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Restraining bends, transpressional deformation and basement controls on development |
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1 Department of Soil Science, Harran University, 63300 
anl
urfa, Turkey
2 Department of Geography, Harran University, 63300 anlurfa, Turkey
3 Scottish Universities' Environmental Research Centre, Rankine Avenue, East Kilbride, Glasgow G75 0QF, UK; Present address: Laboratory for Noble Gas Geochronology, Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Building 54-1013, Cambridge, MA 02139-4307, USA
4 Department of Geology, Çukurova University, 01330 Adana, Turkey; Present address: 41 Kingsway East, Westlands, Newcastle-under-Lyme, Staffordshire, ST5 5PY, UK
5 Faculty of Mathematics and Computing, The Open University, Eldon House, Gosforth, Newcastle-upon-Tyne NE3 3PW, UK; Also at: School of Civil Engineering and Geosciences, University of Newcastle-upon-Tyne, Newcastle-upon-Tyne NE1 7RU, UK (e-mail: robwestaway{at}tiscali.co.uk)
6 Department of Geography, Durham University, South Road, Durham DH1 3LE, UK; Present address: School of Computing, University of Leeds, Leeds LS2 9JT, UK
7 School of Earth Sciences and Geography, Keele University, Keele, Staffordshire ST5 5BG, UK
We report four new Ar/Ar dates and 18 new geochemical analyses of Pleistocene basalts from the Karasu Valley of southern Turkey. These rocks have become offset left-laterally by slip on the N20°E-striking Amanos Fault. The geochemical analyses help to correlate some of the less-obvious offset fragments of basalt flows, and thus to measure amounts of slip; the dates enable slip rates to be calculated. On the basis of four individual slip-rate determinations, obtained in this manner, we estimate a weighted mean slip rate for this fault of 2.89±0.05mm/a (±2
). We have also obtained a slip rate of 2.68±0.54mm/a (±2) for the subparallel East Hatay Fault farther east. Summing these values gives 5.57±0.54mm/a (±2) as the overall left-lateral slip rate across the Dead Sea fault zone (DSFZ) in the Karasu Valley. These slip-rate estimates and other evidence from farther south on the DSFZ are consistent with a preferred Euler vector for the relative rotation of the Arabian and African plates of 0.434±0.012° Ma–1 about 31.1°N, 26.7°E. The Amanos Fault is misaligned to the tangential direction to this pole by 52° in the transpressive sense. Its geometry thus requires significant fault-normal distributed crustal shortening, taken up by crustal thickening and folding, in the adjacent Amanos Mountains. The vertical component of slip on the Amanos Fault is estimated as c. 0.15mm/a. This minor component contributes to the uplift of the Amanos Mountains, which reaches rates of c. 0.2–0.4mm/a. These slip rate estimates are considered representative of time since. 3.73±0.05Ma, when the modern geometry of strike-slip faulting developed in this region; an estimated 11km of slip on the Amanos Fault and c. 10km of slip on the East Hatay Fault have occurred since then. It is inferred that both these faults came into being, and the associated deformation in the Amanos Mountains began, at that time. Prior to that, the northern part of the Africa–Arabia plate boundary was located further east.
