סמינר בחוג למדעי כדור הארץ: A new look to Makhtesh Ramon: Results of Integrated Geophysical, Tectonic, Mineralogical, Petrological, Geochemical and other Investigations

With participation of Alexander Surkov (Moscow Mining Academy), Luodmila Sazonova, Galina Belovitskaya, Igor Modin, Sergey Smirnov, Sergey Kouznetsov (all from the Moscow State University) and Youri Katz (Faculty of Life Sciences, TAU)

Abstract:

The Makhtesh Ramon erosional–tectonic depression (40 km long and approximately 8 km wide) is situated in the Negev Desert, 65 km southwest of the Dead Sea. Its formation terminated approximately 132 Ma ago, during the Levantine tectonic phase. A high magmatic activity in the region occurred approximately 120 Ma ago, which corresponds to the epoch of global tectono-thermal activation. Larson (1995) termed this epoch the Middle Cretaceous maximum in the development of upper mantle hot spots. The developed map of Curie discontinuity shows sufficiently large depth - about 38 km. Other important geophysical regional indicators are: low thermal flow (about 35 mW/m2), and small depth of the crystalline basement occurrence. Detailed magnetic, self-potential investigations and various ion-selective surveys have been successively applied in the designated areas. Here were found such important mineral satellites of diamond as moissanite, corundum, chrome-dropsied, orange garnet, bright crimson pyrope, rutile, picroilmenite, chromespinel, olivine, perovskite, anatase, titanomagnetite and tourmaline as well as other satellites (both binocular and electronic microscopies were applied). The examination of rocks using fluoric and other acids revealed a number of small gold and silver plates accompanied by traces of Rare Earth Elements: lanthanum, cerium, thorium, niobium and tantalum. Later yttrium phosphate and meimechite (rock which is the closest to kimberlite) were identified. Finally, several tens of microdiamonds (< 1 mm) and five diamonds (> 1 mm; the largest crystal has size of 1.37 mm) were detected. Summing all above-mentioned factors we can consider the Makhtesh Ramon area as a ‘natural window’ to the upper mantle.

מארגנת הסמינר: ד"ר רוית חלד