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 syndepositional zircon populations, and their weighted mean 206Pb/238U ages decrease upsection from 512 ± 5 Ma to 483 ± 2 Ma, indicating a sedimentary influx from contemporaneous 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.

中文翻译：

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韩国太白山盆地寒武-奥陶纪砂岩的U-Pb碎屑锆石年龄：台架层序的物源变化及其古地理意义

包括华北克拉通（NCC）在内的东冈瓦南地貌的早期古生代古地理学是有争议的，主要反映了缺乏综合的地质年代学，生物地理学和构造数据集。我们从韩国Taebaeksan盆地的14块砂岩中获得了新的敏感的高分辨率离子微探针数据，表明其平台层架序列以NCC的三叶虫动物群诊断为代表，记录了近代弧岩浆作用的痕迹。从砂岩中分析出的碎屑锆石产生了欧陶纪至奥陶纪早期时代，定义了三种不同类型的分布模式，其特征为：（1）约有两个双峰。NCC基底岩的1.85 Ga和2.50 Ga诊断；（2）约有小峰。除双峰外，还有1.75、1.6和1.2–1.1 Ga；最后（3）散布的晚古元古代至新元古代锆石，缺乏双峰。三种类型之间明显的差异反映了出处的重大变化，最有可能与“索克”海侵期间古水深度的变化有关。沿岸方向或沿岸方向的水流，伴随着水深的增加，显然将外侧碎屑和底栖三叶虫带入了太白山盆地相对平坦的外层。结果，细粒砂岩从远处源头接收到大量碎屑，在锆石年龄模式和三叶虫组合中产生混合特征。除基底砂岩-砾岩单元外，五个硅质碎屑岩地层中存在同沉积锆石种群，它们的加权平均206Pb / 238U年龄使上层活动从512±5 Ma减少到483±2 Ma，表明同时期火山活动导致了沉积物涌入。结合弧相关的块状岩石地球化学和Nd同位素特征，早期的古生代碎屑锆石可能代表了约30 my的第一周期碎屑，该碎屑来自于日本原始弧，最初形成于约20世纪30年代。520毫安。连同ca的发生。古生代弧源碎屑在细粒砂岩中的700–500 Ma碎屑太平洋冈瓦纳锆石表明，朝鲜半岛在古地理学上与一个古老的会聚边缘有关，也许是从Terra Australis造山带中延伸出来的。结合弧相关的块状岩石地球化学和Nd同位素特征，早期的古生代碎屑锆石可能代表了约30 my的第一周期碎屑，该碎屑来自于日本原始弧，最初形成于约20世纪30年代。520毫安。连同ca的发生。古生代弧源碎屑在细粒砂岩中的700–500 Ma碎屑太平洋冈瓦纳锆石表明，朝鲜半岛在古地理学上与一个古老的会聚边缘有关，也许是从Terra Australis造山带中延伸出来的。结合弧相关的块状岩石地球化学和Nd同位素特征，早期的古生代碎屑锆石可能代表了约30 my的第一周期碎屑，该碎屑来自于日本原始弧，最初形成于约20世纪30年代。520毫安。连同ca的发生。古生代弧源碎屑在细粒砂岩中的700–500 Ma碎屑太平洋冈瓦纳锆石表明，朝鲜半岛在古地理学上与一个古老的会聚边缘有关，也许是从Terra Australis造山带中延伸出来的。