ABSTRACT

Afghanistan comprises a collage of many lithotectonic domains sutured together as block terranes on the southern Eurasian Plate by collisional tectonics throughout the Proterozoic and Phanerozoic. Kabul basement rocks are fragments of an Archaean block stabilized in early Precambrian with two later metamorphic events correlating well with global-scale orogenies related to assembly of the Paleoproterozoic Columbia and Neoproterozoic Rodinia supercontinents. These collisional tectonics were followed by igneous episodes and production of multiple ophiolite suites divided into three orogenic episodes of the later Palaeozoic (Devonian – Permian) Variscan (Hercynian) Orogeny, the Mesozoic (Triassic – Early Cretaceous) Cimmerian Orogeny, and the dominantly Cenozoic (Late Cretaceous – Quaternary) Himalayan (Alpine) Orogeny. Variscan, Cimmerian, and Himalayan accreted blocks are separated by prominent suture and fault zones, several of which are active and a source of considerable seismic hazard, especially in eastern Afghanistan. This resulting mélange of small exotic blocks was brought about by a rifting series of narrow ribbon terranes from the Gondwana coast of the Paleotethys and Neotethys seaways. Recent revival of Afghan-led geological lithologic and geochemical assessments has led to new interpretations of tectonic history, as well as of vital surface and groundwater, and other natural resources. Recurrent droughts have decreased water supplies, which have undergone extensive contamination, along with uncontrolled over-pumping of aquifers. Increasing attention to the rich mineral resource base in the country offers solutions to chronic budgetary shortfalls.

摘要

阿富汗包括许多岩石构造域的拼贴画，这些构造域通过整个元古代和显生宙的碰撞构造在欧亚板块南部被缝合在一起，形成块状地体。喀布尔基底岩石是在前寒武纪早期稳定的太古代块的碎片，随后发生了两次变质事件，这些事件与与古元古代哥伦比亚和新元古代罗迪尼亚超大陆组装相关的全球规模造山运动密切相关。这些碰撞构造之后是火成事件和多个蛇绿岩套件的产生，分为晚古生代（泥盆纪-二叠纪）华力西（海西纪）造山运动、中生代（三叠纪-早白垩世）西梅里造山运动和占主导地位的新生代（晚白垩纪-第四纪）喜马拉雅（高山）造山运动。华力士坎、辛梅里安、和喜马拉雅积聚块被突出的缝合带和断层带隔开，其中一些是活跃的，是相当大的地震危险源，特别是在阿富汗东部。由古特提斯和新特提斯海道冈瓦纳海岸的一系列狭长带状地体裂谷带来了这种由异国情调的小块混合而成的混合物。最近由阿富汗领导的地质岩性和地球化学评估的复兴导致了对构造历史以及重要地表水和地下水以及其他自然资源的新解释。经常发生的干旱减少了水供应，这些水受到了广泛的污染，同时含水层不受控制地过度抽水。对该国丰富的矿产资源基础的日益关注为长期预算短缺提供了解决方案。