摘要
根据全岩P_2O_5含量的多寡可将华南富氟花岗岩分为高磷亚类和低磷亚类,它们之间具较大的地球化学差异。高磷亚类以低硅、强过铝和低的REE总量为特征,而低磷亚类则相反。在长石、云母等矿物化学成分上这两亚类花岗岩也有所差异。高磷亚类花岗岩中磷以长石中结构磷和磷铝锂石形式存在,而低磷亚类花岗岩中的磷则主要存在于磷灰石等磷酸盐矿物中。
F-rich granites in South China may be divided into the high-P subtype and low-P subtype according to their whole-rock P2O5 contents. There are obvious differences in chemical compositions of these two subtypes. The high-P subtype is strongly peraluminous and characterized by low-silica, very low REE contents and higher A/NKC and Na/K values, while the low-P subtype is weakly peraluminous and characterized by high-silica, very high REE contents and high CaO and Mg+Fe values. There are also some differences in their mineralization. High-P subtype granites are mainly related to Nb and Ta mineralization, while low-P subtype granites are mainly related to Sn, W and Be mineralization. The micas of high-P subtype granites are richer in Li, while those of low-P subtype granites are richer in Fe. The phosphorus of high-P subtype mainly appears in the feldspar structure as PAlSi_2 or subordinately in the amblygonite as an accessory mineral,and the P2O5 contents in the feldspars are high. On the contrary,the P2O5 contents in the feldspars of low-P subtype granites are very low (<0. 01% , whithin the detection limit of micro-probe analysis) ,and phosphorus is mainly hosted in trace amounts of phosphate minerals.
出处
《地质论评》
CAS
CSCD
北大核心
1998年第6期607-617,共11页
Geological Review
基金
国家自然科学基金(编号49673183
49632080)
