HR: 10:35h
AN: T42B-02    [Abstracts]
TI: New insights into the northern Dead Sea Fault Zone (Karasu Rift and Hatay Graben), Southern Turkey.
AU: * Boulton, S J
EM: sarah.boulton@plymouth.ac.uk
AF: University of Plymouth, SEOES,Drakes Circus, Plymouth, Dev PL4 8AA, United Kingdom
AB: The Karasu Rift forms the northernmost segment of the Dead Sea Fault Zone (DSFZ), trending northwards from the Amik Plain. To the south of the Amik Plain, the Gharb Rift forms the southwards continuation of the DSFZ, while to the east the Hatay Graben trends NE-SW from the Amik Plain to the present Mediterranean coast. Recent fieldwork in the area shows a markedly different style of deformation across the Amik Plain. The northern Gharb fault is a narrow (<10 km wide) structure that is flanked by numerous fault strands, large strike-slip faults have negligible vertical offset. Small-scale faulting accompanying the large faults is uncommon, although the Late Miocene and Pliocene sediments are pervasively fractured, with two sets of joints orientated between 010°-060° and 090°-130°. This may imply that motion along the DSFZ is accommodated along the main faults and internally fault blocks do not undergo any faulting. By contrast, the southern Karasu Rift is 15-20km wide and the bounding faults have a significant vertical component of motion. Palaeozoic to Upper Miocene sediments have been exhumed in the footwall and are faulted as well as jointed, two main populations of faults have been identified, those trending NE-SW (010°- 060°) and those trending ~ N-S (320°-005°), although in some areas there is also a third subset of faults that trend E- W. These differences suggest that the structural controls on the two areas differ, implying that there is no continuity of structure across the Amik Plain. The Hatay Graben is also 15-20km wide; the flanks of the graben are dominated by normal faults mainly striking parallel to the graben (0-180°). In contrast, the graben axis exhibits numerous strike-slip faults, trending from 100° - 200°, and normal faults striking 040°- 060° and 150°-190° (with a subset striking 110°-130°). Normal faults of similar orientation occur in Upper Cretaceous to Quaternary sediments, whereas strike-slip faults are mostly identified within Pliocene and Quaternary sediments exposed near the graben axis. Syn-sedimentary relationships indicate that initial faulting occurred during the Middle Miocene Stress analysis of mostly Pliocene sediments at eleven suitable locations shows that sigma 3 directions are uniform in the northeast and orientated at a high angle to the graben, parallel to the maximum extension direction. Analysis of faulting shows that the Hatay Graben developed due to transtension, whereas the Karasu and Gharb Rifts experienced strike-slip deformation. It is suggested that the orientation of these grabens were probably influenced by pre-existing zones of crustal weakness, related to Early Mesozoic rifting of Neotethys. Then, during the Plio-Quaternary the main tectonic controls were E-W left-lateral ‘tectonic escape' of Anatolia and N-S left- lateral movement along the propagating DSFZ, which lead to extension in the area. This composite origin contrasts with previous models for basin formation where the grabens are considered simply Pliocene to recent structures.
DE: 8010 Fractures and faults
DE: 8107 Continental neotectonics (8002)
DE: 8111 Continental tectonics: strike-slip and transform
DE: 9335 Europe
DE: 9604 Cenozoic
SC: Tectonophysics [T]
MN: 2007 Fall Meeting