内蒙古大青山山前第四纪冲洪积扇填图实践与思考

第四纪地质调查和填图对解决当前人类生存发展面临的生态环境问题具有重要意义，但“填什么，如何填”等相关问题尚处于探索示范阶段。基于在内蒙古大青山山前地区开展的特殊地质地貌区填图工作，查明了大青山山前冲洪积扇的分布特征、期次及影响因素，总结了以冲洪积扇为代表的第四系覆盖区的调查与填图方法。首先，应针对地质地貌的特殊性，初步梳理区域内主要的第四纪地质与环境问题，选取针对性的沉积相模式进行沉积相划分；其次，综合前人资料成果和遥感解译结果编制设计地质图，依靠露头剖面、槽型钻揭露开展野外调查和验证，划分基本填图单元；然后，利用光释光、14C等测年技术，确定填图单元时代，查明区内冲洪积扇发育的时间和期次；最后，选取“时代+成因+沉积相”结合不同岩性花纹的组合表达方式，增强工作区内典型剖面和钻孔的显示度，丰富图面内容和形式。

Geological mapping practice and exploration of Quaternary alluvial-pluvial fans along the Daqing Mountain,Inner Mongolia

The Quaternary geological survey is very important for solving ecological and environmental problems with social development.Therefore, "What to do" and "How to do" become the key issues for the geological workers during the Quaternary geological mapping.On the basis of the Quaternary geological survey results in the Daqing Mountain of Inner Mongolia, the distribution characteristics, stages and main factors of alluvial-pluvial fans were clarified, and the mapping method was reviewed to provide some references for the future Quaternary survey.According to the practice of Quaternary mapping in Daqing Mountain of Inner Mongolia, the following four steps are summarized.Firstly, according to the particularity of geology and geomorphology, the main Quaternary geological and environmental problems in the region should be preliminarily sorted out, and the main sedimentary facies model should be selected to divide sedimentary facies.Secondly, the designed geological map is to be compiled based on the results of previous data and remote sensing interpretation, while field investigation and verification are to be carried out by outcrops, trenchs and drill holes.Then, ages of the mapping units and the different alluvial-pluvial fans are further to be determined by luminescence dating and radiocarbon dating.Finally, the combination of 'age + genesis + sedimentary face' and different lithologic patterns could be used to enhance the display of stratigraphy and enrich the content and form of the map.