Devonian-Carboniferous boundary in China

Abstract

The Devonian-Carboniferous transition is marked by major perturbations to the Earth's climate system and marine redox conditions, a first-order mass extinction, and the succeeding marine ecosystem recovery, recording a sequence of environmental and biotic events. In South China, there exist numerous well-preserved and continuous Devonian-Carboniferous boundary successions that were formed in low-latitude passive margin basin, and this presents a unique opportunity to decipher the strata along a proximal to basinal transect using integrated biostratigraphical, event-stratigraphical, and geochemical approaches. Our geochemical data (δ 13 C carb , δ 15 N bulk , δ 238 U and Mo/U enrichments, I/Ca ratio) indicated local and global C-N cycling perturbations and marine anoxia in the main phase of the Hangenberg Crisis interval (Middle Siphonodella praesulcata Zone), which coincided with a major regression in South China. Stromatoporoid biostromes and most typical Devonian faunas did not survive into the interval, and the deep-water black shales yield only opportunistic survivors, such as ammonoid Postclymenia cf. evoluta and bivalve Guerichina, along with miospores belonging to the LN Zone. The upper Hangenberg Crisis interval (Upper Si. praesulcata Zone, equal to the Protognathodus kockeli Zone) is marked by initial post-glacial transgression, a global δ 13 C carb spike, and opportunistic faunal blooms, coincident with conodont biofacies shift to the polygnathid-protognathodid biofacies. The Protognathodus fauna, nearly absent from platform facies, is often found in the condensed upper crisis interval of the basin, slope, and platform margin facies within the Youjiang Basin, although the abundance is extremely low and the phylogenetic lineage of Pr. meischneri-Pr. collinsoni-Pr. kockeli cannot be recognised in most successions. In South China, the first occurrence of Pr. kockeli seems to correspond to lithofacies changes, recorded in the first level of transgression just above the Hangenberg Sandstone event. Multiple lines of evidence, including great spatial heterogeneity of δ 13 C carb and δ 15 N bulk records, extremes of redox proxies, and lack of macrofossils, suggest that marine habitats remained in a critical/turbulent state during the Upper Si. praesulcata Zone, triggering the opportunistic blooms and minor extinctions. Following the crisis intervals, radiation/ recovery of many fossil groups did not occur until the upper part of the Siphonodella sulcata Zone to the Si. duplicata Zone. In particular, a negative shift of δ 13 C carb to pre-crisis values occurring near the base of the Si. sulcata/Pr. kuehni Zone could be recognised worldwide. The research history, current status, and achievement of Devonian-Carboniferous boundary in China are briefly reviewed.

Enhanced Continental Weathering as a Trigger for the End‐Devonian Hangenberg Crisis

“… Integrative framework for Late Devonian to early Carboniferous including (a) species richness of global seed plants (after Chen, Chen, et al., 2021), (b) conodont δ 18 O apatite compiled from Chen, Ma, et al. (2021) and Grossman and Joachimski (2022), (c) bulk limestone δ 13 C carb from South China (Qie et al., 2021), (d) global 87 Sr/ 86 Sr profiles (after McArthur et al., 2020; Chen, Chen, et al., 2021) and 187 Os/ 188 Os values (Percival et al., 2019; Peucker‐Ehrenbrink & Ravizza, 2020), and (e) δ 7 Li carb records (Kalderon‐Asael et al., 2021 and this study–red open circles). …”

“…(2021) and rugose coral biozonation after Qie et al. (2021). The lithologic legend is shown in Figure 2, and the bransoni ‐ mehli biointerval includes the bransoni , duplicata and mehli zones.…”

Isotopic evidence of environmental changes during the Devonian–Carboniferous transition in South China and its implications for the biotic crisis

“…Well-preserved D-C boundary successions are recorded in the Malanbian and Long'an sections, which consist of shallow-water carbonate or siliciclastic sediments, and detailed studies of diverse fossil groups make them ideal areas for regional comparative studies (Liu et al, 2019;Qie et al, 2015Qie et al, , 2021. Notably, the δ 15 N distribution in the Middle Si.…”

Late Devonian–early Carboniferous ostracods (Crustacea) from South China: taxonomy, diversity and implications

“…1). Dushan County, Guizhou Province, was a part of the Qiangui platform on the passive margin of the South China Craton (Qie et al 2016(Qie et al , 2021 and the palaeoenvironments were dominated by carbonate platforms separated by deeper basins (Dong 1982;Ma & Bai 2002;Hou et al 2011).…”