Newly discovered Sturtian cap carbonate in the Nanhua Basin, South China

Yu, Wenchao; Algeo, Thomas J.; Du, Yu; Zhou, Qi; Wang, Ping; Xu, Yongzhi; Yuan, Liangjun; Pan, Wen

doi:10.1016/j.precamres.2017.03.011

Cited by 65 publications

(29 citation statements)

References 70 publications

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“…The Tiesi'ao Formation represents the Sturtian glacial deposit and consists of >1-15 m thick, massive, dark gray diamictite or dolomitic diamictite gravels, both with poor roundness and sorting. The Datangpo Formation represents the post-Sturtian interglacial and was deposited over a ~10 Myr interval (663-654 Ma) (Zhou et al, 2004;Liu et al, 2015;Yu et al, 2017;Bao et al, 2018). It can be subdivided into three members: the first member consists of 0.5-15 m of laminated or massive Mn-carbonate and Mn-bearing shale or 2-4 m of dolomite; the second is comprised of 1-20 m of pyritic black shales; and the third member consists of 100-700 m of gray and yellow sandy or muddy siltstone (Yu et al, 2016(Yu et al, , 2017.…”

Section: Geological Settingmentioning

confidence: 99%

“…A complete Cryogenian sequence can be found in the Nanhua Basin of the South China Craton (Dobrzinski and Bahlburg, 2007;Huang et al, 2014). Geochronological data suggest that the diamictite deposits in the Jiangkou-Chang'an (or Gucheng, Tiesi'ao) Formation and Nantuo Formation represent Sturtian and Marinoan glacial deposits, respectively (Zhou et al, 2004;Zhang et al, 2008a;Lan et al, 2014Lan et al, , 2015Liu et al, 2015;Yu et al, 2017). The Cryogenian interglacial deposits in South China are collectively referred to as the Datangpo Formation, and are marked by basal Mncarbonate ore deposits (Chen et al, 2008;Li et al, 2012;Wu et al, 2016;Yu et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

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Microbial metallogenesis of Cryogenian manganese ore deposits in South China

Polgári

Gyollai

et al. 2019

Precambrian Research

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The Datangpo Formation manganese deposits (DFMnD) in South China formed during the interglacial stage between the Sturtian and Marinoan glaciations of the Cryogenian period. These black shale-hosted deposits are composed of massive Mncarbonates with microscopic laminae/laminations and cherty veins. To date, it has been thought that the DFMnD formed through inorganic processes, which were controlled by redox changes in the post-Sturtian Nanhua Rift Basin, South China. However, in this study, systematic petrographic, mineralogical, and geochemical analyses indicate a microbially mediated origin of the Mn ore deposits. Mineralized microbial woven micro-textures (observed at the μm scale) and microbial fossils are common in the laminated Mn-carbonate ores. We infer that microbial enzyme activity formed poorly crystallized Mn oxide/hydroxides and carbonaceous material, which 2 transformed to rhodochrosite, kutnohorite, ankerite/dolomite, framboidal pyrite, and apatite via diagenesis. Some micro-scale quartz and K-feldspar may be detrital but most appears to have formed during diagenesis or through hydrothermal activity. A micro-mineralogical profile determined by 2500 spectra via high-resolution in situ micro-Raman spectroscopy also revealed cyclic laminations of Ca-rhodochrosite as microbialite (ankerite/dolomite) and quartz, indicating a mineralized biomat system. Ca-rhodochrosite transformed to kutnohorite under elevated temperatures, as indicated by the maturation level of organic matter (determined via Raman spectroscopy). Alternating micro-laminae denote cyclic changes in microbial groups (Mn-and Fe-oxidizing microbes versus cyanobacteria) during the formation of the Mn ore deposits. Our proposed model for the microbially mediated metallogenesis of Mn-carbonate deposits begins with enzymatic multi-copper oxidase processes associated with autotrophic microbial activity under obligatory oxic conditions, which results in the precipitation of Mn bio-oxides. Following their burial in organic-rich sediments, the Mn(IV) oxides and hydroxides are reduced, producing soluble Mn(II) via processes mediated by heterotrophic microbes under suboxic conditions, which in turn form the Mn-carbonates. This microbial metallogenesis model for the Cryogenian DFMnD in South China is similar to that proposed for the Jurassic Úrkút Mn deposit in Hungary, indicating that a two-step microbially mediated process of Mn ore formation might be common throughout geological history.

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Section: Geological Settingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microbial metallogenesis of Cryogenian manganese ore deposits in South China

Polgári

Gyollai

et al. 2019

Precambrian Research

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“…In fact, in the Nanhua Basin, pre-glaciation successions were dominated by sub-greenschist facies metamorphic siliciclastic rocks, volcanic rocks and marine siliciclastic rocks [36]. The reported dolostone was the Sturtian cap carbonate in the Nanhua Basin [37], and no carbonate clasts were found in diamictites from the Nantuo Formation. Stable carbon isotopic compositions (δ 13 C carb ) of the Sturtian cap carbonate ranged from −4.52% to +3.23% , much higher than in analytical dolostone samples (average δ 13 C carb −7.1% , data not shown in this article) in the Nantuo Formation.…”

Section: Primary Deposit Evaluationmentioning

confidence: 99%

Predominantly Ferruginous Conditions in South China during the Marinoan Glaciation: Insight from REE Geochemistry of the Syn-glacial Dolostone from the Nantuo Formation in Guizhou Province, China

Long

2019

Minerals

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The Neoproterozoic Era witnessed two low-latitude glaciations, which exerted a fundamental influence on ocean-atmosphere redox conditions and biogeochemical cycling. Climate models and palaeobiological evidence support the belief that open waters provided oases for life that survived snowball Earth glaciations, yet independent geochemical evidence for marine redox conditions during the Marinoan glaciation remains scarce owing to the apparent lack of primary marine precipitates. In this study, we explore variability in rare earth elements (REEs) and trace metal concentrations in dolostone samples of the Cryogenian Nantuo Formation taken from a drill core in South China. Petrological evidence suggests that the dolostone in the Nantuo Formation was formed in near-shore waters. All the examined dolostone samples featured significant enrichment of manganese (345-10,890 ppm, average 3488 ppm) and middle rare earth elements (MREEs) (Bell Shape Index: 1.43-2.16, average 1.76) after being normalized to Post-Archean Australian Shale (PAAS). Most dolostone samples showed slight to no negative Ce anomalies (Ce*/Ce 0.53-1.30, average 0.95), as well as positive Eu anomalies (Eu*/Eu 1.77-3.28, average 1.95). This finding suggests that the dolostone samples were deposited from suboxic to iron-enriched and anoxic waters. Although total REE concentrations correlated positively with Th concentrations in dolostone samples, MREE-enriched PAAS-normalized patterns preclude the conclusion that REEs were largely introduced by terrestrial contamination. Rather, we interpret the correlation between REEs and Th as an indication that the former were transported by colloids and nanoparticles in meltwaters. Taken together, we propose that anoxic and ferruginous water columns dominated in South China during the Marinoan glaciation with a thin oxic/suboxic layer restricted to coastal waters. The extreme anoxic and ferruginous conditions prevailing in the Cryogenian would have provided a baseline for subsequent transient Ediacaran ocean oxygenation and life evolution.

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“…at the west of Zhejiang and the northeast of Jiangxi) are dominated by black shale and carbonaceous shale. Manganese deposits and cap carbonate are developed at the bottom in southeast Guizhou and southwest of Hunan (Yu et al, 2017). This formation has its largest thickness at Minle in Huayuan, and at the border of Hunan and Guizhou provinces (i.e., Songtao), where it reaches more than 200 m (Sections 50 and 51 in Fig.…”

Section: Great South China Tectonic-stratigraphic Region 411 Stratimentioning

confidence: 99%

“…from Jiang et al (2007Jiang et al ( , 2011) (Jiulongwan section), δ 13 C data of Datangpo Fm. from Yu et al (2017) and ; Tarim: δ 13 C data of Shuiquan Fm., Zhamoketi Fm. and Altungol Fm.…”

Section: Stratigraphic Sequence and Correlation Of Cryogenian In Chinamentioning

confidence: 99%

Stratigraphic Framework of the Cryogenian in China

Yang

Zhang

et al. 2020

Acta Geologica Sinica (Eng)

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The Cryogenian is a critical period in the history of the Earth. It is marked by multiple extreme climate changes that caused alternating global glacial and interglacial intervals. These dramatically changed the sedimentary system, and metal ores and source rocks distributed widely during this period. Therefore, studying the Cryogenian stratigraphic framework and sedimentary basins is important to improve the stratigraphic resolution for metal mineral and hydrocarbon prospecting and exploration in China. This review paper firstly divides three tectonic‐stratigraphic regions in China in the Cryogenian, including the tectonic‐stratigraphic regions of Great South China, Xingmeng‐Tarim, and North China. Secondly, geochronologic data and geological records are combined to clearly depict the Cryogenian sedimentary sequence of continental blocks and micro‐continental blocks in different tectonic‐stratigraphic regions. The results were used to propose a new comparison scheme of stratigraphy for the Cryogenian in China. Finally, according to differences of sedimentary evolution and tectonic evolvement, sedimentary basins and their lithofacies paleogeography are identified and summarized, respectively.

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Newly discovered Sturtian cap carbonate in the Nanhua Basin, South China

Cited by 65 publications

References 70 publications

Microbial metallogenesis of Cryogenian manganese ore deposits in South China

Microbial metallogenesis of Cryogenian manganese ore deposits in South China

Predominantly Ferruginous Conditions in South China during the Marinoan Glaciation: Insight from REE Geochemistry of the Syn-glacial Dolostone from the Nantuo Formation in Guizhou Province, China

Stratigraphic Framework of the Cryogenian in China

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