含CO_(2)硅酸盐熔体-橄榄岩反应的实验研究:对中国东北异剥橄榄岩和单斜辉石岩捕虏体成因的制约  

An experimental study of CO_(2)-bearing silicate melt-peridotite reactions:constraints on the genesis of wehrlite and clinopyroxenite xenoliths from the northeastern China

作　　者：张薇 王春光[1,2] 许文良[1,2] 杨德彬[1,2] 李本仙[1] ZHANG Wei;WANG Chun-guang;XU Wen-liang;YANG De-bin;LI Ben-xian(College of Earth Sciences,Jilin University,Changchun 130061,China;Key Laboratory of Mineral Resources Evaluation in Northeast Asia,Ministry of Natural Re-sources,Changchun 130061,China)

机构地区：[1]吉林大学地球科学学院,长春130061 [2]吉林大学自然资源部东北亚矿产资源评价重点实验室,长春130061

出　　处：《矿物岩石地球化学通报》2025年第1期72-83,I0003,共13页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：科技部国家重点研发计划项目(2023YFF0804102);国家自然科学基金资助项目(42072072)。

摘　　要：东北地区新生代碱性玄武岩中辉石岩和异剥橄榄岩捕虏体的岩石学和矿物化学特征暗示其形成于含CO_(2)熔体-橄榄岩反应,为进一步限定熔体-橄榄岩反应的类型及其经历的深部过程,本文使用反应偶的方法进行了含CO_(2)熔体和橄榄岩相互作用的系列实验。结果显示,在1.5 GPa、1275℃条件下,CO_(2)从硅酸盐熔体中分离,熔体对橄榄岩的改造作用较弱;在2~3 GPa、1325~1375℃条件下,CO_(2)存在于硅酸盐熔体中,反应造成橄榄岩中单斜辉石的显著富集,尤其在3 GPa、1375℃条件下,在熔体-橄榄岩界面形成单斜辉石岩反应带。含CO_(2)硅酸盐熔体-橄榄岩反应形成的单斜辉石具有较低的Mg/(Mg+Fe)值,矿物成分变异趋势与前人碳酸盐熔体-橄榄岩反应的实验结果相反。通过实验结果与东北地区地幔捕虏体的对比研究,认为汪清单斜辉石岩和异剥橄榄岩捕虏体是含CO_(2)硅酸盐熔体-橄榄岩反应的结果,而双辽、蛟河辉石岩和异剥橄榄岩捕虏体是碳酸盐熔体-橄榄岩反应的结果。Characteristics of petrology and mineral chemistry of mantle xenoliths of wehrlite and clinopyroxenite entrained by Cenozoic alkali basalts in the northeastern China imply that they were formed by reactions of CO_(2)-bearing melt and peridotite.In order to further determine the styles and their experienced deep processes of melt-peridotite reactions,in this work,we have carried out a series experiments of CO_(2)-bearing silicate melt and peridotite reactions using the reaction couple method.At 1.5 GPa and 1275℃,CO_(2) was exsolved from the silicate melt,and the peridotite was relative weakly modified by the melt.At 2~3 GPa and 1325–1375℃,CO_(2) was dissolved in the silicate melt,and reactions of melt-peridotite lead to the obvious enrichment of clinopyroxene in the peridotite,especially a clinopyroxenite zone was formed in the melt-peridotite interface at 3 GPa and 1375℃.Clinopyroxenes formed by reactions of the CO_(2)-bearing melt and peridotite are characterized with relatively low Mg/(Mg+Fe)values,which are contrary to the results of carbonate melt-peridotite reactions by previous researchers.Via the comparison between the experimental results and data of mantle xenoliths from the northeastern China,we concluded that the clinopyroxenite and wehrlite xenoliths in the Wangqing area were formed by reactions of the CO_(2)-bearing melt and peridotite, whereas the pyroxeniteand wehrlite xenoliths in the Shuangliao and Jiaohe areas were formed by the carbonate melt-peridotite reactions.

关 键 词：熔体-橄榄岩反应实验 单斜辉石岩 异剥橄榄岩 地幔捕虏体 中国东北地区 

分 类 号：P589.1[天文地球—岩石学] P581[天文地球—地质学]