Yichen Liu , Benzhong Xian , Qianran Wu , Zhiyong Lu , Haocheng Shi , Mingjin Wu , Zhiyun Yu , Lin Zhao , Junyang Geng , Haiying Chen
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引用次数: 0
Abstract
Fine-grained successions, traditionally interpreted as continuous archives, contain cryptic hiatuses that are critical for evaluating stratigraphic completeness and paleoenvironmental evolution but remain difficult to resolve, especially in deep-water black shales. This study identifies six hiatuses (H1–H6) in the Lower Silurian Longmaxi Formation through integrated sedimentology, cyclostratigraphy, geochemistry, and Evolutive Spectral Analysis (ESA). A 405 kyr eccentricity-tuned astronomical timescale combined with sedimentary noise modeling yields a third-order relative sea-level (RSL) curve, demonstrating controls from both glacio-eustasy and the Kwangsian Orogeny. Our results demonstrate that hiatuses H1–H4 and H6 align with RSL falls, as evidenced by erosion, oxidation, and enhanced bottom-current/gravity-flow activity under cooler climates. Conversely, H5 formed during a warmer highstand, characterized by intense bioturbation and sediment starvation, indicating a non-depositional hiatus. We propose a classification scheme linking ESA spectral features (spectral bifurcation/shifts) with sedimentary attributes, defining seven hiatus types. The Results highlight sea-level fall-driven bottom-current and gravity-flow erosion as the primary hiatus-forming mechanism in deep-water settings. Third-order RSL fluctuations generate major erosional and non-depositional hiatuses (million-year scale), whereas higher-frequency fluctuations induce more subtle and cryptic hiatuses. These surfaces serve as key sequence boundaries, refining sequence stratigraphic frameworks in fine-grained systems. The integrated approach provides a robust methodology for recognizing hiatuses and advances understanding of sedimentary dynamics in deep-water successions.
期刊介绍:
The International Journal of Coal Geology deals with fundamental and applied aspects of the geology and petrology of coal, oil/gas source rocks and shale gas resources. The journal aims to advance the exploration, exploitation and utilization of these resources, and to stimulate environmental awareness as well as advancement of engineering for effective resource management.