太原西山煤田骆驼脖子砂岩特征及物源区分析

Characteristics and provenance area of Luotuobozi sandstone in Taiyuan Xishan coalfield

为了判断太原西山煤田物源区,并探讨物源区构造背景,运用砂岩单碎屑组分法、多碎屑组分法和重矿物组合法,综合分析了七里沟剖面二叠系下石盒子组底部骆驼脖子砂岩的特征。结果表明:骆驼脖子砂岩主要组分为石英和岩屑,石英占80%以上,岩屑占10%左右,长石极少见,体积分数小于1%,且石英和岩屑成因类型以岩浆岩型和变质岩型为主,沉积岩型含量较少;重矿物主要由锆石、磷灰石和金红石组成,揭示出物源区母岩类型为酸性岩浆岩,物源区为北面阴山古陆,砂岩组分的Dickinson三角图解表明,物源区构造背景为再旋回造山带。

In order to determine the provenance area and explore the tectonic background of the provenance area of Taiyuan Xishan coalfield, single detrital component,multi detrital components and heavy mineral assemblages were used to analyze Luotuobozi sandstone at the bottom of Xiashihezi Formation in Qiligou. The results show that quartz and rock debris are the major components of the sandstone, quartz accounts for more than 80%, rock debris account for about 10% and feldspar is rare, at the same time, the genetic tj^pes of quartz and debris are mainly of magmatic rock type and metamorphic rock lype. The heavy minerals in the sandstone are mainly composed of zir-con, apatite and rutile. These evidences display that the parent rocks of the provenance area were acidic magmatic rocks and the provenance area was Yinshan paleoland at the north. In addition, Dickinson’s triangular diagram in- dicated that the tectonic background of the provenance area was the recycled orogenic belt.