HR: 1340h
AN: T33A-1136    [Abstracts]
TI: Uplift and Extensional Deformation Caused By Delaminated Lithosphere of the Eastern Anatolian Plateau
AU: * Gogus, O H
EM: gogus@geology.utoronto.ca
AF: University of Toronto, 22 Russell st, Toronto, ON M5S3B1, Canada
AU: Pysklywec, R N
EM: russ@geology.utoronto.ca
AF: University of Toronto, 22 Russell st, Toronto, ON M5S3B1, Canada
AB: The process of delamination has been invoked to explain the anomalous uplift of various disparate locales such as the Sierra Nevada, Colorado Plateau, Andes, and Alboran Sea/Rif-Betics. In this study, we examine the possible role of delamination in the tectonic evolution of the Eastern Anatolian plateau. This is an enigmatic region of high topography that is absent of mantle lithosphere; and it is bounded by plate convergence but shows appreciable extension across the plateau. Our geodynamic models demonstrate that a rapid delamination of mantle lithosphere (in 7 Myrs) results in broad surface uplift of 2 to 3 km through isostatic adjustment and flow stresses. The amplitude and form of uplift is close to the present day surface topography profile of the Eastern Anatolia along 42° E. Zones of crustal shortening, thickening, and enhanced uplift flank the uplifted plateau. These are caused by a combination of imposed plate convergence in the models and delamination-driven effects. More notably, the delamination also drives a region of extension and crustal thinning within the model plateau, even in the midst of the broader plate convergence. When the plate convergence rate is set to zero, the delamination effects are isolated and we observe amplified extension and thinning, but decreased plateau uplift and shortening/thickening at the plateau flanks. When the convergence rate is doubled, extension/thinning is muted and the contraction and thickening is amplified but is still localized to the sites determined by the delamination. The results suggest that mantle lithosphere delamination may reconcile the presence of extensional structures and half-grabens across Eastern Anatolia within the larger-scale contractional system. Furthermore, the model may be used to understand similar styles of syn-convergent extension at the Apennines- Tyrrhenian, Himalayas and Alboran Sea/Rif-Betics.
DE: 7200 SEISMOLOGY
DE: 8110 Continental tectonics: general (0905)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting