Dolostone-barite-phosphorite sequence in the basal Doushantuo Formation: Origin and implications for post-Marinoan ocean chemistry and phosphogenesis
文献类型：期刊论文
| 作者 | Cao, Kenan7; She, Zhenbing7; Chen, Qun6,7; Jiao, Liangxuan5; Xiao, Qian1,7; Cheng, Meng5; Zhang, Zihu5; Luo, Genming7; Papineau, Dominic2,3,4,7 |
| 刊名 | PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
 |
| 出版日期 | 2024-10-01 |
| 卷号 | 651页码:15 |
| 关键词 | Ediacaran Cap dolostone Redoxcline Barium source Phosphorus reservoir |
| ISSN号 | 0031-0182 |
| DOI | 10.1016/j.palaeo.2024.112400 |
| 英文摘要 | Barite (BaSO4) represents a major component of many post-Marinoan cap dolostones worldwide, recording important information on climate upheavals during the terminal Neoproterozoic. However, its origins and relations with other lithofacies remain to be explored. Here we report new occurrences of barite in the basal Ediacaran Doushantuo Formation at a major phosphate mine in Weng'an, South China, and present results of detailed petrographic and geochemical investigations on the barites and related phases. At the outcrop scale, barite is mainly present as a 1-2 cm-thick layer at the contact of the cap dolostones and overlying phosphorites. Detailed petrographic observations reveal a lithofacies transition from dolostone through a mixture of barite, dolomite and apatite to barite and finally to granular phosphorite. The barites can be categorized into three generations in stratigraphic order, which are present as loose, randomly-oriented blades (B1), dense aggregates (B2), and radially aligned crystal fans (B3), respectively. B1 is dispersed in a matrix of apatite and dolomite, which has an average delta 13Ccarb of -0.61%o. This, along with the common presence of organic matter (OM) in this barite, point to a possible source of Ba from organic degradation. B3 forms a centimeter-scale layer of barite fans that laterally extends over the entire mining pit, whereas B2 is locally distributed between B1 and B3, and occurs as relatively unoriented aggregates. delta 34S values of B3 show a narrow range between +25.9%o and +30.9%o, which is similar to that of contemporaneous seawater and indicate a seawater source of sulfate in barite. Based on the present investigation and a compilation of published data, we propose that B1 is diagenetic barite with a main source of Ba from degradation of organic matter and possibly also from dissolution of previous pelagic barite, whereas B2 and B3 represent seafloor precipitates that resulted from interactions between deep, anoxic Ba-rich waters and oxic, sulfate-rich surface waters during the post-glacial transgression. This episode of barite precipitation was immediately followed by massive accumulations of phosphorites in Weng'an and many areas of South China. The consecutive deposition of cap dolostone, barite and phosphorite signifies the transition from an alkalinity-rich, stagnant anoxic ocean to a dynamic marine regime featuring oxygenated surface waters and upwelling currents. These pH and redox changes likely facilitated the cycling and enrichment of phosphate in the shallow waters that was necessitated by the unprecedented accumulation of Ediacaran phosphorites in South China. |
| WOS关键词 | PROTEROZOIC CYANOBACTERIAL BLOOMS ; YANGTZE PLATFORM ; CAP CARBONATE ; SOUTH CHINA ; O-17-DEPLETED BARITE ; ISOTOPIC EVOLUTION ; CONTINENTAL-MARGIN ; CRITICAL-APPRAISAL ; STRATIFORM BARITE ; TRIPLE OXYGEN |
| 资助项目 | National Key Research and Development Program of China[2023YFC2906601] ; National Natural Science Foundation of China[42130208] ; National Natural Science Foundation of China[42172337] ; Guizhou Provincial Science and Technology Foundation[2016-1407] ; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences[GBL12001] |
| WOS研究方向 | Physical Geography ; Geology ; Paleontology |
| 语种 | 英语 |
| WOS记录号 | WOS:001288742600001 |
| 出版者 | ELSEVIER |
| 资助机构 | National Key Research and Development Program of China ; National Natural Science Foundation of China ; Guizhou Provincial Science and Technology Foundation ; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences |
| 源URL | [http://ir.idsse.ac.cn/handle/183446/11472]  |
| 专题 | 深海科学研究部_深海地质与地球化学研究室 |
| 通讯作者 | She, Zhenbing |
| 作者单位 | 1.Seventh Geol Brigade Hubei Geol Bur, Yichang, Peoples R China 2.Chinese Acad Sci, Inst Deep Sea Sci & Engn, Sanya 572000, Peoples R China 3.UCL, London Ctr Nanotechnol, London, England 4.UCL, Dept Earth Sci, London WC1E 6BT, England 5.Chengdu Univ Technol, Inst Sedimentary Geol, State Key Lab Oil & Gas Reservoir Geol & Exploitat, Chengdu 610059, Peoples R China 6.Guizhou Bur Geol & Mineral Explorat & Dev, Guiyang 550000, Peoples R China 7.China Univ Geosci, Sch Earth Sci, State Key Lab Biogeol & Environm Geol, Wuhan 430074, Peoples R China |
| 推荐引用方式 GB/T 7714 | Cao, Kenan,She, Zhenbing,Chen, Qun,et al. Dolostone-barite-phosphorite sequence in the basal Doushantuo Formation: Origin and implications for post-Marinoan ocean chemistry and phosphogenesis[J]. PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY,2024,651:15. |
| APA | Cao, Kenan.,She, Zhenbing.,Chen, Qun.,Jiao, Liangxuan.,Xiao, Qian.,...&Papineau, Dominic.(2024).Dolostone-barite-phosphorite sequence in the basal Doushantuo Formation: Origin and implications for post-Marinoan ocean chemistry and phosphogenesis.PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY,651,15. |
| MLA | Cao, Kenan,et al."Dolostone-barite-phosphorite sequence in the basal Doushantuo Formation: Origin and implications for post-Marinoan ocean chemistry and phosphogenesis".PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY 651(2024):15. |
入库方式： OAI收割
来源：深海科学与工程研究所
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