Introduction: A long-standing, fundamental question in planetary geoscience is: "How similar are the geological histories of Earth and Venus, and when and how did their evolution diverge?" Did Venus once have oceans and a more Earth-like climate, as suggested by Pioneer-Venus data [1]? If so, when, how, and why did it transition to current conditions, and are traces of this early period, and th...

Mafic enclaves from three plutons in the Chilliwack batholith have been compared with contemporaneous mafic stocks in order to determine (1) the processes by which mafic and felsic magmas hybridize in the plutonic environment and (2) whether analysis of early-formed enclave minerals, particularly apatite, can provide a means of seeing through hybridization effects and deciphering the original t...

[1] The Coast Ridge Belt (CRB, Santa Lucia Mts., central California) comprises mid-crustal rocks (750–800 C and 0.8 GPa) of the California magmatic arc. We estimated the bulk composition of the CRB and converted our results to seismic velocities expected at the observed pressures and temperatures. The bulk composition of this arc section changes abruptly at 25 km depth from a granodiorite to a ...

A significant tin deposit has been identified in the northeast part of the Late Proterozoic Arabian Shield. Cassiterite-topaz-quartz greisens are distributed over 16 km2 in flat-topped cupolas of a highly evolved, zinnwaldite-bearing alkali-feldspar granite which composes part of the silsilah ring complex (lat 26"06'N, long 4240'E). The 587 m.y. old alkali-feldspar granite is overlain by a cara...

The pegmatitic rocks located in the south-east of Côte d'Ivoire between Comoé basin and Sefwi belt are subject this study. geology region consists gneisses, granites, microgranites, amphibolites, mylonites metasediments. All these generally crosscut by quartz pegmatite lodes. petrographic studies allow us to discriminate four groups pegmatites on basis mineralogy: (i) beryl-muscovite bearing (A...

Physico-chemical characteristics and industrial potentials of lepidolites from Ijero-Aramoko pegmatite fields were investigated . Systematic mapping indicates that the lepidolite is associated with steeply inclined pegmatite intruded into the basement rocks of gneisses and schistose assemblages that are in places pulsed with isolated Pan-African granite. The lepidolite has a layered structure, ...

Abstract. The New Exploration Tools for European Pegmatite Green-Tech Resources (GREENPEG) spectral database contains the signature, obtained through reflectance spectroscopy studies, of pegmatites and minerals as well their host rocks. Samples include Nb–Y–F (NYF) Li–Cs–Ta (LCT) chemical types rocks from pegmatite locations in Austria, Ireland, Norway, Portugal, Spain. spectra (raw continuum-r...

It typically occurs as an alteration product at the contact between felsic and mafic or ultramafic rocks such as pyroxenites and dunites. It also occurs in carbonatites and metamorphosed magenesium rich limestone. Associated mineral phases include: corundum, apatite, serpentine and talc. It occurs interlayered with chlorite, biotite and phlogopite.[2] Vermiculite Wikipedia, the free encyclopedi...