Tectonic evolution of the Qumran Basin from high-resolution 3.5-kHz seismic profiles and its implication for the evolution of the northern Dead Sea Basin Ronald K. Lubberts * , Zvi Ben-Avraham Department of Geophysics and Planetary Sciences, Tel Aviv University, Ramat Aviv, Israel Received 2 October 2001 Abstract The Dead Sea Basin is a morphotectonic depression along the Dead Sea Transform. Its structure can be described as a deep rhomb-graben (pull-apart) flanked by two block-faulted marginal zones. We have studied the recent tectonic structure of the northwestern margin of the Dead Sea Basin in the area where the northern strike-slip master fault enters the basin and approaches the western marginal zone (Western Boundary Fault). For this purpose, we have analyzed 3.5-kHz seismic reflection profiles obtained from the northwestern corner of the Dead Sea. The seismic profiles give insight into the recent tectonic deformation of the northwestern margin of the Dead Sea Basin. A series of 11 seismic profiles are presented and described. Although several deformation features can be explained in terms of gravity tectonics, it is suggested that the occurrence of strike-slip in this part of the Dead Sea Basin is most likely. Seismic sections reveal a narrow zone of intensely deformed strata. This zone gradually merges into a zone marked by a newly discovered tectonic depression, the Qumran Basin. It is speculated that both structural zones originate from strike-slip along right-bending faults that splay-off from the Jordan Fault, the strike-slip master fault that delimits the active Dead Sea rhomb-graben on the west. Fault interaction between the strike-slip master fault and the normal faults bounding the transform valley seems the most plausible explanation for the origin of the right-bending splays. We suggest that the observed southward widening of the Dead Sea Basin possibly results from the successive formation of secondary right-bending splays to the north, as the active depocenter of the Dead Sea Basin migrates northward with time. D 2002 Published by Elsevier Science B.V. Keywords: Neotectonics; Pull-apart basin; Strike-slip; Basin formation; Dead Sea; Israel 1. Introduction The study area is situated along the northwestern margin of the Dead Sea and occupies a small part of what is known as the Dead Sea Transform or Rift (Fig. 1). The Dead Sea Transform forms the arcuate plate boundary between the Arabian plate and the Sinai subplate, part of the African plate (Quennell, 1959; Freund et al., 1970; Garfunkel, 1981; Kashai and Croker, 1987). The plate boundary is segmented into left-stepping NNE-trending strike-slip faults, arranged en echelon. At locations where the left lateral faults overlap and step to the left, morphotectonic depressions are formed, often referred to as rhomb- grabens or pull-aparts (Quennell, 1959; Freund et al., 1968; Garfunkel, 1981). 0040-1951/02/$ - see front matter D 2002 Published by Elsevier Science B.V. PII:S0040-1951(01)00230-X * Corresponding author. Present address: Oude Schans t.o. 62, 1011 LG Amsterdam, The Netherlands. Fax: +31-20-646-2457. E-mail address: ronald.lubberts@wxs.nl (R.K. Lubber ts). www.elsevier.com/locate/tecto Tectonophysics 346 (2002) 91– 113