Origin and geochemistry of Pan-African granitoid rocks in the Gabal Um Shomer area,Southwestern Sinai,Egypt |
| |
Authors: | M M El-Tokhi A Musallum B M Amin |
| |
Institution: | Geology Department, College of Science, United Arab Emirates University, United Arab Emirates |
| |
Abstract: | Geological, petrological and geochemical studies indicated that there are two distinct types of granitoid rocks: older quartz
diorites to granodiorite assemblage and younger granitoids, the latter occurring in two phases. The older granitoids have
a meta-aluminous chemistry and a calc-alkaline character, with high MgO, Fe2O3, TiO2, CaO, P2O5, Sr and low SiO2, K2O, and Rb. Their major and trace elements data, together with low 87Sr/86Sr ratios (0.7029±0.0008) are indicative of I-type affinities. The second- and third-phase granitoids range from calc-alkaline
to alkaline, respectively. The second-phase granitoids have a peraluminous chemistry and high Sr, Ba, CaO, MgO, Al2O3 and Ti2O and low SiO2, K2O, Nb, Y and Rb relative to the third-phase granitoids. The corundum normative nature and field observations suggested that
it was formed by partial melting of the lower crust. The third-phase granitoids are alkaline in nature and characterized by
higher SiO2, Rb, Y, Nb and lower MgO, Sr and Ba values than the younger granitoids (phase II). They are A-type granitoids which were
generated from below or within the existing continental crust. |
| |
Keywords: | origin and geochemistry Pan-African granitoid rocks Gabal Um Shomer area southwestern Sinai Egypt |
本文献已被 CNKI 维普 万方数据 SpringerLink 等数据库收录! |
|