• 责任者：Xu Jialin (Key Laboratory of Exploration Technologies for Oil and Gas Resources ; Ministry of Education ; School of Geosciences ; Yangtze University ; Jingzhou 434023 ; China) ; Liu Yanxue
• 刊名：Geological Bulletin of China
• 出版年：2013
• 卷期：32(2/3)
• 关键词：沉积环境 ; sedimentary environment ; 盆地演化 ; basin evolution ; 吐哈盆地 ; Tu-Ha Basin
• 页码：p.424-442
• 图表：illus., 3 tables, 107 refs.
• 分类号：0803
• issnNo：ISSN1671-2552
• isbnNo：CN11-4648/P

The Early Permian Yierxim Formation widely distributed in Turpan-Hami area of Xinjiang provides a record of paleoclimate, paleogeography, basin and tectonic evolution in the Early Permian period. There exists much controversy concerning sedimentology, basin evolution and tectonic background of the Yierxitu Formation. This paper briefly reviewed previous researches on the Yierxitu Formation in Turpan-Hami area. Furthermore, on the basis of geological survey, the authors studied stratigraphy, sedimentary facies, provenance and paleocurrents of the Yierxitu Formation, and the results indicate that the Yierxitu Formation was spatially and temporally involved in an evolution of sedimentary facies from alluvial fan or river to shallow lake, semi-deep or deep lake in upward succession. Volcanic lithological associations of the Yierxitu Formation are characterized by the bimodal volcanic rock assemblages of olivine basalt, basaltic andesite and rhyolite. The distribution of lithofacies and lithological associations indicates that the volcanic constituents of the Yierxim Formation gradually increase from west to east, which means the volcanic activities were stronger in the east than in the west. Meanwhile, marine flysch formations intercalated with volcanic rocks were developed in the northern Bogda Mountain. Petrologic characteristics and geochemistry show that, in the northern Bogda Mountain, there existed bimodal volcanic rock assemblages. Studies show that marine rift existed in the northern Bogdashan Mountain whereas a continental rift occurred in the southern Bogda Mountain. Paleocurrents show a bio-direction pattern, and currents from the northern and southern Bogda Mountain were concentrated in the central Bogda Mountain area （the center of the rift）. Provenance analysis shows that conglomerate sediments of the Early and Middle Permian period in northern Turpan-Hami area are mainly composed of andesite, tufts and rhyolitic volcanics as well as sandstone, silica or limestones, suggesting that they were derived from the underlying Devonian and Carboniferous strata.