Mineralogical and isotopic characterization of graphite deposits in the western part of the North Qaidam Orogen and East Kunlun Orogen, northeast Tibetan Plateau, China
Mineralogical and isotopic characterization of graphite deposits in the western part of the North Qaidam Orogen and East Kunlun Orogen, northeast Tibetan Plateau, China
复制标题
青藏高原东北部柴北造山带西部和东昆仑造山带石墨矿床的矿物学和同位素特征
DOI：
10.1016/j.oregeorev.2020.103788
复制
发表时间：
2020-11
影响因子：
3.3
通讯作者：
Shaoqing Zhao
中科院分区：
文献类型：
--
作者：
Maoqiang Yan;Daohan Zhang;Jan Marten Huizenga;Junhao Wei;Huan Li;Guomeng Li;Xiaokun Huang;Xinming Zhang;Shaoqing Zhao
北方柴达木盆地周缘广泛分布着中、高级变质岩系，其中石墨矿床众多。本文介绍了柴达木盆地周缘三个石墨矿点的结构、X射线衍射和拉曼光谱特征、石墨和同生方解石的δ 13 C结果以及方解石的δ 18 O结果。石墨显示六方片状、不规则多边形、卵形形态，偶尔有球晶结构。结合XRD和拉曼光谱对石墨的形貌进行了表征，结果表明石墨具有较高的结晶度。石墨的拉曼显微光谱表明，峰值变质温度在690和801 °C之间变化。石墨的δ 13 CV-PDB值在-26.3 ‰ ~-21.6‰之间，表明有机碳是石墨的主要碳源。方解石δ 13 CV-PD和δ 18 OV-SMOW值分别为-10.8 ‰ ~+3.9‰和+6.6 ‰ ~+29.5‰。方解石δ 13 CV-PDB结果表明，有机碳与无机碳混合，导致δ 13 CV-PDB增加。方解石δ 18 OV-SMOW值表明石墨矿床经历了晚期水-岩作用。方解石δ 13 CV-PDB的正、负异常反映了大氧化事件末期局部发生的有机质氧化再循环作用。柴达木盆地周缘广泛分布的区域变质有机成因石墨矿床为古元古代大规模生物活动提供了证据。
Medium to high-grade metamorphic rocks comprising numerous graphite deposits are widely distributed in the periphery of the Qaidam Basin, Northern Tibetan Plateau, China. We present textural, XRD, and Raman spectroscopy characteristics of graphite, δ13C results of graphite and cogenetic calcite, and δ18O results of calcite in three graphite occurrences located at the periphery of Qaidam Basin. Graphite displays hexagonal platy, flaky, irregular polygonal, ovate morphologies with occasional spherulitic textures. Graphite morphologies, combined with XRD and Raman spectroscopy, indicate that graphite has relatively high crystallinity. Raman microspectroscopy of graphite shows that peak metamorphic temperatures vary between 690 and 801 °C. Graphite δ13CV-PDBvalues range between –26.3 and –21.6‰, indicating organic carbon as the major carbon source for graphite. Calcite δ13CV-PDBand calcite δ18OV-SMOWvalues range between –10.8 and +3.9‰, and between +6.6 and +29.5‰, respectively. Calcite δ13CV-PDBresults show that organic carbon was mixed with inorganic carbon, which resulted in an increase of δ13CV-PDB. Calcite δ18OV-SMOWvalues indicate that the graphite deposits experienced late-stage water–rock interaction. The positive and negative anomalies of calcite δ13CV-PDBindicate that organic matter oxidation and recycling locally occurred during the final stage of the Great Oxidation Event. The wide distribution of regional metamorphic organogenic graphite deposits provides evidence for large-scale Paleoproterozoic biological activity in the periphery of the Qaidam Basin.
登录
查看更多内容
影响因子：
3.9
作者：
Shuguang Song;Lifei Zhang;Y. Niu;L. Su;B. Song;Dunyi Liu
通讯作者：
Shuguang Song;Lifei Zhang;Y. Niu;L. Su;B. Song;Dunyi Liu
影响因子：
8
作者：
Haoshu Tang;Yan‐jing Chen;K. Li;Weiyu Chen;Xiaoqing Zhu;Kunyue Ling;Xiaohui Sun
通讯作者：
Haoshu Tang;Yan‐jing Chen;K. Li;Weiyu Chen;Xiaoqing Zhu;Kunyue Ling;Xiaohui Sun
影响因子：
10.9
作者：
Zhou Zhou-Zhou;W. Bouwman;H. Schut;C. Pappas
通讯作者：
Zhou Zhou-Zhou;W. Bouwman;H. Schut;C. Pappas
影响因子：
--
作者：
Li Huai-kun
通讯作者：
Li Huai-kun
影响因子：
12.1
作者：
San-zhong Li;Shujuan Zhao;Xin Liu;Huawen Cao;Shan Yu;Xiyao Li;I. Somerville;Sheng‐yao Yu;
通讯作者：
San-zhong Li;Shujuan Zhao;Xin Liu;Huawen Cao;Shan Yu;Xiyao Li;I. Somerville;Sheng‐yao Yu;