哈拉哈塘凹陷奥陶系岩溶古地貌及岩溶缝洞体发育模式

Karst Paleogeomorphology and Development Model of Karst Fracture-Cave Bodies of Ordovician in Halahatang Sag

针对塔北哈拉哈塘地区北部潜山风化壳岩溶区和南部埋藏岩溶区不同的地质特征,分别运用印模法和地层古构造与印模残差组合法恢复奥陶系古地貌和古水系。在此基础上,对4种不同古地貌环境条件下岩溶缝洞体发育特征及形成机理进行研究,建立了潜山风化壳岩溶区、上岩溶缓坡地、下岩溶缓坡地和岩溶盆地4种岩溶缝洞体发育模式。潜山风化壳岩溶区以发育表层岩溶缝洞系统为主;上岩溶缓坡地发育一间房组—鹰山组大型缝洞体及暗河管道系统;下岩溶缓坡地发育良一段—良二段和一间房组—鹰山组2套大型缝洞储集体;岩溶盆地沿断裂发育岩溶缝洞体。

In view of different geological features of buried-hill weathering crust areas in the north and buried karst area in the south ofHalahatang area in the northern Tarim basin, the Ordovician paleolandform and ancient drainage systems are restored using impressionmethod and a combination method of paleostructure and residual impression. The karst fracture-cave body development characteristics andits formation mechanism are studied under 4 different paleo-landform environments, and 4 karst fracture-cave body development patternsare established such as buried-hill weathering crust zone, upper karst slope, lower karst slope and karst basin. The buried-hill weatheringcrust zone is dominated by surface-karst fracture-cave system; large fracture-cave bodies of Yijianfang formation-Yingshan formation andunderground river channel systems mainly occur in the upper-karst slope; 2 sets of large fracture-cave bodies namely Liang-1-Liang-2member and Yijianfang formation-Yingshan formation are developed on the lower karst slope; and karst fracture-cave bodies are distribut-ed along faults in the karst basin.