摘要
雀莫错基性-超基性岩带为单辉橄榄岩-橄榄辉长岩-辉长岩-辉绿岩组合,橄榄辉长岩单颗粒锆石年龄为31～44Ma,属喜马拉雅期。岩石化学研究表明,镁铁质-超镁铁质岩具有SiO2,K2O,Na2O,TiO2,P2O5含量低的特征,且Na2O>K2O,而贫大离子亲石元素Sr和Ba,以及高场强元素Zr,Nb和不相容元素Rb,具大洋拉斑玄武岩特征。其形成是地幔物质上涌,产生具有大洋性质的拉斑玄武质系列岩浆,并沿贡日-温泉兵站大断裂侵位。
The Quemocuo maficultramafic rock zone is composed of wehrlite,olivine gabbro,gabbro and diabase,among which the olivine gabbro has a single zircon UPb age of 31～44 Ma.Petrochemical study shows that the maficultramafic rocks are low in SiO2,K2O,Na2O,TiO2 and P2O5 with Na2O >K2O,poor in largeions lithophile elements(such as Sr,Ba),Zr,Nb and Rb,showing the features of ocenic tholeiite.So the rock zone might be crystallized from tholeiitic magma which might be derived from upwelling of mantle materials and emplaced along the GongriWenquanbingzhan deepseated fault.
出处
《华南地质与矿产》
CAS
2003年第3期12-17,共6页
Geology and Mineral Resources of South China
基金
中国地质调查局1:25万赤布张错幅项目(200013000135).
关键词
长江源
雀莫错
基性-超基性岩带
特征
构造意义
mafic-ultramafic rock zone
tectonic significance
Quemocuo
source area of the Yangtze River
