毕节地区晚二叠世煤层稀土元素的示踪研究

Tracing Study on REEs of Coal Measure in Late Permian in Bijie City,Guizhou Province,China

对取自贵州西部毕节地区,晚二叠世11个可采煤层的13个样品的稀土元素进行了电感耦合等离子体质谱法分析。研究发现:海洋来源对稀土元素的富集作用极其微弱;来自植物成因的物质来源小于1%;稀土元素的物质来源主要受陆源影响和控制。煤层与玄武岩稀土元素的∑REE,LREE,HREE,以及稀土元素配分模式有相似性。∑REE值最高的M12煤层形成于龙潭晚期,而这一时期玄武岩喷发集中于包括毕节地区的贵州西部。认为毕节晚二叠世煤层的稀土元素属于陆源成因沉积,峨眉山玄武岩是煤层稀土元素的主要物质来源和控制因素。

Analyses of rare earth elements （REEs） in 13 coal samples collected from coal measure in Bijie City, western Guizhou Province in Late Permian were conducted using Inductively Coupled Plasma-Mass- Spectrometry （ICP-MS）. The results showed that the source of REEs from sea was few, and the source from land plants was about 1%. It was proved by the nega- tive anomaly of δEu that the major source of REEs was ofigined from terrigenous material. There were similar distribution patterns of REEs between Bijie＇s coal and Emeishan basalt. The highest ∑REE of M12 coal seam appeared in late Permian, which was closely correlative to eruption of Emeishan basalt. The Emeishan basalt contributed to REEs enrichment of M12. So the paper considered that the source of REEs in Late Permian in Bijie＇s coal measure was controlled by terrigenous material, and the Emeishan basalt was the major terrigenous material.