R.W.H. Butler1, S. Spencer2 & H.M. Griffiths1
1Department of Earth Sciences, The University of Leeds, Leeds LS2
9JT, UK (e-mail: butler@earth.leeds.ac.uk)
2Department of Geology, American University of Beirut, Beirut, Lebanon
Fault activity within the Lebanese transpression zone, one of the classic examples of restraining bend development on a continental transform, is here investigated using dated geomorphological features. The northern part of the Yammouneh Fault, commonly considered to be the principal active strand on this part of the Dead Sea Transform, has been inactive for the past 5 Myr. Field observations show that basalts, dated as late Pliocene in age, apparently offset by the Yammouneh fault, unconformably overlie it. The active transcurrent structure is principally, perhaps exclusively, the Roum Fault. The Lebanese transpressive zone has evolved through time, with migration of fault activity. These results confirm the overlapping transform hypothesis for the Dead Sea system, require the active triple junction between the transform and the Tethyan collision belt to lie offshore SE Cyprus, and have profound implications for assessing seismic hazard in the Levant.
Complete reference: Butler, R.W.H., Spencer, S. & Griffiths, H.1997. Transcurrent fault activity on the Dead Sea Transform in Lebanon and its implications for plate tectonics and seismic hazard. J. Geol. Soc. London 154, 757-760.
NOTE: see also Discussion of this paper by J. Fleury, C. Chorowicz and J. Somma (reply by the authors). J. Geol. Soc. London 156, 1243-1248 (1999).