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面理化含榴花岗岩是大别-苏鲁中生代碰撞造山带内大面积出露的一类特殊岩石类型,它一般与高压超高压变质岩共生.当前研究对该类岩石的成因、构造演化及与超高压变质岩关系等存在不同认识.选择西大别北缘浒湾高压变质单元中的面理化花岗岩岩体进行锆石SHRIMP定年与构造变形特征分析.测年结果表明,岩体的锆石SHRIMP年龄为(762±15)Ma(MSWD=1.7),代表了岩体侵位结晶年龄,表明岩体形成于新元古代中晚期.野外观测与显微构造分析显示,浒湾岩体自侵位后经历多期构造变形.早期变形表现为残留面理(S1)构成的片内无根褶皱,主体变形表现为向北中等倾斜的透入性片麻理(S2)和韧性剪切变形,这是岩体在NNE向SSW的近南北向挤压作用下与围岩共同变形的结果,代表了浒湾高压单元在印支期向南逆冲的构造特征.晚三叠世后,岩体发育向南逆冲的脆性断层和向北正向滑动的断层,代表了浅层次伸展引张的构造体制.
The palygorsed granitic granites are a special type of rocks exposed extensively in the Mesozoic orogenic belt of the Dabie-Sulu Mesozoic and are generally associated with high-pressure and ultrahigh-pressure metamorphic rocks.Researches on the genesis, tectonic evolution, UHP metamorphic rocks.During the study of SHRIMP dating and tectonic deformation of the granites in the Huwan high-pressured metamorphic unit on the northern margin of the Xidabaebou, dating results show that the zircon SHRIMP (762 ± 15) Ma (MSWD = 1.7), representing the emplacement age of the rock mass, indicating that the rock mass was formed in the middle and late Neoproterozoic. Field observations and microstructural analyzes show that the intrusive position After several years of tectonic deformation, the early deformation showed no root folds formed by the residual physiognomy (S1), and the main deformation presented as mid-dip transgressive sheeting (S2) and ductile shear deformation The result of joint deformation of the rock mass with the surrounding rock under the NNE-SSW compression near the north-south direction represents the tectonic feature of the high-pressure unit of the Hu Bay southward during the Indo-Chinese epoch. After Late Triassic, the rock mass developed Southern thrust brittle fault and slide northward Fault, on behalf of the shallow stretch lead tectonic regime sheets.