Abstract
The Dead Sea transform fault, a prominent deep-seated suture zone with sinistral displacement, marks the boundary between the Arabian and African plates, sensu lato, with the Dead Sea-Jordan Valley rift as its morphological expression. Hematite-ankerite-goethite deposits in the environs of Warda, an apatite deposit near Suweileh, hot brine sinter terraces with a varied spectrum of Ca-Fe-Mn-Ba mineralization on the banks of the Yarmouk and Jordan River, and strata-bound goethite mineralization on different uplifted blocks northeast of the Dead Sea have been investigated for their mineral assemblages, major and trace element chemistry signatures, and stable isotope (C, O, S) signatures. The data have been used to interpret the origins of these pre-and synrift hypogene styles of mineralization along the prominent plate boundary.
During a Paleogene prerift extensional phase, northeast-to-southwest en echelon extension structures enabled low-temperature hydrothermal solutions to circulate in the eastern block of the Dead Sea transform fault. The strata- and fault-bound orebodies of the Warda Fe ore deposit resulted from low-temperature, epi-thermal replacement processes. The hydrothermal solutions affecting Late Cretaceous massive limestone at Warda may have tapped a magmatic source of sulfur during the Paleogene. In the neighboring Suweileh P deposit, the Maastrichtian phosphorite beds underwent strong hydrothermal remobilization during the Paleo-gene, with a moderate contribution of sulfur from underlying Triassic evaporite series. The northeastern shore zone of the Dead Sea and the drainage system of the Yarmouk River had an initial Fe accumulation as early as the Paleogene, with precipitation occurring from hot brines that interacted with Triassic marine evaporites.
The Neogene-Quaternary compressional phase gave rise to tight, recumbent folds in Cretaceous rocks along the eastern side of the Dead Sea transform fault and promoted development, at Warda and Suweileh, of southwest to northeast–trending ore anticlines and flexure bulges. Hydrothermal activity lasted until the Quaternary along the fault. Iron mineralization took place during that period near the main fault area of the Dead Sea transform fault. Parasite faults striking almost north to south in the western Yarmouk area enabled hot brines to ascend and cover the banks of the modern river drainage system with sinter terraces. In the study area northeast of the Dead Sea, Fe accumulated in subaquatic lacustrine settings. Neotectonic uplift of these anticlines and the formation of raised platforms caused part of the hanging-wall rocks to be removed from the ore and turned some of these Fe-enriched rocks into desert varnish under arid climatic conditions.
