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吉黑造山带古生代构造古地理演化   总被引:1,自引:1,他引:9  
吉黑同山带夹持于华北板块和西伯利亚板块之间。对该构域古生代构造古地理演化规律的研究,是恢复板块间碰撞拼合及古亚洲洋发展演化历史的关键。在早古生代期间,华北板块与西伯业板块间通过古亚洲洋板块相接。  相似文献
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根据辽东半岛上寒武统长山阶三叶虫的纵向分布和演化序列,划分了6个生物带和2个亚带,其中新建立生物带2个.并与国内外进行了对比.长山期三叶虫包括80个种,分属50个属或亚属.由于篇幅所限,本文仅描述部分新种,地层剖面从略.  相似文献
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The pollen and spores found in the Early Cretaceous strata of two cores from the Shuangliao Fault Depression were studied systematically, and two palynological assemblages have been recognized. Assemblage I from the Yingcheng Formation is named Paleoconiferus-Pinuspollenites; the assemblage is characterized by an extremely high content of Paleoconifer pollen. Assemblage II from Member 1 of the Denglouku Formation is named Cicatricosisporites-Cyathidites-Pinuspollenites; the assemblage is characterized by the abundant presence of Laevigati spores, but less Paleoconifer pollen. According to the palynological data and zircon U-Pb dating, the geological age of the Yingcheng Formation is thought to be Aptian-Albian, and that of the Denglouku Formation is thought to be Early Albian. On the basis of the composition of each assemblage, we can infer that during the depositional period of the Yingcheng Formation, the paleovegetation was mainly conifer forest, the paleoclimate was consistent with the temperate climate of today, and the paleoenvironment was humid feature. During the depositional period of Member 1 of the Denglouku Formation, the paleovegetation was mainly conifer forest and shrubs, the paleoclimate was consistent with the subtropical climate of today, and the paleoenvironment was humid. The results significantly improve our understanding of the stratigraphy in the Shuangliao Fault Depression, provide biostratigraphic evidence for the division and correlation of Early Cretaceous strata in the Shuangliao Fault Depression, and provide new data for analyzing paleovegetation and paleoclimate in the Songliao Basin.  相似文献
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正Objective The Shahezi Formation is the main source rock stratum during the faulting stage of the Songliao Basin,and could not be distinguished from the coal-bearing clastic member of the Yingcheng Formation in lithostratigraphy.Previous petroleum geologists have done a lot of research on palynostratigraphy in drill cores inside the Songliao Basin.The understanding of the palynological assemblage  相似文献
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