Petrology and rare earth element geochemistry of clastic metasedimentary rocks from the Isua supracrustal belt, West Greenland
نویسندگان
چکیده
منابع مشابه
Mass-independent fractionation of sulfur isotopes in sulfides from the pre-3770 Ma Isua Supracrustal Belt, West Greenland
Redox chemistry of the coupled atmosphere–hydrosphere system has coevolved with the biosphere, from global anoxia in the Archean to an oxygenated Proterozoic surface environment. However, to trace these changes to the very beginning of the rock record presents special challenges. All known Eoarchean ( c . 3850–3600 Ma) volcanosedimentary successions (i.e. supracrustal rocks) are restricted to h...
متن کاملSetting and origin for problematic rocks from the \3.7 Ga Isua Greenstone Belt, southern west Greenland: Earth’s oldest coarse clastic sediments
Whether or not coarse detrital sedimentary rocks occur within the \3.7 Ga Isua Greenstone Belt (IGB), southern west Greenland, has been debated for some time. Repeated, regional metamorphic, deformational, and metasomatic events have obscured most protolith lithologies leading to misunderstandings about the stratigraphy and environments of deposition. Rocks here interpreted as meta-conglomerate...
متن کاملPetrology and Geochemistry of the Eocene Volcanic Rocks in the West of Sechangi, Lut Block
The Eocene volcanic rocks exposed in the NW Sechangi area of Lut block, include pyroclastic deposits and lavas. These volcanic rocks are basalt, basaltic andesite, andesite, andesite-trachyandesite, trachydacite, dacite and rhyolite-ignimbrite in composition. Based on our field observations, the volcanic rocks erupted in four stages in the aquous to subaerial environments. The volcanic rocks ar...
متن کاملThe Petrology and Geochemistry of Granitoid Rocks of Troud Area in South-West of Shahrood
The area of study is located 120 Km north-east of Shahrood city. In terms of structure and geological classification, this area is located in the northern part of central Iran zone. Granitoids of Troud ranging from monzonite to granite. The main minerals of granitoids are quartz, plagioclase, and orthose. The accessory minerals are biotite, hornblende, sphene, and opaque minerals. Various textu...
متن کاملGeology, Age and Origin of Supracrustal Rocks at Akilia, West Greenland
New mapping, geochronology, and geochemistry of the supracrustal enclave and associated orthogneisses at Akilia, West Greenland, support a >3825 6 Ma age for the sequence and a chemical sedimentary origin for the controversial Fe-rich quartz-pyroxene gneisses. Lithologies of the enclave comprise laterally continuous, mappable units of mafic amphibolite, ultramafic rocks, and two Fe-rich quartzp...
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ژورنال
عنوان ژورنال: Rapport Grønlands Geologiske Undersøgelse
سال: 1983
ISSN: 2597-2944,0418-6559
DOI: 10.34194/rapggu.v112.7810