introduction the area of this study is located near hamadan within the sanandaj - sirjan tectonic zone. in the hamadan area, consisting mainly of mesozoic plutonic and metamorphic rocks, aplites and pegmatites locally contain garnets.(baharifar et al., 2004, amidi and majidi, 1977; torkian, 1995. garnet-bearing schists and hornfelses in the area are products of regional metamorphism shown by sl...

molybdenite occurs in five forms in the sar cheshmeh porphyry copper deposit, namely, (1)-veinlets with quartz-molybdenite, (2)-veinlets with quartz-molydenite that were filled with pyrite, (3)-veinlets with quartz-molybdenite-pyrite–chalcopyrite, (4)-molybdenite veinlets with very low quartz and (5)-disseminated molybdenite grains. because of their large size, the veinlet-related molybdenite g...

OBJECTIVES Little information is available on the quantitative risks of respiratory disease from quartz in airborne dust in the heavy clay industry. Available evidence suggested that these risks might be low, possibly because of the presence in the dust of other minerals, such as illite and kaolinite, which may reduce the harmful effects of quartz. The aims of the present cross sectional study ...

Introduction: Research into the origin of color of common varieties of quartz has shown that many longheld beliefs regarding the origin of the colored varieties are incorrect. In particular, the widely stated role of rutile inclusions in the coloration of rose and blue quartz must now be re-evaluated on the basis of new studies. Rose Quartz: Spectroscopic studies have shown that the color of ro...

A new model accounts for crystal growth patterns and internal textures in quartz cement in sandstone fractures, including massive sealing deposits, thin rinds or veneers that line open fracture surfaces, and bridge structures that span otherwise open fractures. High-resolution cathodoluminescence imaging of bridge structures and massive sealing deposits indicates that they form in association w...

Collisional orogens commonly include mono-metamorphic and poly-metamorphic units, their different evolution can be difficult to recognize reconcile. The Theodul Glacier Unit (TGU) in the Western Alps consists of an association metasedimentary metamafic rocks embedded within Zermatt-Saas tectonic unit. In spite recent petrological studies, it remains unclear whether these underwent one or multip...

Fieldand petrographic studies of the Paleozoic metamorphic rocks of New York City suggest a new interpretation of the stratigraphy and structure of the region and has delineated a number of ductileand brittle faults. The belt of rocks originally lumped together as the Manhattan Schist is now interpreted to consist of three mappable units structurally imbricated by two major ductile faults, the ...

A detailed oxygen isotope study of detrital quartz and authigenic quartz overgrowths from shallowly buried (<1 km) quartz arenites of the St. Peter Sandstone (in SW Wisconsin) constrains temperature and fluid sources during diagenesis. Quartz overgrowths are syntaxial (optically continuous) and show complex luminescent zonation by cathodoluminescence. Detrital quartz grains were separated from ...