The link between exceptional fossil preservation and palaeo‐redox conditions in the Middle Triassic Luoping Biota from South China

Abstract

The Luoping Biota represents of the recovery of marine ecosystems after the Permian-Triassic Mass Extinction. To better understand the palaeoenvironmental background of the Luoping Biota, sedimentary analysis and multi-geochemical proxies (Mo, U, V, V/Cr, Mo EF , U EF , and V EF ) were assessed in Member II of the Middle Triassic Guanling Formation of the Xiangdongpo section in Luoping County, Yunnan Province. According to the facies characteristics and redox-sensitive elemental proxies, in combination with macrofossil and bioturbation evidence, five intervals (I, II, III, IV, and V) were recognized. The exceptional preservation of the fossils is related to two anoxic intervals (II and IV) sandwiched by three suboxic intervals (I, III, and V).Based on this study and regional correlation, it is concluded that anoxia in the watercolumn increased the preservation potential of macrofauna fossils and inhibited the survival of trace-making organisms. In addition, microbial mats could produce local anoxic and restricted micro-environments, preventing the disarticulation of the carcasses by water turbulence. Therefore, we demonstrate that anoxic conditions played a key role in the exceptional fossil preservation of the Luoping Biota.

Late Palaeozoic‐Mesozoic palaeontology and stratigraphy in China: A tribute to the achievements of Professor Zhuoting Liao

“…Z. Ma, Hu, et al (2021) present geochemical analyses of multi-geochemical proxies from the Middle Triassic Guanling Formation that yields the Luoping biota, representing ecosystem recovery from the P-Tr crisis (Chen & Benton, 2012). The results show that anoxic water-column increased the preservation potential of macrofauna fossils and inhibited the survival of trace-making organisms of the Luoping Biota.…”

“…Four papers focus on biotic, palaeoecological, and environmental variations across the Permian–Triassic (P‐Tr) boundary (Cui & Cao, 2021; Miao et al, 2021; Sun et al, 2021; H. Wu, Zhang, & Sun, 2021). Two papers (X. Shi, Lang, et al, 2021; H. Yang, Chen, Mei, & Sun, 2021) and one paper (Z. Ma, Hu, et al, 2021) concerns the Early Triassic palaeoecology and Middle Triassic palaeoenvironments, respectively. One paper attempts to reconstruct the Early Jurassic palaeoclimate regime based on palaeoecological analysis of dinosaur fossils ( H. Shen et al , 2021), and another documents the middle Campanian (Cretaceous) shallow marine red beds, which are coeval with the typical “Cretaceous oceanic red beds (CORBs)” from elsewhere in the world.…”

“…Regionally, five papers concern biosedimentary and fossil records, with one each from Henan, Hubei, Jiangxi, Zhejiang, and Inner Mongolia provinces, respectively (Bai et al, 2021; Mao et al, 2021; Sun et al, 2021; M. Wang et al (2021); Wei et al, 2021). Two papers document fossil records from Hainan and Guizhou provinces, respectively (Lan et al, 2021; Miao et al, 2021; H. Wu et al, 2021; Yao et al, 2021), and three papers each from Yunnan and Tibet provinces, respectively (Q. Chen, Chen, et al, 2021; Y. W. Li et al, 2021; Z. Ma, Hu, et al, 2021; Qiao et al, 2021; H. Shen et al, 2021; X. Wang et al, 2021). Six and seven papers address sedimentary and palaeontology of Guangxi and northern Xinjiang Province, respectively (F. Chen, Xue, et al, 2021; Cui & Cao, 2021; Z. Guo, Chen, Harper, & Huang, 2021; W. Guo, Nie, Lu, et al, 2021; X. Huang, Wang, et al, 2021; Q. Ma, Ye, et al, 2021; X. Shi, Lang, et al, 2021; T. M. Shi, Li, et al, 2021; Song et al, 2021; Wan et al, 2021; Wang F. et al, 2021; Wei et al, 2021; Zong et al, 2021; Figure 1).…”

“…Yang, Chen, Mei, & Sun, 2021) and one paper (Z. Ma, Hu, et al, 2021) concerns the Early Triassic palaeoecology and Middle Triassic palaeoenvironments, respectively. One paper attempts to reconstruct the Early Jurassic palaeoclimate regime based on palaeoecological analysis of dinosaur fossils (H. Shen et al, 2021), and another documents the middle Campanian (Cretaceous) shallow marine red beds, which are coeval with the typical "Cretaceous oceanic red beds (CORBs)" from elsewhere in the world.…”

“…Wu et al, 2021;Yao et al, 2021), and three papers each from Yunnan and Tibet provinces, respectively (Q. Z. Ma, Hu, et al, 2021;Qiao et al, 2021;H.…”