Pyrite morphology in the first member of the Late Cretaceous Qingshankou Formation, Songliao Basin, Northeast China

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• 作者：Pingkang Wang ; Yongjian Huang ; Chengshan Wang ; Zihui Feng ; Qinghua Huang
• 关键词：Pyrite morphology ; Redox condition ; First member of the Qingshankou Formation ; South well of &ldquo ; SLCORE I&rdquo ; Songliao Basin
• 刊名：Palaeogeography, Palaeoclimatology, Palaeoecology
• 出版年：2013
• 出版时间：1 September, 2013
• 年：2013
• 卷：385
• 期：Complete
• 页码：125-136
• 全文大小：1974 K

文摘

The study of sedimentary pyrite morphological characteristics provides useful information on depositional environments and early diagenic processes and can be used as an indicator of redox conditions in ancient lake bottom waters. The results of this study in the Songliao basin in northeastern China show that euhedral crystals and framboids are the dominant pyrite forms in the mudstones of the first member of the Qingshankou Formation (K₂qn¹). The framboidal size distribution indicates that during the deposition of K₂qn¹, redox conditions in the bottom water fluctuated from oxic-dysoxic to euxinic-anoxic to oxic-dysoxic. The presence of euxinic-anoxic bottom water suggests that an anoxic event developed in the Songliao ancient-lake and continued for 196 ka. The development of an anoxic bottom environment was the most important factor in hydrocarbon source rock formation in the Songliao Basin.