Growth mechanisms and environmental implications of carbonate concretions from the similar to 1.4 Ga Xiamaling Formation, North China

doi:10.1186/s42501-019-0036-4

CORC > 地质与地球物理研究所 > 中国科学院地质与地球物理研究所 > 中国科学院油气资源研究重点实验室

	Growth mechanisms and environmental implications of carbonate concretions from the similar to 1.4 Ga Xiamaling Formation, North China
	Liu, An-Qi 1,2; Tang, Dong-Jie 1,2; Shi, Xiao-Ying 1,3; Zhou, Li-Min 4; Zhou, Xi-Qiang 5; Shang, Mo-Han 3; Li, Yang 3; Song, Hu-Yue 6
刊名	JOURNAL OF PALAEOGEOGRAPHY-ENGLISH
	2019-05-16
卷号	8 页码:16
关键词	Mid-Proterozoic Carbonate concretion Early diagenesis Manganese reduction Bicarbonate
ISSN号	2095-3836
DOI	10.1186/s42501-019-0036-4
英文摘要	Carbonate concretions provide unique records of ancient biogeochemical processes in marine sediments, and have the potential to reflect seawater chemistry indirectly. In fine-siliciclastic settings, they preferentially form in organic-rich mudstones, owing to a significant fraction of the bicarbonate required for carbonate precipitation resulted from the decomposition of organic matter in sediments. In the Member IV of the Xiamaling Formation (ca. 1.40-1.35 Ga), North China, however, carbonate concretions occur in organic-poor green silty shales (avg. TOC = similar to 0.1 wt%). In order to elucidate the mechanism of the concretion formation and their environmental implications, a thorough study on the petrographic and geochemical compositions of the concretions and their host rocks was conducted. Macro- to microscopic fabrics, including deformed shale laminae surrounding the concretions, "cardhouse" structures of clay minerals and calcite geodes in the concretions, indicate that these concretions are of early diagenetic origin prior to the significant compaction of clay minerals. The carbon isotope compositions of the concretions (- 1.7 parts per thousand to + 1.5 parts per thousand) are stable and close to or slightly lower than that of the contemporaneous seawater, indicating that the bicarbonates required for the concretion formation were mainly sourced from seawater by diffusion rather than produced by methanogenesis or anoxic oxidation of methane (AOM); the rare occurrence of authigenic pyrite grains in the concretions likely indicates that bacterial sulfate reduction (BSR) did not play a significant role in their formation either. Almost all the calcite in the concretions has low Mn-Fe in nuclei but high Mn-Fe in rims with average Mn/Fe ratio close to 3.3. The calcite shows positive Ce anomalies (avg. 1.43) and low Y/Ho ratios (avg. 31). This evidence suggests that Mn reduction is the dominant process responsible for the formation of calcite rims while nitrate reduction probably triggered the precipitation of calcite nuclei. Prominence of Mn reduction in the porewater likely indicates that there was sufficient oxygen to support active Mn-redox cycling in the overlying seawater.
资助项目	National Natural Science Foundation of China[41672336] ; Fundamental Research Funds for the Central Universities[2652018005] ; Fundamental Research Funds for the Central Universities[2652017050]
WOS关键词	RARE-EARTH-ELEMENTS ; CONTINENTAL-MARGIN SEDIMENTS ; ATMOSPHERIC OXYGEN ; DOUSHANTUO FORMATION ; ISOTOPIC COMPOSITION ; BILLION YEARS ; SOUTH CHINA ; SHALE ; SUPERCONTINENT ; OXIDATION
WOS研究方向	Geology ; Paleontology
语种	英语
出版者	SPRINGER SINGAPORE PTE LTD
WOS记录号	WOS:000469096200001
资助机构	National Natural Science Foundation of China ; National Natural Science Foundation of China ; Fundamental Research Funds for the Central Universities ; Fundamental Research Funds for the Central Universities ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Fundamental Research Funds for the Central Universities ; Fundamental Research Funds for the Central Universities ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Fundamental Research Funds for the Central Universities ; Fundamental Research Funds for the Central Universities ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Fundamental Research Funds for the Central Universities ; Fundamental Research Funds for the Central Universities
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/92114]
专题	地质与地球物理研究所_中国科学院油气资源研究重点实验室
通讯作者	Tang, Dong-Jie
作者单位	1.China Univ Geosci Beijing, State Key Lab Biogeol & Environm Geol, Beijing 100083, Peoples R China 2.China Univ Geosci Beijing, Inst Earth Sci, Beijing 100083, Peoples R China 3.China Univ Geosci Beijing, Sch Earth Sci & Resources, Beijing 100083, Peoples R China 4.Natl Res Ctr Geoanal, Beijing 100037, Peoples R China 5.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Petr Resources Res, Beijing 100029, Peoples R China 6.China Univ Geosci Wuhan, State Key Lab Biogeol & Environm Geol, Wuhan 430074, Hubei, Peoples R China
推荐引用方式 GB/T 7714	Liu, An-Qi,Tang, Dong-Jie,Shi, Xiao-Ying,et al. Growth mechanisms and environmental implications of carbonate concretions from the similar to 1.4 Ga Xiamaling Formation, North China[J]. JOURNAL OF PALAEOGEOGRAPHY-ENGLISH,2019,8:16.
APA	Liu, An-Qi.,Tang, Dong-Jie.,Shi, Xiao-Ying.,Zhou, Li-Min.,Zhou, Xi-Qiang.,...&Song, Hu-Yue.(2019).Growth mechanisms and environmental implications of carbonate concretions from the similar to 1.4 Ga Xiamaling Formation, North China.JOURNAL OF PALAEOGEOGRAPHY-ENGLISH,8,16.
MLA	Liu, An-Qi,et al."Growth mechanisms and environmental implications of carbonate concretions from the similar to 1.4 Ga Xiamaling Formation, North China".JOURNAL OF PALAEOGEOGRAPHY-ENGLISH 8(2019):16.