Characteristics and models of weathering paleo-karst in Upper Sinian,Sichuan Basin
【Abstract】 The development of ancient weathering crust karst in Sinian is the main factor of the breakthrough in Dengying Formation of Sichuan Basin. With a lot of outcrops,drilling coring,thin sections,seismic and well logging data,geochemistry analysis,and on the basis of the comprehensive arguments about the two sets of weathering paleo-karst in Dengying Formation,weathering paleo-karst characteristics and differences between the vertical and horizontal structures were studied to further establish corresponding weathering paleo-karst models. It is concluded that the weathering paleo-karsts in Dengying Formation can be described by the ramp model. However,affected by the different palaeogeomorphology gradient,the strata near the unconformity of the fourth Member of Dengying Formation has the strongest karstification and easy to develop caverns,breccia and mudstone filling. The horizone-phreatic zone and deep-slow-flowing zone are the main part of the karst vertical zonation. The strata near the unconformity of the second Member of Dengying Formation has a relatively slow karstification,with the small size of the dolomite breccia,dolomite as its cave fillings,and mainly develop vertical vadose zone,horizone-phreatic zone and deep-slow-flowing zone.
【Key words】 weathering paleo-karst； paleo-karst structure； paleo-karst models； Upper Sinian； Dengying Formation； Sichuan；
- 【文献出处】 中国石油大学学报(自然科学版) ,Journal of China University of Petroleum(Edition of Natural Science) , 编辑部邮箱 ,2015年03期