Enriched Pt-Re-Os isotope systematics in plume lavas explained by metasomatic sulfides

被引：112

作者：

Luguet, Ambre ^{[1
]}

Pearson, D. Graham ^{[1
]}

Nowell, Geoff M. ^{[1
]}

Dreher, Scott T. ^{[1
]}

Coggon, Judith A. ^{[1
]}

Spetsius, Zdislav V. ^{[2
]}

Parman, Stephen W. ^{[1
]}

机构：

[1] Univ Durham, Dept Earth Sci, No Ctr Isotop & Elemental Tracing, Durham DH1 3LE, England

[2] ALROSA Joint Stock Co, Yakutian Res & Design Inst Diamond Min Ind, Mirny 678170, Yakutia, Russia

来源：

SCIENCE | 2008年 / 319卷 / 5862期

关键词：

D O I：

10.1126/science.1149868

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

To explain the elevated osmium isotope ( (Os-187Os)-Os-186) signatures in oceanic basalts, the possibility of material flux from the metallic core into the crust has been invoked. This hypothesis conflicts with theoretical constraints on Earth's thermal and dynamic history. To test the veracity and uniqueness of elevated Os-186-Os-187 in tracing core- mantle exchange, we present highly siderophile element analyses of pyroxenites, eclogites plus their sulfides, and new Os-186/Os-188 measurements on pyroxenites and platinum- rich alloys. Modeling shows that involvement in the mantle source of either bulk pyroxenite or, more likely, metasomatic sulfides derived from either pyroxenite or peridotite melts can explain the Os-186-Os-187 signatures of oceanic basalts. This removes the requirement for core- mantle exchange and provides an effective mechanism for generating Os isotope diversity in basalt source regions.

引用

页码：453 / 456

页数：4

共 29 条

[1] In situ Os isotopes in abyssal peridotites bridge the isotopic gap between MORBs and their source mantle [J].