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The tectonic setting of the eastern margin of the Sino-Korean Block inferred from detrital zircon U-Pb age and Nd isotope composition of the Pyeongan Supergroup (upper Palaeozoic - Lower Triassic), Korea

Mun Gi Kim, Yong Il Lee, Taejin Choi and Yuji Orihashi
The tectonic setting of the eastern margin of the Sino-Korean Block inferred from detrital zircon U-Pb age and Nd isotope composition of the Pyeongan Supergroup (upper Palaeozoic - Lower Triassic), Korea
Geological Magazine (March 2019) 156 (3): 471-484

Abstract

The upper Palaeozoic succession (Pyeongan Supergroup) in central eastern Korea is well correlated with the equivalent successions distributed in North China, suggestive of the Korean upper Palaeozoic being part of the Sino-Korean Block. Detrital zircon U-Pb ages and Sm-Nd isotope compositions of the Pyeongan Supergroup in the Samcheok coalfield of the Taebaeksan Basin were analysed. A single predominant zircon age peak at c. 1.9 Ga (> 70%) is marked in all sedimentary units, followed by varying amounts of minor late Palaeozoic grains (up to 30%). The rarity of Meso- to Neoproterozoic- and Silurian-aged zircons confirms that sediment influx from the South China and Qinling blocks was insignificant. The 2.0-1.8 Ga-dominated zircon age pattern and the Nd isotope composition (average epsilon Nd(0) = -15.5+ or -4.0) of the Pyeongan Supergroup most closely reflect the signature of the Yeongnam Massif basements, which supports a previous hypothesis that the Pyeongan Supergroup was mostly derived from a palaeo-orogen located to the east-southeast. Relatively higher epsilon Nd(0) values (> -10.1) in the lowermost and the upper parts of the succession are closely matched by the increased occurrence of syn-depositional-aged zircons, which indicates considerable mixing of juvenile materials at c. 320 Ma and 260 Ma. Both arc-related magmatic events are interpreted to have been related to oceanic subduction, suggesting that the eastern margin of the Sino-Korean Block was an active continental margin during late Palaeozoic times.


ISSN: 0016-7568
EISSN: 1469-5081
Coden: GEMGA4
Serial Title: Geological Magazine
Serial Volume: 156
Serial Issue: 3
Title: The tectonic setting of the eastern margin of the Sino-Korean Block inferred from detrital zircon U-Pb age and Nd isotope composition of the Pyeongan Supergroup (upper Palaeozoic - Lower Triassic), Korea
Affiliation: Seoul National University, School of Earth and Environmental Sciences, Seoul, South Korea
Pages: 471-484
Published: 201903
Text Language: English
Publisher: Cambridge University Press, London, United Kingdom
References: 73
Accession Number: 2019-029402
Categories: GeochronologyStructural geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table, geol. sketch maps
N37°00'00" - N37°25'00", E128°00'25" - E129°00'00"
Secondary Affiliation: Chosun University, KOR, South KoreaUniversity of Tokyo, JPN, Japan
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Abstract, Copyright, Cambridge University Press. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 2019
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