Carbon, oxygen, strontium, and sulfur isotopic compositions in late Precambrian rocks of the Patom Complex, central Siberia: Communication 1. results, isotope stratigraphy, and dating problems

Покровский, Б. Г.; Melezhik, Victor A.; Bujakaite, M. I.

doi:10.1134/s0024490206050063

Cited by 113 publications

(42 citation statements)

References 25 publications

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“…This hypothesis is consistent with emerging data from the Patom Complex in central Siberia, where the Ura Formation that bears Ediacaran acanthomorphs is stratigraphically below the Zhuya Group that is characterized by a -10‰ δ 13 C carb excursion which is a potential equivalent to EN3 and the Shuram excursion [44,45].…”

Section: Anoxia and The Decline Of Doushantuo Acanthomorphssupporting

confidence: 89%

Rare earth elements and carbon isotope geochemistry of the Doushantuo Formation in South China: Implication for middle Ediacaran shallow marine redox conditions

et al. 2012

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The middle Ediacaran Shuram excursion, the largest negative δ 13 C carb excursion in Earth history, has been interpreted as indirect evidence for episodic oxidation and remineralization of deep ocean DOC (dissolved organic carbon). It has been hypothesized that such oxidation event may have occurred when anoxic DOC-laden deep water was brought to shallow shelves during oceanic upwelling, which is expected to cause localized anoxia in shallow environments. To test this prediction, we systematically analyzed rare earth elements (REE) and δ 13 C carb of the upper Doushantuo Formation carbonates in the Yangtze Gorges area of South China, which were deposited in an inner shelf environment and record a large negative δ 13 C carb excursion correlated to the Shuram event. The REE data show a significant positive shift in Ce/Ce* values, synchronous with a pronounced negative δ 13 C carb shift. This positive Ce/Ce* shift is interpreted to represent an oceanic anoxia event in shallow shelf environments, which may have been caused by the upwelling or impingement of oxygen-depleted and 12 C-enriched deep water onto shelves. This anoxia event coincides with a sharp decline in the abundance and diversity of Ediacaran acanthomorphic acritarchs, raising the possibility that these two geobiological events may be causally related. Carbon and sulfur isotope data indicate that deep oceans were episodically oxygenated and deep ocean DOC progressively remineralized during the Ediacaran Period [1,2]. These remineralization events likely involved upwelling of anoxic DOC-laden water to shallow shelves, impacting on the shallow-water redox conditions and biological evolution. Indeed, the Ediacaran fossil record shows a significant biotic turnover in shallow shelf environments during the middle Ediacaran Period, with the early Ediacaran biota characterized by globally distributed acanthomorphic acritarchs [3], and the late Ediacaran ones by classical Ediacara megafossils [4]. Previous researchers have argued that this turnover may have been driven by a middle Ediacaran glaciation event [5], predation pressure from macrophagous metazoans [3], or the oxygenation of continental shelves that released the ecological impetus for the development of acanthomorphic resting stages [6]. Integrated paleobiological and geochemical data from the Doushantuo Formation in the Yangtze Gorges area suggest that this turnover is coincident with a pronounced negative δ 13 C carb excursion that is correlated with the Shuram excursion [7], and thus may be related to shallow water anoxia resulting from upwelling of deep marine waters. The Doushantuo Formation (635-551 Ma in age, including four lithostratigraphic members I-IV in ascending order; Figure 1) in the Yangtze Gorges area was considered to

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Section: Anoxia and The Decline Of Doushantuo Acanthomorphssupporting

confidence: 89%

Rare earth elements and carbon isotope geochemistry of the Doushantuo Formation in South China: Implication for middle Ediacaran shallow marine redox conditions

et al. 2012

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“…Diverse acanthomorphic acritarchs assigned to species of Tanarium, Cavaspina, Appendisphaera, Dicrospinasphaera, corroborate chemostratigraphic data (Pokrovskii et al, 2006) Scale as the lower boundary of Vendian System). Together, chemostratigraphy and Ura microfossils reframe the time available for Baikalian tectonic events.…”

Section: Paleobiogeographysupporting

confidence: 68%

“…Moreover, coupled C and Sr isotopic data show a pattern of secular variation in the Dalnyaya Taiga and overlying successions that closely matches those of early to mid-Ediacaran rocks on other continents (Sovietov, 2002;Pokrovskii et al, 2006;Chumakov et al, 2007). This includes not only a negative C-isotopic anomaly in cap carbonates above the diamictite, but also a pronounced negative C-isotopic excursion in carbonates of the Zhuya Group that immediately overlie Dalnyaya Taiga strata, and a pattern of increasing 87 Sr/ 86 Taken at face value, then, C and Sr isotopes indicate that fossiliferous Ura shales were deposited in early but not earliest Ediacaran times, and predate most known Ediacaran macrofossil deposits.…”

Section: Introductionmentioning

confidence: 72%

“…Sr from about 0.70725 to 0.70799 through the two groups (Pokrovskii et al, 2006). The interpretation of strong negative C-isotopic excursions in Ediacaran successions has been the subject of recent debate (e.g., Derry, 2010), but an isotopic excursion of unusual magnitude occurs essentially globally in Ediacaran successions older than 551 Ma (Condon et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

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Ediacaran Microfossils from the Ura Formation, Baikal-Patom Uplift, Siberia: Taxonomy and Biostratigraphic Significance

Сергеев

Knoll

Воробьева

2011

Journal of Paleontology

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“…Diverse assemblages of large, morphologically complex acritarchs occur in the Pertatataka Formation, Amadeus Basin, Australia (Zang and Walter, 1992;Grey, 2005); the Ungoolya Group, Officer Basin, Australia (Jenkins et al 1992;Grey, 2005;Willman et al, 2006); the Doushantuo Formation, China (Yuan et al, 2002, and references therein); the Scotia Group, Spitsbergen (Knoll, 1992); the Infrakrol Formation, India (Tiwari and Knoll, 1994); the Motta, Parshin, and Kursov formations, Siberia (Moczydlowska et al, 1993;Moczydlowska, 2005); the Biskopås Conglomerate, Norway (Vidal, 1990); and the Ura Formation, Patom Uplift, Siberia (Nagovitsyn et al, 2004;Vorob'eva et al, 2008; see also recent chemostratigraphic data of Pokrovskii et al, 2006, and. Most of these assemblages lie above glaciogenic rocks considered correlative with those that subtend the Ediacaran System, and none have been interpreted as pre-Ediacaran.…”

mentioning

confidence: 99%

Neoproterozoic microfossils from the margin of the East European Platform and the search for a biostratigraphic model of lower Ediacaran rocks

Воробьева

Сергеев

Knoll

2009

Precambrian Research

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A ca. 600 m thick siliciclastic succession in northern Russia contains abundant and diverse microfossils that document early to middle Ediacaran deposition along the northeastern margin of the East European Platform. The Vychegda Formation is poorly exposed but is well documented by a core drilled in the Timan trough region (Kel'tminskaya-1 borehole). Vychegda siliciclastics lie unconformably above Tonian to lower Cryogenian strata and below equivalents of the late Ediacaran Redkino succession that is widely distributed across the platform. The basal ten meters of the formation preserve acritarchs and fragments of problematic macrofossils known elsewhere only from pre-Sturtian successions. In contrast, the upper, nearly 400 m of the succession contains abundant and diverse large acanthomorphic acritarchs attributable to the Ediacaran Complex Acanthomorph Palynoflora (ECAP). This distinctive set of taxa is known elsewhere only from lower, but not lowermost, Ediacaran rocks. In between lies an additional assemblage of relatively simple filaments and stratigraphically long ranging Manuscript Click here to view linked References 2 sphaeromorphic acritarchs interpreted as early Ediacaran in age. Bearing in mind that knowledge of late Cryogenian (post-Strurtian/pre-Marinoan) microfossils is sparse, the Vychegda record is consistent with data from Australia and China which suggest that diverse ECAP microfossil assemblages appeared well into the Ediacaran Period.Accumulating paleontological observations underscore both the promise and the challenges for biostratigraphic characterization of the early Ediacaran Period.

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Carbon, oxygen, strontium, and sulfur isotopic compositions in late Precambrian rocks of the Patom Complex, central Siberia: Communication 1. results, isotope stratigraphy, and dating problems

Cited by 113 publications

References 25 publications

Rare earth elements and carbon isotope geochemistry of the Doushantuo Formation in South China: Implication for middle Ediacaran shallow marine redox conditions

Rare earth elements and carbon isotope geochemistry of the Doushantuo Formation in South China: Implication for middle Ediacaran shallow marine redox conditions

Ediacaran Microfossils from the Ura Formation, Baikal-Patom Uplift, Siberia: Taxonomy and Biostratigraphic Significance

Neoproterozoic microfossils from the margin of the East European Platform and the search for a biostratigraphic model of lower Ediacaran rocks

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