驻马店市第四纪地层研究

STUDY OF THE QUATERNARY STRATIGRAPHY IN ZHUMADIAN

本文基于驻马店市控制性钻孔BK2的古地磁测试分析、ESR样品测试、孢粉分析,对该孔第四系进行研究。结果认为:BK2孔沉积了早更新世冲湖积地层、中更新世中期冲洪积地层,二者之间为不整合接触关系,缺失中更新世早期沉积地层以及中更新世晚期(含)以来沉积地层。早更新世和中更新世沉积的地层分界位于深度48.0 m处。其中,深度48.0—156.2 m属于早更新世中期、晚期沉积地层,深度1.5—48.0 m属于中更新世中期沉积地层。钻孔总体记录了早更新世中期(深度119.7—154.6 m)温干气候、晚期(深度48.0—119.7 m)冷干气候;中更新世中期(深度3.7—48.0m)温干气候,缺失中更新世早期的冷干气候记录。BK2孔第四纪地层沉积速率的变化是由该区域第四纪沉积气候环境演化和第四纪震荡性构造(升降)运动等共同作用的结果。

In this study,a detailed analysis of Quaternary strata in BK2 drill hole of Zhumadian were conducted based on methods of the paleomagnetostratigraphy,electron spin resonance,and sporopollen assemblage.The results show that the boundary of Early Pleistocene and Middle Pleistocene located at the depth of^48.0 m.The strata at 48.0-156.2 m depth belong to the alluvial-lacustrine formed in the middle-late stage of Early Pleistocene,and the one at 1.5-48.0 m depth belong to alluvial formed in the middle stage of Middle Pleistocene.The index records of BK2 drill hole indicate that the paleo-climate were relatively warm and dry(119.7-154.6 m),cold and dry(48.0-119.7 m)during the middle-late stage of Early Pleistocene,and revealed the warm and dry climate(3.7-48.0 m)variation during the middle stage of Middle Pleistocene.The sedimentary rate variations of Zhumadian strata during Quaternary may be linked to the Quaternary climate evolution and the regional tectonic activities.