阳泉—井陉一带石炭二叠纪煤田的沉积环境探讨

THE RESEARCH ON THE SEDIMENTARY ENVIRONMENTS OF PERMO-CARBONIFEROUS COALFIELD OF YANGQUAN-JINGXING, NORTH CHINA

本文运用现代沉积学的理论与方法,分析了位于华北晚古生代聚煤区中北带的阳泉,井陉煤田含煤岩系的岩相类型、沉积环境及古地理演化。提出,阳泉、井陉一带石炭纪中、晚期及早二叠世早期沉积的古地理类型均属滨海平原型,北部边缘的阴山古陆为聚煤区陆源碎屑沉积物的主要供给区,同时,五台、太行、吕梁隆起区也可提供部分陆源碎屑沉积物。

Yangquan coal district is located in the eastern part of Shanxi Province. Its aera is about 275 km2 and coal resources are rich there. It is one of the main coal bases in China. Jing-xing coal district is located in the western part of Hebei Province, with an aera of about 120 km2. The main coal bearing Formations of these aeras are Taiyuan Formation and Shanxi Formation of Permo-Carboniferous age. The Late Carboniferous Taiyuan Formation, which consists mainly of grey and darkgrey marine limestones, argillites, arenaceous argillites, sandstones and coal seams, is about 120 m thick, It contains 4-9 coal seams, of which the bottom one is the main minable one. The Early Permian Shanxi Formation overlying the Taiyuaa Formation in succession is about 60 m thick and composed chiefly of grey sandstones, darkgrey arenaceous argillites, argillites and coal seams. It contains 6 coal seams, and the No. 3 is the main minable one.The present study shows that the coai bearing series in these areas can be divided into ten lithofacies and consist mainly of coastal plain, delta and interdelta deposits, formed under the tropic to subtropic climate. From bottom to top, acording to the sedimentary characteristics, the Taiyuan Formation can be divided into five sedimentary cycles. During the Late Carboniferous Period at least 3 times of transgression occurred as was shown by the 3 beds of the marine limestone, in which, corals, branchiopoda, foraminifera and crinoidal stem are abundant. The Shanxi Formation is composed only of delta deposits developed successively on the top of the Taiyuan Formation. It underwent a process of construction-destruction-construction.The present study also shows that most of the sediments of these coal bearing Formation were derived from Yinshan old Land which is located at the northern margin of North China, and might have been influenced by Uplands of Wutai, Taihang and Luliang.