Meta-ultramafi c rocks occur as small (2 to 100 m long), podiform bodies in all three major Precambrian rock suites of the Tobacco Root Mountains of southwest Montana. Most samples consist of a randomly oriented, coarse-grained assemblage of orthopyroxene, olivine, and magnesiohornblende ± spinel, partially replaced by a fi ne-grained assemblage that may include anthophyllite, talc, cummingtoni...

In the western part of Sierra de los Filabres area, there are fine-grained metamorphic rock bands, showing a field aspect simitar to slates, as previously described in geological literature studied region. They variable thickness, from millimeters tens meters and appear intercalated schist succession. The geochemical resemblance between both types rocks (major, minor trace elements), determined...

The Eastern Andean Metamorphic Complex at Península La Carmela (48°50’S) consists of quartz-rich metaturbiditic sequences with tectonic slices pillow metabasalt bodies deformed under low-grade metamorphic conditions. Previous and new detrital zircon U–Pb geochronological data from metasandstones indicate a preferred early Carboniferous maximum depositional age the protolith, interpreted younges...

This work investigates the pre-collisional (before ca. 650 Ma) history of Dom Feliciano Belt in southernmost Brazil through geochronological and zircon oxygen isotope study. U–Pb SHRIMP dating two orthogneiss samples from Várzea do Capivarita Complex one metarhyolite sample Porongos yielded crystallisation ages 786 ± 5 Ma, 780 10 Ma 787 respectively. The mean values calculated for 790 cores ort...

Precambrian and Early Paleozoic magmatic activities in the Lhasa terrane provides important context for distinguishing between North South terranes, deciphering nature geotectonic history of northern margin Rodinia Gondwana supercontinents. Here, we conducted a detailed petrological, geochemical, geochronological study mafic to granitic meta-intrusive rocks Bomi complex eastern segment terrane....

Exposure to natural occurrences of asbestos (NOA) and other potentially hazardous elongated mineral particles (EMPs) may pose a risk human health the environment. Weathering forces anthropic activities alter cohesion NOA-bearing outcrops disperse EMPs in air, water, soil. The current paradigm for fibre toxicity indicates that morphology crystal chemistry are key parameters determining toxicolog...

Eclogites, metagabbros, and paragneisses from the Variscan Münchberg Massif record a complex succession of igneous, hydrothermal metamorphic processes. The geodynamic setting related to protolith formation impact different types fluid-rock interactions have been uncertain up now. We use major trace element chemistry as well oxygen isotopes disentangle geochemical signatures stages rocks' histor...

Xenoliths of quartz-absent Fe-rich aluminous metapelite are common within the platinum group element-rich mafic ⁄ultramafic magmatic rocks of the Platreef. Relative to well-characterized protoliths, the xenoliths are strongly depleted in K2O and H2O, and have lost a substantial amount of melt (>50 vol.%). Mineral equilibria calculations in the NCKFMASHTO system yield results that are consistent...

Three distinct groups of eclogites (low-Mg–Ti eclogites, high-Ti eclogites and Mg-rich eclogites) and ultramafic rocks from the depth interval of 100–680 m of the Chinese Continental Scientific Drill Hole were studied. The lowMg#s (=100⁎molar Mg/(Mg+Fe)) (81–84%) and low Ni (1150–1220 ppm) and high Fe2O3 total (13–15 wt.%) contents of ultramafic rocks suggest a cumulate origin. Mgrich eclogites...