陕西渭北煤田5#煤层粘土岩夹矸的研究

A STUDY ON TONSTEINS IN SEAM 5 # OF WEIBEI COALFIELD IN SHAANXI

渭北煤田面积约１０万ｋｍ２。分布于太原组顶部５＃煤层中的粘土岩夹矸，上部层位分为两上分层，上分层夹矸厚度薄，下分层夹矸厚约０２ｍ，俗称“２００矸”；下部层位夹矸厚度变化较大。该文详细论述了粘土岩夹矸的岩矿特征。根据“２００矸”中含有副象β－石英、高透长石、锆石、磁铁矿等高温矿物组合，特有的粒序层理和岩性在全煤田十分稳定等特点，表明其原始物质来源于降落火山灰。根据ＴｉＯ２／Ａｌ２Ｏ３比值的明显变化，探讨了陆源组分的加入对火山灰蚀变粘土岩夹矸化学成分的影响。以“２００矸”为等时标志层，解决了５＃煤层在区域上的对比。

Weibei coalfield is about 10,000 km 2 in area.The seam 5 # at the top of Taiyuan Formation contain two layers of tonsteins.The upper tonstein layer can further be divided into two subbeds, upper tubbed and lower subbed.The upper subbed is thinner in thickness and the lower is about 0.2m thick and ,thererore,is popularly called`200 band'.The lower tonstein layer is changing in thickness.The paper has in detail discussed the characteristics of the rock and minerals of the toustein.The original matter of the `200 band'comes from the fallen volcanic ash,according to the assemblage of the high-temperature minerals such as paramorph β-quartz.high sanidine.zircon,magnetite and so on,peculiar graded bedding,and stable lithology in all coalfield in the `200 band'.The influence of terrigenous constituent on the chemical composifion of the fonstein altered by the ash was studied in accordance with the variation of the artio tiO 2/Al 2O 3.The correlation of the seam 5 # in the region has been solued with the `200 band'as is chronous key bed.