THE WAY AND IMPLICATIONS OF REBUILDING PALAEOGEOMORPHOLOGY Taking the research of palaeogeomorphology of the Ordos Basin before Jurassic deposition as example
ZHAO Jun xing, CHEN Hong de, SHI Zhi qiang (Chengdu University of Technology, China)
Palaeogeomorphology is one of the main factors. It controls not only the development and distribution of the late sedimentary facies but also the assemblage of reservoirs and capping formations. Just like the modern geomorphology, it is influenced by the tectonic position, climate, base level, and so on. Rebuilding the palaeogeomorphology is a complex work. The Jurassic sedimentary strata of the Ordos Basin develops upon the denudation surface generated during the Indosinian orogeny, and their characteristics are being controlled by palaeogeomorphology. Therefore, the renewing work of the palaeogeomorphology of Ordos before Jurassic deposition can efficiently direct the exploration of the Jurassic oil reservoir. The palaeogeomorphology of the Ordos Basin shows that the northern and western parts are high but the southern and eastern parts are low in the basin. It includs five palaeogeomorphologic units, that is, highland, valley plain, hilly area depression area and palaeo river. The paper mainly discusses the ways of rebuilding palaeogeomorphology and its relationship with the late oil reservoir through rebuilding the palaeogeomorphology of the Ordos Basin before Jurassic.