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Cap carbonate of the early Ediacaran period represents an abrupt climate shift from severe Marinoan glaciation to a post‐glacial warm environment. Some consensuses on the distinctive negative excursion of δ13Ccarb and the origin of its unique sedimentary structures have been reached over the past decades, but certain aspects such as the distribution and redox conditions of cap carbonate still remain controversial. To resolve these issues, we collected detailed samples of the Doushantuo cap carbonate from the Ganlong‐Fanyang section and the Poutoushang reservoir section in the Danzhai County, southeast Guizhou Province, respectively. We conducted carbon and oxygen isotope analysis and trace element analysis in this study. The Ganlong‐Fanyang section was possibly situated in a submarine highland because of its higher carbon isotope than that of the Potoushang section according to the carbon isotopic gradient. Negative carbon isotope excursions at the basal Doushantuo cap carbonate from the two sections correlate well with those from other equivalent cap carbonates and were corresponding to the first one (SN1 or EN1) of the carbon isotopic curve during the Ediacaran period, implying a remarkable global event after the post‐Marinoan glaciation. Geochemical features of trace elements and rare earth elements support an overall oxygen‐rich condition with syn‐depositional or pene‐contemporaneous hydrothermal activities and methane seeps during the deposition of cap carbonate. We reconstruct a new sedimentary model that the Doushantuo cap carbonates were mainly precipitated in relatively shallow‐ to deep‐water shelf environments without disturbance by abundant terrestrial materials, which may be on isolated platforms over the early developed grabens in a deep‐water basinal condition, rather than within the entire oceanic basin. [ABSTRACT FROM AUTHOR]

Trace and rare earth elements (REEs) geochemistry of carbonate rocks of the Ediacaran Doushantuo Formation, northeast Guizhou province were studied to present spatio-temporal variations of trace elements and REEs from two suites of different sedimentary facies, so as to discuss simultaneously differing palaeo-environmental conditions during the deposition of Ediacaran carbonate formation. Results demonstrate that the depositional seawater of the Nongjing section is more oxygen-depleted than those of the Tongluo section during the early Doushantuo period. For the whole Doushantuo Formation, the sedimentary water column of the lower Doushantuo Formation is much more oxygen deficient than those of the upper, and is the most anoxic in the middle formation, which is consistent with sedimentary model of the Doushantuo Formation in this area. Relative to average marine carbonate, the depletion and enrichment of certain trace elements indicate that the sedimentary condition of the Doushantuo carbonates deposition was anoxic (the early)-oxic (the middle)-anoxic (the later), with more intensive volcanic and hydrothermal accompanying with lower palaeoproductivity. The North American shale composite-normalized REE + Y patterns of Doushantuo carbonates from two sections are both characteristic of a slightly negative Ce anomaly, positive Eu anomaly and superchondritic Y/Ho ratio. Geochemical characteristics of trace elements and REEs reveal that these carbonates of the Doushantuo Formation formed generally in an alternant anoxic-oxic environment and a moderately stratified ocean with influx of high-temperature hydrothermal fluids and volcanic material. Different from the stepwise and protracted oxidation, an anoxic-oxic switching process of sedimentary water column with two episodic anoxic events had taken place, and would have contributed to a stimulus for increased evolution at that time. [ABSTRACT FROM AUTHOR]