HR: 1330h
AN: T12A-0434    [PDF]
TI: Structural Evolution and Rift History Leading to Breakup at the Deep Galicia Margin .
AU: Leythaeuser, T
EM: tleythaeuser@geomar.de
AF: GEOMAR, Wischhofstr. 1-3, Kiel, 24148 Germany
AU: * Reston, T J
EM: treston@geomar.de
AF: GEOMAR, Wischhofstr. 1-3, Kiel, 24148 Germany
AU: Perez-Gussinye, M
EM: martap@earth.ox.ac.uk
AF: Dept Earth Sciences, Parks Road, Oxford, OX1 3PR United Kingdom
AU: Ranero, C R
EM: cranero@geomar.de
AF: GEOMAR, Wischhofstr. 1-3, Kiel, 24148 Germany
AU: Klaeschen, D
EM: dklaeschen@geomar.de
AF: GEOMAR, Wischhofstr. 1-3, Kiel, 24148 Germany
AU: Sawyer, D
EM: dale@rice.edu
AF: Rice University, 6100 Main St, Houston, TX 77005 United States
AB: The Deep Galicia margin is a classic example of non-volcanic margin and was the first where unroofed mantle rocks (the Peridotite Ridge) and a detachment fault (S) were recognised. We have completed the prestack depth migration of in total eight sub-parallel profiles across the margin, which reveal the fault block structure in unprecedented detail. In addition, we have depth migrated seismic profiles across the Galicia Interior Basin, providing an overview of the structure and evolution of the entire margin. In this poster, we summarise the main results, presenting depth sections, velocity sections and structural restorations across the margin. The sections reveal the tilted fault block structure of the margin. In the most recent sections, it can however be seen that the sediment tilted within the fault block occurs in at least two orientations, implying multiple phases of faulting. Some of these earlier faults may be imaged as short segments offset by the latest set of block-bounding faults. Restoring the latest phase of extension aligns the earlier structures and allows more detailed analysis of the structural history of the margin. Together with the depth images and structural reconstructions, the stratigraphic evolution as determined by drilling and submersible sampling constrains the rift history of the margin. Rifting started in the Berriasian, resulting in the drowning of Tithonian carbonate platforms and producing deep-water conditions for subsequent deposition. A second phase of rifting in the Valanginian-Hauterivian was accompanied by the deposition of locally thick sequences of deep water clastics. As these are thicker in the south than the north, extension may not have been east-west. The third phase of faulting, producing the tilted fault block structure that is imaged, probably occurred between the Barremian-Aptian, but may have migrated westwards as a rolling hinge system, consistent with the geometries of the latest phase of faulting.
DE: 3025 Marine seismics (0935)
DE: 8010 Fractures and faults
DE: 8109 Continental tectonics--extensional (0905)
SC: Tectonophysics [T]
MN: 2003 Fall Meeting