摘要
确定了具有从上部糜棱岩带-上混合岩带-花岗岩带-下混合岩带-下部糜棱岩带的垂向分带性的滑动系统是粤西深层次推覆活动断裂变质和部分熔融的产物,糜棱岩化、混合岩化、花岗岩化导致了滑动系统中金元素的活化、转移,在低能带——顶,底两条糜棱岩带中成矿.并认为未遭剥蚀的底部糜棱岩带很可能隐伏了一个超大型中、低品位的糜棱岩型金矿床.
There are many Sinian-Cambrian (Z^c-?b) epimetamorphic blocks either in groups or scatteredly covering the granitoids in the area of Guangning-Zhaoqing, the northwestern part of wuchuan-Sihui faults in western Guangdong. Through the field work and lab studies on the deep-level nappe structural zone, it has been shown that the blocks are allochthonous, i.e. klippe of thrust, and the granitoids are of a part of the slip system which consists vertically of upper mylonite and migmatite-granite-lower migmatite and mylonite from top to bottom in the deep-lower migmatite and mylonite in the deep-level nappe structural zone. The authors believe that the slip system zoned vertically was generated by dynamometamorphism and partial melting within the zone. The genetic relationships of mylonite, migmatite and granite are also discussed by the stuides of deformation structure, frictional heating (shear strain heating) and melt-enhanced deformation, etc.. The authors emphasize that, during the evolution of the thrust from earlier to later geological periods, mylonites were generated in the first time. Migmatites were reformed from mylonites. Granites were the last production of the migmatization. This process (mylonitization, migmatization and granitization) leads to mobilization and migration of gold. the gold-bearing metamorphic fluid migrates from migmatite zone and granite zone to upper mylonite zone and lower mylonite zone in the slip system. The allochthonous upperly and the autochthonous lowerly rule as geochemistry obstructs in the process of migration of the fluid. Au and Fes_2 were assembled and deposited in the double-paired mylonite zones when geochemistry equilibrium of the fluid was broken. There may be a super large gold deposit lain concealed in the lower mylonite zone undenuded.
出处
《地质找矿论丛》
CAS
CSCD
1993年第3期1-13,共13页
Contributions to Geology and Mineral Resources Research
基金
国家自然科学基金(项目编号:49272133)
