New paleomagnetic results from imbricated Adria: Ist Island and related areas
Article Sidebar
Main Article Content
Abstract
For the purpose of this work samples for palaeomagnetic analysis were taken from Upper Cenomanian and Lower Senonian shallow water limestones, as well as from Senonian pelagic limestones from both Ist and the surrounding islands. This area belongs to Imbricated Adria, which is characterized by gently folded and faulted strata with a Dinaridic (NW–SE) trend. An exception is Premuda island where the beds are strongly folded and are subvertical. A total of 96 samples were drilled from 10 localities distributed between eight islands. The samples were then subjected to standard palaeomagnetic laboratory analysis and statistical evaluation. Eventually, six localities yielded statistically well-defined palaeomagnetic directions, which were shown pre date the folding in age.
The overall mean palaeomagnetic direction obtained for the study area, characterizing the Cenomanian–Early Senonian time period had a Declination of 334°, Inclination=+46°, with statistical parameters k=188, a95=4.9°, defining a palaeomagnetic pole at l(N)=63°, f(E)=254°, dp=4.0°, dm=6.2°. This was compared with palaeomagnetic directions obtained for rocks of similar ages from stable Istria and the Kvarner islands. As the three palaeomagnetic directions are statistically identical, we conclude that there was no significant relative movement between the three areas after the Early Senonian. The palaeomagnetic declination for the study area, which characterizes the post-Early Senonian rotation of the Adriatic microplate, is the same as the declination for the Pannonian–Pontian age group from the South Pannonian basin. As the palaeomagnetic signals in both cases are primary, the results of the present paper not only support the conclusion that the rotating Adriatic microplate triggered rotations in the South Pannonian basin, but also suggest that the Adriatic platform did not change its orientation between the late Cretaceous and the Early Pontian.
Downloads
Article Details
Authors have copyright and publishing rights on all published manuscripts.
References
FISHER, R.A. (1953): Dispersion on a sphere.– Proceedings of the Roy-al Society London, 217, 295–305.
GUŠIĆ, I. & JELASKA, V. (1990): Stratigrafi ja gornjokrednih naslaga otoka Brača u okviru geodinamske evolucije Jadranske karbonatne platforme [Upper Cretaceous stratigraphy of the Island of Brač within the geodynamic evolution of the Adriatic carbonate platform– in Croatian].– Djela Jugoslavenske akademije znanosti i umjet-nosti, Zagreb, 69, 160.
HERAK, M. (1991): Dinaridi-mobilisticki osvrt na genezu i strukturu [Dinarides – mobilistic view of the genesis and structures – in Cro-atian].– Acta Geol., 21/2, 35–117.
KAPOVIĆ, B. & BAUER, V. (1970): Sedimentološke, biofacijalne i ambijentalne karakteristike gornjokrednih naslaga otoka Premuda i Dugog Otoka [Sedimentary, biofacies and environmental charac-teristics of the Upper Cretaceous sediments of the Premuda Island and Dugi otok – in Croatian].– Nafta, 22/12, 561–572.
KIRSCHVINK, J.L. (1980): The least-squares line and plane and the analysis of palaeomagnetic data.– Geophys. J. Roy. Astro. Soc., 62, 699–718.
MAMUŽIĆ, P. (1970): Osnovna geološka karta SFRJ: 100 000, list Mo-lat L 33–138 [Basic Geological Map of SFRY 1:100 000, sheet Mo-lat – in Cro atian].– Savezni geološki zavod Beograd.
MAMUŽIĆ, P. & SOKAČ, B. (1967). Tumač za listove Silba i Molat L 33–126, L 33 138 [Geology of the Silba and Molat sheets – in Croatian].– Savezni geološki zavod Beograd, 45 p.
MAMUŽIĆ, P., SOKAČ, A. & VELIĆ, I. (1970): Osnovna geološka karta SFRJ 1:100 000, list Silba L 33–126. [Basic Geological Map of SFRY 1:100 000, sheet Silba – in Croatian].– Savezni geološki zavod Beo grad.
MÁRTON, E. (2006): Palaeomagnetic evidence for Tertiary countercloc-wise rotation of Adria with respect to Africa.– In: Pinter, N., Grenerczy, Gy., Weber, J., Stein, S. Medak, D. (eds.): The Adria micro-plate: GSP Geodesy, Tectonics and Hazards. NATO Science Series IV-61, 71–80.
MÁRTON, E. & VELJOVIĆ, D. (1983): Palaeomagnetism of the Istria peninsula, Yugoslavia.– Tectonophys., 91, 73–87. doi: 10.1016/ 0040-1951(83)90058-6
MÁRTON, E. & VELJOVIĆ, D. (1987): Palaeomagnetism of Creta-ceous carbonates from the northwestern part of the Dinaric fold belt.– Tectonophys., 134, 331–338. doi: 10.1016/0040-1951(87) 90345-3
MÁRTON, E., MILICEVIĆ, V. & VELJOVIĆ, D. (1990): Palaeomag-netism of the Kvarner Islands, Yugoslavia.– Phys. Earth Plan. Int., 62, 70–81. doi: 10.1016/0031-9201(90) 90193-2
MÁRTON, E. & MILICEVIĆ, V. (1994): Tectonically oriented palaeo-magnetic investigation in the Dinarids, between Zadar and Split.– Geophys. Transact., 39, 4, 227–232.
MÁRTON, E., PAVELIĆ, D., TOMLJENOVIĆ, B., PAMIĆ, J. & MÁR-TON, P. (1999): First palaeomagnetic results on Tertiary rocks from the Slavonian mountains in the southern Pannonian basin, Croatia.– Geol. Carpat., 50, 273–279.
MÁRTON, E., PAVELIĆ, D., TOMLJENOVIĆ, B., AVANIĆ, R., PAMIĆ, J. & MÁRTON, P. (2002): In the wake of a counterclockwise rotat-ing Adriatic microplate: Neogene palaeomagnetic results from northern Croatia.– Int. J. Earth Sci., 91, 514–523. doi: 10.1007/s00531-001-0249-4
MÁRTON, E., PAVELIĆ, D., TOMLJENOVIĆ, B., MÁRTON, P. & AVANIĆ, R. (2005): Palaeomagnetic investigations in the Croatian part of the Pannonian basin: a review.– Acta Geol. Hung., 48/2, 225–233. doi: 10.1556/AGeol.48.2005.2.8
MÁRTON, E., JELEN, B., TOMLJENOVIĆ, B., PAVELIĆ, D., POL-JAK, M., MÁRTON, P., AVANIĆ, R. & PAMIĆ, J. (2006): Late Neogene counterclockwise rotation in the SW part of the Pannon-ian Basin.– Geol. Carpat., 57, 41–46.
MÁRTON, E., DROBNE, K., COSOVIC, V. & MORO, A. (2003): Pala eo- magnetic evidence for Tertiary counterclockwise rotation of Adria.– Tectonophys., 337, 143–156. doi: 10.1016/j.tecto.2003.08.022
MÁRTON, E., COSOVIĆ, V., MORO, A. & ZVOCAK, S. (2008): The motion of Adria during the Late Jurassic and Cretaceous: New pal-aeomagnetic results from stable Istria.– Tectonophys., 454, 44–53. doi: 10.1016/j.tecto.2008.04.002
MIKES, T., BÁLDI-BEKE, M., KÁZMÉR, M., DUNKL, I. & EYNAT-TEN, V. H. (2008): Calcareous nannofossil age constrains on Miocene flysch sedimentation in the Outer Dinarides (Slovenia, Croatia, Bosnia-Herzegovina and Montenegro).– In: SIEGESMUND, S., FÜGENSCHUN, B. & FROITZHEIM, N. (eds.): Tectonic Aspects of the Alpine–Dinaride–Carpathian System. Geological Society, London, Special Publications, 298, 335–363.
MORO, A. (1993): Litostratigtafi ja gornjokrednih naslaga otoka Ista, Oliba i Silbe [Lithostratigraphy of the Upper Cretaceous deposits of Ist, Olib and Silba Islands – in Croatian, with an English Summary].– Unpubl. MSc. Thesis, Faculty of Science, University of Zagreb, 60 p.
MORO, A. & JELASKA, V. (1994): Upper Cretaceous Peritidal Depos-its of Olib and Ist Islands (Adriatic Sea, Croatia).– Geol. Croat., 47/1, 53–65.
MORO, A., SKELTON, W.P. & ĆOSOVIĆ, V. (2002): Palaeoenvironmental setting of rudists in the Upper Cretaceous (Turonian–Maastrichtian) Adriatic carbonate Platform (Croatia), based on sequence stratigraphy.– Cretac. Res., 23, 489–508. doi: 10.1006cres.2002. 1017
TARI, V. (2002): Evolution of the northern and western Dinarides: a tectonostratigraphic approach.– EGS Stephan Mueller Publication Series, European Geophysical Society, 1, 1–21.
VLAHOVIĆ, I., TIŠLJAR, J., VELIĆ, I. & MATIČEC, D. (2005): Evolution of the Adriatic Carbonate Platform: Palaeogeography, main events and depositional dynamics.– Palaeogeogr., Palaeoclimatol., Palaeoecol., 220, 333–360. doi: 10.1016/j.palaeo.2005.01.011