内蒙古大青山晚古生代煤系中火山事件层的物质来源及地层意义

在内蒙古大青山晚古生代煤系地层中发现了９层以上火山事件层，主要由凝灰熔岩、火山角砾岩、熔结凝灰岩、凝灰岩、沉凝灰岩及各种凝灰质沉积岩组成。通过剖面层序分析和岩石学、岩石化学、稀土元素和同位素比值研究，可将本区火山事件层划分为９个喷发旋回；根据火山事件层的分布，本区煤层可与山西大同同时代的煤层相对比；这一研究结果为大区域煤层对比提供了重要的科学依据。根据本区的研究工作并与内蒙海槽火山活动资料相对照，本区火山碎屑物质来自内蒙海槽钙碱性岛弧型火山活动的观点得到证实，也为华北板块与古亚洲洋板块之间的封闭机理，提供了新的资料。

The Provenance and Stratigraphic Sicance of Volcanic Event Layers in Late Paleozoic Coal Measures from Daqingshan,Inner Mongolia

More than nine volcanic event layers have been discovered in Late-Paleozoic coal mea-sures from Daqingshan, Inner-Mongolia,China,they consist mainly of tuffaceous lava,vol-canic breccia,ignimbrite,tuff,tuffite and various tuffaceous sedimentary rocks. Based onthe analysis of profile sequence and study of petrology,petrochemistry, rare-earth elementsand isotope ratio,the volcanic event layers of this area can be divided into nine eruptive cy-cles. According to the distribution of the volcanic event layers,the coal seams of this area canbe correlated with those of corresponding period in Datong,Shanxi.This result provides im-portant scientific basis for the comparison of regional coal seams. In the light of the researchwork of this area and by comparison with the data of volcanic activity of Inner-MongoliaGeosycline,the view point of volcanic clastic materials of this area coming from calc-alkali is-land arc volcanic activity of Inner-Mongolia Geosycline has been verified.This result alsoprovides a new information for further resolving the sealing mechanism between the NorthChina Plate and Paleo-Asia Ocean Plate.