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89 / 2025-03-31 16:21:06
Role of paleoenvironment conditions and microbial activities in spatiotemporal distribution of ‘Orsten’-type biota: evidence from the early Cambrian of the Three Gorge area, South China
‘Orsten’-type preservation, Doushantuo-type preservation, microbes, Lagerstätte, taphonomy
Theme 3: Earth-Life Co-evolution Through Time > Session 3b: Evolution of the Earth-Life System During the Neoproterozoic-Paleozoic Transition
摘要待审
Ying Wu / Chengdu University of Technology
Lei Zhang / Chengdu University of Technology
The Ediacaran–Cambrian transition marks a major biological revolution characterized by the rapid emergence of diverse metazoan phyla and the establishment of metazoan-dominated ecosystems, as evidenced by globally distributed exceptional fossil assemblages. Among these, ‘Orsten’-type preservation provides unique insights into meiofaunal communities typically underrepresented in other taphonomic modes. From the Ediacaran to Ordovician, two key trends coincide with the diversification of ‘Orsten’-preserved meiofaunal organisms: (1) a progressive decline in fossil fidelity of the ‘Orsten’-preservation and (2) a spatial migration of environments favoring preservation from shallow to relatively deep marine settings, with a critical transition possibly occurring during Cambrian Series 2, Stage 3. To investigate the drivers of this shift, we analyzed two sections deposited synchronously during Cambrian Series 2, Stage 3 under contrasting water depths, namely Changkan (shallow) and Qiaojiaping (deep) sections of the eastern Three Gorges area, South China. Both sections yield abundant cuticular fossils associated with microbial assemblages, with six and five distinct microbial morphotypes identified in the Shuijingtuo and Shipai formations, respectively. Integrated paleontological and geochemical data (Mo-EF vs. U-EF) suggest that the observed contrasts in fossil abundance, diversity, and fidelity between the two sections reflect divergent paleoredox conditions, opposing pore-water phosphorus enrichment trends, and fundamentally distinct microbial roles in preservation pathways. Broader analysis implies that the spatiotemporal migration of ‘Orsten’-type preservation reflects multidirectional feedback mechanisms, including: (1) marine oxygenation episodes; (2) altering dissolved phosphorus reservoirs in water column and pore-water; and (3) biological innovations such as “substrate revolution” and “culture revolution” brought by grazing pressure, which suppressed microbial mat proliferation while enhancing biomixing. These processes may have shoaled the oxygen penetration depth, diversified microbial decomposer communities, and intensified microbial engagement in diagenetic phosphorus cycling. Ultimately, sustained environmental perturbations and ventilated irrigation regimes reshaped microbial mediation of taphonomy, facilitating the rise of modern marine ecosystems. The spatiotemporal evolution and eventual decline of ‘Orsten’-type preservation thus record a transformative interplay between biosphere evolution and Earth system dynamics during the Cambrian radiation

 
重要日期

  • 会议日期

    06月10日

    2025

    至

    06月13日

    2025

  • 04月15日 2025

    初稿截稿日期

主办单位
National Natural Science Foundation of China
Geobiology Society
National Committee of Stratigraphy of China
Ministry of Science and Technology
Geological Society of China
Paleontological Society of China
Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (CAS)
Institute of Vertebrate Paleontology and Paleoanthropology, CAS
International Commission on Stratigraphy
International Paleontological Association
承办单位
State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (CUG, Wuhan)
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