Carbon isotopic evolution of the terminal Neoproterozoic and early Cambrian: Evidence from the Yangtze Platform, South China

Guo, Qianqian; Strauß, Harald; Liu, Cong‐Qiang; Goldberg, Tatiana; Zhu, Maoyan; Pi, Dao-Hui; Heubeck, Christoph; Vernhet, E.; Yang, Xing; Fu, Pingqing

doi:10.1016/j.palaeo.2007.03.014

Cited by 97 publications

(78 citation statements)

References 49 publications

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“…On the other hand, although thermal metamorphism can increase C/N ratios to hundreds and even thousands, ␦ 15 N values might only increase to a small extent, depending on metamorphic grade, with increases of ∼1-2‰ at greenschist facies and of ∼3-4‰ at amphibolite facies (Bebout and Fogel, 1992;Jia, 2006;Mingram and Bräuer, 2001). As the ␦ 15 N bulk values from our studied successions are unlikely to have been modified significantly by post-depositional thermal alteration because of high H/C ratio values having been measured at the nearby coeval Yanwutan-Lijiatuo section (Guo et al, 2007b), nitrogen isotopic shifts if any caused by thermal alteration should be expressed consistently through the section in such a limited stratigraphic interval.…”

Section: Evaluation Of Nitrogen Isotope Datamentioning

confidence: 64%

“…High organic H/C ratios (0.3-1.8) of the Liuchapo and Xiaoyanxi (equivalent to the Niutitang Formation) formations at the Yanwutan-Lijiatuo section, which is about 75 km away from Sancha section and only 4 km away from Yuanjia section in Hunan Province (Guo et al, 2007b), suggest that the studied area did not experienced greenschist facies metamorphism (Hayes et al, 1983). Observations on the petrography of sedimentary rocks at the studied sections and on the regional geology also show that the Ediacaran and early Cambrian strata in this region preserve original structures of the shales and mudstones, suggesting little metamorphism occurred to the strata.…”

Section: Geological Settingmentioning

confidence: 99%

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Marine redox variations and nitrogen cycle of the early Cambrian southern margin of the Yangtze Platform, South China: Evidence from nitrogen and organic carbon isotopes

Wang

Struck

Guo

et al. 2015

Precambrian Research

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Section: Evaluation Of Nitrogen Isotope Datamentioning

confidence: 64%

Section: Geological Settingmentioning

confidence: 99%

Marine redox variations and nitrogen cycle of the early Cambrian southern margin of the Yangtze Platform, South China: Evidence from nitrogen and organic carbon isotopes

Wang

Struck

Guo

et al. 2015

Precambrian Research

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“…The relatively low values of Th/U in stage 1 and lower stage 2 of the three sections correspond to more negative organic carbon isotope values. Moreover, a steep rise of Th/U values corresponds to the positive shift in δ 13 C org , which suggests an increase in the concentration of dissolved oxygen (Goldberg et al, 2007;Guo et al, 2007a). This change to less negative δ…”

Section: Implication For the Rise Of Oxygenmentioning

confidence: 96%

“…2 (Pan et al, 2004;Guo et al, 2007aGuo et al, , 2007bYang et al, 2007;Guo et al, 2013;Och et al, 2013;Pi et al, 2013).…”

Section: Yuanjiamentioning

confidence: 99%

“…C Corg values, e.g., Guo et al, 2007aGuo et al, , 2007bGuo et al, 2013) and S (the minimum δ 34 S values; e.g., Goldberg et al, 2007;Guo et al, 2007a;Feng et al, 2014;Och et al, 2015). In contrast, oxygenation of near-bottom waters has been proposed because of the occurrence of the various benthic organisms, such as sponges and arthropods (e.g., Xiao et al, 2005;Zhao et al, 2014).…”

mentioning

confidence: 99%

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REE and trace element patterns from organic-rich rocks of the Ediacaran–Cambrian transitional interval

et al. 2016

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It has been established that important changes in the marine environment and the biosphere occurred during the Cambrian. However, the relationships between the so-called "Cambrian Explosion" and the concomitant environmental changes are not yet fully understood. This study presents new geochemical data from the black shale successions from different facies belts of the Yangtze Platform in South China. Variations in the concentrations of REE and trace elements (varying Ce/Ce*, Th/U, V/Sc, and V/Cr ratios) in kerogen as well as in bulk rocks from different depositional environments along a transect from platform to basin indicate two oxidation events, which led to the oxygenation of the water column in shallow-marine environments and euxinic conditions (weak correlation between TOC, V, U, and Mo) in the deeper sea. During the first oxidation event in the late Terreneuvian, anoxic conditions in bottom waters rapidly changed to euxinic conditions. Subsequently, the second oxidation event during the early Epoch 2 of the Cambrian led to oxic-suboxic conditions in deeper seawater.

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Fluctuations of continental chemical weathering control primary productivity and redox conditions during the Earliest Cambrian

Zhao

Zhu

et al. 2023

Geological Journal

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The Ediacaran – Cambrian transition witnessed dramatic changes in the marine environment that are thought to have strongly influenced biological evolution. Previous studies have linked biological innovations to palaeo‐redox changes and suggested that increased productivity is the primary driver of the marine environment. However, the primary productivity and redox control mechanism still need to be clarified. Here, we present new organic carbon isotopes, total organic carbon contents, major elements, and trace and rare earth elements in drill‐core ZK107 from South China to reveal the continental chemical weathering, primary productivity, and redox control mechanism during the Earliest Cambrian (E‐C). Our studies have shown intense continental weathering, and primary productivity fluctuations that were supported by weathering (CIA, Rb/Al) and productivity (Babio, P) indicators. Additionally, the quantitative reconstructed productivity proxies (PP18, PP21, PP23) indicate a high primary productivity level in the E‐C ocean, surpassing that of the modern oceans. The strengthening of continental weathering mainly causes high primary productivity because it can alter the nutrient supply to the oceans. We suggest that changes in primary productivity closely associated with continental weathering are the leading cause of marine anoxia during the E‐C. This study establish a linkage between the land and marine system during the E‐C, confirming the terrestrial controls on the marine chemical changes and providing new insights into understanding the evolution of the Earth's surface changes during the Ediacaran – Cambrian transition.

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Carbon isotopic evolution of the terminal Neoproterozoic and early Cambrian: Evidence from the Yangtze Platform, South China

Cited by 97 publications

References 49 publications

Marine redox variations and nitrogen cycle of the early Cambrian southern margin of the Yangtze Platform, South China: Evidence from nitrogen and organic carbon isotopes

Marine redox variations and nitrogen cycle of the early Cambrian southern margin of the Yangtze Platform, South China: Evidence from nitrogen and organic carbon isotopes

REE and trace element patterns from organic-rich rocks of the Ediacaran–Cambrian transitional interval

Fluctuations of continental chemical weathering control primary productivity and redox conditions during the Earliest Cambrian

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