摘要
There ekist two parallel A-type syenitegranite belts on both banks of the Yangtze River inAnhui Province : one is the Dalongshan- Chengshan- Huangmeijian belt on the north bank and theother is the Huayuangong- Maotan- manshiling belt on the south bank. Both of them consist ofsyenite, quartz-syenite and alkali feldspar granite, which were formed at about 125 Ma ago and areenriched in alkalies and high-field-strength elements but depleted in water, with the total alkali ac-counting for 9- 12%, and H2O+ only for 0.50%’ The Ga x 10-4/Al raho is as high as 2.7 to 3.8for granite. They were formed in the extension stage of ancient riffing. So they are considered to bethe A-type Syenite-granite belts. Granites in the two belts resulted from a syedte magma by an AFCmechanism While the magma was derived from alkali basalt magma through thefractio nal-crystallization-dominated AFC mechanism.
There ekist two parallel A-type syenitegranite belts on both banks of the Yangtze River inAnhui Province : one is the Dalongshan- Chengshan- Huangmeijian belt on the north bank and theother is the Huayuangong- Maotan- manshiling belt on the south bank. Both of them consist ofsyenite, quartz-syenite and alkali feldspar granite, which were formed at about 125 Ma ago and areenriched in alkalies and high-field-strength elements but depleted in water, with the total alkali ac-counting for 9- 12%, and H2O+ only for 0.50%' The Ga x 10-4/Al raho is as high as 2.7 to 3.8for granite. They were formed in the extension stage of ancient riffing. So they are considered to bethe A-type Syenite-granite belts. Granites in the two belts resulted from a syedte magma by an AFCmechanism While the magma was derived from alkali basalt magma through thefractio nal-crystallization-dominated AFC mechanism.
