HR: 08:45h
AN: T21D-03    [Abstracts]
TI: Continental Extension in Basin and Range, USA and Western Anatolia Extended Terrane (WAET) in western Turkey: A review
AU: * Cemen, I
EM: icemen@okstate.edu
AF: Oklahoma State University, Boone Pickens School of Geology OKalhoma State University, Stillwater, OK 74078,
AU: Catlos, E
EM: ej.catlos@okstate.edu
AF: Oklahoma State University, Boone Pickens School of Geology OKalhoma State University, Stillwater, OK 74078,
AU: Axen, G
EM: gaxen@ees.nmt.edu
AF: New Mexico Tech, Earth & Environmental Science, New Mexico Tech, Socorro, NM 87801,
AB: The Basin and Range of western USA and Western Anatolia Extended Terrane (WAET) of western Turkey are two major extended terranes that share many characteristics. They both contain many common structural elements indicative of pervasive continental extension such as well-developed metamorphic core complexes (MCC), detachment surfaces, turtleback faults, extensional folds, supra detachment basins, and extensional shear sense indicators. The Basins and Ranges extension began in Eocene with MCC development in NW USA in a back-arc setting. The extension progressively moved southward into the eastern Great Basin in Late Oligocene-Early Miocene time. Extension in the southern Basin and Range was underway in early-middle Miocene. Well after the onset of extensional faulting in these areas, volcanic activity changed from calc-alkaline to bimodal. Current geological work in the Basin and Range is concentrated on the amount and percentage of extension with respect to extensional faulting, and amount of displacement along major strike-slip fault zones. Continental extension in the WAET initiated in Late Oligocene and progressively developed in three stages. During the first stage, a north-dipping extensional simple-shear zone formed probably due to orogenic collapse. During this stage, erosion and extensional unroofing brought high-grade metamorphic rocks of the central and northern Menderes Massif to the surface by the Early Miocene. The second stage of extension started in Early Miocene, probably caused by slab roll-back of the Hellenic arc. It produced the north-dipping Alasehir and the south-dipping Buyuk Menderes Detachment surfaces which control the Miocene supra detachment sedimentation in the Alasehir and Buyuk Menderes Grabens. The third stage may have started ~5 Ma when the North Anatolian Fault initiated and the westward tectonic escape of the Anatolian Plate started. This stage produced high angle faults within the Alasehir, Buyuk Menderes and Kucuk Menderes Grabens. Current geological work in WAET is concentrated on the age and nature of the metamorphism in the Menderes massif; the exhumation history of the metamorphic rocks along the low angle detachment surfaces; and the amount and percentage of extension.
DE: 8109 Continental tectonics: extensional (0905)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting