Acta Geographica Sinica ›› 1985, Vol. 52 ›› Issue (3): 215-224.doi: 10.11821/xb198503003

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MORPHOTECTONIC PATTERNS OF NINGX1A HUI AUTONOMOUS REGION AND ITS FORMATION AND EVOLUTION

Zhou Texian, Wang Li, Chao Mingzhi   

  1. Bureau of Geology and Mineral Resources, Ningxia, China
  • Online:1985-07-15 Published:1985-07-15

Abstract: Two different types of morphotectonie pattern are found in the Ningxia Hui Autonomous Eegion. Its northern part is characterized by a N-S aligned zonal pattern consisting of mountain ranges and basins in the west and a plateau in the east, whereas its southern part is represented by a NW-SE striking arcuate pattern convexing toward NE and composed of three mountain ranges alternating with two series of basins.During Cenozoic, the northern part was in a tensional stress state with the axis of NNW-SSE or NW-SE, while the southern part was in a eompressive stress with the axis of SW-NE.Since Oligocene, as a result of the action of these tectonic stresses strong tensional movement along the NNE-trending faults which were formed in Mesozoic has been occu-ring in the northern block of Ningxia resulting in the formation of subsided Yinchuan basin, uplifted Helanshan mountain range and the Ordos plateau, and hence the zonal pattern.While pushed toward NE, the southern block of Ningxia was stopped by two ancient rigid blocks in its northern and eastern sides respectively. As a result, the deformation of crust there occurred, causing the formation of the above-mentioned arcuatepattern. This precess expreienced three major stages──from the end of Oligocene toearly Miocene, from the end of Pliocene to early Pleistocene and from the middle Pleistocene to present.