the felsic pegmatitic rocks are exposed in the north of golpayegan. the dominate mineral assemblage is quartz, k-feldspar, plagioclase, muscovite, tourmaline and garnet. the elevated spessartine content of the garnets in the studied rocks along with their idiomorphic shape, the absence of resorption feature and garnet-free country rocks may point to their magmatic origin and crystallization at ...

The present study indicate that the copper mineralization in the area is of the nature of scattered sporadic occurrences of narrow lenticular and impersistent stringers and veins of copper-ore in vein-quartz and pegmatite traversing the amphibolite and garnetiferous mica schist country rock. The old workings for copper ore at Garimanipenta, which had a checkered history since early times, are b...

In the lithium-cesium-tantalum-type pegmatite dikes of San Diego County, California, USA, tourmaline is the main reservoir for Li, except in the cores and the pockets of the dikes where other Li-bearing minerals also occur. Tourmaline from three subhorizontal dikes was analyzed for bulk Li concentrations and Li isotope ratios. The bottom portion of each dike includes rhythmically layered aplite...

Lithium concentrations and isotopic compositions in the country rocks (amphibolites and schists) of the Tin Mountain pegmatite show systematic changes with distance to the contact. Both Li and δLi decrease dramatically along a ∼10m traverse from the pegmatite into amphibolite, with Li concentration decreasing from 471 to 68ppm and δLi decreasing from +7.6 to −19.9. Rubidium and Cs also decrease...

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...

We have analyzed a frondelite mineral sample from the Cigana mine, located in the municipality of Conselheiro Pena, a well-known pegmatite in Brazil. In the Cigana pegmatite, secondary phosphates, namely eosphorite, fairfieldite, fluorapatite, frondelite, gormanite, hureaulite, lithiophilite, reddingite and vivianite are common minerals in miarolitic cavities and in massive blocks after triphyl...

Major element compositions of glass inclusions in olivine and plagioclase phenocrysts from representative Mariana arc lavas show that mafic Mariana arc liquids are tholeiitic and not high-alumina, implying that the high-alumina characteristic of these lavas reflects accumulation of plagioclase. Glass inclusions also show the common occurrence of felsic melts previously unrecognized among Marian...

In this paper we show that the pegmatite-forming processes responsible for the formation of the Malkhan pegmatites started at magmatic temperatures around 720 °C. The primary melts or supercritical fluids were very waterand boron-rich (maximum values of about 10% (g/g) B2O3) and over the temperature interval from 720 to 600 °C formed a pseudobinary solvus, indicated by the coexistence of two ty...

Direct, on-line mass spectrometric analyses were performed on volatiles released from microscopic fluid inclusions in quartz, feldspar, and tourmaline from the miarolitic Belo Horizonte #1 pegmatite in the San Jacinto district, and Himalaya pegmatite dike system in the Mesa Grande district of southern California. These analyses are the first inclusion volatile studies to indicate the presence o...