نتایج جستجو برای: pegmatite

تعداد نتایج: 412  

2012
D. B. Sankar Sai Prasad

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...

2008
Werner Schreyer Jennifer S. MALONEY Ralf HALAMA

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...

2006
Fang-Zhen Teng William F. McDonough Roberta L. Rudnick Richard J. Walker

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...

Journal: :Anais da Academia Brasileira de Ciencias 2005
Ana C M Ferreira Valderez P Ferreira Dwight R Soares Hugo S Vilarroel-Leo

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...

Journal: :Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy 2013
Ray L Frost Yunfei Xi Ricardo Scholz Fernanda M Belotti Martina Beganovic

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...

2012
Rainer Thomas Paul Davidson

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...

1995
A. E. WILLIAMS

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...

Journal: :Minerals 2022

The mineralogical studies of rare-element (REL) pegmatites are important for unraveling the ore-forming process and evaluating REL mineralization potential. Chinese Altai orogenic belt hosting more than 100,000 pegmatite dykes is famous rare-metal resources worldwide diverse types. In this paper, we present results EMPA LA-ICP-MS muscovite from typical Altai. studied Li-Be-Nb-Ta, Li-Nb-Ta, Nb-T...

Zamanabad area is located in southern of Hamedan Province and belong to Sanandaj-Sirjan magmatic-metamorphic Zone. Lithologic units of this area comprising slate, phyllite, andalusite-garnet bearing schists, metamorphic complex including sillimanite bearing schists, hornfels, pegmatitic unit and recently alluviums. The most important of geological unit is Alvand granitoid pluton at age middle J...

طهماسبی, زهرا,

Pyralespite garnet group (Almandine group) is common minerals in the metamorphic and igneous complex of Boroujerd area. Moreover, Almandin (Fe enriched garnet) is the most common mineral but the content of Spessartin (Mn enriched garnet) is high in this area. The changes of mineral composition in different grains show that these minerals are zoning chemical and core to rim composition is varied...

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