Geochemical, Petrographic and Magnetic Characteristics of Spinel Lherzolite Mantle Xenoliths from Jabal Remah Volcano, Jordan

Abstract

Peridotite ultramafic mantle xenoliths are occurring abundantly in the Harrat Al-Shaam basaltic province. Jabal Remah volcano is located in the Jordanian parts of the plateau and contains considerable amounts of mantle xenoliths within its pyroclastic successions. Mineralogical investigations show that the xenoliths are mostly of the spinel lherzolite type, which are characterized by a protogranular texture. Modally, the xenoliths are composed of olivine (55-65%), orthopyroxene (12-16%), clinopyroxene (10-15%) and spinel (~ 5%). The xenoliths are classified as Type I and belong to the Cr-diopside group. They are characterized by a high content of MgO (42.1-43.2%), Cr (2465-2538 ppm) and Ni (2196-2301 ppm). Three selected mantle-xenolith samples were analyzed for their magnetic characteristics. They were found to behave similarly in their ferrimagnetic phase, as indicated by their narrow hysteresis curves and because they never reach saturation even at high applied field. They exhibit ferrimagnetic hystertesis curves similar to world known mantle xenoliths, which is due to the presence of Fe in the form of oxides.