青藏高原中北部地貌变形的遥感表征及其生态地质学意义

REMOTE SENSING CHARACTERISTICS OF THE GEOMOPHIC DEFORMATION IN MID-NORTHERN QINGHAI-TIBET PALTEAU AND THEIR ECO-GEOLOGICAL SIGNIFICANCE

遥感地质特征显示青藏高原北部,在澜沧江—温泉与东昆仑南缘—阿尼玛卿两条岩石圈断裂之间区域存在着4个正交叠加在早期北西—南东向构造地貌上的北东—南西向第四纪坳陷。其中西羌塘北部坳陷和长江源坳陷的地堑式裂陷地貌特征明显,而黄河源坳陷和若尔盖坳陷发育程度较低,但它们均是在青藏高原大陆构造变形的统一动力学背景下,地貌发生东西向伸展变形的产物。进一步研究表明,它们的形成不仅与青藏高原中南部所发育的近南北向裂谷具有同样的动力学意义,而且已成为影响该地区生态系统的主要因素。

Remote sensing geological features of Mid-northern Qinghai-Tibet plateau show that four NE-trending Quaternary depressions exist in the area between Lancangjiang-Wenquan and the southern margin of eastern Kunlun-Animaqing lithospheric faults. The graben geomorphic characteristics of Northern Xiqiangtang and Changjiang Riverhead depressions are obvious, whereas the Huanghe Riverhead and Ruoergai depressions are of relatively low development degree. However, they are products of the east-west geomorphic extensive deformation, and the dynamic background of the deformation is the same as that of the continental tectonic deformation of Qinghai-Tibet plateau. Studies further show that the deformation of these depressions not only has the same dynamic significance as the NS-trending rifts in mid-southern Qinghai-Tibet plateau but also serve as important factors affecting the ecological system of that region.