Discovery of Microdiamonds and Associated Minerals in the Makhtesh Ramon Canyon (Negev Desert, Israel)

摘要

The Makhtesh Ramon erosional-tectonic depression (canyon), 40 km long and approximately 8 km wide, is situated in the Negev Desert (southern Israel), 65 km southwest of the Dead Sea. The canyon rim and center are located at an altitude of 800-1000 and 400-600 m, respectively. In terms of tectonics, this structure represents the southern margin of the Syrian-Sinai block-fold belt. A comprehensive analysis of the available regional geophysical data revealed a collision-related origin of the belt. Its formation terminated approximately 132 Ma ago, i.e., during the Levantine tectonic phase .The subsequent origination of the Levantine marginal volcanic suture promoted the accumulation of postcollisional trap rocks (alkaline basaltic, alkaline gabbroic, and kimberlitic associations). The kimberlitic association, which was first discovered in western Syria, is represented in the study region by diatremes filled with kimberlite-type rocks containing eclogitic xenoliths. Maximal magma-tism in the region occurred approximately 120 Ma ago, which corresponds to the epoch of global tectonother- mal activation (the Middle Cretaceous maximum in the development of upper mantle hot spots).