济宁市中心城区第四纪地层划分及地质结构特征

Quaternary Stratigraphy Division and Geological Characteristics in Central Urban District of Ji'ning City

摘要:

济宁市中心城区第四纪地层广泛分布，是影响城市发展建设的重要地质因素。长久以来，区内第四纪地层划分的研究薄弱，各单位划分标准不统一，地层划分混乱，相关地质资料通用性差。本文依托“济宁市城市地质调查项目”，采用多种测年手段进行地质年代测定，并与工程地质钻探、岩土工程勘察相结合，对第四纪地层进行了研究划分。结果表明，全新世与晚更新世地层界线为黑土湖组；晚/中更新世地层界线埋深约为20.0~28.0m，为一层钙质结核富集黏土层；中/早更新世地层界线亦为钙质结核富集黏土层，埋深约在50.0~65.0m。第四系厚度一般90.0~130.0m，与新近纪馆陶组呈不整合接触，二者地层特征差异明显。本次研究工作可为济宁市中心城区地质调查、岩土工程勘察等工作提供参考依据，弥补了以往研究的不足。

Abstract:

Quaternary deposits are widely distributed in the central urban district of Ji'ning city. It play a significant role as geological constraints in affecting urban development and construction. For a long time, study on stratigraphic division of Quaternary in this area is weak. Standards for dividing various units are inconsistent, stratigraphic classification is in confusion, and related geological data has poor generalizability .In this paper, based on "Urban Geology Survey Project in Ji'ning City ", by using multiple dating techniques , geological ages have been determined. Combining with engineering geological drilling and geotechnical investigations, classification on Quaternary strata have been studied. It is indicated that the boundary between Holocene and late Pleistocene strata is Heituhu formation. The burial depth of late and middle Pleistocene stratigraphic boundary is calcareous nodule enriched clay layer with the depth of about 20.0~28.0m. The boundary between the middle and early Pleistocene strata is also a clay layer enriched with calcium nodules. The burial depth is approximately 50.0~65.0m. The thickness of Quaternary system is generally 90.0~130.0m. It is in unconformity contact with Neogene Guantao formation with significant differences in stratigraphic characteristics between the two. This research work can provide reference basis for geological surveys, geotechnical engineering surveys, and other work in the central urban area of Ji'ning city.