Composition and age of volcanic rocks from the Sinii Utes Depression, Southern Primoye

New data are reported on structure of sections, chemical composition, and age of volcano-sedimentary and volcanic rocks from the Sinii Utes Depression in the Southern Primorye region. The Sinii Utes Depression is filled with two sequences: the lower sequence composed of sedimentary-volcanogenic coaliferous rocks (the stratotype of the Sinii Utes Formation) and the upper sequence consisting of tephroid with overlying basalts. This work considers chemical composition and problems of K-Ar dating of basalts. The uppermost basaltic flow has K-Ar age 22.0±1.0 Ma. The dates obtained for the middle and upper parts of lava flows are underestimated. It is explained by their heating due to combustion of brown coals of the Sinii Utes Formation underlying the lava flow. Calculations show that argon could only partly have been removed from the basalts owing to conductive heat transfer and was lost largely due to infiltration of hot gases in heterogeneous fissured medium. Basaltic volcanism on continental margins of the southern Primorye region and the adjacent Korean and Chinese areas at the Oligocene-Miocene boundary preceded Early-Middle Miocene spreading and formation of the Sea of Japan basin. Undifferentiated moderately alkaline basalts of intraplate affinity developed in the Amba Depression and some other structures of the southern Primorye region and intraplate alkali basalts of the Phohang Graben in the Korean Peninsula serve as indicators of incipient spreading regime in the Sea of Japan. Potassic basalt-trachybasalt eruptions occurred locally in riftogenic depressions and shield volcanoes. In some structures this volcanism was terminated by eruptions of intermediate and acid lavas. Such evolution of volcanism is explained by selective contamination of basaltic melts during their interaction with crustal acid material and generation of acid anatectic melts.

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Brandt, I S, Rasskazov, S V, Popov, V K, Brandt, S B (2009). Dataset: Composition and age of volcanic rocks from the Sinii Utes Depression, Southern Primoye. https://doi.org/10.1594/PANGAEA.775368

DOI retrieved: 2009

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Field Value
Imported on November 30, 2024
Last update November 30, 2024
License CC-BY-3.0
Source https://doi.org/10.1594/PANGAEA.775368
Author Brandt, I S
Given Name I S
Family Name Brandt
More Authors
Rasskazov, S V
Popov, V K
Brandt, S B
Source Creation 2009
Publication Year 2009
Resource Type application/zip - filename: Brandt_2009
Subject Areas
Name: Lithosphere

Related Identifiers
Title: Potassic specifics of basalts from the Sinii Utes Depression: Geochemical correlations and problems of K-Ar dating (Southern Primorye region)
Identifier: https://doi.org/10.1134/S1819714009040058
Type: DOI
Relation: IsSupplementTo
Year: 2009
Source: Translated from Tikhookeanskaya Geologiya, 2009, 28(4), 75-89
Authors: Brandt I S , Rasskazov S V , Popov V K , Brandt S B .