Petrological Characteristics and Genesis of the Central Indian Ocean Basin Basalts

作     者：Pranab DAS Sridhar D.IYER Sugata HAZRA Pranab DAS;Sridhar D.IYER;Sugata HAZRA

作者机构：National Institute of Oceanography(Council of Scientific and Industrial Research)Dona PaulaGoa 403004India Department of Applied GeologyIndian School of MinesDhanbad 826004India School of Oceanographic StudiesJadavpur UniversityKolkata 700032India 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：2012年第86卷第5期

页      面：1154-1170页

核心收录：

学科分类：0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 070601[理学-气象学] 0706[理学-大气科学] 

基　　金：the project "Surveys for Polymetallic Nodules" project funded by Ministry of Earth Sciences, (previously Department of Ocean Development), New Delhi PD acknowledges the Councilof Scientific and Industrial Research, New Delhi, for financial assistance in the form of a Research Fellowship 

主　　题：basalts Genesis Central Indian Ocean Basin 

摘      要：The Central Indian Ocean Basin （CIOB） basalts are plagioclase-rich, while olivine and pyroxene are very few. The analyses of 41 samples reveal high FeOT （～10-18 wt%） and TiO 2 （～1.4-2.7 wt%） indicating a ferrobasaltic composition. The basalts have high incompatible elements （Zr 63-228 ppm; Nb ～1-5 ppm; Ba ～15-78 ppm; La ～3-16 ppm）, a similar U/Pb （0.02-0.4） ratio as the normal midoceanic basalt （0.16±0.07） but the Ba/Nb （12.5-53） ratio is much larger than that of the normal midoceanic ridge basalt （～5.7） and Primitive Mantle （9.56）. Interestingly almost all of the basalts have a significant negative Eu anomaly （Eu/Eu＊=0.78-1.00） that may have been a result of the removal of feldspar and pyroxene during crystal fractionation. These compositional variations suggest that the basalts were derived through fractional crystallization together with low partial melting of a shallow seated magma.