The mineralization and early diagenesis of deep-sea coral Madrepora oculata

doi:10.1016/j.chemgeo.2022.120966

CORC > 海洋研究所 > 中国科学院海洋研究所 > 海洋生物分类与系统演化实验室

	The mineralization and early diagenesis of deep-sea coral Madrepora oculata
	Wang, Maoyu 1,2; Xu, Kuidong 3; Li, Tao 1,2; Robinson, Laura F.4; Liu, Yuanyuan 1,2; Shao, Qingfeng 5; Li, Gaojun 1,2; Chen, Tianyu 1,2,6
刊名	CHEMICAL GEOLOGY
	2022-09-20
卷号	606 页码:11
关键词	Early diagenesis Biomineralization Organic matter U-series geochronology Madrepora oculata
ISSN号	0009-2541
DOI	10.1016/j.chemgeo.2022.120966
通讯作者	Chen, Tianyu(tianyuchen@nju.edu.cn)
英文摘要	The skeletons of aragonitic corals carry essential information about oceanic environmental changes in the past. However, coral-based geochemical proxies are sensitive to vital effect and post-depositional diagenetic processes, which have not been well understood for deep-sea corals. In this study, we have investigated the mineralization and early diagenetic process of the dendroid stem of a dead deep-sea scleractinian coral sample (Madrepora oculata) collected by Remote Operated Vehicle (ROV) from a seamount in the Caroline Ridge, western Pacific. Despite being only similar to 270 years old, as dated by the U-series disequilibrium method, this sample already has extensive diagenesis including a visible chalky layer. The outermost chalky layer and the adjacent pristine skeleton of the sample were characterized by multiple mineralogical (SEM, XRD, EBSD, Raman Spectroscopy) and geochemical (ICP-OES, LA-ICP-MS, IR-MS, MC-ICP-MS) techniques. Skeletal stable C and O isotopes display strong linearity, with a trend pointing toward the theoretical isotopic composition of inorganically-precipitated aragonite from local seawater. This observation suggests that the epithecal mineralization of M. oculata is far from equilibrium with seawater and can be quantitatively explained by bio-mineralization models developed for solitary scleractinian corals. We further show that chalking of the outer layer, a common feature in sub-fossilized deep-sea corals, is caused by microbial-driven boring and mu m-scale dissolution voids at an average rate of 3.5 mu mol/cm(2)/y (scaled to the skeleton surface) without notable secondary infillings or mineralogical alternations. The higher average delta C-13 and delta O-18 of the chalky part than the pristine part might be due to the preferential dissolution of carbonate relatively depleted in C-13 and O-18 during alteration, and/or reduced isotope fractionation from seawater during coral mineralization of the outer layer. The chalky layer shows significantly higher Mn/Ca and Th/Ca ratios than the pristine part, characterized by Th/Mn ratios similar to that of the dissolved component of local seawater. Our study suggests that the incorporation of external Th into the coral skeleton is most likely associated with organic binding rather than detrital contamination, secondary carbonate mineral formation, adsorption onto surfaces of chalky aragonite or ferromanganese oxides, with important implications for coral U-series geochronology.
资助项目	Strategic Priority Research Program (B) of the Chinese Academy of Sciences[XDB40010200] ; National Natural Science Foundation of China[41822603] ; National Natural Science Foundation of China[41930533] ; Science & Technology Basic Resources Investigation Program of China[2017FY100804] ; Natural Environment Research Council (NERC)[NE/S001743/1] ; China Scholarship Council ; Senior User Project of R/V KEXUE
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	ELSEVIER
WOS记录号	WOS:000818728500003
内容类型	期刊论文
源URL	[http://ir.qdio.ac.cn/handle/337002/179658]
专题	海洋研究所_海洋生物分类与系统演化实验室
通讯作者	Chen, Tianyu
作者单位	1.Nanjing Univ, Sch Earth Sci & Engn, State Key Lab Mineral Deposit Res, Nanjing, Peoples R China 2.Nanjing Univ, Frontiers Sci Ctr Crit Earth Mat Cycling, Nanjing, Peoples R China 3.Chinese Acad Sci, Inst Oceanol, Dept Marine Organism Taxon & Phylogeny, Qingdao, Peoples R China 4.Univ Bristol, Sch Earth Sci, Bristol, Avon, England 5.Nanjing Normal Univ, Coll Geog Sci, Nanjing, Peoples R China 6.Chinese Acad Sci, Deep Sea Res Ctr, Inst Oceanol, Qingdao, Peoples R China
推荐引用方式 GB/T 7714	Wang, Maoyu,Xu, Kuidong,Li, Tao,et al. The mineralization and early diagenesis of deep-sea coral Madrepora oculata[J]. CHEMICAL GEOLOGY,2022,606:11.
APA	Wang, Maoyu.,Xu, Kuidong.,Li, Tao.,Robinson, Laura F..,Liu, Yuanyuan.,...&Chen, Tianyu.(2022).The mineralization and early diagenesis of deep-sea coral Madrepora oculata.CHEMICAL GEOLOGY,606,11.
MLA	Wang, Maoyu,et al."The mineralization and early diagenesis of deep-sea coral Madrepora oculata".CHEMICAL GEOLOGY 606(2022):11.