HR: 1340h
AN: T23D-1661 [Abstracts]
TI: Insights upon upper crustal arhitecture of a subduction zone and its surroundings - Vrancea Zone and Focsani Basin - substantiated by geophysical studies
AU: * Bocin, A
EM: abocin@falw.vu.nl
AF: Faculty of Geology and Geophysics, University of Bucharest, 6 Traian Vuia Street,
Bucharest, RO-020956, Romania
AU: * Bocin, A
EM: abocin@falw.vu.nl
AF: Faculteit der Aard- en Levenswetenschappen, Vrije Universiteit, De Boelelaan 1085-1087,
Amsterdam, 1081 HV, Netherlands
AU: Stephenson, R
EM: randell.stephenson@falw.vu.nl
AF: Faculteit der Aard- en Levenswetenschappen, Vrije Universiteit, De Boelelaan 1085-1087,
Amsterdam, 1081 HV, Netherlands
AU: Mocanu, V
EM: mocanu@gg.unibuc.ro, vi_mo@yahoo.com
AF: Faculty of Geology and Geophysics, University of Bucharest, 6 Traian Vuia Street,
Bucharest, RO-020956, Romania
AB:
The DACIA PLAN (Danube and Carpathian Integrated Action on Processes in the Lithosphere and Neotectonics)
deep seismic reflection survey was performed in August-September 2001, with the proposed objective of
obtaining new information on the deep structure of the external Carpathians nappes and the architecture of
Tertiary/Quaternary basin developed within and adjacent to the Vrancea zone, including the rapidly subsiding
Focsani Basin. The DACIA-PLAN profile is about 140 km long, having a roughly NW-SE direction, from near the
southeast Transylvanian Basin, across the mountainous southeastern Carpathians and their foreland to near the
Danube River. A high resolution 2.5D velocity model of the upper crust along the seismic profile has been
determined from a tomographic inversion and a 2D ray tracing forward modelling of the DACIA PLAN first arrival
data.
Peculiar shallow high velocities indicate that pre-Tertiary basement in the Vrancea Zone (characterised by
velocities greater than 5.6 km/s) is involved in Carpathian thrusting while rapid alternance, vertically or
horizontally, of velocity together with narrowingly contemporary crustal events suggests uplifting. Further to the
east, at the foreland basin-thrust belt transition zone (well defined within velocity values), the velocity model
suggests a nose of the Miocene Subcarpathians nappe being underlain by Focsani Basin units. A Miocene and
younger Focsani Basin sedimentary succession of ~10 km thickness is ascertained by a gradual increase of
velocities and strongly defined velocity boundaries.
DE: 1140 Thermochronology
DE: 1815 Erosion
DE: 8038 Regional crustal structure
DE: 8102 Continental contractional orogenic belts and inversion tectonics
DE: 8175 Tectonics and landscape evolution
SC: Tectonophysics [T]
MN: 2007 Fall Meeting