Petrogenesis of Late Proterozoic granitoids in the Ras Gharib magmatic province, northern Eastern Desert, Egypt: petrological and geochemical constraints
Mohamed, F. H.; Moghazi, A. M.; Hassanen, M. A.
published: May 26, 1999
ArtNo. ESP154017403006, Price: 29.00 €
The late Proterozoic magmatic province of the Ras Gharib district, northern Egyptian Shield, includes wide surface areas of granitoid rocks, that occur in the form of separate plutons and large batholiths. Based on petrographic and geochemical characteristics, the granitoid rocks can be divided into three main suites, namely: a calc-alkaline suite of granodiorite, monzogranite and syenogranite, a trondhjemite suite, and an alkali granite suite. The granodiorite-monzogranite-syenogranite suite (63-76 % Si=2) is peraluminous (A/CNK = 1-1.35) with small negative Eu anomalies (Eu/ Eu* = 0.65-0.8), and shows moderate enrichment in the light rare earth elements (LREE) (LaN/YbN = 10-22), and the large ion lithophile elements (LILE). It displays chemical characteristics of volcanic arc granites. The trondhjemite suite is more silicic, muscovite-bearing, strongly peraluminous (A/CNK = 1.2-1.4), and has very low concentrations of REE (Σ 14 REE = 29 ppm), Fe2O3* (0.96-1.3 %), MgO (0.19-0.45 %), Rb (50-65 ppm), and Zr (28-35 ppm).The alkali granite suite is depleted in Al2O