Concentric layers of weathered materials around core-stones show the porphyritic biotite granite to experience sequential, but gradational, changes in visible features, textures and mineralogy as it transforms from ‘rock’ into ‘soil’. The start with opening-up grain boundaries micro-cracks (stage 1) followed by their dark brown staining 2) subsequent alteration (to sericite clay minerals) groun...

The Vengen Granite, one of early Paleozoic granitic rocks crops out the southern end ridge, Kanino-tsume Peak at Main Shear Zone (MSZ) Sør Rondane Mountains, East Antarctica. This granite is composed medium- to fine-grained mylonitic biotite and cuts MSZ Zone. two-mica dykes locally intrude Granite. have foliations parallel Granite plagioclase, quartz, K-feldspar, biotite, muscovite with trace ...

Abstract in English The granite of Abeokuta is part the Older Granite suite basement complex southwestern Nigeria. Field observation has identified as porphyritic texture, with a preferred alignment megacrysts K-feldspar >5 cm that are mostly euhedral to subhedral shape. predominantly yellowish, but whitish and pinkish colouration also been observed. dark grey porphyritic, mafic rock composi...

-The alteration experiments of phlogopite with 0.01 N HC1 solution containing 0.1 M NaC1 at 50*, 80* and 120"C have been carried out to aid in the understanding of the dissolution process of mica and the formation of secondary phases such as vermiculite and interstratified mica/vermiculite. Twenty milligrams of phlogopite samples were suspended in 20 ml or 100 ml of leaching solution. In these ...

metagabbro, metadiabase and metabasalt of the chah palang and me'raji mountains associated with lower paleozoic metamorphites are situated in the south of arousan. metabasites of these areas are relatively similar in terms of mineralogy and geochemical characteristics. rock-forming minerals of the me'raji metabasites are feldspar, amphibole, biotite, sphene, epidote, chlorite ± calcite. metagab...

An alkaline volcanic activity with a relative Plio-Quaternary age (based on the succession of layers field) occurred in northern part Uromieh Dokhatar magmatic belt, Iran. Hornblendite xenoliths mostly displaying cumulitic texture occur trachyandesites from this episode. The thermobarometric results indicate that these formed within crust. Based mineralogical and chemical characteristics, are d...

Two methods using nujol and hexachloro-butadiene mulls are described to analyse the water content of powdered granite samples. The nujol mull analyses were carried out on a Unicam SP Ioo spectrometer using the silica content of the rock as an internal standard. The hexachlorobutadiene mull analyses were done by a twin-path Unicam SP 2oo spectrometer, using hexachlorobutadiene as the internal st...

introduction the investigated area is situated in the south west of the khorasan razavi province along the north west of the lut block. different types of metal ore bodies along with non-metal deposits have already been documented in the lut block (karimpour et al., 2008). most of the study area is covered with granitoid rocks. metamorphic rocks with unknown age are present in the north of the ...

The Alto Quixaba pegmatite, Seridó region, northeastern Brazil, is a 60 degrees/80 degrees SW-trending subvertical dike discordantly intruded into biotite schists of the Upper Neoproterozoic Seridó Formation. It has three distinct mineralogical and textural zones, besides a replacement body that cuts the pegmatite at its central portion and in which occur, among other gem minerals, colored elba...