HR: 1340h
AN: GP43C-1482    [Abstracts]
TI: No Significant Rotation of the Moesian platform and Rhodope (Bulgaria) since the early Oligocene: implications for the Aegean and Balkan tectonic history
AU: Oud, K
EM: k.oud@students.uu.nl
AF: Paleomagnetic Laboratory 'Fort Hoofddijk', Utrecht University, Budapestlaan 17, Utrecht, 3584 CD, Netherlands
AU: * van Hinsbergen, D J
EM: hins@geo.uu.nl
AF: Paleomagnetic Laboratory 'Fort Hoofddijk', Utrecht University, Budapestlaan 17, Utrecht, 3584 CD, Netherlands
AU: Dupont-Nivet, G
EM: gdn@geo.uu.nl
AF: Paleomagnetic Laboratory 'Fort Hoofddijk', Utrecht University, Budapestlaan 17, Utrecht, 3584 CD, Netherlands
AU: Nakov, R
EM: radnac@geology.bas.bg
AF: Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Bl. 24, Sofia, 1113, Bulgaria
AB: Here, we present new paleomagnetic data from Oligocene (~30-35 Ma) and lower Miocene (~20 Ma) volcanic rocks exposed on the Moesian platform and Rhodope mountains of Bulgaria. A total of 467 samples were analysed from 58 lava sites obtained from 6 volcanic centers. Each lava yields high k-values, typically well above 100, and we interprete the results of a lava site as representing a spot reading of the earth's magnetic field. Rock magnetic tests showed that the ChRM is carried by titano-magnetite. A total of 56 successful lava sites was averaged, resulting in an average direction of D/I = 9.8°/60.5°, and a k/á95 of 23.4/4.0. The k-value can well be explained by secular variation of the earth's magnetic field and we consider this direction reliable. The expected direction for 30 Ma for Eurasia according to Besse & Courtillot (2002) is D: 6.8±4.8° and I: 57.4±3.6°, leading to a non-significant rotation of 3.0±7.6° and a non-significant flattening of –3.1±4.3°. This finding has important implications for the tectonic evolution of the Aegean-Balkan-Carpathian orogenic system. Between 13 and 8 Ma, a 600 km long block in the west-Aegean region between northern Albania and the southern Peloponnesos underwent a 50° clockwise rotation. Classically, this rotating block has been suggested to rotate around a pole in northern Albania. However, the absence of significant rotation in the Moesian platform and Bulgarian Rhodope is at odds with this interpretation: the rotation difference would in this case be accommodated by more than 300 km extension. Even though extension is active in the central and northern Aegean region in this time, it is certainly less than 100 km. In this presentation we will postulate a scenario aiming to solve this space problem, including the relocation of the rotation pole in western Greece, and the accommodation of west-Aegean rotation in the Dinarid-Carpathian system, which can form ground for further analysis of the Neogene horizontal motions around the Moesian platform
UR: http://www.geologist.nl
DE: 1525 Paleomagnetism applied to tectonics: regional, global
DE: 1527 Paleomagnetism applied to geologic processes
DE: 8104 Continental margins: convergent
DE: 8109 Continental tectonics: extensional (0905)
DE: 8170 Subduction zone processes (1031, 3060, 3613, 8413)
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Fall Meeting