الفهرس 
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Abstract
The present work deals with mineralogical and geochemical studies of Gabal Garf (South Easten Desert) and Wadi Hammariya (Central Eastern Desert areas, Egypt. Both of the two areas are characterized by the occurrence of ophiolites. The ophiolite of Gabal Garf forms an intact ophiolite assemblage while that of Wadi Hammariya occurs as a dismembered one. The Gabal Garf ophiolite consists of serpentinites, metagabbros, sheeted metadiabase dykes and metavolcanics. The same assemblage of ophiolite is exposed in Wadi Hammariya except the sheeted dykes Mineral chemistry shows that olivines of Gabal Garf peridotite serpentinite are forsterite in composition. The pyroxenes from Gabal Garf metapyroxenite are augite-diopside in composition with tholeiitic characters. The amphiboles from Gabal Garf have a composition mostly ferroan pargasite in serpentinites; actinolite, magnesio-hornblende and actinolitic hornblende in metagabbros and actinolite and actinolitic hornblende in metavolcanics. While amphiboles of Wadi Hammariya metagabbros are dominated by magnesio- and magnesio-hastingsitic-hornblende. Plagioclases in both areas are mainly Na-rich reflecting their deviation from spilitic magma. They vary in composition from albite to labradorite. Plagioclase in both areas is mostly homogeneous. Zonation in plagioclase is observed in few spots (reversed-type in Gabal Garf and normaltype in Wadi Hammariya) which suggest a progressive differentiation of parental basaltic magma Co-existing amphibole-plagioclase pair of metagabbros of Gabal Garf suggest that they were formed at temperature ranges from 475o to 575oC and pressure range from 1- to 9 Kbar whereas those of Wadi Hammariya were formed at temperature range from 350o to 620oC and pressure range from 4- to 9 Kbar The chlorites of both Gabal Garf serpentinites and Wadi Hammariya metagabbros are classified as ripidolite. The analysed epidotes of metagabbros from both areas are mostly accessories except for few spots in Wadi Hammariya.