Upper Viséan coral biostrome in a volcanic-sedimentary setting from the Eastern Tianshan, Northwest China
Huang, X.; Aretz, M.; Zhang, X.; Du, Y.; Luan, T. (2019). Upper Viséan coral biostrome in a volcanic-sedimentary setting from the Eastern Tianshan, Northwest China. Palaeogeogr. Palaeoclimatol. Palaeoecol. 531(Part B): 108739. https://dx.doi.org/10.1016/j.palaeo.2018.04.014
In: Palaeogeography, Palaeoclimatology, Palaeoecology. Elsevier: Amsterdam; Tokyo; Oxford; New York. ISSN 0031-0182; e-ISSN 1872-616X, more
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Siphonodendron biostrome; Biostratigraphy; Paleoecology; Mississippian; Northwest China |
| Authors | | Top |
- Huang, X.
- Aretz, M.
- Zhang, X.
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| Abstract |
For the first time, a Mississippian coral biostrome is described from the Eastern Tianshan, Xinjiang Province, Northwest China. Rugose corals and foraminifers show that the biostrome developed during the late Viséan in one of the rare carbonate levels in the mainly volcanic-siliciclastic succession of the Yamansu Formation. A single fasciculate coral, Siphonodendron irregulare, dominates (>80%) this biostrome. Of the 22 coral genera found in the Yamansu Formation, 5 colonial and 6 solitary dissepimented corals are recorded in the biostrome. The biostrome can be divided vertically into two parts. In the main thick part dominate large patches of in situ Siphonodendron irregulare colonies. In the thinner uppermost part, Siphonodendron irregulare and Lithostrotion formed locally isolated small patches in a capping bed. The initial growth of the coral patches was related to slight topographic irregularities in the underlying volcano-sedimentary rocks. Siphonodendron irregulare appears to have been the best adapted species to the environmental pressures in the unstable tectono-sedimentary environment of the Yamansu Formation. It flourished and outnumbered the other corals when volcanic activity ceased and carbonate production became active for a short time. The development of the Siphonodendron biostrome ceased due to increases in sea-level and volcanic activity. Compared to Siphonodendron biostromes in the western and eastern Paleotethys, the Siphonodendron biostrome in Yamansu is unique for having developed in an island arc setting. To date, the Yamansu biostrome is the only documented coral bioconstruction at similar latitudes in the Central Asian Orogenic Belt (CAOB). Formation of this coral biostrome was controlled by extrinsic factors, such as changes in global climate and ocean currents, and intrinsic factors, such as the pioneering nature of the fast-growing Siphonodendron irregulare. Both sets of factors are responsible for the expansion of the tropical reef belt into previously more temperate environments. |
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