[SCG54-P05] Lithological and petrophysical variation of the lower crustal section from the ICDP Oman drilling project Holes GT1A and GT2A
Keywords:Oman Ophiolite, layered gabbro, foliated gabbro, Magnetic susceptibility
Both GT1A and GT2A cores consist of ~65% of olivine gabbro, ~25% of olivine-bearing gabbro and olivine melagabbro. Minor rock types are anorthositic gabbro, troctolitic gabbro, orthopyroxene-bearing gabbro, gabbronorite, dunite, gabbro, gabbronorite, varitextured gabbro, troctolite, and troctolitic gabbro. Intercalation of minor rock types into major rock types exhibits “layering” structure, but also major rock types show layering and foliation consist of mineral size, mode and structure.
Variable layering and foliation intensity is common feature of the lower crust, but it is difficult to describe it standardize due to the thickness changes from < mm to meter order. We tried to use magnetic susceptibility (MS), luminance value (L*, a*, b*) of the archive half cores measured by Multi-Sensor Core Logger with 2 cm step interval. Generally, MS and luminance are sensitive in olivine mode and alteration, respectively.