Research output: Contribution to journal › Article › peer-review
High-Potassium Volcanism Approximately 640 Ma in the Southwestern Siberian Platform (Biryusa Uplift, Sayan Region). / Letnikova, E. F.; Izokh, A. E.; Kosticin, Y. A.; Letnikov, F. A.; Ershova, V. B.; Federyagina, E. N.; Ivanov, A. V.; Nojkin, A. D.; Shkolnik, S. I.; Brodnikova, E. A.
In: Doklady Earth Sciences, Vol. 496, No. 1, 04.03.2021, p. 53-59.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - High-Potassium Volcanism Approximately 640 Ma in the Southwestern Siberian Platform (Biryusa Uplift, Sayan Region)
AU - Letnikova, E. F.
AU - Izokh, A. E.
AU - Kosticin, Y. A.
AU - Letnikov, F. A.
AU - Ershova, V. B.
AU - Federyagina, E. N.
AU - Ivanov, A. V.
AU - Nojkin, A. D.
AU - Shkolnik, S. I.
AU - Brodnikova, E. A.
N1 - Publisher Copyright: © 2021, Pleiades Publishing, Ltd. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/3/4
Y1 - 2021/3/4
N2 - Abstract: On the basis of petrographic and mineralogical studies, we have established the presence of clastic rocks with a strong predominance of K-feldspar among the rock-forming fragments within the Late Precambrian sedimentary sequence in the southwestern part of the Siberian Platform. Two types of mineralogical occurrence of K-feldspars are determined: (1) huge zonal crystal clasts with increased Ba concentrations in the central parts of the grains and (2) the main mineral phase in the form of a decrystallized glassy mass. In both cases, low concentrations of Na (lower than 0.1 wt %) are detected. K-feldspars of the second type contain intergrowths of idiomorphic rhombic dolomite with a high ankerite component. Dolomite grains contain inclusions of K-feldspar. The prevailing accessory minerals are F-apatite (with high concentrations of REEs), zircon (with high concentrations of Th), magnetite, rutile, monacite, and sinchizite. Encasement minerals with an idiomorphic shape are identified, with K-feldspar being located in the center, while the middle shell is formed by apatite with a high REE content, and the outer shell is formed by apatite without rare earth elements. These rocks are products of high-potassium volcanic activity. The age of this event has been established on the basis of U–Pb zircon dating to about 640 Ma. The Lu–Hf zircon systematics for these rocks indicates the connection of volcanism with igneous events of mantle genesis within its range. The products of explosive eruption, which are widespread within the Biryusa uplift of the Siberian Platform, were erroneously considered earlier as Riphean sedimentary rocks of the Karagas Series.
AB - Abstract: On the basis of petrographic and mineralogical studies, we have established the presence of clastic rocks with a strong predominance of K-feldspar among the rock-forming fragments within the Late Precambrian sedimentary sequence in the southwestern part of the Siberian Platform. Two types of mineralogical occurrence of K-feldspars are determined: (1) huge zonal crystal clasts with increased Ba concentrations in the central parts of the grains and (2) the main mineral phase in the form of a decrystallized glassy mass. In both cases, low concentrations of Na (lower than 0.1 wt %) are detected. K-feldspars of the second type contain intergrowths of idiomorphic rhombic dolomite with a high ankerite component. Dolomite grains contain inclusions of K-feldspar. The prevailing accessory minerals are F-apatite (with high concentrations of REEs), zircon (with high concentrations of Th), magnetite, rutile, monacite, and sinchizite. Encasement minerals with an idiomorphic shape are identified, with K-feldspar being located in the center, while the middle shell is formed by apatite with a high REE content, and the outer shell is formed by apatite without rare earth elements. These rocks are products of high-potassium volcanic activity. The age of this event has been established on the basis of U–Pb zircon dating to about 640 Ma. The Lu–Hf zircon systematics for these rocks indicates the connection of volcanism with igneous events of mantle genesis within its range. The products of explosive eruption, which are widespread within the Biryusa uplift of the Siberian Platform, were erroneously considered earlier as Riphean sedimentary rocks of the Karagas Series.
KW - high-potassium volcanism
KW - Late Riphean
KW - mineralogy
KW - Siberian Platform
KW - U–Pb and Lu-Hf dating
UR - http://www.scopus.com/inward/record.url?scp=85102126157&partnerID=8YFLogxK
U2 - 10.1134/S1028334X21010128
DO - 10.1134/S1028334X21010128
M3 - Article
AN - SCOPUS:85102126157
VL - 496
SP - 53
EP - 59
JO - Doklady Earth Sciences
JF - Doklady Earth Sciences
SN - 1028-334X
IS - 1
ER -
ID: 75463281