塔北南坡差异构造隆升及其对古岩溶发育的影响

Influence of Differential Tectonic Uplift on Karst Development in the Southern Slope of Tabei Uplift

利用平衡剖面恢复法,研究了塔北南坡各次级单元构造演化的时空差异性,结合寒武系—奥陶系储层不整合面的发育特征,进一步探讨差异隆升过程对古岩溶尤其是表生岩溶发育的影响。研究结果表明:英买力凸起和库尔勒鼻凸形成于加里东中期早幕,至燕山晚期基本定型;构造隆升对应了加里东中期早幕—燕山中期的岩溶作用,岩溶持续时间长、溶蚀作用强烈,但古岩溶也在长期暴露过程中遭到剥蚀。阿克库勒凸起和草湖凹陷则形成于加里东中期Ⅰ幕,定型于印支期;构造隆升时间与加里东中期Ⅰ幕—海西晚期的岩溶作用相对应,抬升暴露适度,有利于大规模岩溶的形成和保存。哈拉哈塘凹陷形成于加里东中期Ⅰ幕,海西晚期已基本定型,对应加里东中期Ⅰ幕和Ⅲ幕的岩溶作用,表生岩溶作用的影响相对较弱。

The temporal and spatial variations of sub-structural units in the southern slope of Tabei uplift were analyzed by using balanced section technology,and then the control of differential evolution on ancient karstification,especially on epigenic karstification was discussed combined with the analysis of Cambrian-Ordovician unconformity types. The result indicated that Yingmaili uplift and Halahatang sag were being formed in the early episode of Middle Caledonian period and formed in Late Yanshanian period corresponding to the early episode of Middle Caledonian-Middle Yanshanian karstification,which has the characteristics of long duration,strong dissolution and erosion. Akekule uplift and Caohu sag were being formed in the episode Ⅰ of Middle Caledonian period and formed in Indosinian period corresponding to the early episode of Middle Caledonian-Late Hercynian karstification,which has the characteristics of moderate exposure and good condition for karst formation and conservation. Halahatang sag was being formed in the episode Ⅰ of Middle Caledonian period and formed in Late Hercynian period corresponding to the episode I and episode Ⅲ of Middle Caledonian karstification,which has the characteristics of relatively weak erosional dissolution.