The tectonics of the Timna region in southern Israel and the evolution of the Dead Sea rift

Abstract

The Timna region is located in the western margin of the southern Arava Valley at a junction between two regional, orthogonal fault systems—the Dead Sea rift and the Temed fault. The Dead Sea rift trends N—S and extends from the northern Red Sea to southern Anatolia, and the Temed fault trends E—W from the Gulf of Suez to the Arava Valley. Structural analysis of the Timna region showed the effects of two tectonic phases that were active there since the Miocene. The first tectonic phase formed the dextral strike-slip Temed fault and two systems of secondary faults trending NW—SE and NE—SW. The second tectonic phase downfaulted the rift floor and uplifted the rift shoulders simultaneously, forming a regional N—S trending joint system along the rift shoulder. Subsequent sinistral strike-slip faulting along the rift caused a drag on the eastern part of the Timna region, and the resulting 2.5 km northward displacement reactivated pre-existing faults and formed several rifts and uplifted blocks. A correlation of the structural data of the Timna region with recently acquired geophysical, structural and stratigraphic findings from various places along the Dead Sea rift indicates that the first tectonic phase in Timna is the Erythrean phase. This phase formed systems of E—W trending faults in the Negev and northern Sinai, as well as NW—SE trending faults in Saudi Arabia, Jordan, Israel and Egypt. This tectonic phase was active in the Miocene and is associated with the first evolutionary phase of the Red Sea spreading center. During this phase the spreading center extended northwards towards the Suez rift. The second tectonic phase in Timna is the Levantine phase that formed the Dead Sea rift and its uplifted shoulders. This phase has been active since the Pleistocene and is associated with the second tectonic phase of the Red Sea spreading. The structural and geophysical data suggest that the Dead Sea rift is an incipient spreading center, extending from the Red Sea, whereas the Suez rift was not reactivated during this phase. The change of trend of the northern Red Sea spreading center, from NW—SE to N—S, deformed the east shoulder of the southern Dead Sea rift, so that a limited sinistral strike-slip displacement occurred. Recent seismic activity indicates that the evolution of the Dead Sea rift is presently active.