【作者】 成洪江；

【导师】 万晓樵； 邓成龙；

【作者基本信息】 中国地质大学（北京） ， 古生物学与地层学， 2011， 硕士

【摘要】 白垩纪在地质历史时期是一个极其特殊的时期,期间全球生物界、古地理和古气候均发生急剧变化。因此白垩纪是地质历史时期地球系统研究的典型范例时期。陆地和海洋是构成统一地球表层系统的不可分割的单元。关于全球海相白垩纪沉积已经有了很深入系统的研究;而对白垩纪陆相沉积的研究则远未达到海相白垩纪的水准。我国白垩纪海相地层仅有限分布于新疆、西藏、黑龙江以及台湾等地区,白垩纪以陆相沉积为主,其中以松辽盆地规模最大,拥有完整的白垩纪陆相沉积记录。目前,尚未对松辽盆地各组地层时代取得完全一致的认识,从而对白垩系上、下限,甚至对白垩系上、下统的界线存在一定分歧。“松科1井”是中国大陆第一口以白垩纪地层为主的全取心科学钻探,也是国际大陆科学钻探（ICDP）框架下第一口陆相白垩系科学钻探;该钻井地层连续,无缺失;沉积厚度小;外源碎屑影响小,以深湖相泥岩沉积为主。本论文对松科1井北孔进行了详细的磁性地层年代学研究。主要运用磁性地层学的方法,结合岩石磁学、同位素年代学结果,将获得的北孔地磁极性序列与国际上通用的地磁极性年表（GTPS）对比,获得松科1井北孔各个组、段的地层年龄和界线划分:K/Pg界线位于北孔明水组二段上中部、磁极性带R1（即C29r）中;嫩江组(K_2n)和四方台组(K_2s)的界线的年龄为79.075 Ma;嫩二段和嫩三段界线（K₂n₂-K₂n₃）的年龄为82.172 Ma、嫩三段和嫩四段界线（K₂n₃-K₂n₄）的年龄为81.591 Ma、嫩四段和嫩五段界线（K₂n₄-K₂n₅）的年龄为80.478 Ma;四方台组和明水组界线(K_2s-K_2m)的年龄为72.155 Ma;明水组一段和二段界线(K_2m2-K_2m1)的年龄为70.132 Ma。基于本文作者等建立的松科1井北孔的磁性地层年代格架,本文将松科1井北孔陆相地层的与全球海相层序进行了对比,即松科1井北孔（从嫩江组一段到明水组二段）保存了Campanian早期到Danian早期之间的沉积地层,白垩纪/古近纪界线位于明水组二段上部。更多还原

【Abstract】 In geological history, the Cretaceous is a very special period, during which the global biosphere, paleogeography and paleoclimate changed dramatically. Therefore, the Cretaceous period of geologic history is a typical example of the Earth system.The marine Cretaceous has been intensively studied. However, systematic research for Cretaceous continental deposits remains scarce. The Songliao Basin in northeastern China which is one of the largest nonmarine petroliferous basins in the world, contains a complete Cretaceous sequence of terrestrial sediments. However, correlation of the Cretaceous terrestrial sequences of the Songliao Basin to marine strata remains ambiguous due to the absence of a reliable chronology.The Cretaceous Continental Scientific Drilling borehole in the Songliao Basin （CCSD-SK-I） offers a unique opportunity for probing into the nature of the terrestrial Cretaceous world. The CCSD-SK-I sedimentary sequence consists of two borehole cores: the north core being upper; and the south core, lower. The strata of the north core comprise the Nenjiang, Sifangtai and Mingshui Formations; and of the south core, the Quantou, Qingshankou, Yaojia and Nenjiang Formations.In this dissertation, I carried out high-resolution magnetostratigraphic investigation on the north core. Correlation of the recognized magnetozone to the geomagnetic polarity timescale was achieved by combining magnetostratigraphic and SIMS U-Pb zircon geochronologic data of the south core. Our correlation suggests that the north core sedimentary sequence spans from the upper chron C34n to chron C29r. The age of the north core sedimentary sequence from the lower Nenjiang Formation to the Mingshui Formation in the Songliao Basin can thus be constrained to an interval from the early Campanian to the Maastrichtian ages. I futher get ages between the lithostratigraphic formations/members in the CCSD-SK-Ⅰn: K/T boundary is located in the upper part of member 2 of the Mingshui Formation, that is, within magnetic polarity with magnetozone R1 （C29r）; the age of boundary between Nenjiang (K_2n)and Sifangtai formation (K_2s) is 79.075 Ma; the age of boundary between the member 2 of Nenjiang formation and the member 3 of Nenjiang formation （K₂n₂-K₂n₃） is 82.172 Ma; the age of boundary between the member 3 of Nenjiang formation and the member 4 of Nenjiang formation （K₂n₃-K₂n₄） is 81.591 Ma; the age of boundary between the member 4 of Nenjiang formation and the member 5 of Nenjiang formation （K₂n₄-K₂n₅） is 80.478 Ma; the age of boundary between Sifangtai and Mingshui formation (K_2s-K_2m) is 72.155 Ma; the age of the boundary between the member 1 and the member 2 of Mingshui formation (K_2m2-K_2m1) is 70.132Ma. The CCSD-SK-I（north） records the sedimentary succession from the early Campanian to the early Danian, the boundary between the Cretaceous/Paleogene is in the upper part of member 2 of Mingshui Formation.更多还原