Controls on carbonate platform architecture and reef recovery across the Palaeozoic to Mesozoic transition: A high-resolution analysis of the Great Bank of Guizhou |
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| Authors: | Brian M Kelley Daniel J Lehrmann Meiyi Yu Adam B Jost Katja M Meyer Kimberly V Lau Demir Altiner Xiaowei Li Marcello Minzoni Ellen K Schaal Jonathan L Payne |
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| Institution: | 1. Department of Geological Sciences, Stanford University, Stanford, CA, 94305 USA;2. Geosciences Department, Trinity University, San Antonio, TX, 78212 USA;3. Department of Resources and Environmental Engineering, Guizhou University, Caijiaguan, Guiyang, 550003 Guizhou Province, China;4. Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, 54-1025, Cambridge, MA, 02139 USA;5. Department of Environmental & Earth Sciences, Willamette University, Collins 215, 900 State Street, Salem, OR, 97301 USA;6. Department of Geology & Geophysics, University of Wyoming, 1000 E. University Ave., Laramie, WY, 82071 USA;7. Department of Geological Engineering, Middle East Technical University, Dumlupinar Blv. No: 1, Ankara, 06531 Turkey;8. Department of Geological Sciences, University of Alabama, Tuscaloosa, AL, 35487 USA;9. Department of Environmental Science and Studies, DePaul University, 1110 10. W Belden Ave., Chicago, IL, 60614 USA |
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| Abstract: | Carbonate platforms spanning intervals of global change provide an opportunity to identify causal links between the evolution of marine environment and depositional architecture. This study investigates the controls on platform geometry across the Palaeozoic to Mesozoic transition and yields new stratigraphic and palaeoenvironmental constraints on the Great Bank of Guizhou, a latest Permian to earliest Late Triassic isolated carbonate platform in the Nanpanjiang Basin of south China. Reconstruction of platform architecture was achieved by integrating field mapping, petrography, biostratigraphy, satellite imagery analysis and δ13C chemostratigraphy. In contrast to previous interpretations, this study indicates that: (i) the Great Bank of Guizhou transitioned during Early Triassic time from a low-relief bank to a platform with high relief above the basin floor (up to 600 m) and steep slope angles (preserved up to 50°); and (ii) the oldest-known platform-margin reef of the Mesozoic Era grew along steep, prograding clinoforms in an outer-margin to lower-slope environment. Increasing platform relief during Early Triassic time was caused by limited sediment delivery to the basin margin and a high rate of accommodation creation driven by Indosinian convergence. The steep upper Olenekian (upper Lower Triassic) slope is dominated by well-cemented grainstone, suggesting that high carbonate saturation states led to syndepositional or rapid post-depositional sediment stabilization. Latest Spathian reef initiation coincided with global cooling following Early Triassic global warmth. The first Triassic framework-building metazoans on the Great Bank of Guizhou were small calcareous sponges restricted to deeper water settings, but early Mesozoic reef builders were volumetrically dominated by Tubiphytes, a fossil genus of uncertain taxonomic affinity. In aggregate, the stratigraphic architecture of the Great Bank of Guizhou records sedimentary response to long-term environmental and biological recovery from the end-Permian mass extinction, highlighting the close connections among marine chemistry, marine ecosystems and carbonate depositional systems. |
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| Keywords: | Biotic recovery carbonate platform architecture end-Permian extinction Great Bank of Guizhou Triassic reefs |
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