Um Adawi Granites information

This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages) This article may be too technical for most readers to understand. Please help improve it to make it understandable to non-experts, without removing the technical details. (May 2008) (Learn how and when to remove this message) This article relies largely or entirely on a single source. Relevant discussion may be found on the talk page. Please help improve this article by introducing citations to additional sources. Find sources: "Um Adawi Granites" – news · newspapers · books · scholar · JSTOR (May 2008) (Learn how and when to remove this message)

The Um Adawi Granites are igneous rocks exposed in the southeastern part of the Sinai Peninsula. They exhibit field relations, petrographic characteristics, and chemical characteristics similar to the island arc older granitoids of the Arabian-Nubian Shield. They have a batholithic dimension and occur as composite plutons intruding the metasediments and the metavolcanics, while the younger granites intrude them.

Petrographically, the rocks are homogeneous, light to dark grey and medium- to coarse-grained. They consist of quartz monzodiorite, tonalite and granodiorite. Plagioclase (An21-32), quartz, k-feldspar, hornblende and biotite represent the essential minerals. Accessory minerals are apatite and Fe-Ti oxides.

Whole rock and mineral chemistry indicate that the Um Adawi older granites are calc-alkaline with metaluminous signature. They were emplaced in a compressional regime in an arc tectonic setting within a crust of about 30 km thickness. The rare earth element patterns of these granites suggest that they were subduction related, supporting the obtained magmatic affinity and the tectonic setting.