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| 1 | Trace Elements Characteristics of Black Shales from the Ediacaran Doushantuo Formation, Hubei Province, South China: Implications for Redox and Open vs. Restricted Basin Conditions显示文摘In the present study, we carried out trace element analyses of black shales of the Ediacaran Doushantou Formation from two sections(Jiulongwan, Baiguoyuan) in Hubei Province, South China. Mo-U characteristics of black shales from the two sections and compiled Mo-U data of Doushantuo black shales from sections of a variety of sedimentary facies described the temporal/spatial variability in the redox conditions of paleo-seawater during deposition of the Doushantuo Formation. Changes in Mo-U patterns of the Doushantuo Member Ⅱ(DST2) shales of open marine environments are consistent with a shift from a predominately oxic to a predominately anoxic ocean during their deposition. Mo-U patterns of the DST2 black shales from intra-shelf sections reflect basin restriction may have happened in the intra-shelf basin and are compatible with the redox-stratified model of the intra-shelf basin. Mo-U patterns of black shales of the Doushantuo Member IV(DST4) reveal that the shales from intra-shelf sections have more pronounced Mo enrichment and more significant enrichment of Mo over U than the slope shales, indicating the operation of a Mn particulate shuttle in the intra-shelf basin. High Mo/TOC ratios of the DST4 at the intra-shelf sections, in combination with similar Mo-TOC patterns of the DST4 from both intra-shelf and slope sections, indicate the intrashelf basin was well connected to the open ocean during deposition of the DST4. | Bi Zhu Shaoyong Jiang Daohui Pi Lu Ge Jinghong Yang | 2018 | Journal of Earth Science2018，29，2： | 11 |
| 2 | Rare Earth Element Geochemistry of Phosphatic Rocks in Neoproterozoic Ediacaran Doushantuo Formation in Hushan Section from the Yangtze Gorges Area, South China显示文摘Phosphatic rocks are widely distributed in Neoproterozoic Ediacaran Doushantuo Formation in Yangtze Gorges Area, South China. In this study, rare earth element geochemistry of eight phosphatic rock samples from the Hushan Section has been studied. All the samples display typical hat-shaped REE patterns, moderate negative Ce anomalies(Ce/Ce*=0.55 to 0.67), slightly positive Eu anomalies(Eu/Eu*=1.05 to 1.22) and low Y/Ho ratios(38.2±5.6). The hat-shaped REE patterns indicate diagenetic alteration of the primary REE signatures, which coincides with detrital siliciclastic sources of REE based on the Y/Ho ratios. The degree of Negative Ce anomalies and positive Eu anomalies may have recorded the redox features of diagenetic fluids, suggesting an anoxic environment during the phosphogenesis processes in Neoproterozoic Ediacaran Doushantuo Formation, South China. The geochemical comparison between the Lower Phosphorite Layer and Upper Phosphorite Layer at Hushan indicates a greater degree of diagenesis occurred in the Upper Layer than the Lower one. Besides the terrigenous sources of REE, organic materials could have also played a role on the REE characteristics. | Hong Xin Shaoyong Jiang Jinghong Yang Heping Wu Daohui Pi | 2016 | Journal of Earth Science2016，27，2： | 7 |
| 3 | Organic Carbon Isotope Geochemistry of the Neoproterozoic Doushantuo Formation,South China显示文摘The Neoproterozoic Doushantuo Formation on the Yangtze Platform,South China,documents a sedimentary succession with different sedimentary facies from carbonate platform to slope and to deep sea basin,and hosts one of the world-class phosphorite deposits.In these strata,exquisitely preserved fossils have been discovered:the Weng’an biota.This study presents carbon isotope geochemistry which is associated paired carbonate and organic matter from the Weng’an section of a carbonate platform(shelf of the Yangtze Platform,Guizhou Province)from the Songtao section and Nanming section of a transition belt(slope of the Yangtze Platform,Guizhou Province)and from the Yanwutan section(basin area of the Yangtze Platform,Hunan Province).Environmental variations and bio-events on the Yangtze Platform during the Late Neoproterozoic and their causal relationship are discussed.Negative carbon isotope values for carbonate and organic carbon(mean δ13Corg = ?35.0‰)from the uppermost Nantuo Formation are followed by an overall increase in δ13C up-section.Carbon isotope values vary between ?9.9‰ and 3.6‰ for carbonate and between ?35.6‰ and ?21.5‰ for organic carbon,respectively.Heavier δ13Ccarb values suggest an increase in organic carbon burial,possibly related to increasing productivity(such as the Weng’an biota).The δ13C values of the sediments from the Doushantuo Formation decreased from the platform via the slope to basin,reflecting a reduced environment with minor dissolved inorganic carbon possibly due to a lower primary productivity.It is deduced that the classical upwelling process,the stratification structure and the hydrothermal eruption are principally important mechanisms to interpret the carbon isotopic compositions of the sediments from the Doushantuo Formation. | GUO Qingjun LIU Congqiang Harald STRAUSS Tatiana GOLDBERG ZHU Maoyan PI Daohui WANG Jian | 2006 | Acta Geologica Sinica(English Edition)2006，80，5： | 3 |
| 4 | Zircon U–Pb dating of Pubei granite and strontium isotope from sphalerite of the Xinhua Pb–Zn–(Ag) deposit,Yunkai Area of Guangxi Province,South China显示文摘The Yunkai Area is located at the southern South China Block and is part of the Qinzhou Bay-Hangzhou Bay Metallogenic Belt, which is a famous polymetallic mineralization belt. The Xinhua Pb–Zn–(Ag)deposit is located in the western part of Yunkai Area, with an abundance of Pubei batholiths. Zircon U–Pb geochronology of Pubei batholiths shows that crystallization age ranges from 251.9 ± 2.2 to 244.3 ± 1.8 Ma, thus belonging to Indosinian orogeny. Geochemistry and Sr isotopic compositions of the Pubei batholiths show that it is derived from the partial melting of large scale crustal melting during the stage of exhumation and uplifting of the lower-middle crust. In addition, strontium isotope of sphalerite from the Xinhua Pb–Zn–(Ag) deposit, has limited ranges in ^(87)Rb/^(86)Sr and ^(87)Sr/^(86)Sr, ranging from 0.4077 to 1.0449, and 0.718720 to 0.725245, respectively. The initial ^(87)Sr/^(86)Sr ratios of sphalerite ranges between 0.718720 and 0.725245, which is higher than that of upper continental crust and lower than that of the Pubei batholiths, illustrating the fluid might be derived from the mixing of Pubei pluton and upper continental crust. | Minfang Wang Xubo Zhang Daohui Pi Xiaonan Guo | 2016 | Acta Geochimica2016，35，2： | 2 |
| 5 | Depositionat environ- ments for stratiform witherite deposits in the Lower Cambrian black shale sequence of the Yangtze Platform, southern Qinling region,SW China: Evidence from redox-sensitive trace element geochemistry 显示文摘 | Pi Daohui Jiang Shaoyong Luo Li | 2014 | Palaeogeography Palaeoclimatology Palaeo- ecology2014，398，： | 1 |
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