نتایج جستجو برای: greenschist
تعداد نتایج: 222 فیلتر نتایج به سال:
The massive sulfide deposits (VMS) from Mănăilă are associated with the metamorphic formations of Tulgheș Lithogroup Bucovinian Nappes Crystalline-Mesozoic Zone in Eastern Carpathians, Romania. following types ore were identified: pyrite-polymetallic, pyrite copper, compact and precompact quartz-precompact copper. polymetallic mineralization consists pyrite, chalcopyrite, sphalerite, galena, su...
introduction the occurrence of blueschist metamorphic facies is believed to mark the existence of former subduction zones. this facies is represented in the main constituents of subduction-accretion complexes, where it occurs in separate tectonic sheets, imbricated slices, lenses, or exotic blocks within a serpentinite mélange (volkova et al., 2011). the evidence of the presence and maturity of...
The studied serpentinites occur as isolated masses, imbricate slices of variable thicknesses and as small blocks or lenses incorporated in the sedimentary matrix of the mélange. They are thrusted over the associated island arc calc-alkaline metavolcanics and replaced by talccarbonates along shear zones. Lack of thermal effect of the serpentinites upon the enveloping country rocks, as well as th...
[1] A >500-km-long east-west trending metamorphic belt in the Qiangtang terrane of central Tibet consists of tectonic melange that occurs in the footwalls of Late Triassic–Early Jurassic domal low-angle normal faults. The melange is comprised of a strongly deformed matrix of metasedimentary and mafic schists that encloses lesser-deformed blocks of metabasites, Carboniferous–Triassic metasedimen...
In this article, we for the first time fully describe geology and petrography of iron quartzite formation, localized in Southeast Guinea Simandou mountain range. region, a meridional distribution belt banded magnetite quartzites (itabirite) Lower Proterozoic metamorphic series has been mapped. The rocks form an extended (210 km) narrow (0.4-7 complex synclinal structure background Archean grani...
Abstract The Proterozoic Chotanagpur Granite Gneiss Complex (CGGC) at the northern boundary of Central Indian Tectonic Zone (CITZ) eastern shield preserves relics fossilized oceanic back-arc crust. We describe field, petrographical and geochemical characteristics mafic rocks comprising pillow basalts dolerites from Bathani area fringe CGGC, India. consist plagioclase feldspar, hornblende, opaqu...
Moine metasedimentary rocks of northern Scotland are characterized by arcuate map patterns mineral lineations that swing progressively clockwise from orogen-perpendicular E-trending in greenschist facies mylonites above the thrust on foreland edge Caledonian Orogen, to S-trending at higher structural levels and metamorphic grades hinterland. Quartz c-axis fabrics measured a west east coast tran...
The Ellsworth belt is one of several fault-bounded blocks exposed along the southeastern coast Maine that formed within Ganderia. New ID-TIMS U–Pb geochronological data integrated with field relationships provide additional insights into timing magmatism and deformation in belt. deformed Lamoine Granite was selected for zircon analysis to: (i) establish protolith age; (ii) direct temporal const...
A chloritoid schist from the Medvednica Mts. (Croatia, Zagorje-Mid-Transdanubian zone) is part of metasedimentary succession a Palaeozoic-Mesozoic Metamorphic Complex. The studied samples show mineral association chloritoid, chlorite, quartz and white mica. P-T pseudosection, combined with modal chemical isopleths, classical thermobarometric calculations yield peak metamorphic conditions 0.8 – ...
Located at the westernmost tip of Mediterranean, Gibraltar Arc is a segment Alpine belt that exhibits peridotite massifs associated with high-grade crustal metamorphic units. The timing and mechanisms exhumation these crust–mantle associations are still debated in Rif Morocco as well Betic Cordilleras Spain. A structural, petrographic, geochronological study ( 40 Ar– 39 Ar method) performed Ben...
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