内蒙古二连盆地早三叠世地层及孢粉组合的发现

二连盆地曾被认为是缺失三叠纪沉积的地区。通过阿拉坦合力凹陷坦参１井的孢粉化石分析，首次证实了在二连盆地存在早三叠世地层。坦参１井的下三叠统的视厚度１ ３３９ｍ （井深５５８～１ ８９７ｍ ），以紫红色、棕红色的泥岩为主，夹灰绿色泥岩，向下岩性变粗，含砾泥岩、砂砾岩增加，与上覆侏罗系及下伏上二叠统皆呈不整合接触。井深７００～１ ８９６ｍ 产以Ｌｉｍ ａｔｕｌａｓｐｏｒｉｔｅｓ大量出现、Ｔａｅｎｉａｅｓｐｏｒｉｔｅｓ具一定含量、出现Ｌｕｎｄｂｌａｄｉｓｐｏｒａ、Ａｒａｔｒｉｓｐｏｒｉｔｅｓ和Ｌｕｅｃｋｉｓｐｏｒｉｔｅｓ为主要特征的早三叠世孢粉化石组合。这一发现对重新认识二连盆地的地质发育历史颇有意义

Discovery of the Early Triassic Strata and Palynomorphs in Eren Basin,Nei Mongol

The discovery of spore pollen assemblage from the Tancan 1 borewell proves,for the first time,the existence of the Lower Triassic strata in Eren Basin,Nei Mongol Autonomous Region of China.The Lower Triassic series with an apparent thickness of 1 339m lies unconformably on the Upper Permian and beneath the Jurassic rocks,and lithologically consists mainly of purple red and brown red mudstone,intercalated with gray green musdtone and downwards with more and more such coarser sediments as silty mudstone,pebble bearing mudstone and sandy conglomerate.The spore pollen assemblage from the gray green mudstone is characterized by plenty of Limatulasporites,Taeniaesporites and presence of Lundbladispora,Aratrisporites,Lueckisporites and is comparable with the Early Triassic assemblages from the Erdos,Junggar Basins and east central Qinghai Province of northwestern China.This discovery is significant in renewing our know ledge about the history of Eren Basin.