甘肃北山地区晚第四纪构造变形特征及演化趋势

通过对甘肃北山地区ETM影像的细致分析和初步野外考察，对北山地区晚第四纪以来断裂活动时代和运动性质进行了研究。结合附近地区天山构造带、青藏高原北部边缘断裂的演化过程和区域构造应力场状态，对北山地区晚第四纪以来变形机制和演化趋势进行了研究。认为北山地区现今构造格局是在印度板块与欧亚板块相碰撞形成的北东向挤压构造应力场的作用下，重新激活东西向的晚古生代、中生代断裂，并产生北东向新生断裂而形成。晚第四纪以来，北山地区构造变形以南北向缩短为主，伴随有东西向伸展。随着印度板块的向北运移，北山地区的构造变形将进一步增强，即南北向缩短和东西向的扩展将进一步增强。

Tectonic Deformation and Evolution Trend of Beishan Region,Gansu Province since Late Quaternary

By ETM-image analysis and preliminary field investigation in Beishan Region, Gansu Province, the era of faults and the related movement features since late Quaternary are studied.Combined with the tectonic evolution process and stress field in Tianshan active tectonic zone and in northern boundary of Qinghai-Tibetan Plateau, the deformation mechanism and evolution trend of Beishan Region since late Quaternary are deduced.The collision between India plate and Euro-Asia plate reactivates west-east oriented structures formed in Paleozoic and Mesozoic and produces north-east oriented new faults in Beishan Region.Since late Quaternary, the predominant crust in Beishan Region is shrinking in north-south direction and stretching in west-east direction.Along with further northward movement of the India Plate, such deformation trend will become greater.