论江西双桥山群的底界问题  

ON THE LOWER BOUNDARY OF THE SHUANGQIAOSHAN GROUP IN JIANGXI

作　　者：谢国刚 

机构地区：[1]江西地勘局地矿调研大队

出　　处：《中国区域地质》1997年第4期410-414,共5页Regional Geology of China

摘　　要：１∶５万庐山地区区域地质调查和专题研究，在星子县黄岭一带发现一套巨厚层状复成分的变质砾岩。根据该变质砾岩的砾石成分、变形组构及区域分布特点，以及上部（双桥山群）与下部（星子岩群）地层在变质与变形方面存在明显差别，认为变质砾岩应属于双桥山群的底部层位，是中元古界双桥山群与下伏下元古界星子岩群不整合关系的佐证。由于受后期构造叠加改造的影响，现今二者呈断层或隐蔽不整合接触关系。The lower boundary of the Shuangqiaoshan Group in Jiangxi is a long stanging problem. Through recent 1∶50 000 regional surveys and study on the Lushan area, a suite of very thick bedded metaconglomerate of complex composition has been found in the vicinity of Huangling, Xingzi county. On the basis of the gravel composition, fabrics and regional distribution of the metaconglomerate coupled with the marked difference in metamorphism and deformation of the upper part (Shuangqiaoshan Group) and lower part (Xingzi Group Complex) of the suite, the author holds that the metaconglomerate should be assigned to the base of the Shuangqiaoshan Group. It is evidence of the unconformity between the Middle Proterozoic Shuangqiaoshan Group and the underlying Lower Proterozoic Xingzi Group Complex. Owing to the influence of tectonic superimposition and reworking at the late stage, both show fault or hidden unconformable contact relationships at present.

关 键 词：变质砾岩 变形组构 双桥山群 砾岩 震旦系 底界 

分 类 号：P534.31[天文地球—古生物学与地层学]