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DIAGENESIS AND DIAGENETIC ENViRONMENTS OF PHOSPHORITE FROM DOUSHANTUO FORMATION, SINIAN SYSTEM. Shan Mansheng . This paper lays emphasis on the diagenesis of the phosphorite and its connection to the sedimentary environments. Five diagenetic sequences have been recognized based on the primary character of the sediments, and then later changes, especially their
The cap carbonate is followed by unit 2 or lower phosphorite that is char acterized by thinbedded, peloidal phosphorite with in terbedded dolostone. Unit 3 is a 2–4 m thick massive dolostone, also known as the midDoushantuo dolo stone, with a prominent karstification surface on top.
Here we report a SIMS zircon U–Pb age of 609 ± 5 Ma for a tuffaceous bed immediately above the upper phosphorite unit in the Doushantuo Formation at Zhangcunping, Yichang, South China. Litho, bio and chemostratigraphic correlations suggest that the upper phosphorite unit at Zhangcunping can be well correlated with the upper phosphorite unit at Weng''an, which is the main horizon of the
Fossil preservation in the Neoproterozoic Doushantuo phosphorite Lagerstatte, South China. Xiao S(1), Knoll . Author information: (1)Botanical Museum, Harvard University, Cambridge, MA 02138, USA. sxiao Phosphorites of the late Neoproterozoic Doushantuo Formation exposed in the vicinity of Weng''an, Guizhou Province, and Chadian, Shaanxi Province, South China, contain
The Neoproterozoic Doushantuo Formation was deposited after the Cryogenian ''Snowball Earth'' interval, between about 635 and 550 Ma, and is famous for cellularlevel preservation of delicate fossils, including metazoan embryos. The unit is exposed through much of south China, with the most fossiliferous locations known to date occurring in the Weng''an area of Guizhou Province.
Phosphorite, phosphate rock or rock phosphate is a nondetrital sedimentary rock that contains high amounts of phosphate phosphate content of phosphorite (or grade of phosphate rock) varies greatly, from 4% to 20% phosphorus pentoxide (P 2 O 5).Marketed phosphate rock is enriched ("beneficiated") to at least 28%, often more than 30% P 2 O 5.
Putative fossil embryos and larvae from the Precambrian phosphorite rocks of the Doushantuo Formation in Southwest China have been examined in thin section by bright field and polarized light microscopy. Although we cannot completely exclude a nonbiological or nonmetazoan origin, we identified what appear to be modern cnidarian developmental stages, including both anthozoan
New microfossils from the late Neoproterozoic Doushantuo Formation at Chaoyang Phosphorite Deposit in Jiangxi Province, South China, Acta Palaeontologica Sinica (in
Phosphatized animals and animal embryos of the Neoproterozoic Doushantuo Formation of Southwest China provide what is likely the earliest fossil evidence for animals, including bilaterians. This research utilizes field and petrographic analyses of the animalfossilbearing interval of the Doushantuo Formation and general observations of animal and animalembryo preservation in order to gain
Phosphorite of the Ediacaran Doushantuo Formation accumulated in the central Guizhou province during the NeoproterozoicCambrian Phosphogenic Event, producing the first true phosphorite giant in
The formation of phosphorites in marine sediments is a major longterm sink for phosphorus, removing it from the biosphere. The initial step in phosphorite formation is the precipitation of phosphatecontaining minerals, for example, hydroxyapatite, followed by many other processes such as sediment transport, winnowing, and recrystallization (1, 2).
DoushantuoFormation Die DoushantuoFormation ist eine aus Sedimenten des Ediacariums entstandene Formation in den chinesischen Provinzen westliches Hubei und nordöstliches Guizhou (Kreis Weng''an). Sie ist bekannt für ihre sehr alten und vorzüglich erhaltenen Fossilien mit sehr frühen Metazoa und eventuellen Bilateria.
Abstract – The Ediacaran Doushantuo Formation at Weng''an, South China hosts wellpreserved phosphatized microfossils known as the Weng''an biota. A laser ablation ICPMS analysis of rare earth element (REE) characteristics of the fossilbearing black phosphorite unit of the Doushantuo Formation at Weng''an was conducted, with the aim of unravelling the depositional conditions and
The Doushantuo Formation in South China, radiometrically constrained between 635 and 551Ma, has the potential to clarify the global picture of earlymiddle Ediacaran evolution. Here we present preliminary biostratigraphic data from the Doushantuo Formation in the East Yangtze Gorges area and new d13C chemostratigraphic data from the Doushantuo Formation at Weng''an. These and previously
· In the later depositional stage of the Doushantuo Formation, transgressions occurred again, and microorganism thrived in Weng''an, forming a biogenic phosphorite layer. Similarly, Kaiyang became a tidal flat, and also developed phosphate sediments ( Wang et al., 2016 ).
The Doushantuo formation itself has three layers representing aquatic sediments that formed as sea levels rose with the melting of worldwide glaciation. Biomarkersindicate highly saline conditions, such as might be found in a lagoon, low oxygen levels, and very little sediment that had been washed off
Petrographic and spectroscopic analyses of proximal phosphorites from the Ediacaran Doushantuo Formation near the Yangtze Gorges area of South China reveal the presence of interlaminated pristine, muddy, and granular phosphorites that were cemented by early diagenetic iron phosphate, an additional, previously undocumented seafloor P sink.
Die DoushantuoFormation ist eine aus Sedimenten des Ediacariums entstandene Formation in den chinesischen Provinzen westliches Hubei und nordöstliches Guizhou (Kreis Weng''an). Sie ist bekannt für ihre sehr alten und vorzüglich erhaltenen Fossilien mit sehr frühen Metazoa und eventuellen Bilateria Geologie. Die Geologie im Ablagerungsbereich der DoushantuoFormation war bereits im Jr
The Weng''an and Kaiyang phosphorite deposits are located in Central Guizhou, southwestern China, and formed within the Sinian (Ediacaran) Doushantuo Formation. A systematic investigation of the geology, mineralogy, and geochemistry of these phosphorites was conducted to constrain the redox environment, origin, and genetic mechanisms of Ediacaran phosphorite. In the lower ore layer (layer
The Doushantuo Formation in South China was deposited after the Nantuo glaciation but before the evolution of complex Ediacaran metazoans. It contains multiple taphonomic windows, in its cherts
In this study, we investigated the phosphorite samples from the uppermost Doushantuo Formation in South China. Carbon isotope compositions of authigenic calcite cements and nodules in the phosphorites are as low as 34‰ (VPDB). Petrographic and geochemical investigations indicate that the 13 Cdepleted carbonates likely formed as the result of microbial sulfate and iron reduction that
The assemblage occurs in the lowermost phosphorite horizon in foreland basin deposits on the Khuvsgul terrane; lithostratigraphic and δ13C correlation with the Zavkhan terrane of southwestern Mongolia establishes a latest Ediacaran age for the fossiliferous phosphorites. Thus, this is the youngest Doushantuotype assemblage yet reported.
The Doushantuo Formation directly overlies the Nantuo Formation glacial sedimentary rocks in the Sichuan Basin and its periphery. The Doushantuo Formation has a thickness of 0–420 m and generally increases in thickness from the inside the basin towards the margin of the basin (Wang et al., 2019b). Given that the Doushantuo Formation
Putative fossil embryos and larvae from the Precambrian phosphorite rocks of the Doushantuo Formation in Southwest China have been examined in thin section by bright field and polarized light microscopy. Although we cannot completely exclude a nonbiological or nonmetazoan origin, we identified what appear to be modern cnidarian developmental stages, including both anthozoan planula larvae
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