their rapid ascend towards the surface (Embey-Isztin & Kurat, 1996). Figure 2. Simplified geological map of the Grad area with the neighbouring outcroppings of basaltic rocks in Austria (after Pleni~ar, 1968 & Winkler, 1927) Slika 2. Poenostavljena geolo{ka karta obmo~ja Grada z bli‘njimi izdanki bazaltnih kamnin v Avstriji (po Pleni~arju, 1968 in Winklerju, 1927) Volcanic activity at Grad occurred in an active continental sedimentary environment characterized by alluvial fan and braided river systems (Kralj, 2000 b). Rapid deposition of coarse-grain dominated detritus was closely related to the rise of the South Burgenland Swell and the subsidence of the Radgona depression. During Early Pliocene, a system of alluvial fans formed along the 246 Polona Kralj south-eastern slopes of the South Burgenland Swell, and towards the south, east and south-east it continued as a system of braided rivers, although the main transport direction was from north-west to south-east. The present maximum thickness of clastic deposits in the Radgona depression amounts to about 2000 m. Lavas and pyroclastic deposits occurring in such active depositional environment had little preservation potential and rapidly underwent redistribution by fluvial currents. Magmas ascending towards the surface reached water-bearing strata and consequently, and with the time, the style of eruptions became essentially influenced by hydrovolcanic processes. Their violent explosions additionally contributed to destruction of primary volcanic edifices and lavas (Plate 1 – Figure 1) which already had little preservation potential in such dynamic fluvial sedimentary environment (Kralj, 1995; 2000a, b). Chemical composition of alkali basaltic rocks leotransport direction. Stradner Kogel was eliminated in the first place since the composition of nephelinite lavas is too declined from the composition of lava clasts from of the Grad Member volcaniclastics as evidenced from preliminary petrographic studies. Chemical composition of the studied rocks is shown in Table 1 and Table 2. General overview of chemical analyses indicates that among major oxides silica and K2O do not differ significantly in the studied samples. The rocks from Austria have higher abundance of TiO2, CaO, MgO and Na2O, and are lower in P2O5. Rock fragments from the Grad Member volcaniclas-tics tend to be enriched in almost all trace elements – Rb, Be, Sr, Ba, Ag, Zn, Th, U, Zr, Hf, Ta, W, Y, REEs, As and Sb, and depleted in Cu, V, Ni and Sc. The magma(s) producing rock fragments from the Grad Member volcaniclastics seem to be more differentiated than those from Austria. Depleted CaO, MgO, TiO2, Cu, V, Ni and Sc might be related to the removal of pyroxenes from the melt by crystal fractionation. Chemical composition of alkali basaltic rocks in Styria and Burgenland is extensively treated by Poulditis (1981) and Pould-itis & Scharbert (1986). Their absolute age was determined by Balogh et al. (1994). At Stradner Kogel, the most differentiated varieties - nephelinites occur in the form of lava massive. At Klöch and Kindsberg, lavas of nephelinite basanite composition outcrop. At Neuhaus, alkali basalts occur. They penetrated soft sands, probably soaked with water, and consequently, they underwent extensive autobrecciation (Plate 1 – Fig. 2). In such form, they could be easily eroded and transported by water currents. In order to minimize analytical errors related to procedures in different laboratories, rock samples from potential locations in Austria were analyzed in the same laboratory and under the same analytical conditions as the samples from Grad. The analyses were performed in X-RAL Activation Services Inc. in Ann Arbor, Michigan and Don Mills, Ontario, and it encompasses determination of 73 elements by combined wet chemical method, atomic absorption spectroscopy, and inductively coupled plasma source and mass spectroscopy. The rocks from Klöch, Kindsberg, Dölling and Neuhaus were determined as potential sources with respect to the general pa- Discussion The studied basaltic rock samples occupy mainly the fields of trachybasalt and basalt (Fig. 3) in the Na2O + K2O vs. SiO2 diagram after LeBas et al. (1986). Only one sample from Klöch falls in the field of tephrite and basanite. Based on the content of alkali oxides and silica, the samples from Austria and the Grad Member volcaniclastics do not vary significantly, although the samples from the Grad Member tend to be more rich in silica at a given Na2O + K2O content. Similar trend can be observed in the Al2O3 vs. SiO2variation diagram (Fig. 4). In the diagram MgO vs. SiO2, the samples from Klöch, Kindsberg and Dölling are clearly separate from the others. One of the samples from Neuhaus is positioned close to the Grad Member population, while the other shows extremely low abundance of MgO, possibly owing to alteration processes. In the diagram TiO2 vs. SiO2 the samples from Austria clearly separate from the Grad Member rock fragments. This trend is even more obvious in the diagrams of SiO2 vs. Zr, Sc vs. Zr and TiO2 vs. Zr (Fig. 5); herein, a further distinction between the samples from Klöch, Kindsberg and Dölling, and Neuhaus can be seen. The origin of volcanic rock fragments in Upper Pliocene Grad Member of the Mura Formation,... 247 Figure 3. Na2O + K2O vs. SiO2 (after LeBas et al., 1986) for the studied basaltic rocks. Closed circles (1-10) are for the samples from the Grad Member, crosses (1-4) for the samples from Klöch, Kindsberg and Dölling, and asterisks for the samples from Neuhaus Slika 3. Diagram Na2O + K2O vs. SiO2 (po LeBas-u et al., 1986) za preiskane vzorce bazaltnih kamnin. Polni krogi (1-10) predstavljajo vzorce iz Gra{kega ~lena, kri‘i (1-4) vzorce iz Klöcha, Kindsberga in Döllinga, ter zvezdice vzorce iz Neuhausa Al203 (wt. %) 20 19 IS 17 IS 15 14 4D 10 MgO z'3 7 ,9.B Si02 (wt %) fin 60 (wt. %) ; a •in 3 . Si02 (wt. %) 40 2.5 ÜO2 50 60 2.4 2.3 2.2 2.1 2.0 1.9 1.8 40 (Wt. %) ¦3 Si02 (wt %) 50 60 Conclusions Geochemical characteristics of basaltic rocks from Klöch, Kindsberg, Dölling, and Neuhaus and basaltic rock fragments from the Grad Member volcaniclastics based on the abundance of major oxides and trace elements have shown the following: • Chemical composition of the Grad Member rock fragments and basaltic rocks from potential source locations in Austria is different. It is not likely that the lava fragments from the Grad Member are eroded and redistributed detritus from the occurrences in Austria. • Rock fragments from the Grad Member volcaniclastics could have two sources (volcanoes), or one, from which the magmas underwent differentiation during volcanic activity. • Late-stage hydrovolcanic explosions produced proclastic surges, large lahars and volcanic debris flows that destroyed the former volcanic edifice(s) including lava flows and cinder cones. In spite of numerous works (Hinter-lechner-Ravnik & Mi{i~, 1986; Kralj, 1995; 2000a, b; Lugovi} & Kralj, 2006), the study of the Grad Member is far from completed and will continue in the future. Figure 4. Variation diagrams Al2O3 vs. SiO2, MgO vs. SiO2, and TiO2 vs. SiO2 for the studied basaltic rock samples. Closed circles (1-10) are for the samples from the Grad Member, crosses (1-4) for the samples from Klöch, Kindsberg and Dölling, and asterisks for the samples from Neuhaus Slika 4. Variacijski diagrami Al2O3 napram SiO2, MgO napram SiO2 in TiO2 napram SiO2 za analizirane vzorce bazaltnih kamnin. Polni krogi (1-10) predstavljajo vzorce iz Gra{kega ~lena, kri‘i (1-4) vzorce iz Klöcha, Kindsberga in Döllinga, ter zvezdice vzorce iz Neuhausa 248 Polona Kralj Figure 5. Variation diagrams SiO2 vs. Zr, Sc vs. Zr, and TiO2 vs. Zr for the studied basaltic rock samples. Closed circles (1-10) are for the samples from the Grad Member, crosses (1-4) for the samples from Klöch, Kindsberg and Dölling, and asterisks for the samples from Neuhaus Slika 5. Variacijski diagrami SiO2 napram Zr, Sc napram Zr in TiO2 napram Zr za analizirane vzorce bazaltnih kamnin. Polni krogi (1-10) predstavljajo vzorce iz Gra{kega ~lena, kri‘i (1-4) vzorce iz Klöcha, Kindsberga in Döllinga, ter zvezdice vzorce iz Neuhausa References Balogh, K., Ebner, F. , Ravasz, Cs., Herrmann, P. , Lobitzer, H. & Solti, G. 1994: Alter tertiärer Vulkanite der südöstlichen Steiermark und des südlichen Burgenlands.- Jubiläumsschr. 20 Jahre Geolog. Zusammenarbeit ÖsterreichUngarn, Teil 2, 55-72, Wien. Embey-Isztin, A. & Kurat, G. 1996: Young alkali basalt volcanism from the Graz Basin to the Eastern Carpathians.- Advances in Austrian-Hungarian Joint Geological Research, 159-175, Budapest. Hinterlechner-Ravnik, A. & Mi{i~, M. 1986: Peridotitne nodule v bazaltnem tufu pri Gradu v Prekmurju.- Geologija 28/29, 205-218, Ljubljana. Kisovar, M. 1979: prilog rje{avanja strukturnih odnosa na{eg dijela Murske depresije, ZNS, JAZU, III God. Skup. Zbor rad. Knj. I, Novi Sad, 311-322, Zagreb. Kralj, P. 1995:Litofaciesi pliocenskog fluvi-alnog i vulkanoklasti~nog kompleksa podru~ja Grada u sjeveroisto~noj Sloveniji.- Ph.D. Thesis, University of Zagreb, 174 pp, Zagreb. Kralj, P. 2000a: Accretionary lapilli in Pliocene volcaniclastics from Grad, northeastern Slovenia. – Geologija, 43/1, 67-73, Ljubljana. Kralj, P. 2000b: Upper Pliocene alkali basalt at Grad, northeastern Slovenia. – Geologija, 43/2, 213-218, Ljubljana. Kralj, P. 2001: Pliocene clastic sediments in Western Gori~ko, Northeastern Slovenia. - Geologija, 44/1, 73-79, Ljubljana. LeBas, M. J., LeMaitre, R. W., Streckeisen, A. & Zanettin, B. 1986: A chemical classification of volcanic rocks based on total alkali – silica diagram. - J. Petrology 27, 745-750, Oxford. Lugovi}, B. & Kralj, P. 2006: Spinel lherzolite xenoliths from Upper Pliocene potassic trachy-basalts at Grad, NE Slovenia. Book of Abstracts, 2. Slovenski geolo{ki kongres, p.64, Idrija. Martin, U. & Németh, K. 2004: Mio/Plio-cene phreatomagmatic volcanism in the western Pannonian Basin, Hungary, U. Martin (ed.) & K. Németh (ed.): Geologica Hungarica 26, 193 pp., Budapest. Oberhauser, R. (ed.) 1980: Der geologische Aufbau Österreichs.- Springer, 700p., Wien. Pleni~ar, M. 1968: Osnovna geolo{ka karta SFRJ, 1:100.000, list Gori~ko. - Zvezni geolo{ki zavod, Beograd. Pleni~ar, M. 1970: Manuskriptna geolo{ka karta Gori~kega. - Arhiv Geolo{kega zavoda Slovenije, Ljubljana. Pöschl, I. 1991: A model for the depositional evolution of the volcaniclatic successions of a Pliocene maar volcano in the Styrian basin (Austria). - Jb. Geol. B.-A. 134/4, 809-843, Wien. Poulditis, Ch. 1981: Petrologie und geochi-mie basaltischer Gesteine des steirischen Vulkan-bogens in der Steiermark und im Burgenland.-Diss. Univ. Wien, 146 pp., Wien. Poulditis, Ch. & Scharbert, H. G., 1986: Bericht über geochemisch-petrologische Untersuchungen an der Transdanubischen Vulkanischen region. - Anz. Österr. Akad. Wiss., math.-natur-wiss. Klasse, 123, 65-76, Wien. Rijavec, L., Bistri~i}, A. & Jenko, M. 1985: Mura Basin. - In: Steininger, F. F. (ed.), Senes, J. (ed.), Kleemann, K. (ed.) & Rögl, F. (ed), Neogene of the Mediterranean Thethys and Paratethys 1&2, 73-74. Institute of paleontology, University of Vienna, Vienna. [imon, J. 1966: Litostratigrafske jedinice u tercijarnom kompleksu Murske potoline. - Fond stru~. Dok. INA-Naftaplin, Zagreb in INA-Nafta Lendava, Zagreb. Tollmann, A. 1986: Geologie von Österreich, Band 3.- Franz Deuticke Wien, 718p., Wien. Winkler, A. 1927: Elauterungen zur geologischen Spezialkarte der Republik Österreich, Blatt gleichenberg. - Geologische bundesanstalt, 164 pp., Wien. The origin of volcanic rock fragments in Upper Pliocene Grad Member of the Mura Formation,... 249 A. Sample Oxide (wt.%) 1 Klöch 7 2 Klöch 9 3 Kindsberg 4 Dölling 5 Neuhaus 3 6 Neuhaus 4 Si02 44,5 43,9 44,3 48,1 41,1 46,4 Ti02 2,27 2,22 2,19 2,15 2,21 2,25 A1203 14,6 14,8 14,9 13,8 16,6 15,9 Fe203 3,54 3,75 6,63 4,66 5,20 3,51 FeO 5,9 5,3 2,8 4,0 3,1 5,2 MnO 0,18 0,17 0,17 0,15 0,25 0,14 MgO 8,98 8,40 8,58 7,73 4,61 6,61 CaO 10,3 9,28 9,63 8,90 13,3 8,73 Na20 4,07 4,09 3,70 1,45 1,90 3,60 K20 2,15 1,47 1,30 1,11 1,26 2,22 P2O5 0,74 0,75 0,74 0,50 0,51 0,49 H20+ 0,9 2,2 2,5 4,3 3,2 3,2 H20 0,5 0,9 1,0 2,1 2,0 1,0 co2 0,28 0,02 0,02 <0,01 4,34 0,50 Sum 99,48 98,30 98,75 99,55 100,2 100,3 B. Element (ppm) 1 Klöch 7 2 Klöch 9 3 Kindsberg 4 Dölling 5 Neuhaus 3 6 Neuhaus 4 Be 3 4 5 4 2 3 B 31 10 29 30 <10 26 Sc 19,4 19,2 19,8 20,5 18,9 17,9 V 220 230 230 200 197 207 Cr 140 120 110 120 137 178 Co 46 43 45 48 43 56 Ni 180 180 160 170 90 77 Cu 37,4 40,3 39,4 37,0 36,8 41,7 Zn 99,1 99,9 110,1 87,1 92,2 94,8 Rb 71 59 31 51 32 67 Sr 939 991 1000 681 613 607 Y 30 20 20 <10 37 <10 Zr 260 240 241 239 186 179 Nb 101 111 131 99 57 59 Cd 2 2 <1 1 1 2 Sb <0,2 <0,2 <0,2 0,4 0,2 0,3 Cs <1 2 1 1 1 2 Ba 682 851 954 902 789 608 La 56,3 62,2 65,5 49,8 36,9 35,6 Ce 105 114 110 98 72 72 Nd 39 42 46 36 31 29 Sm 6,4 6,8 7,3 6,7 5,8 5,5 Eu 2,0 2,2 2,9 2,2 2,1 2,2 Tb 0,6 0,7 0,8 0,9 0,7 0,6 Yb 1,6 1,8 1,9 1,4 1,5 1,4 Lu 0,25 0,25 0,26 0,20 0,21 0,19 Hf 4,1 5,2 4,9 5,1 4,5 4,4 Ta 5 6 5 5 3 3 W 75 48 43 67 25 120 Th 7,6 8,6 9,6 8,1 5,7 5,2 U 2,6 3,1 3,2 1,1 2,4 1,6 250 Polona Kralj TABELA 2 A. Sample Oxide (wt.%) 1 B 1 2 B2 3 B 3 4 BB 5 GGo4 6 KaW 7 P 53 8 KuKIA 9 KuSc4 10 KuSc6 Si02 48,9 46,3 47,0 46,8 45,4 47,7 43,6 47,9 46,9 41,6 Ti02 1,76 1,83 1,80 1,81 1,85 1,85 1,84 1,85 1,93 2,43 A1203 14,3 14,4 14,4 14,5 14,8 14,6 14,2 14,1 14,9 14,2 Fe203 3,47 3,63 3,58 4,15 5,08 4,57 5,18 4,89 5,08 7,28 FeO 5,2 5,3 5,2 4,7 4,4 4,6 4,2 4,3 4,6 3,7 MnO 0,18 0,19 0,19 0,19 0,20 0,19 0,22 0,19 0,52 0,21 MgO 6,34 6,76 6,66 6,60 5,93 6,80 5,93 5,88 5,55 6,10 CaO 8,49 9,28 9,02 8,78 9,20 9,08 9,83 8,88 9,58 11,6 Na20 3,90 3,89 3,97 2,20 2,63 3,16 1,61 3,86 2,96 0,41 K20 2,27 2,11 2,01 2,20 2,15 1,79 1,89 1,99 2,45 1,15 P2O5 0,88 0,94 0,92 0,97 1,28 0,99 1,78 0,93 1,02 1,00 H20+ 2,0 2,2 1,9 3,0 2,9 3,3 5,6 2,9 3,4 5,8 H20 0,5 1,1 1,0 1,7 1,5 1,8 2,6 1,1 0,7 3,3 co2 0,32 0,51 0,44 0,04 0,04 0,05 0,14 0,16 0,04 0,01 Sum 98,87 99,00 98,51 99,35 98,96 100,5 99,37 99,40 100,3 100,3 B. Element (ppm) 1 B 1 2 B2 3 B 3 4 BB 5 GGo4 6 KaW 7 P 53 8 KuKIA 9 KuSc4 10 KuSc6 Be 6 4 3 6 5 4 5 4 5 4 B 30 10 20 30 20 20 10 20 27 10 Sc 14,7 14,2 14,5 13,8 14,4 14,8 14,5 13,6 14,1 16,1 V 191 171 162 161 182 169 179 161 184 191 Cr 120 130 120 110 130 120 92 100 140 180 Co 25 37 43 39 51 25 28 52 42 38 Ni 81 110 110 110 110 85 100 124 128 145 Cu 29,4 36,0 37,2 36,9 37,5 29,4 21,9 34,1 24,7 29,9 Zn 110 110 140 110 130 110 110 120 134 157 Rb 68 60 50 70 70 48 54 70 81 35 Sr 1060 1160 1120 1200 1310 1150 1280 975 909 706 Y 26 10 40 30 30 41 30 20 32 29 Zr 310 360 340 320 340 310 320 330 322 361 Cd <0,2 2 1 1 2 <0,2 <0,2 2 2 2 Sb 0,7 0,5 0,6 0,7 0,7 0,5 0,6 0,3 n.d. n.d. Cs 2 1 2 1 2 1 1 1 3 1 Ba 920 900 920 1300 1400 1000 1100 970 1080 800 La 73,4 77,8 74,6 74,5 80,3 78,3 90,5 73,8 81,3 71,8 Ce 138 143 133 133 146 133 155 137 145 140 Nd 57,2 54 50 52 54 62,1 63,6 50 51 59 Sm 9,5 8,9 8,3 8,2 8,8 9,8 10,5 8,2 7,8 10,4 Eu 2,8 2,6 2,6 2,4 2,7 3,3 3,2 2,5 3,7 3,2 Tb 1,0 1,1 1,0 1,0 1,2 1,1 1,1 0,9 0,9 1,3 Yb 2,3 2,1 2,3 2,1 2,6 2,5 2,8 2,0 2,2 2,8 Lu 0,38 0,28 0,31 0,28 0,34 0,41 0,40 0,27 0,39 0,27 Hf 8,0 7,1 7,2 6,1 7,1 8,4 7,6 6,2 6,5 8,4 Ta 6 6 6 5 6 6 7 6 6 6 W 150 110 120 130 160 110 97 370 170 14 Th 12 11 11 11 11 11 12 11 11 13 U 4,1 3,4 3,1 3,7 3,2 3,7 5,6 3,4 4,3 1,1 Explanation: n.d. – not defined The origin of volcanic rock fragments in Upper Pliocene Grad Member of the Mura Formation,... 251 Plate 1 – Tabla 1 1 Basaltic rock fragments from the Grad Member volcaniclastics. Odlomki bazaltnih kamnin iz vulkanoklastitov Gra{kega ~lena 2 A lava sample from Neuhaus which underwent disintegration into hyaloclasts after being frozen in a solution of hydrogene peroxide. The largest clast is about 3,5 cm long. Vzorec lave iz Neuhausa, ki je po zmrzovanju v raztopini vodikovega peroksida razpadel v {tevilne hialoklaste. Najve~ji hialoklast meri približno 3,5 cm v dolžino