Fluorite Deposits at Voznesenka in the Khanka Massif, Russia: Geology and Age of Mineralization |
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| Authors: | Kohei Sato Kazuhiro Suzuki Munetomo Nedachi Shigeru Terashima Margarita D Ryazantseva Anatoly A Vrublevsky Alexander I Khanchuk |
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| Institution: | Geological Survey of Japan, Higashi 1–1-1 Central 7, Tsukuba, Ibaraki 305–8567, Japan [e-mail: ];Center for Chronological Research, Nagoya University;Faculty of Sciences, Kagoshima University;Committee on Geology and Mineral Resources of Primorie Province, Vladivostok, Russia;Institute of Complex Analysis of Regional Problems, Russian Academy of Sciences, Birobidzhan, Russia (Died on June 24, 2001);Far East Geological Institute, Russian Academy of Sciences, Vladivostok, Russia |
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| Abstract: | 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. |
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| Keywords: | fluorite deposit Voznesenka Khanka massif Russia Ordovician Silurian Permian Li-F-rich granite greisen alteration Cambrian limestone K-Ar & CHIME ages Li-mica zircon monazite xenotime Grodekovo batholith metallogeny |
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