Permian-Triassic conodonts from Dajiang (Guizhou, South China) and their implication for the age of microbialite deposition in the aftermath of the End-Permian mass extinction

Environmental Controls on the Genesis of Marine Microbialites and Dissolution Surface Associated With the End-Permian Mass Extinction: New sections and Observations From the Nanpanjiang Basin, South China

“…In contrast, Liu et al (2007), Ezaki et al (2008) and Jiang et al (2014) have reported the occurrence of the conodont H. parvus immediately above the truncation surface bounding the upper Permian skeletal packstone and microbialite at Dawen and Dajiang sections with the implication that the hiatus at the truncation was slightly longer, spanning from beds 25 to 27c. It is difficult to assess the report of Ezaki et al (2008) which lacks illustrated conodont elements.…”

“…Detailed stratigraphic, petrographic, paleontologic, and geochemical studies were made on each of the sections, which correlate across the platform interior of the GBG ( Fig. 2A; Lehrmann 1999;Lehrmann et al 2003;Payne et al 2004Payne et al , 2007Payne et al , 2010Krull et al 2004;Xie et al 2005;Kershaw et al 2007;Ezaki et al 2008;Chen et al 2009;Collin et al 2009;Brennecka et al 2011;Yang et al 2011;Jiang et al 2014). PermianTriassic facies of the Great Bank of Guizhou are also well exposed in the region east of the Bianyang syncline in a structurally undisturbed area within the platform interior ( Fig.…”

Comment on “Quantitative biochronology of the Permian–Triassic boundary in South China based on conodont unitary associations” by Brosse et al. (2016)

“…We interpret the discrepancy between the newly proposed UAZ correlations (Brosse et al, 2016) and current biozones to be due to the failure to use the most recent published conodont ranges from some key Chinese sections (i.e., Jiang et al, 2011;Chen et al, 2015). (Liu et al, 2007), Dajiang (Jiang et al, 2014), and Cili (Wang et al, 2016)]. This is likely because the Permian conodonts have been concentrated as insoluble residues at karstification surfaces seen at the base of some microbialite beds and subsequently co-samled with Triassic conodonts (Chen et al, 2009;Jiang et al, 2014).…”

“…(Liu et al, 2007), Dajiang (Jiang et al, 2014), and Cili (Wang et al, 2016)]. This is likely because the Permian conodonts have been concentrated as insoluble residues at karstification surfaces seen at the base of some microbialite beds and subsequently co-samled with Triassic conodonts (Chen et al, 2009;Jiang et al, 2014). Such effects, and the rarity of conodonts in microbialite facies, suggests caution must be exercised when assessing conodont ranges in microbialite beds.…”

Permian–Triassic boundary microbialites (PTBMs) in southwest China: implications for paleoenvironment reconstruction

“…Analysis of conodont biostratigraphy, mega-to microscopic microbialite structures, stratigraphic variations in abundance and size of metazoan fossils, and total organic carbon (TOC) and total sulfur (TS) contents within the PTBM reveals the following results: (1) the microbialites occur mainly in the Hindeodus parvus Zone but may cross the Permian-Triassic boundary, and are comprised of, from bottom to top: lamellar thrombolites, dendritic thrombolites and lamellarreticular thrombolites; (2) most metazoan fossils of the microbialite succession increase in abundance upsection, so does the sizes of bivalve and brachiopod fossils; (3) TOC and TS values of microbialites account respectively for 0.07 and 0.31 wt% on average, both of which are very low. The Kershaw et al 2007Kershaw et al , 2009Kershaw et al , 2011Yang et al 2011;Forel et al 2013;Kershaw et al 2012;Loope et al 2013;Jiang et al 2014;Wu et al 2014;Lehrmann et al 2015;Wu et al 2016). Microbialites also occur later in the Early Triassic (Schubert and Bottjer 1992;Lehrmann 1999;Pruss and Bottjer 2004;Pruss et al 2006;Mary and Woods 2008;Mata and Bottjer 2011;Marenco et al 2012;Chen et al 2014;Vennin et al 2015), where they are commonly described as having formed in anoxic, harsh environments (e.g., Pruss and Bottjer 2004;Pruss et al 2006;Mary and Woods 2008;Mata and Bottjer 2011).…”