松辽盆地林深4井早白垩世孢粉化石的地质意义

GEOLOGICAL SIGNIFICANCE OF EARLY CRETACEOUS SPOROPOLLEN FOSSILS IN LINSHEN NO. 4 WELL OF SONGLIAO BASIN

林深4井是林甸地区一口新钻的重要探井，为解决该井地层划分对比问题，采用氢氟酸-盐酸法对14块岩心样品进行处理，在5块样品中发现孢粉化石，其中2块样品发现的孢粉化石具有确定地质时代和层位的意义，代表了2个不同的孢粉组合，为林深4井深层地层的划分对比提供了生物地层学依据。依据孢粉化石组合特征，结合岩性、电性资料，将林深4井深层自下而上划分为45个小层，并确定1—2层为沙河子组、3—8层为营城组、9—45层为登娄库组（3段＋4段）。依据孢粉化石确定了林深4井登娄库组的地质时代为Aptian期，营城组时代为Hauterivian—Barremian期。依据孢粉化石推测登娄库组沉积时期为湿润的热带气候，营城组沉积时期为湿润的中亚热带气候。

Linshen No. 4 well is an important new-drilled exploration well in Lindian region. In order to solve the problem of the division and correlation of the strata in this well, 14 core samples has been processed by the method of hydrofluoric acid-hydrochloric acid. Sporopollen fossils are discovered in 5 samples, among them, two of them have a certain geoehron and stratigraphie significances for they represent 2 different sporopollen assemblages, thus provide biostratigraphic evidence for the solving of above problem. According to the characteristics of these sporopollen assemblages and by integrating lithological and electrical data, 45 subzones are divided from bottom to top in this deep well and furthermore Subzones 1 -2, 3 -8, 9 -45 are determined respectively to Shahezi, Yingcheng and Denglouku （ Interval 3 ＋ 4） Formations. According to the sporopollen fossils, the geochron of Den- glouku Formation of this well is determined to be Aptian Period, and moreover the age of Yingcheng Formation is Hauterivian-Barremian Period. And furthermore, by means of the sporopollen fossils, the sedimentary period of Denglouku Formation is humid tropical climate and that of Yingcheng Formation in humid subtropical climate.