Megabeds in Istrian Flysch as markers of synsedimentary tectonics within the Dinaric foredeep (Croatia)

Main Article Content

Krešimir Petrinjak
Marko Budić
Stanislav Bergant
Tvrtko Korbar


Istrian Flysch was deposited during the Eocene in the Dinaric foredeep and is composed of hemipelagic marls and various gravity flow deposits. The latter are predominantly 5-40 cm thick turbidites, developed mostly as laminated and cross-rippled sandstone beds (Tb-e, Tc-e and Td-e Bouma sequences). In addition to the turbidites, there are deposits characterized by a significant thickness, occasionally more than 10 m, described as complex (bipartite) megabeds. The megabeds are composed of debrites in the lower part (Division I), and high-density turbidites in the upper part (Division II). The distinct clast composition of each megabed indicates that the lithoclasts were derived from tectonically active slopes and fault scarps along which collapses of the different parts of the Cretaceous to Palaeogene neritic carbonate succession, (that underlie the Flysch), occurred. The Division II deposits are well cemented, normally graded calcirudite/calcarenites composed mostly of orthophragminids, nummulitids, and red algae, originating from outer ramp environments. Redeposited marl, observed in the matrix of the debrites and as intraclasts in some megabeds, implies that the collapses along the synsedimentary fault scarps and steep slopes also occurred within the foredeep itself, during the rapid tectono-sedimentary evolution of the Dinaric foreland basin.


Download data is not yet available.

Article Details

Original Scientific Papers


ABBATE, E., BORTOLOTTI, V. & PASSERINI, P. (1970): Olistostromes and olistoliths.– In: SESTINI, G. (ed.): Development of the northern Apennines geosyncline: Sedimentary Geolology, 4, 521–557.

AMY, L., KNELLER, B. & MCCAFFREY, W. (2007): Facies architecture of the Grès de Peïra Cava, SE France: Landward stacking patterns in ponded turbiditic basins.– Journal of The Geological Society, 164/1, 143–162. doi: 10.1144/0016-76492005-019

AUBOUIN, J., BLANCHET, R., CADET, J.-P., CELET, P., CHARVET, J., CHOROWICZ, J., COUSIN, M. & RAMPNOUX, J-P. (1970): Essai sur la geologie des Dinarides.– Bulletin de la Société Géologique de France, 12/6, 1060–1095.

BABIĆ, LJ. & ZUPANIČ, J. (1983): Paleogene clastic formations in northern Dalmatia.− In: BABIĆ, LJ. & JELASKA, V. (eds.): Contributions to Sedimentology of some Carbonate and Clastic Units of the Coastal Dinarides, Excursion Guidebook. International Association of Sedimentologists 4th Regional Meeting, Split, 37–61.

BABIĆ, LJ., & ZUPANIČ, J. (1996): Coastal Dinaric flysch belt: palaeotransport model for the Pazin Basin, and the role of a foreland uplift.– Natura Croatica, 5, 317– 327.

BABIĆ LJ., HERNITZ-KUČENJAK, M., ĆORIĆ, S. & ZUPANIČ, J. (2007): The Middle Eocene age of the supposed Late Oligocene sediments in the flysch of the Pazin Basin (Istria, Outer Dinarides).– Natura Croatica: periodicum Musei historiae naturalis Croatici, 16/2, 83–103.

BARATTOLO, F., BASSI, D. & ROMANO, R. (2007): Upper Eocene larger foraminiferal– coralline algal facies from the Klokova Mountain (southern continental Greece).– Facies, 53, 361–375. doi: 10.1007/s10347-007-0108-2

BARNOLAS, A. & TEIXELL, A. (1994): Platform sedimentation and collapse in a carbonate- dominated margin of a foreland basin (Jaca basin, Eocene, south Pyrenees).– Geology, 22/12, 1107–1110. doi: 10.1130/0091-7613(1994)022<1107:PSACIA>2.3.CO;2

BASSI, D. (2005): Larger foraminiferal and coralline algal facies in an Upper Eocene storm-influenced, shallow water carbonate platform (Colli Berici, northeastern Italy).– Palaeogeography Palaeoclimatology Palaeoecology, 226/17, 17–35. doi: 10.1016/j.palaeo.2005.05.002

BENIĆ, J. (1991): The age of the Istria Flysch deposits based on calcareous nannofosils.– In: DROBNE, K. & PAVLOVEC, R. (eds.): Introduction to the Paleogene SW Slovenia and Istria. Field-Trip Guidebook IGCP Project, Early Paleogene Benthos, 2nd meeting Postojna (Slovenia, Istria), p. 25.

BERGANT, S., TIŠLJAR, J. & ŠPARICA, M. (2003): Eocene Carbonates and Flysch Deposits of the Pazin Basin.– In: VLAHOVIĆ, I. & TIŠLJAR, J. (eds.): Field Trip Guidebook - 22nd IAS Meeting of Sedimentology – Opatija 2003, 57–63.

BERGANT, S., MATIČEC, D., FUČEK, L., PALENIK, D., KORBAR, T., ŠPARICA, M., KOCH, G., GALOVIĆ, I. & PRTOLJAN, B. (2020): Basic Geological Map of the Republic of Croatia scale 1:50.000, sheet: Rovinj 2– Department of Geology, Croatian Geological Survey, Zagreb.

BOSENCE, D.W.J. (2005): A genetic classification of carbonate platforms based on their basinal and tectonic settings in the Cenozoic.− Sedimentary Geology, 175/1–4, 49–72. doi: 10.1016/j.sedgeo.2004.12.030

BOUMA, A.H. (1987): Megaturbidite: An acceptable term?– Geo-Marine Letters, 7, 63–67. doi: 10.1007/BF02237985

CROATIAN GEOLOGICAL SURVEY (2009): Geological Map of the Republic of Croatia at the Scale 1:300. 000.– Croatian Geological Gurvey, Department of Geology, Zagreb.

ĆORIĆ, S., BABIĆ, LJ., HERNITZ KUČENJAK, M. & ZUPANIČ, J. (2008): Conflicting dating of the coastal Dinaric flysch, and implications: Eocene or Miocene? The case of north Dalmatia and Istria.– Geophysical Research Abstracts, p. 10.

ĆOSOVIĆ, V., DROBNE, K. & MORO, A. (2004): Paleoenvironmental model for Eocene foraminiferal limestones of the Adriatic carbonateplatform (Istrian Peninsula).– Facies, 50, 61–75.

ĆOSOVIĆ, V., MARJANAC, T., DROBNE, K. & MORO, A. (2008): Outer Dinarides: eastern Adriatic coast. Paleogene and Neogene.− In: McCANN, T. (ed.): The Geology of Central Europe, Volume 2: Mesozoic and Cenozoic. The Geological Society London, London, 1031–1139.

ĆOSOVIĆ, V., MRINJEK, E, NEMEC, W., ŠPANIČEK, J. & TERZIĆ, K. (2018): Development of transient carbonate ramps in an evolving foreland basin.– Basin Research, 30, 746–765, doi: 10.1111/bre.12274

DROBNE, K. (1977): Alvéolines paléogènes de la Slovénie et de l’Istrie.– Mémoires suisses de Paléontologie, 99, 174 p.

DUNHAM, R.J. (1962): Classification of carbonate rocks according to depositional texture.– In: HAM, W.E. (ed.): Classification of Carbonate Rocks. American Association of Petroleum Geologists Memoir, 1, 108–121.

EMBRY, A.F. & KLOVAN, J.E. (1971): A late Devonian reef tract on northeastern Banks Island, N.W.T.– Bulletin of Canadian Petroleum Geology, 19/4, 730–781.

FALLGATTER, C., KNELLER, B., PAIM, P.S. & MILANA, J.P. (2016): Transformation, partitioning and flow–deposit interactions during the run-out of megaflows.– Sedimentology, 64/2, 359–387. doi: 10.1111/sed.12307

FELIX, M., LESZCZYŃSKI, S., SLACZKA, A., UCHMAN, A., AMY, L. & PEAKALL, J. (2009): Field expressions of the transformation of debris flows into turbidity currents, with examples from the Polish Carpathians and the French Maritime Alps.– Marine and Petroleum Geology, 26/10, 2011–2020. doi: 10.1016/j.marpetgeo.2009.02.014

FESTA, A., PINI, G. A., OGATA, K. & DILEK, Y. (2019): Diagnostic features and fieldcriteria in recognition of tectonic, sedimentary and diapiric mélanges in orogenic belts and exhumed subduction-accretion complexes.– Gondwana Research, 74, 7–30. doi: 10.1016/

FLÜGEL, E. (2004): Microfacies of Carbonate Rocks: Analysis, Interpretation and Application.– Springer-Verlag, Berlin, 976 p. doi: 10.1017/S0016756806221940

GOBO, K., MRINJEK, E. & ĆOSOVIĆ, V. (2021): Mass-transport deposits and the onset of wedge-top basin development: An example from the Dinaric Foreland Basin, Croatia.– Journal of Sedimentary Research, 90/11, 1527–1548. doi: 10.2110/jsr.2019.192

HAGN, H., PAVLOVEC, R. & PAVŠIĆ, J. (1979): Excursion G, Gračišće near Pićan, Istria-Eocene.– In: Excursions Guidebook, 16. European Micropalaeontological Colloquium, Ljubljana, 185–190.

HALLOCK, P. & GLENN, E.C. (1986): Larger Foraminifera: A Tool for Paleoenvironmental Analysis of Cenozoic Carbonate Depositional Facies.– Palaios, 1/1, 55–64. doi: 10.2307/3514459

HAMPTON, M.A. (1972): The role of subaqueous debris flow in generating turbidity currents.– Journal of Sedimentary Research, 42/4, 775–793. doi: 10.1306/74D7262B-2B21-11D7-8648000102C1865D

HAUGHTON, P., BARKER, S. & MCCAFFREY, W. (2003): ‘Linked’ debrites in sandrich turbidite systems ‐ origin and significance.– Sedimentology, 50/3, 459–482. doi: 10.1046/j.1365-3091.2003.00560.x

HAUGHTON, P., DAVIS, C., MCCAFFREY, W. & BARKER, S. (2009): Hybrid sediment gravity flow deposits – classification, origin and significance.– Mar. Petroleum Geology, 26/10, 1900–1918. doi: 10.1016/j.marpetgeo.2009.02.012

HAQ, B., HARDENBOL, J.R. & VAIL, P. (1987): Chronology of Fluctuating Sea Levels Since the Triassic.– Science, 235/4793, 1156–67. doi: 10.1126/science.235.4793.1156

JURAČIĆ, M. (1980): Depth of sedimentation of Marl with crabs estimated from the ratio between planktonic and benthic foraminifera.– Geološki vjesnik, 31, 61–67.

KLEVERLAAN, K. (1987): Gordo Megabed: a possible seismite in a Tortonian submarine fan, Tabernas Basin, Province Almeria, southeast Spain.– Sedimentary Geolology, 51/3–4, 165–180. doi: 10.1016/0037-0738(87)90047-9

KORBAR, T. (2009): Orogenic evolution of the External Dinarides in the NE Adriatic region: a model constrained by tectonostratigraphy of Upper Cretaceous to Paleogene carbonates.– Earth-Science Reviews, 96/4, 296–312. doi: 10.1016/j.earscirev.2009.07.004

KRAŠENINNIKOV, V.A., MULDINI-MAMUŽIĆ, S. & DŽODŽO-TOMIĆ, R. (1968): Signification des foraminiferes planctoniques pour la division du Paléogene de la Yougoslavie et comparaison avec les autres régions examinées.– Geološki vjesnik, 21, 117–145.

LABAUME, P., MUTTI, E. & SEGURET, M. (1987): Megaturbidites: A depositional model from the eocene of the SW-Pyrenean Foreland basin, Spain.– Geo-Marine Letters, 7/2, 91–101. doi: 10.1007/BF02237988

LOWE, D.R. (1982): Sediment gravity flows: II depositional models with special reference to the deposits of high-density turbidity currents.– Journal od Sedimentary Petrology, 52/1, 279–297. doi: 10.1306/212F7F31-2B24-11D7-8648000102C1865D

MAGAŠ, N. (1973): Osnovna geološka karta SFR Jugoslavije, 1:100000, Tumač za list Cres L33-113, [Basic Geological Map of SFRY 1:100.000, Geology of the Cres sheet – in Croatian, English Abstr.].– Institut za geološka istraživanja, Zagreb, Savezni geološki zavod, Beograd, 42 p.

MAGDALENIĆ, Z. (1972): Sedimentologija fliških naslaga Srednje Istre [Sedimentology of Central Istria flysch deposits – in Croatian, English abstr.].– Prirodoslovna istraživnja, knjiga, 39, 71–100.

MARINČIĆ, S. (1981): Eocenski fliš Jadranskog pojasa [Eocene flysch of Adriatic area – in Croatian, English abstr.].– Geološki vjesnik, 34, 27–38.

MARINČIĆ, S., ŠPARICA, M., TUNIS, G. & UCHMAN, A. (1996): The eocene flysch deposits of the Istrian peninsula in Croatia and Slovenia. Regional, stratigraphic, sedimentological and ichnological analysis.– Annales, 9, 139–156.

MARJANAC, T. (1990): Reflected sediment gravity flows and their deposits in flysch of Middle Dalmatia, Yugoslavia.– Sedimentology, 37/5, 921–929.

MARJANAC, T. (1991): Importance of megabeds for reconstruction of Paleogene flysch basin in Split hinterland (Middle Dalmatia).– Geološki vjesnik, 44, 201–213.

MARJANAC, T. (1993): Evolution of Eocene–Miocene flysch basin of Central Dalmatia, Croatia.– Unpubl. PhD Thesis, University of Zagreb, 348 p.

MARJANAC, T. (1996): Deposition of megabeds (megaturbidites) and sea-level change in a proximal part of Eocene-Miocene flysch of central Dalmatia (Croatia).– Geology, 24/6, 543–546. doi: 10.1130/0091-7613(1996)024<0543:DOMMAS>2.3.CO;2

MARJANAC, T. & ĆOSOVIĆ, V. (2000): Tertiary depositional history of Eastern Adriatic realm.– Vijesti Hrvatskog geološkog društva, 37/2, 93–103.

MATIČEC, D., VLAHOVIĆ, I., VELIĆ, I. & TIŠLJAR, J. (1996): Eocene limestones overlying Lower Cretaceous deposits of western Istria (Croatia): Did some parts of present Istria form land during the Cretaceous?– Geologia Croatica, 49/1, 117–127.

MIKES, T. & BÁLDI-BEKE, M. & KAZMER, M. & DUNKL, I. & EYNATTEN, H. (2008): Calcareous nannofossil age constraints on Miocene flysch sedimentation in the Outer Dinarides (Slovenia, Croatia, Bosnia-Herzegovina and Montenegro).– Geological Society, London, Special Publications, 298, 335–363. doi: 10.1144/SP298.16

MULDER, T. & ALEXANDER, J. (2001): The physical character of subaqueous sedimentary density flow and their deposits.– Sedimentology, 48/2, 269–299. doi: 10.1046/j.1365-3091.2001.00360.x

MUTTI, E., RICCI LUCCHI, F., SEGURET, M. & ZANZUCCHI, G. (1984): Seismoturbidites: A new group of resedimented deposits.– Marine Geology, 55/1–2, 103–116. doi: 10.1016/0025-3227(84)90135-X

OGATA, K., POGAČNIK, Ž., PINI, G.A., TUNIS, G., FESTA, A., CAMERLENGHI, A. & REBESCO, M. (2014): The carbonate mass transport deposits of the Paleogene Friuli Basin (Italy/Slovenia): Internal anatomy and inferred genetic processes.– Marine Geology, 356, 88–110. doi: 10.1016/j.margeo.2014.06.014

OGATA, K., POGAČNIK, Ž.,TUNIS, G., PINI, G.A., FESTA, A. & SENGER, K. (2019): A Geophysical-Geochemical Approach to the Study of the Paleogene Julian— Slovenian Basin “Megabeds” (Southern Alps—Northwestern Dinarides, Italy/Slovenia).– Geosciences, 9/4, 1–17. doi: 155. 10.3390/geosciences9040155

OGATA, K., FESTA, A., PINI, G.A. & ALONSO, J.L. (2020): Submarine Landslide Deposits in Orogenic Belts: Olistostromes and Sedimentary Mélanges in Submarine Landslides.– In OGATA, K., FESTA, A. & PINI, G.A. (eds): Submarine Landslides: Subaqueous Mass Transport Deposits from Outcrops to Seismic Profiles, Geophysical Monograph 246, American Geophysical Union. John Wiley & Sons, 3–26. doi: 10.1002/9781119500513.ch1

OTONIČAR, B. (2007): Upper Cretaceous to Paleogene forbulge unconformity associated with foreland basin evolution (Kras, Matarsko podolje and Istria; SW Slovenia and NW Croatia).– Acta Carsologica, 36/1, 101–120. doi: 10.3986/ac.v36i1.213

PAYROS, A., PUJALTE, V. & ORUE-ETXEBARRIA, X. (1999): The South Pyrenean Eocene carbonate megabreccias revisited: new interpretation based on evidence from Pamplona Basin.– Sedimentary Geology, 125/3–4, 165–194. doi: 10.1016/S0037-0738(99)00004-4

PICCOLI, G. & PROTO DECIMA, F. (1969): Ricerche biostratigrafiche sui depositi flyschoidi della regione adriatica settentrionale e orientale.– Memorie degli Instituti di Geologia Mineralogia dell’Universitŕ di Padova, 27, 1–23.

PINI, G.A., OGATA, K., CAMERLENGHI, A., FESTA, A., LUCENTE, C.C. & CODEGONE, G. (2012): Sedimentary melanges and fossil mass‐transport complexes: A key for better understanding submarine mass movements?– In: YAMADA, Y., KAWAMURA, K., IKEHARA, K., OGAWA, Y., URGELES, R., MOSHER, D., CHAYTOR, J. & STRASSER, M. (eds.), Submarine mass movements and their consequences, Advances in Natural and Technological Hazards Research, 31, Dordrecht, Springer Science+BusinessMedia B.V., 585–594. doi: 10.1007/978-94-007-2162-3_52

POLŠAK, A. & ŠIKIĆ, D. (1973): Osnovna geološka karta SFR Jugoslavije, 1:100000, Tumač za list Rovinj L30-100, [Basic Geological Map of SFRY 1:100.000, Geology of the Rovinj sheet – in Croatian, English Abstr.].– Institut za geološka istraživanja, Zagreb, Savezni geološki zavod, Beograd, 51 p.

RASSER, M.W., & PILLER W.E. (2004): Crustose algal frameworks from the Eocene Alpine Foreland.– Palaeogeography, Palaeoclimatology, Palaeoecology, 206/1–2, 21–39. doi: 10.1016/j.palaeo.2003.12.018

SCHMID, S.M., BERNOULLI, D., FÜGENSCHUH, B., MATENCO, L., SCHEFER, S., SCHUSTER, R., TISCHLER, M. & USTASZEWSKI, K. (2008): The Alpine- Carpathian-Dinaridic orogenic system: correlation and evolution of tectonic units.– Swiss Journal of Geosciences, 101, 139–183. doi: 10.1007/s00015-008-1247-3

SHANMUGAM, G. (2006): Deep-water processes and facies models: Implications for sandstone petroleum reservoirs: Amsterdam, Elsevier.– Handbook of petroleum exploration and production, 5, 476 p.

SINCLAIR, H.D. (1997): Tectonostratigraphic model for underfilled peripheral foreland basins.– GSA Bulletin, 109/8, 324–346. doi: 10.1130/0016-7606(1997)109<0324:TMFUPF>2.3.CO;2

ŠIKIĆ, D. & POLŠAK, A. (1973): Osnovna geološka karta SFR Jugoslavije, 1:100000, Tumač za list Labin L33-101 [Basic Geological Map of SFRY 1:100.000, Geology of the Labin sheet – in Croatian, English Abstr.].– Institut za geološka istraživanja, Zagreb, Savezni geološki zavod, Beograd, 55 p.

ŠIKIĆ, D. & PLENIČAR, M. (1975): Osnovna geološka karta SFR Jugoslavije, 1:100000, Tumač za list Ilirska Bistrica L33-89 [Basic Geological Map of SFRY 1:100.000, Geology of the Ilirska Bistrica sheet – in Croatian, English Abstr.].– Institut za geološka istraživanja, Zagreb, Geološki zavod. Ljubljana, Savezni geološki zavod, Beograd, 51 p.

ŠPELIĆ, M., DEL BEN, A. & PETRINJAK, K. (2021): Structural setting and geodynamics of the Kvarner area (Northern Adriatic).– Marine and Petroleum Geology, 125, 104857. doi: 10.1016/j.marpetgeo.2020.104857

TALLING, P. (2013): Hybrid submarine flows comprising turbidity current and cohesive debris flow: Deposits, theoretical and experimental analyses, and generalized models.– Geosphere, 9, 460–488. doi: 10.1130/GES00793.1

TARLAO, A., TUNIS, G. & VENTURINI, S. (1995): Lutetian Transgression in Central Istria: the Rogovići-Mećari section case.– In: VLAHOVIĆ, I., VELIĆ, I. & ŠPARICA, M. (eds): Proceedings 2, First Croatian Geological Congress. Institute of Geology, Zagreb, 613–618.

TARLAO, A., TUNIS, G. & VENTURINI, S. (2005): Dropstones, pseudoplanktonic forms and deep-waterdecapod crustaceans within a Lutetian condensed succession of central Istria (Croatia): relation to palaeoenvironmental evolution and palaeogeography.– Palaeogeography, Palaeoclimatology, Palaeoecology, 218/3–4, 325–345. doi: 10.1016/j.palaeo.2004.12.023

TOMASSO, M. & SINCLAIR, H. (2004): Deep-water sedimentation on an evolving fault-block: The Braux and St Benoit outcrops of the Grès d’Annot.– Geological Society, London, Special Publications, 221, 267–283. doi: 10.1144/GSL.SP.2004.221.01.14

TUNIS, G. & VENTURINI, S. (1992): Evolution of the Southern Margin of the Julian Basin with Emphasis on the Mega Beds and Turbidites Sequence of the Southern Julian Prealps (NE Italy).– Geologia Croatica, 45, 127–150.

VLAHOVIĆ, I., TIŠLJAR, J., VELIĆ, I. & MATIČEC, D. (2005): Evolution of the Adriatic Carbonate Platform: Palaeogeography, main events and depositional dynamics.– Palaeogeography, Palaeoclimatology, Palaeoecology, 220/3–4, 333–360. doi: 10.1016/j.palaeo.2005.01.011

VLAHOVIĆ, I. & VELIĆ, I. (2009): Liburnijske naslage, foraminiferski vapnenci i prijelazne naslage (?gornji paleocen, donji i srednji eocen –?Pc, E1,2) [Liburnian deposits, Foraminiferal limestones and Transitional Beds (?Upper Paleocene, Lower and Middle Eocene –?Pc, E1,2 – in Croatian].− In: VELIĆ, I. & VLAHOVIĆ, I. (eds.): Tumač Geološke karte Republike Hrvatske 1:300000 [Explanatory Notes of Basic Geological Map of Croatia 1:300.000 – in Croatian]. Hrvatski geološki institut, Zagreb, 76−77.

VELIĆ, I., TIŠLJAR, J., VLAHOVIĆ, I., MATIČEC, D. & BERGANT, S. (2003): Evolution of the Istrian part of the Adriatic Carbonate Platform from the Middle Jurassic to the Santonian and Formation of the Flysch Basin during the Eocene: Main Events and Regional Comparison.– In: VLAHOVIĆ, I. & TIŠLJAR, J. (eds.): Field Trip Guidebook – 22nd IAS Meeting of Sedimentology – Opatija. Croatian Geological Survey, Zagreb, 57–63.

VELIĆ, I. (2007): Stratigraphy and Palaeobiogeography of Mesozoic Benthic Foraminifera of the Karst Dinarides (SE Europe).– Geologia Croatica, 60/1, 1–113.

ŽIVKOVIĆ, S. & BABIĆ, LJ. (2003): Paleoceanographic implications of smaller benthic and planktonic foraminifera from the Eocene Pazin Basin (Coastal Dinarides, Croatia).– Facies, 49, 49–60. doi: 10.1007/s10347-003-0024-z

ŽIVKOVIĆ, S. & GLUMAC, B. (2007): Paleoenvironmental reconstruction of the Middle Eocene Trieste-Pazin basin (Croatia) from benthic foraminiferal assemblages.– Micropaleontology, 53/4, 285–310. doi: 10.2113/gsmicropal.53.4.285