气候变化领域集成服务门户(CCPortal): U-Pb detrital zircon ages of Cambrian–Ordovician sandstones from the Taebaeksan Basin, Korea: Provenance variability in platform shelf sequences and paleogeographic implications

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DOI	10.1130/B35521.1
	U-Pb detrital zircon ages of Cambrian–Ordovician sandstones from the Taebaeksan Basin, Korea: Provenance variability in platform shelf sequences and paleogeographic implications
	Cho M.; Cheong W.; Ernst W.G.; Kim Y.; Yi K.
发表日期	2021
ISSN	167606
起始页码	488
结束页码	504
卷号	133 期号:2021-03-04
英文摘要	The early Paleozoic paleogeography of East Gondwanan terranes, including the North China Craton (NCC), is contentious, primarily reflecting the paucity of integrated geochronological, biogeographic, and tectonic data sets. Our new sensitive high-resolution ion microprobe data from 14 sandstones of the Taebaeksan Basin, Korea, indicate that its platform shelf sequences, typified by trilobite faunal assemblages diagnostic of the NCC, record the vestige of coeval arc magmatism. Detrital zircons analyzed from the sandstones yielded Eoarchean to Early Ordovician ages, which define three distinct types of distribution patterns characterized by: (1) double peaks at ca. 1.85 Ga and 2.50 Ga diagnostic of basement rocks in the NCC; (2) minor peaks at ca. 1.75, 1.6, and 1.2–1.1 Ga in addition to double peaks; and finally (3) a scattered array of late Paleoproterozoic to Neoproterozoic zircons lacking double peaks. The marked contrasts among the three types reflect significant changes in provenance, most likely linked to variations in paleo-water depths during the “Sauk” transgression. Longshore- or onshore-directed currents, associated with an increase in water depth, apparently brought outboard oceanic detritus and benthic trilobites into the relatively flat outer shelf of the Taebaeksan Basin. As a result, fine-grained sandstones received a large amount of detritus from distal sources, yielding mixed signatures in zircon age patterns and trilobite assemblages. Excluding the basal sandstone-conglomerate unit, five siliciclastic formations contain syn-depositional zircon populations, and their weighted mean 206Pb/238U ages decrease upsection from 512 ± 5 Ma to 483 ± 2 Ma, indicating a sedimentary influx from con-temporaneous volcanic activity. In conjunction with arc-related bulk-rock geochemistry and juvenile Nd isotopic signature, early Paleozoic detrital zircons likely represent the first-cycle detritus supplied for ∼30 m.y. from the proto-Japan arc that initially formed at ca. 520 Ma. Together with the occurrence of ca. 700–500 Ma detrital Pacific Gondwana zircons in fine-grained sandstones, Paleozoic arc-sourced detritus suggests that the Korean Peninsula was paleogeographically linked to an ancient convergent margin, perhaps extending from the Terra Australis orogen. © 2020 Geological Society of America
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184710
作者单位	Department of Earth and Environmental Sciences, Chungbuk National University, Cheongju, 28644, South Korea; Department of Geological Sciences, Stanford University, Stanford, California 94305-2115, United States; Division of Earth and Environmental Sciences, Korea Basic Science Institute, Cheongju, 28119, South Korea
推荐引用方式 GB/T 7714	Cho M.,Cheong W.,Ernst W.G.,等. U-Pb detrital zircon ages of Cambrian–Ordovician sandstones from the Taebaeksan Basin, Korea: Provenance variability in platform shelf sequences and paleogeographic implications[J],2021,133(2021-03-04).
APA	Cho M.,Cheong W.,Ernst W.G.,Kim Y.,&Yi K..(2021).U-Pb detrital zircon ages of Cambrian–Ordovician sandstones from the Taebaeksan Basin, Korea: Provenance variability in platform shelf sequences and paleogeographic implications.Bulletin of the Geological Society of America,133(2021-03-04).
MLA	Cho M.,et al."U-Pb detrital zircon ages of Cambrian–Ordovician sandstones from the Taebaeksan Basin, Korea: Provenance variability in platform shelf sequences and paleogeographic implications".Bulletin of the Geological Society of America 133.2021-03-04(2021).