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Petrochemical characteristics of leucogranite and a case study of Bengbu leucogranites 总被引:1,自引:0,他引:1
Leucogranites have a relatively narrow variation in SiO2 content (70.5%-75.5%). Giving similar SiO2 content, leucogranites have relatively higher Al2O3 (〉13.5%) and lower TFeO + MgO (〈2.5%) contents than those of normal granites. These petrochemical characteristics suggest that leucogranites are de- rived from partial melting at relatively low temperature and are not significantly affected by fractional crystallization. In the present study, we propose that the Al2O3 vs SiO2 and TFeO + MgO vs SiO2 dia- grams can be used to distinguish leucogranites from normal granites. In addition, we report the major element compositions of the Jurassic granitic intrusions from Jingshan-Tushan-Mayishan in the Bengbu area, east-central China. Using the Al2O3 vs SiO2 and TFeO + MgO vs SiO2 diagrams and the comparison with the High Himalayan leucogranites in mineralogical and petrochemical characteristics, we suggest that the Jingshan-Tushan-Mayishan intrusions belong to a leucogranite belt. Similar to those of the High Himalayan leucogranites, the Bengbu leucogranites have low Mg# values, indicating that they resulted from low temperature dehydration partial melting of the subducted continental crust of the South China Block at the crustal depth. 相似文献
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