Chemical compositions and precipitation timing of basement calcium carbonate veins from the South China Sea

CORC > 南海海洋研究所 > 中国科学院南海海洋研究所 > 中科院边缘海地质重点实验室

	Chemical compositions and precipitation timing of basement calcium carbonate veins from the South China Sea
	Ding, WW; Chen, YF; Sun, Z; Cheng, ZH; yfchen@gig.ac.cn
刊名	MARINE GEOLOGY
	2018
卷号	394 页码:116-124
英文摘要	Sixteen calcium carbonate veins (CCVs) within the igneous basement recovered from both East and Southwest Sub-basin, close to the fossil spreading ridge of the South China Sea during the Integrated Ocean Drilling Program (IODP) Expedition 349 were investigated. The CCVs are composed primarily of either calcite or aragonite, and some of mixed aragonite and calcite. The delta O-18 values of CCVs range from 25.5 to 31.8%o VSMOW, indicating these are typical low temperature basement carbonates precipitated at temperatures of 12-40 degrees C. The Sr-87/Sr-86 ratios of CCVs from Site U1431 show a strong negative correlation with delta O-18-calculated temperatures, regardless of carbonate phases calcite or aragonite, indicating CCVs with lower Sr-87/Sr-86 ratios have precipitated from moderately warmer and more geochemically evolved hydrothermal fluids, and reflecting that precipitation of CCVs might have occurred any time between 14.5 and 0 Ma at Site U1431. The formation timing of CCVs at Site U1431 is consistent with the ongoing hydrothermal flow and circulation led by recharging seawater into the volcanic basement through the nearby outcropped seamount. The oldest ages of CCVs from Site U1433 at the Southwestern sub-basin of SCS were determined to be similar to 18-11 Ma, based on basement age of 18.5 Ma and the well-established seawater Sr-87/Sr-86 ratio curve. It indicates that the hydrothermal circulation at Site U1433 which is more distal to a recharging/discharging site was only active until similar to 11 Ma. In consequence, the CCVs within basalts from Sites U1431 and U1433 provide more insights into the past hydrologic conditions and hydrothermal circulation along the fossil ridge flank in the SCS.
学科主题	Geology ; Oceanography
资助项目	MSG
WOS关键词	Calcium carbonate veins ; Low temperature basement carbonates ; Sr-87/Sr-86 ratios ; Precipitation timing ; The South China Sea ; IODP expedition 349
内容类型	期刊论文
源URL	[http://ir.scsio.ac.cn/handle/344004/17166]
专题	南海海洋研究所_中科院边缘海地质重点实验室
通讯作者	yfchen@gig.ac.cn
推荐引用方式 GB/T 7714	Ding, WW,Chen, YF,Sun, Z,et al. Chemical compositions and precipitation timing of basement calcium carbonate veins from the South China Sea[J]. MARINE GEOLOGY,2018,394:116-124.
APA	Ding, WW,Chen, YF,Sun, Z,Cheng, ZH,&yfchen@gig.ac.cn.(2018).Chemical compositions and precipitation timing of basement calcium carbonate veins from the South China Sea.MARINE GEOLOGY,394,116-124.
MLA	Ding, WW,et al."Chemical compositions and precipitation timing of basement calcium carbonate veins from the South China Sea".MARINE GEOLOGY 394(2018):116-124.