Sedimentary Environment of Ediacaran Sequences of South China: Trace Element and Sr-Nd Isotope Constraints
Sedimentary Environment of Ediacaran Sequences of South China: Trace Element and Sr-Nd Isotope Constraints
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华南埃迪卡拉层序沉积环境：微量元素和Sr-Nd同位素约束
DOI：
10.1086/688668
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发表时间：
2016-10
影响因子：
1.8
通讯作者：
Chen Fukun
中科院分区：
文献类型：
--
作者：
Hu Rong;Wang Wei;Li Shuang-Qing;Yang Yi-Zeng;Chen Fukun
对华南扬子地块的后马里诺时代沉积岩进行了调查，以寻求其物源、与古气候的成因关系、沉积环境和变化的约束。对扬子地块九龙湾段陡山沱组沉积岩进行了全岩微量元素和Sr-Nd同位素分析。在陡山沱盖碳酸盐岩中获得的平坦至中度稀土元素 (REE) 富集 REE 加钇模式、负到正 Ce 异常（Ce/Ce* 为 0.86–1.40）、正 La 异常（La/La* 为 1.02–1.42）以及软骨上 Y/Ho 比值（36.8–49.5）表明其沉积于波动的内陆架环境，淡水和海水混合在一起，并且不存在海底热液的影响。所有陡山沱碳酸盐岩和页岩都具有不同的锶同位素组成，初始锶同位素比（0.704030-0.712720）支持陡山沱组沉积期间河水的显着贡献。从沉积剖面采集的陡山沱组样品显示，Nd 同位素组成和诊断性微量元素比 (Th/Sc) 存在明显差异。盖帽碳酸盐从冰川时代结束后立即经历广泛风化的广阔大陆区域接收到大量输入。相比之下，陡山沱组上部沉积物从附近的太古宙崆岭杂岩中获得了更多成熟的碎屑，反映了海平面的下降。与陡山沱下部岩石中观察到的负 Ce 异常相反，陡山沱上部岩石中可忽略不计的 Ce 异常表明存在缺氧环境，这与磷酸结核的生长以及黄铁矿蔓状体的存在和较高浓度的有机质一致。
Post-Marinoan sedimentary rocks from the Yangtze block in South China were investigated to seek constraints on their provenance, genetic relationship with paleoclimate, depositional environment, and changes. Sedimentary rocks from the Doushantuo Formation in the Jiulongwan section of the Yangtze block were collected for whole-rock trace elements and Sr-Nd isotopic analyses. Flat-to-slightly middle rare earth element (REE)–enriched REE-plus-yttrium patterns, negative-to-positive Ce anomalies (Ce/Ce* of 0.86–1.40), positive La anomalies (La/La* of 1.02–1.42), and suprachondritic Y/Ho ratios (36.8–49.5) obtained for the Doushantuo cap carbonates indicate their deposition in a fluctuating inner-shelf setting where freshwater and seawater mixed together and the influence of hydrothermal fluid from the seafloor is absent. All Doushantuo carbonates and shales have variable Sr isotopic compositions, with initial Sr isotopic ratios (0.704030–0.712720) that support significant river-water contribution during the deposition of the Doushantuo Formation. Samples of the Doushantuo Formation collected across sedimentary profiles show distinct variations in Nd isotopic compositions and diagnostic trace elemental ratios (Th/Sc). The cap carbonates received significant input from a broad continental area undergoing extensive weathering immediately after the cease of the glaciation era. In contrast, the upper Doushantuo Formation sediments received more mature detritus from the nearby Archean Kongling complex, reflecting receding sea levels. In contrast to the negative Ce anomalies observed in lower Doushantuo rocks, negligible Ce anomalies in upper Doushantuo rocks suggest an anoxic setting, in agreement with the growth of phosphatic concretions and the presence of framboids of pyrite and a higher concentration of organic matter.
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影响因子：
2.4
作者：
Zhang, Shihong;Han, Yigui;Jiang, Ganqing
通讯作者：
Jiang, Ganqing
影响因子：
3.8
作者：
J. Zhao;Mei‐Fu Zhou;Jianping Zheng
通讯作者：
J. Zhao;Mei‐Fu Zhou;Jianping Zheng
DOI：
10.1086/341762
发表时间：
2002-09
期刊：
The Journal of Geology
影响因子：
--
作者：
Mei‐Fu Zhou;A. Kennedy;M. Sun;J. Malpas;C. Lesher
通讯作者：
Mei‐Fu Zhou;A. Kennedy;M. Sun;J. Malpas;C. Lesher
影响因子：
3.8
作者：
Kang Chen;Shan Gao;Y. Wu;Jing‐Liang Guo;Zhaochu Hu;Yongsheng Liu;K. Zong;Zhengwei Liang;
通讯作者：
Kang Chen;Shan Gao;Y. Wu;Jing‐Liang Guo;Zhaochu Hu;Yongsheng Liu;K. Zong;Zhengwei Liang;
古元古代岩浆和变质事件将长江与努纳超大陆劳伦大陆西北部连接起来
影响因子：
5.3
作者：
Wang, Wei;Cawood, Peter A.;Zhou, Mei-Fu;Zhao, Jun-Hong
通讯作者：
Zhao, Jun-Hong