Acta Scientiarum Naturalium Universitatis Pekinensis ›› 2020, Vol. 56 ›› Issue (2): 242-252.DOI: 10.13209/j.0479-8023.2019.126

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Mineralogical Characteristics of Aphanitic Cryptocrystalline in Yantongshan and Its Significance for Origin

CHENG Siyu, CHUAN Xiuyun, YANG Yang, LIN Chao, CHEN Siyu   

  1. Key Laboratory of Orogenic Belts and Crustal Evolution (MOE), School of Earth and Space Sciences, Peking University, Beijing 100871
  • Received:2019-03-22 Revised:2019-06-27 Online:2020-03-20 Published:2020-03-20
  • Contact: CHUAN Xiuyun, E-mail: xychuan(at)pku.edu.cn

烟筒山隐晶质石墨的矿物学特征及其成因指示意义

程思雨, 传秀云, 杨扬, 林超, 陈思雨   

  1. 造山带与地壳演化教育部重点实验室, 北京大学地球与空间科学学院, 北京100871
  • 通讯作者: 传秀云, E-mail: xychuan(at)pku.edu.cn
  • 基金资助:
    国家自然科学基金(51774016)和北京大学开放测试基金(0000012321)资助

Abstract:

By means of optical microscope, field emission scanning electron microscope, X-ray diffraction and laser Raman spectroscopy, the mineralogical characteristics of cryptocrystalline graphite in Yantongshan, Jilin Province and its indication significance for the genesis of the deposit are studied. The diameter of graphite microcrystals is La=59?175 nm, and the stacking height is Lc=32?93 nm. The graphitization degree value ranges from 0.573 to 1.000, and the interval (002) layers vary from 0.3352 to 0.3370 nm. The intensity ratio of D1 peak and G peak arranges between 0.07 to 0.28. On the base above, the metamorphic temperature range was calculated as 526℃ to 622℃, with the average is 561℃, indicating that the metamorphic degree could reach the amphibolite facies in its formation. The graphitization degree varied greatly, and much higher near Fe bearing minerals, indicating that the crystallization process of graphite could be catalyzed with the different spots of one graphite ore slice by Fe containing compounds.

Key words: aphanitic graphite, microscopic morphology, crystallinity, metamorphic phase, catalysis

摘要:

采用光学显微镜、场发射扫描电子显微镜、X射线衍射和激光拉曼光谱等方法, 研究吉林省烟筒山隐晶质石墨的矿物学特征及其对矿床成因的指示意义。矿石样品中石墨微晶的直径La=59~175 nm, 堆叠高度Lc=32~93 nm; 石墨化程度值在0.573~1.000之间, (002)层面间距在 0.3352~0.3370 nm范围内变化, D1峰与G峰的强度比值分布在0.07~0.28之间, 据此计算得到变质温度范围为526~622℃, 平均561℃, 表明其变质程度可达普通角闪石角岩相。矿石光薄片中不同位置石墨的石墨化程度变化较大, 含Fe矿物附近石墨化程度更高, 指示石墨的结晶过程中受到含Fe化合物的催化作用。

关键词: 隐晶质石墨, 微观形貌, 结晶程度, 变质相, 催化作用