Occurrence and origin of minerals in a chamosite-bearing coal of Late Permian age, Zhaotong, Yunnan, China
Occurrence and origin of minerals in a chamosite-bearing coal of Late Permian age, Zhaotong, Yunnan, China
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中国云南昭通晚二叠世含菱锰矿煤中矿物的赋存与来源
DOI：
10.2138/am.2007.2496
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发表时间：
2007-08-01
影响因子：
3.1
通讯作者：
Chou, Chen-Lin
中科院分区：
文献类型：
--
作者：
Dai, Shifeng;Chou, Chen-Lin
云南昭通煤田晚二叠世5号煤的矿物组成主要为高岭石、黄铁矿、高岭石、石英、方解石等，并有少量伊利石和伊蒙混层。高岭石在粘土矿物中所占的比例为32 ~ 56wt%，平均为46wt%。菱沸石不仅分布于胶碎屑岩中，而且还以细胞充填物的形式存在于丝质体、半丝质体和黄长石中。高岭石的高含量和产状表明它是在早期成岩作用中与富铁镁流体相互作用形成的。除少量陆源石英外，大部分石英为自生石英，由高岭石脱硅作用形成。5号煤中方解石含量1.4.6.3%（平均为3%），主要分布在煤岩中，并作为成煤植物的细胞填料。方解石来源于泥炭堆积过程中海水的侵入。黄铁矿以几种方式出现：块状，framboidal，孤立的单形/非单形和自形形式。此外，大量黄铁矿化红藻的存在为泥炭堆积过程中海水入侵提供了有力证据。红藻可能在煤中硫的富集过程中起了重要作用。该矿床独特的矿物组合是由独特的盆地环境造成的，矿物质来源于玄武岩源区、火山活动和成煤期的海水海侵
Abstract The minerals found in the no. 5 coal (Late Permian) from the Zhaotong Coalfield, Yunnan Province, southwestern China, have been examined and found to consist mainly of kaolinite, pyrite, chamosite, quartz, and calcite, with trace amounts of illite and mixed-layer illite-smectite. The proportion of chamosite in clay minerals ranges from 32 to 56 wt%, with an average of 46 wt%. Chamosite is distributed not only in collodetrinite, but also occurs as cellfillings in fusinite, semifusinite, and telinite. The high content and mode of occurrence of chamosite in this mine indicate its formation by interaction of kaolinite with Fe-Mg-rich Fluids during early diagenesis. Except for a minor amount of terrigenous quartz, most quartz is of authigenic origin and formed from kaolinite desilication. The calcite content of the no. 5 coal is 1.4.6.3% (with an average of 3%) and is distributed in collodetrinite and as cellfillings of coal-forming plants. Calcite originated from seawater invasion during peat accumulation. Pyrite occurs in several ways: as massive, framboidal, isolated enhedral/anhedral, and euhedral forms. In addition, the presence of a large amount of pyritized red algae provides strong evidence of seawater invasion during peat accumulation. The red algae may have played an important role in the enrichment of sulfur in the coal. The characteristic assemblage of minerals in this mine resulted from a unique basinal environment in which the mineral matter was derived from a basaltic source region, volcanic activity, and seawater transgression during coal formation