Geochemical characteristics of some rare element-bearing granites in southeast China and physico-chemical conditions of their formation |
| |
| Authors: | Wu Zongxu |
| |
| Institution: | (1) Institute of Geology, State Seismological bureau, China |
| |
| Abstract: | The formation of ore-bearing granites in the Yenshanian movement in southeast China and the geochemical characteristics of
some RE-bearing granites have been studied through multivariate statistical analysis and physicochemical approach. The main
conclusions have Been drawn as follows: (1) The granites are believed to be products of anatexis of the crustal materials.
The formation temperature of granitic magma is estimated at about 600°C and the crystallization temperatures range from 600°
to 500°C. The temperature of Li-, Fand H2O-rich residual magma in the latest stage of magmatism is probably below 500°C. (2) A rock series from early lepidomelane-granite
through protolithionite-and zinnwalditegranite to lithioniteor lepidolite-granite is considered as a result of actual crystallization.
(3) The mineral paragenesis and fades zonation of granite plutons are mainly controlled by Ph2o, μNa2O and μK2O in the magma. (4) During the magmatic evolution the ore-forming elements (REE, Nb, Ta, etc.) are variable in geochemistry.
REEs, similar to mafic components, were highly concentrated at the early stage of the magmatic evolution and deposited under
favourable conditions in the zinnwaldite-and protolithionite-granites; Nb and Ta have a preference for felsic and volatile
components, thus are mainly concentrated at later stages of the magmatic evolution. Nb ore deposits are formed in the lithionite
and lepidolite granites, for Ta is intimately associated with Na2O, Li2O, F and H2O. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
