海洋科学2016，Vol.40Issue(8)：108-118,11.DOI:10.11759/hykx20150514002
西北印度洋中脊玄武岩源区地幔特征
Mantle source features of basalts in the Northwest Indian Ridge
摘要
Abstract
The geochemical features and variation in major elements, trace elements, and isotopic compositions of CR, NCIR, and SCIR MORBs, collected from the PetDB database, are examined to investigate mantle source het-erogeneity and the variation in magmatic processes along a ridge axis. The trace element and isotopic composition of the basalts are nearly identical to that of N-MORB, except for an anomaly in some segments, and are different from typical Indian Ridge basalts. The basaltic magma is a product of spinel lherzolite mantle melting, and the mantle source comprises two mantle domain components, namely DMM and EMⅡ, which contribute 69% and 27%, respectively. The enrichment of the EMⅡ-type component may be a result of ancient crustal contamination. The iso-topic composition of Sr, Nd, and Pb is heterogeneous, reflecting that the composition of mantle source is similar for the basalts from the CR, NCIR, and SCIR. The basalts show that there is heterogeneity in the mantle source near the SCIR 19°S segment .In addition, it shows that the significant feature of the EMⅡ-type component mixed. There is enrichment of K, Ba, La, and U in the basalts near the CR 3.5°N segment; however, the features of the mantle source need to be further studied because of the lack of isotopic composition data. Based on these research results, we define large-scale mapping, intensive survey sampling, and laboratory analysis as a basis for further research the CR. An ex-tensive isotopic analysis of Sr, Nd, Pb and Re, Os, and Be could provide evidence on the mantle heterogeneity of the CR. Furthermore, clarification on the degree of influence of Indian Ocean Mantle on the CR could contribute to a bet-ter understanding of the causes of mantle heterogeneity and its dynamic processes.关键词
西北印度洋中脊/玄武岩/沿脊轴变化/地幔不均一性Key words
the Northwest Indian Ridge/basalt/variation along ridge axis/mantle heterogeneity分类
海洋科学引用本文复制引用
淳明浩,于增慧,李怀明,翟世奎..西北印度洋中脊玄武岩源区地幔特征[J].海洋科学,2016,40(8):108-118,11.基金项目
国家重点基础研究发展计划项目(2013CB429702) （2013CB429702）
中国大洋矿产资源研究开发协会“十二五”重大项目(DY125-11-R-01, DY125-12-R-03)@@@@National Key Basic Research and Development Program, No.2013CB429702 （DY125-11-R-01, DY125-12-R-03）
The 12th Five-Year Plan major projects of China Ocean Mineral Resources Research and Development Association, No. DY125-11-R-01, No. DY125-12-R-03。 （）
