HR: 16:30h
AN: V12J-03    [PDF]
TI: Structure and Tectonics of the Moho and Surrounding Part of the Oman Ophiolite, West Sohar
AU: * Allawati, H
EM: h_allawatia@hotmail.com
AF: Univ. of Tsukuba, Institute of Geoscience, Tennodai 1-1-1, Tsukuba, Ibaraki, 305-8571 Japan
AU: Ogawa, Y
EM: yogawa@arsia.geo.tsukuba.ac.jp
AF: Univ. of Tsukuba, Institute of Geoscience, Tennodai 1-1-1, Tsukuba, Ibaraki, 305-8571 Japan
AB: We report on a field study and subsequent analysis of ophiolites, which are on-shore examples of the ancient oceanic lithosphere, in the Bat area of Wadi Zabin and its southern extension areas in the Northern Oman Mountains. The study focuses on the extensive flow and shear structures including mylonite thrust faults, and folds. These mylonite thrust faults and folds are mapped and structurally analyzed. Each rock body, except for the later stage intrusive bodies, is always associated with strong shear zones. Exposures of regionally persistent serpentinized peridotite appears to have formed at the bottom of a dome at Bat, bounded by faults to W and covered with massive and layered gabbro to E. The mylonite and schist of ultramafic composition strikes NW approximately parallel to the inferred paleo-spreading direction suggesting that it may represent a detachment fault plastically deformed, with dextral dragged slip zones. Small-scale isoclinal folds asymmetric folds and thrusts characterize the deformation both in the mylonite and shear zones. Consideration of these structural characteristics, attitude and vergences indicate that the flow and shear structures occurred at several stages, first under high temperature conditions to form ductile deformations, and later semi brittle deformations. This deduction is consistent with an early spreading phase and a later stage of converging tectonics, possibly at the obduction stage.
DE: 3040 Plate tectonics (8150, 8155, 8157, 8158)
DE: 8005 Folds and folding
DE: 8010 Fractures and faults
DE: 8030 Microstructures
DE: 8120 Dynamics of lithosphere and mantle--general
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting