| 青海省河南县三叠系伊利石结晶度与极低级变质作用 |
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| 作者姓名： | 王燚 杨学俊 白宪洲 叶春林 贾小川 熊昌利 黄柏鑫 罗改 |
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| 作者单位： | 1.四川省地质调查院,成都 610081; 2.四川稀有稀土战略资源评价与利用重点实验室,成都 610081 |
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| 基金项目： | 青海省原国土资源厅“青海省河南县托叶玛地区I47E00723、I47E00823、I47E00923、I47E00924四幅1:5万区域地质矿产调查(编号: 中铝基金200803)”项目资助 |
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| 摘 要： | 在开展“青海省河南县托叶玛地区I47E007023、I47E008023、I47E009023、1I47E009024四幅1∶5万区域地质矿产调查”时,为验证该地区三叠系变质情况,针对三叠系中泥岩(页岩)的伊利石结晶度做了分析测试。30件样品的实验结果表明北部宗务隆—泽库地层分区三叠系泥岩(页岩)伊利石Kübler结晶度指数为0.312~0.537,晶胞参数b0为0.8980~0.9032 nm,判断其变质温度小于350℃,具葡萄石-绿纤石和沸石相;南部西倾山地层分区三叠系泥岩(页岩)的伊利石Kübler结晶度指数为0.21~0.318,b0为0.8981~0.9014 nm,变质温度主要分布在200~350℃,局部>350℃,具葡萄石-绿纤石和绿片岩相。研究认为青海省河南县地区区域变质程度较低,为极低级变质作用或者未发生区域变质作用,且南部西倾山地层分区的变质程度略高于北部宗务隆—泽库地层分区变质程度。这一变质相带研究结论与前人认为的“区域低温动力变质作用及低绿片岩相变质带”不一致,变质程度相对更低。该研究证实了在青海省河南县地区三叠系地层中不存在大面积区域变质作用,仅存在极低级区域变质作用。
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| 关 键 词： | 极低级变质作用 晶胞参数b0 青海省河南县 Kübler结晶度指数 |
| 收稿时间： | 2019-04-04 |
Crystallinity and metamorphism of illite from Triassic strata in Henan County of Qinghai Province |
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| Authors: | WANG Yi YANG Xuejun BAI Xianzhou YE Chunlin JIA Xiaochuan XIONG Changli HUANG Baixin LUO Gai |
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| Institution: | 1. Sichuan Geological Survey Institute, Chengdu 610081, China; 2. Key Laboratory of the Evaluation and Utilization of Strategic Rare Mentals and Rare Earth Resources of Sichuan Province, Cheng Du 610081, China |
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| Abstract: | In order to verify the Triassic stratum metamorphism in this area, the crystallinity of illite in mudstone (shale) of Triassic stratum was analyzed and tested during the 1:50 000 regional mineral geological survey (I47E007023, I47E008023, I47E009023,1I47E009024)in Tuoyema area of Henan Mongolian Autonomous County in Qinghai Province. According to the experimental results of 30 samples, the crystallinity index of Triassic mudstone (shale) illite Kübler in Zongwulong-Zeku stratigraphic division in the north is 0.312-0.537, and the cell parameter b0 is 0.898-0.903 2 nm. The metamorphic temperature is less than 350 ℃, with the grape-chlorite and zeolite facies. The crystallinity index of Triassic mudstone (shale) illite Kübler in the western inclined mountain stratigraphic division in the south is 0.21-0.318, and the b0 value is 0.898 1-0.901 4 nm. The metamorphic temperature is mainly between 200 and 350 ℃, with the local temperature above 350 ℃ and grape-chlorite and greenschist facies. It is considered that the regional metamorphism grade in this area is very low or has no regional metamorphism. The metamorphism degree of the western dipping mountain stratum in the south is slightly higher than that of Zongwulong-Zeku stratum in the north. The measured metamorphic facies belts are not consistent with the previous thought, that is "regional low temperature dynamic metamorphism and low greenschist facies metamorphic belts", and the degree of metamorphism is relatively lower. It is confirmed that there is no large area regional metamorphism in the Triassic strata of Henan County in Qinghai Province, but only very low-level regional metamorphism. |
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| Keywords: | very low-grade metamorphism cell parameter b0 Henan Mongolian Autonomous County Kübler index |
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