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北东向延伸的松辽平原位于中国东北地区中部,其西部与大兴安岭接壤,东部与长白山脉邻接。松辽平原主要是一个中新生代沉积盆地,其内沉积了巨厚的侏罗纪-白垩纪地层和420～530m厚的古近纪-新近纪地层,以及75～200m厚的第四纪地层。本文根据松辽平原北部500多个钻孔揭示的第四纪地层沉积序列和岩性,确定松辽平原第四纪早期的沉积物主要为厚层粘土,厚度55～68m,埋藏深度从11m到75m。对乾安令字孔和大庆7901孔的岩芯样品进行了粒度分析,对大安CAD01孔的岩芯样品进行了粒度分析、孢粉分析、古生物化石鉴定和古地磁年龄测试,对莫莫格XY2孔的岩芯样品进行了粘土矿物X衍射分析。结果表明,这些第四纪早期的沉积物主要为湖相沉积。对粘土层进行的古地磁定年结果表明,这些第四纪早期沉积物的年龄为0.20～2.15MaB.P.,属于早更新世-中更新世沉积。所以,松辽平原在早更新世-中更新世时存在一个古大湖,古大湖的边界沿着林甸与依安之间的三兴—齐齐哈尔东南的烟筒屯—坦途—白城东—洮南—安定—乌兰花—瞻榆—太平川—科左中旗东北—长岭—前郭尔罗斯—扶余—肇源—安达西等一线分布,总面积约5×10~4km~2。晚更新世初松辽平原的古大湖衰亡,该区进入了河流作用时期。
The northeastward extension of the Songliao Plain lies in the middle of northeast China, bordering the Greater Hinggan Mountains in the west and adjacent to the Changbai Mountain in the east. The Songliao Plain is mainly a Mesozoic-Cenozoic sedimentary basin with thick Jurassic-Cretaceous and 420-530 m thick Paleo-Cenozoic and 75-200 m Quaternary formations . Based on the sequence and lithology of the Quaternary sedimentary sequences revealed by more than 500 boreholes in the northern Songliao Plain, the sediments of the early Quaternary in the Songliao Plain are mainly thick clay with a thickness of 55 ~ 68m and a depth of burial from 11m to 75m. The grain size of the core samples of Qian’anling hole and 7901 hole in Daqing was analyzed. The core samples of Daan CAD01 were analyzed by particle size analysis, sporopollen analysis, paleontology and ancient geomagnetic age. The Mogier XY2 The core samples of the pores were analyzed by X-ray diffraction of clay minerals. The results show that these early Quaternary sediments are mainly lacustrine deposits. The paleomagnetic dating results of clay layers show that the age of these Quaternary sediments is 0.20 ~ 2.15MaB.P., Belonging to the Early Pleistocene-Middle Pleistocene sediments. Therefore, the Songliao Plain existed an ancient Great Lake during the Early Pleistocene-Middle Pleistocene. The boundary of the Great Lakes along the Sanxing between Lindian and Yi’an - the Chutang - Tancheng - Baichengdong - Taonan - stable in the southeast of Qiqihar - Wulanhua - Zhanyu - Taiping Chuan - Kezuozhongqi northeast - Changling - Qian Guoerluosi - Fuyu - Zhaoyuan - Andasai and other first-line distribution, with a total area of about 5 × 10 ~ 4km ~ 2. During the late Pleistocene, the ancient Great Paleo in the Songliao Plain declined, and the area entered a river period.