松辽盆地达深1井早白垩世孢粉化石的发现及其地质意义

DISCOVERY AND ITS GEOLOGICAL SIGNIFICANCE OF EARLY- CRETACEOUS SPOROPOLLEN FOSSILS IN DA NO. 1 DEEP WELL OF SONGLIAO BASIN

达深1井是安达地区一口重要探井，为解决该井地层划分对比问题，采用氢氟酸-盐酸冷处理法对33块样品进行孢粉分析。在玄武岩所夹的沉积岩中发现了具有确定地质时代和层位意义的孢粉化石，命名为桫椤孢Cyathidites-周壁粉Perinopollenites-原始松柏粉Protoconiferus组合。其特征为裸子类花粉占绝对优势（80．0％～96．0％），蕨类孢子含量低（4．0％～20．0％），未见被子类花粉，裸子类花粉中气囊分化不好的古松柏类花粉含量极高，是该孢粉组合的最主要特点。依据孢粉化石组合特征，结合同位素、岩性、电性资料，将达深1井3221．0～3723．0m井段自下而上划分为11个小层，并确定这套火山碎屑岩地层为营城组，其地质时代为早白垩世Hauterivian—Barremian期。推测营城组沉积时期为亚热带-温带气候。

Da No. 1 Deep Well is an important exploration well in Anda region. In order to solve the problem of the stratigraphie classification and contrast of this well, the sporopollen analyses for 33 samples are conducted by means of hydrofluoric acid-hydrochloride cold process method. In the sedimentary rock interbedded in basalt, the sporopollen fossils with the significances of determining the geological age and horizon are discovered, and then they are named the assemblage of Cyathidites-Perinopollenites-Protoconiferus. The characteristics of the assemblage are that Gymnospermae pollens are dominant （ 80. 0% - 96.0% ） , fern spores occupy less （4.0% - 20. 0%） , angiosperm pollens are not discovered and the content of Palaeoconiferus pollen with not-well-differentiated balloons in Gymnospermae pollens is extremely high. According to the assemblage features of the sporopollen fossils and integrating with the data of isotopes, lithology and electricity, the hole interval （3 221.0 -3 723.0 m） of Da No. 1 Deep Well is classified into 11 individual layers from bottom to top and at the same time the set of pyroelastic formations is determined to be Yingcheng Formation, its geological age is Hauterivian-Barremian Age of early Cretaceous Epoch. The predicted sedimentary environment of Yingcheng Formation belongs to subtropics-extratropical climate.