or the length of time which the process requires. The allanite replacements in the Tan-y-Grisiau microgranite suggest that unmixing was completed before hydrothermal minerals began to crvstallize and suggests, therefore, that in some instances, at least, unmixing ma.v belong to an early, relatively high temperature post-magmatic phase' The reason for the selective replacement of K-feldspar b.v ...

El Sela shear zone occurs in the younger granite rock of Gabal El Sela area, south Eastern Desert, Egypt near the Sudan Frontier. It comprises lines-arranged intrusions trending ENE-WSW and extend for about 1.5 km in length and reach up to 40 meters in width. These lines-arranged intrusions include multi-phase quartz veins, altered microgranite and altered basic dykes. These dykes hosting or ac...

Abstract The exposed rocks in Abu Hawis area, North Eastern Desert (NED), Egypt, consist of tonalite-granodiorite and monzogranite, dissected by post-granite felsic (microgranite rhyolite) mafic (basaltic-andesite) dikes. investigated radioactive minerals Zr-, Nb-, REE-bearing were restricted to dikes having E–W NE–SW trends. Uraninite, uranothorite, thorite occur as the main microgranite dikes...

At Hadhb't Ad-Dayheen, in the central Arabian Shield, a post-collisional igneous complex called Ad-Dayheen intrusion is exposed. It was emplaced Early Ediacaran (613–625 Ma), during final tectono-magmatic stage of Shield development. Despite limited and discontinuous ring-shaped outcrops due to alluvial cover later faulting, three pulses can be recognized field: an early pulse monzogranite; sec...

Distribution patterns, petrography, whole-rock and mineral chemistry, and shape and fabric data are described for the most representative basement lithologies occurring as clasts (granule to boulder grain-size class) from the 625 m deep CRP-2/2A drillcore. A major change in the distribution pattern of the clast types occurs at c. 310 mbsf, with granitoid-dominated clasts above and mainly doleri...

A 1:12,000 geological map of the Macao Special Administrative Region has been produced through detailed field work supported by petrographic, mineralogical, geochronological and geochemical data obtained in previous studies. This aims to represent a reliable tool understand evolution region for management territory. The geology is dominated two groups Jurassic granitic rocks belonging an intrus...