Formation of fault-related calcite precipitates and their implications for dating fault activity in the East Anatolian and Dead Sea fault zones

Nuriel P., Rosenbaum G., Uysal T. I., Zhao J., Golding S. D., Weinberger R., ...More

GEOLOGY OF THE EARTHQUAKE SOURCE: A VOLUME IN HONOUR OF RICK SIBSON, vol.359, pp.229-248, 2011 (SCI-Expanded) identifier identifier


Fault-related calcite precipitates taken from different segments along the East Anatolian (SE Turkey) and Dead Sea (Israel) fault zones were investigated structurally, geochemically and geochronologically. The results indicate major differences in the nature of calcite precipitates and temporal relationship to faulting. In the Duzici Fault, calcite-filled veins and hydraulic fractures precipitated co-seismically during three consecutive faulting events. Calcite precipitated in veins at the Har Zefiyya Fault was controlled by near-surface karst processes. Initial opening of the veins occurred prior to about 500 ka and may represent the onset of an east-west contractional deformation. In the Carmel Fault Zone the calcite coating the fault plane precipitated by karst processes, with no evidence of subsequent deformation. Calcite fault gouge from the same site are a mix of host-rock gouge and newly formed authigenic calcite, and their overall geochemistry suggests pervasive fluid-rock interaction in the fault zone. In the Baraq Fault Zone the precipitation of calcite within syntectonic tension gashes and veins occurred prior to 540 ka by the pervasive infiltration of meteoric water into the fault zone. The results demonstrate that geochemical and structural analyses, combined with U-Th geochronology, can shed light on co-seismic and inter-seismic fault activity, and can potentially provide precise age constraints on the timing of brittle deformation.