中祁连东段花石山群与湟中群之间不整合关系讨论

中祁连地块东段花石山群与湟中群之间的接触关系，前人一般认为是平行不整合或整合关系。但我们对煌中县东岔沟剖面花石山群、但中群和惶源群的沉积、变形、变质特征研究表明：花石山群与下伏惶中群之间存在着沉积环境。构造变形、变质作用的间断或不连续性，接触部位上、下地层产状也不一致。因此认为花石山群与下伏惶中群可能为角度不整合关系。这一角度不整合的确定使得已经建立起来并为广泛接受的中祁连地块东段前寒武纪地展格架等问题需要重新审视和研究。

Angular Unconformity between the Huashishan Group and Huangzhong Group in the Eastern Mid-Qilian Massif:Identification and Implications

The contact relationship between the Huashishan Group and Huangzhon Groupin the eastern Mid-Qilian Massif was generally considered as confondty or parallel unconfndty.However, our recent prirnary studies on the sedimentary environmnts, deformation style andhistory, and metarnorphism of the Huashishan Group and Huangzhon Group empd over theDengchagou section in the western Huangzhong County indicate that between the HuashishanGroup and Huangzhong Group exists the gaps or discontinuities in sedirnefltery setting,deformation, and metamomhism and that upper strata and lower strata adjacent to the contactplane between the two Groups have different structural accurences, which stJggest that betweenthe two Groups is the angular unConformity rather than parallel unconformty- The identificatedangular unconformity between the Huahsishan Group and Huangzhong Group would Inake theestablished and generally acepted Precambrian strata framewwh in the eastern Mid - Qilian Massifandbasement archistructure of the Mid - Qilian Massif need to be reexamined or further studied.