地质通报2017，Vol.36Issue(2)：445-458,14.
贵州白层超基性岩对右江盆地燕山晚期拉张环境深源岩浆演化作用的启示 ——来自地球化学的证据
Deep magma evolution in the extensional Youjiang Basin in late Yanshanian pe-riod:Evidence from geochemical characteristics of Baiceng ultramafic rock, Guizhou Province
摘要
Abstract
The ultramafic rocks in Baiceng area are located on the southwest margin of Yangtze block. There exist multi-stage mag-matic activities and quite a few ultramafic rocks in this area. Lots of research work on ultramafic rocks has been done in this area, but some important questions remain unsolved. In this paper, the authors analyzed major elements, minor elements (including REE) and PGE for 11 samples of ultramafic rocks from Baiceng area. The results show that their major elements vary in a narrow range, imply-ing the characteristics of high potassium and low sodium. These rocks are also enriched in LILE (Ba, Sr, Rb), HFSE (Nb) and rare earth elements. The enrichment of LREE forms a right inclined curve, which indicates definite fractionation of REE. The anomalies of Eu and Ce are negative. The total content of platinum group element is low, and the differentiation is not significant. Geochemical characteristics of these ultramafic rocks indicate that the rocks were formed under a tectonic setting of large-scale lithospheric exten-sion in Youjiang Basin. The magma was derived from the mantle with a low degree of partial melting, with garnet and sulfide being left over during the melting. Obvious crustal contamination never happened during the process of magma rising. The crystallization and differentiation level of magma was not high. The fractionation of clinopyroxene and olivine occurred during magma intruding while there was no fractionation of plagioclase.关键词
扬子地台/超基性岩/地球化学/伸展减薄/地壳混染/结晶分异Key words
Yangtze block/ultramafic rocks/geochemistry/extension and thinning/crustal contamination/crystallization and differen-tiation分类
天文与地球科学引用本文复制引用
吴松洋,侯林,丁俊,张锦让,朱斯豹..贵州白层超基性岩对右江盆地燕山晚期拉张环境深源岩浆演化作用的启示 ——来自地球化学的证据[J].地质通报,2017,36(2):445-458,14.基金项目
中国地质调查局项目《贵州贞丰金-铀多金属成矿区控矿因素与找矿方法研究》(编号:12120113094400) （编号:12120113094400）
