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Abstract

A group of intrusive and extrusive igneous rocks are located south of Wadi Abu Ziran, central eastern desert. These rocks have diverse petro-graphic compositions ranging from gabbros to granites with their volcanic equivalents. They belong to four distinct Neoproterozoic units of the eastern desert, namely; 芒�?�?metagabbros (MG), older granites (OG), metavolcanics (MV) and younger granites (YG)芒�?聺. Both major and trace elements are compiled to deduce their genetic relationships. 1/Sr vs. Rb/Sr and Rb/Ba vs. Rb plots suggests that these rock units exhibit comparative magmatic relationships. The trace elements data and the numerical modeling are treated according to the general equation of partial melting and Rayleigh equation of fractional crystallization. These rock types favor complex petro-genetic processes during their generation. The magmatic model is based on 芒�?�?in-sequence芒�?聺 genesis between partial melting and fractional crystallization as well as magma mixing processes in the late stage. It is evident that these rocks are resulted from five essential stages during magmatic evolution of the area; the gabbroic rocks (MG) were derived by partial melting (42.5-45.93%) of oceanic crust followed by fractional crystallization (30-50%) of the resulted ultramafic magma; rocks of granodiorite (OG) were derived throughout partial melting (30-39.47%) of gabbroic parent followed by (55-80%) fractional crystallization of gabbroic magma; the metandesite (MV) was generated throughout partial melting (0.4%) of granodiorite (OG) followed by fractional crystallization (25-50%); the monzogranite (YG) was derived throughout (3-6.02%) partial melting of granodiorite (OG) followed by (40-65%) fractional crystallization of granitic magma, finally; the recorded hybrid granodiorite rocks (YG) were generated by partial melting of both gabbroic rocks (MG) (29.58%) and granodiorite (OG) (6.02%) followed by magma mixing and (35-60%) fractional crystallization.

Biography

Email: ghoneimf@science.tanta.edu.eg