基于景观单元稳定性的晋中盆地北部区域地壳稳定性评价

Crustal Stability in Northern Jinzhong Basin of China Based on the Stability of Landscape Units

晋中盆地北部是山西省太原—晋中城市群扩建重点地区,研究该区域景观单元稳定性和区域地壳稳定性对于当地城市群及景观规划具有重要意义。已有研究从活动断裂和地裂缝等地质灾害角度对局部场地安全问题进行了探讨,但关于整体性的景观单元稳定性和区域地壳稳定性定量评价仍较缺乏。本文通过构造岩相学五维一体综合方法,对晋中盆地北部进行了景观单元划分和景观年代物质学研究,从景观异质性及景观演化角度分析了景观单元的稳定性,并且在此基础上进行了构造岩相学视角下的区域地壳稳定性定量评价。结果表明:(1)晋中盆地北部侵蚀性中低山基岩景观区景观单元稳定性相对较高,盆山过渡带景观区及河流湿地水域区景观单元稳定性相对较低。(2)区域地壳相对稳定区面积占比为45%,主要分布在汾河冲积平原区和南东部的侵蚀性中低山基岩景观区,相对不稳定区面积占比为33%,主要分布在盆山过渡带景观区和山前倾斜洪积平原区。(3)区域地壳稳定性决定了景观单元稳定性,景观单元稳定性是区域地壳稳定性的表现之一。本研究可为晋中盆地北部工程场址选择、景观格局优化及区域减灾防灾提供科学参考。

The northern part of the Jinzhong Basin,located at Shanxi province of China,is a typical area of urban agglomeration expansion.Research on the stability of landscape units and regional crustal stability is a prerequisite for urban agglomeration and landscape planning in this area.Although the issues of local site safety relevant to geological disasters such as active faults and ground fissures had been addressed by professionals,there was yet a lack of quantitative evaluation from broader perspective of combination of overall landscape unit stability with regional crustal stability.In this study,landscape units and landscape chronology in northern Jinzhong Basin was divided by the five-dimensional method of tectonic lithofacies.The stability of landscape units was analyzed based on landscape characteristics and evolution,and regional crustal stability was quantitatively evaluated from the perspective of tectonic lithofacies.The following conclusions can be drawn from the results:(1)The landscape units from the mountain to the interior of the basin were formed in an order as,successively,the erosive middle-low mountain bedrock landscape area,the basin-mountain transition zone landscape area,the piedmont slope alluvial plain area,the Fenhe alluvial plain area,and the river wetland water area.(2)Among them,the erosive mid-low mountain bedrock landscape area had higher stability whereas the basin-mountain transition zone and the river wetland water area were low stable.(3)The area with relative crustal stability in the region accounted for 45%of the total area,mainly distributed in the Fenhe alluvial plain area and the erosive mid-low mountain bedrock landscape area in the southeast;the area with relative crustal instability accounted for 33%,mainly in the basin-mountain transition zone landscape area and the piedmont sloped alluvial plain area.(4)Regional crust stability controlled landscape unit stability,which,in turn,was one of the external manifestations of regional crustal stability.The research results provide a scientific reference for site selection,landscape pattern optimization,and regional disaster reduction and prevention in the northern Jinzhong Basin.