松辽盆地LD17井晚白垩世—古新世孢粉地层与气候演变

发布时间：2018-06-27 07:03

本文选题：松辽盆地 + 明水组　；参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：松辽盆地是中国最大的白垩纪生油气湖相盆地,保存有完整而良好的白垩纪地层。它和周边盆地是研究陆相白垩纪—古近纪(K-Pg)界线的潜在地区。大陆钻探项目“松科1井”研究已经获得初步结果。其生物地层学、磁性地层学和旋回地层学等多学科研究将K-Pg界线划在明水组二段上部。孢粉是K-Pg界线的重要识别标志。据前人研究,松科1井在360.6 m之上化石保存较差,在将近100 m的剖面中(井深360.6~263.4 m),孢粉化石稀少,使界线位置有一定的不确定性。从相邻钻井资料中获取更多信息,有助于完善松辽盆地K-Pg界线附近孢粉地层学。LD17井是松辽盆地西部斜坡区上的一口地质钻井,揭示的地层为姚家组—明水组。为了进一步确定松辽盆地K-Pg界线位置和晚白垩世末气候-环境变化,本次研究对位于LD17井明水组的孢粉化石开展了研究。通过分析,识别出该井明水组一段、二段3个孢粉组合:Taxodiaceaepollenites-Wodehouseia-Aquilapollenites组合(组合1)、Schizaeoisporites-Pinuspollenites-Callistopollenites组合(组合2)、Pinuspollenites-Ulmipollenites-Tricolpollenites组合(组合3)。组合1位于明一段中下部,时代为Maastrichtian期早期;组合2位于明一段上部至明二段下部,为Maastrichtian期中—晚期;组合3位于明二段中上部,时代跨越K-Pg界线,其中下部含化石稀少,可能发生孢粉灭绝事件,上部呈现新生代植物面貌,推测K-Pg界线位于明二段中部,界线可能在209.85~193.54 m之间。通过对该井孢粉比较丰富的明水组一段化石的定量分析,认为其总体上反映了一种半湿润的亚热带气候面貌,植被以针阔混生林和草丛为主。在明一段中部沉积期即Maastrichtian期早期可能发生了一次极冷极湿事件。
[Abstract]:The Songliao basin is the largest Cretaceous oil and gas lacustrine basin in China and has a complete and good Cretaceous strata. It and its surrounding basins are potential areas for the study of the continental Cretaceous Paleogene (K-Pg) boundary. The Continental Drilling Project, "songke 1", has obtained preliminary results. Its biostratigraphy, magnetic stratigraphy and gyratory fields Multidisciplinary studies, such as stratigraphy, put the K-Pg boundary on the upper part of the two section of the Ming Shui group. Sporopollen is an important identification mark of the K-Pg boundary. According to previous studies, the fossils of the 1 well on 360.6 m are poorly preserved, and in the near 100 m section (well depth 360.6~263.4 m), the sporopollen fossils are scarce and the boundary position is uncertain. From the adjacent drilling data In order to obtain more information, the palynological stratigraphy.LD17 well near the K-Pg boundary of Songliao basin is a geological drilling in the western slope of Songliao basin. The strata revealed are Yao Jia formation and Ming Shui formation. In order to further determine the position of the K-Pg boundary in the Songliao Basin and the climate change of late Cretaceous at the end of the late Cretaceous, this study is located in the LD17 well. The sporopollen fossils of the water group have been studied. Through analysis, we identified the one section of the Ming Shui group and 3 sporopollen combinations in two segments: Taxodiaceaepollenites-Wodehouseia-Aquilapollenites combination (combination 1), Schizaeoisporites-Pinuspollenites-Callistopollenites combination (combination 2), and Pinuspollenites-Ulmipollenites-Tricolpollenites combination (combination 3). The combination 1 is located in the middle and lower part of the Ming one section, the age is in the early stage of Maastrichtian; the combination 2 is located in the upper part of the Ming one section to the lower part of the Ming two section and is in the middle and late stage of the Maastrichtian period; the combination 3 is located in the upper middle of the Ming two section, and the times span the K-Pg boundary, and the lower fossils are rare in the lower part, and the sporopollen extinction events may occur and the upper part of the new generation plant is assumed to be in the upper part. The K-Pg boundary is located in the middle of the Ming two section and the boundary line may be between the 209.85~193.54 m. By quantitative analysis of the one segment of the fossil of the Ming Shui group, which is rich in the sporopollen of the well, it is considered that it generally reflects a semi humid subtropical climate. The vegetation is dominated by the coniferous and broad-leaved mixed forest and the grass. In the middle of the middle Ming Dynasty, the period of the Maastrichtian period was early in the period of the period of the Ming Dynasty. A very cold and extremely wet event may have occurred during the period.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q914;P532

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