STRUCTURAL EVOLUTION OF FEIRAN-SOLAF METAMORPHIC BELT, SOUTHWEST SINAl

Abstract

The Feiran-Solaf metamorphic belt is

bouJ1ded by latitudes 28° 31 •, 28° 49' N and 1

longitudes 33° 1 o•, 33° 48' E. It" covers an ara over 250 km 2, and comprises a part of SW

inai, which is covered by igneous and metamorphic rocks of the basement complex belonging I '• to the late Proterozoic rocks of the Arabian-Nubian Shield.

Migmatitic, amphibolite-grade gneisses: make up a significant portion of the Feiran- 1

Solaf belt, where gneisses and migmatites are. the main outcropping rock units. Outcrops of • I

migmatitic gneisses of the Feiran Zone show sirong layering ranging from the centimeter- to decimeter-scale. lnterlayered with migmatitic g eisses are plagioclase + quartz + hornblende ± biotite ± diopside ± garnet ± ortho-pyroxene t'onalitic gneisses in addition to plagioclase + 'I

biotite + quartz ± garnet ± ortho-pyroxene paragneisses. White plagioclase + quartz-rich

I leucosomes within the darker melanosome layerS gives the rock its migmatitic appearance (Fig. I ' J.O). Field studies revealed that Feiran migmatites have different structural types, namely

stromatic, agmatic, and ptygmatic types.

The Feiran-Solaf belt is subdivided here into two zones: one to the south-east, the Solaf I Zone, and another to the north-west, the Feiran 'Zone (Figs. 32, 33). Within each zone ten or

I more cross-strike transects are made, along which the available planar and linear structural

clements arc measured.

The belt was systematically mapped during the field work to eliminate the personal bias

' I in choosing the field orientation data.