| 华北克拉通新元古界长龙山组石英砂岩物源组成及其古地理意义 |
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| 关键词:Changlongshan Formation provenance North China Craton Yan–Liao Rift Basin Neoproterozoic paleogeography |
| 基金项目:本文由国家自然科学基金项目(编号: 42302125)、中国地质调查局地质调查项目(编号: DD20242607; DD20240027; DD20221727-03)和深地国家科技重大专项“深地大数据共享管理与数字深地系统”项目(编号: 2024ZD1001200; 2024ZD1001206)联合资助。 |
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| Provenance of the Quartzose Sandstones in the Changlongshan Formation (Neoproterozoic) of the North China Craton and Its Paleogeographic Implications |
| The Changlongshan Formation is an important stratigraphic unit of the Qingbaikou System (Neoproterozoic) within the Yan–Liao Rift Basin of the North China Craton, considered to be the earliest sedimentary record following the breakup of the Rodinia supercontinent. However, it remains unclear as to whether there are any substantial spatial differences in the detailed provenance composition of the Yan–Liao Rift Basin. In this study, we performed lithofacies analysis, detrital zircon U-Pb dating, and Hf isotopic analysis of quartzose sandstones from the Changlongshan Formation in the Zhuolu and Xinglong areas to elucidate their provenance composition and tectonic-paleogeographic implications. The quartzose sandstones were found to be medium-thick bedded and moderately/well sorted. The sedimentary structures include tabular cross-bedding, large-scale trough cross-bedding, and wave ripples, indicative of a high-energy foreshore depositional environment. The detrital zircons are characterized by two distinct age clusters: (1) Late Neoarchean to Early Paleoproterozoic (2 582–2 422 Ma; peak at ~2.5 Ga), with εHf(t) values ranging from –3.4 to +5.5, and corresponding crustal model ages of 2.7–3.2 Ga; and (2) Paleoproterozoic (2 016–1 725 Ma; peak at ~1.8 Ga), with εHf(t) values between –17.0 and –7.4, and crustal model ages of 3.0–3.6 Ga. These two age peaks are primarily inherited products of the two major tectonic–thermal events that occurred during the Precambrian era of the North China Craton. The ~2.5 Ga detrital zircons provide a record of crustal growth and initial cratonization, whereas the ~1.8 Ga detrital zircons coincide with the collision and amalgamation of the eastern and western blocks of the North China Craton, forming a unified crystalline basement that corresponds to the assembly of the Columbia supercontinent. The age spectra of the detrital zircons of the Changlongshan Formation are characterized by substantial spatial variations across the Yan–Liao Rift Basin, thus indicating that during the depositional period of the Changlongshan Formation, rather than being a unified sedimentary basin, the Yanliao Rift Basin may have comprised multiple relatively independent sedimentary units with distinct source-to-sink systems controlled by the paleogeographic framework. These findings will provide a new perspective for comprehending the differential response of the North China Craton during the initial stages of the breakup of the Rodinia supercontinent. |
| MENG Zhongyu,SUN Lixin,REN Bangfang,TIAN Jian,LI Weitong,LIU Wei,TONG Yunxiao.2026.Provenance of the Quartzose Sandstones in the Changlongshan Formation (Neoproterozoic) of the North China Craton and Its Paleogeographic Implications[J].Acta Geoscientica Sinica,47(4):703-714. |
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