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East Russia (east + russia)

Distribution by Scientific Domains
Earth and Environmental Science100%

Kinds of East Russia

  • far east russia
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    Selected Abstracts

    Source selectivity: An assessment of volcanic glass sources in the southern primorye region, far East Russia

    GEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 2 2008
    Trudy Doelman
    Artifacts made from volcanic glass have been found in archaeological contexts dating from the Late Palaeolithic (ca. 20,000 yr B.P.) through to the end of the Bronze Age (ca. 2700 yr B.P.) in the southern Primorye region of Far East Russia. A geoarchaeological survey of volcanic glass outcrops assessed the various potential sources to determine their potential for sustained exploitation. A characterization study of source samples and artifacts from 27 spatially and temporally dispersed sites using a combination of PIXE-PIGME and relative density identified which sources had actually been exploited and a technological analysis of the assemblages described patterns of use. The combination of these three approaches shows the impact of a relatively stable geological environment on patterns of procurement and exchange. © 2008 Wiley Periodicals, Inc. [source]

    Fluorite Deposits at Voznesenka in the Khanka Massif, Russia: Geology and Age of Mineralization

    RESOURCE GEOLOGY, Issue 3 2003
    Kohei Sato
    Abstract. A huge fluorite deposit at Voznesenka in the Khanka massif, Far East Russia is concluded to have formed at ca. 450 Ma in Late Ordovician time based on the K-Ar ages for Li-micas in the fluorite ore and greisenized leucogranite within the deposit. This conclusion is inconsistent with the current view of Devonian mineralization that stemmed from widely scattered whole-rock Rb-Sr isotope data for the heterogeneous leucogranite stocks influenced by strong alteration. The Voznesenka and neighboring fluorite deposits may have formed in Cambrian limestone in relation to the intrusion of the Li-F-rich felsic magma which has a similar chemistry to representative Li-F-rich felsic rocks including topaz granite and ongonite or topaz rhyolite; these rocks may be classified as a specific group of highly fractionated felsic magmas. Biotite granite plutons exposed in the Voznesenka district are divided in age into two groups based on the CHIME age data for zircon, monazite and xenotime: Ordovician and Permian. The Ordovician plutons seem to be coeval to the fluorite deposits and are characterized by F-rich chemistry, reduced nature and association of tin mineralization with the deposition of fluorite and tourmaline. The biotite granite magmas of initially enhanced F contents could have been highly fractionated to form Li-F-rich leucogranite cupolas that provided fluorite deposits within the host limestone. Future prospecting for similar fluorite deposits is to be focused on areas of intersection between Ordovician Li-F-rich granite and Cambrian carbonate sequences. The Permian granite of southeastern margin of the Grodekovo batholith is characterized by lesser F content, oxidized nature and the lack of tin and fluorite mineralization in contrast to the Ordovician granite. The result of Permian age does not support the current view of Silurian age for the batholith and requires overall chronological reinvestigation in connection with the tectonic history of the Khanka massif because the Grodekovo is a representative of Paleozoic batholiths in Primorie. [source]

    Mid,Cretaceous Episodic Magmatism and Tin Mineralization in Khingan-Okhotsk Volcano,Plutonic Belt, Far East Russia

    RESOURCE GEOLOGY, Issue 1 2002
    Kohei SATO
    Abstract: Age of magmatism and tin mineralization in the Khingan-Okhotsk volcano,plutonic belt, including the Khingan, Badzhal and Komsomolsk tin fields, were reviewed in terms of tectonic history of the continental margin of East Asia. This belt consists mainly of felsic volcanic rocks and granitoids of the reduced type, being free of remarkable geomagnetic anomaly, in contrast with the northern Sikhote-Alin volcano,plutonic belt dominated by oxidized-type rocks and gold mineralization. The northern end of the Khingan-Okhotsk belt near the Sea of Okhotsk, accompanied by positive geomagnetic anomalies, may have been overprinted by magmatism of the Sikhote-Alin belt. Tin,associated magmatism in the Khingan-Okhotsk belt extending over 400 km occurred episodically in a short period (9510 Ma) in the middle Cretaceous time, which is coeval with the accretion of the Kiselevka-Manoma complex, the youngest accretionary wedge in the eastern margin of the Khingan-Okhotsk accretionary terranes. The episodic magmatism is in contrast with the Cretaceous-Paleogene long,lasted magmatism in Sikhote,Alin, indicating the two belts are essentially different arcs, rather than juxtaposed arcs derived from a single arc. The tin-associated magmatism may have been caused by the subduction of a young and hot back-arc basin, which is inferred from oceanic plate stratigraphy of the coeval accre-tionary complex and its heavy mineral assemblage of immature volcanic arc provenance. The subduction of the young basin may have resulted in dominance of the reduced-type felsic magmas due to incorporation of carbonaceous sediments within the accretionary complex near the trench. Subsequently, the back-arc basin may have been closed by the oblique collision of the accretionary terranes in Sikhote,Alin, which was subjected to the Late Cretaceous to Paleogene magmatism related to another younger subduction system. These processes could have proceeded under transpressional tectonic regime due to oblique subduction of the paleo-Pacific plates under Eurasian continent. [source]