【作者】 王焯；

【导师】 李勇； 王平；

【作者基本信息】 长安大学 ， 古生物学与地层学， 2006， 硕士

【摘要】 本文在广泛收集汾渭盆地新生代地层古生物资料的基础上，对陕西渭南宋家北沟的三门组地层进行了系统的地层学研究；对在该区域内采集的样品分别作了古生物化石处理、鉴定和描述，对磁化率样品作了定量测试，研究成果为本区域提供了内容丰富的三门组地层新资料。 1、通过对本剖面三门组的岩石地层特征、生物地层特征及前人已有的磁性地层学特征进行了地层的划分和对比，做出了系统的地层学研究。阐明本剖面三门组地层分为两段，即前人所指的“黄三门”、“绿三门”。但由于三门组地层具“穿时性”，用“黄”、“绿”不具普适性，因此作者将其分为三门组上段和三门组下段。 2、对本剖面所获得的介形虫化石进行了系统的研究。描述介形虫化石12属27种，并对其时空分布特征、组合特征、化石丰度和分异度等进行了探讨，建立了宋家北沟剖面三门组的两个介形虫化石组合。 3、综合研究区各剖面的前人资料和本次研究获得的新资料，对渭南地区新近纪至第四纪三门期的环境和气候变化进行了初步探讨。认为： a．本剖面三门组上、下段颜色的差异主要是由沉积环境不同而导致的，这也恰能反映出当时的古湖泊演化过程中的环境变化； b．通过对磁化率的分析研究，为三门组环境提供了可参考的数据指标； c．介形虫化石的丰度和分异度能较好的反映本区域三门组的环境演化； d．本区域三门期的环境，自下而上，由温暖、湿热，转为干燥、寒冷。更多还原

【Abstract】 On the base of the extensive collection of the Cenozoic strata and fossils in the Fen-Wei basin,this text made a systemic study on the strata of the Sanmen Formation in the Songjiabeigou,Weinan,Shannxi.After dealing, identification and description with the fossils,and making the fix quantify test on the magnetic susceptibility about the sample,the study provide new abundant Sanmen Formation’s information.1、 Make a systemic study on the strata of the Sanmen Formation with characters of the rock-stratigraphic, the biostratigrapic and the magnetostratigraphy. Then make a clarify that the Sanmen Formation should be divided into two members,as the "Yellow Sanmen", "Green Sanmen" which pointed by formers. But as Sanmen Formation strata of the "wear," and used "yellow" and "green" is not a universal nature and therefore the author divided it into Sanmen Formation High Member and Sanmen Formation Lower Member.2、 Make a systemic study on the ostracode fossils which collected from the section. 12genus 27 species of fossil insects are described, and the spatial and temporal distribution of their character, portfolio characteristics, fossil abundance and sub-degrees, from the exploration, establish 2 ostracode worms fossils assemblage in the Songjiabeigou Sanmen Formation profile.3、 Comprehensive study in the area and the profile of the predecessors of this research obtained new information on the environment and climate change to the preliminary examination from the Neogene to Quaternary Sanmen Age in Weinan areas.Consider that:a、 The profile of Sanmen Formation High Member and Lower Member, which the differences resulting from different sediment environment, then this exactly reflect the evolution of ancient lakes environmental change; b、 Frequency Susceptibilities can sensitively reflect environmental changesdetails of Sanmen Formation; c、 Ostracode fossils from the abundance of sub-degree and the region could wellreflect the environmental evolution of Sanmen Formation; d、 The environment of Sanmen Age in the region from warm, hot and damp, to dry and cold.更多还原