Petrology and geochemistry of MORB from 25-degrees-E to 46-degrees-E along the Southwest Indian Ridge: Evidence for contrasting styles of mantle enrichment

Citation:
Leroex, AP, Dick HJB, Fisher RL.  1989.  Petrology and geochemistry of MORB from 25-degrees-E to 46-degrees-E along the Southwest Indian Ridge: Evidence for contrasting styles of mantle enrichment. Journal of Petrology. 30:947-986.

Date Published:

Aug

Abstract:

The 1984 PROTEA expedition, leg 5, to the central Southwest Indian Ridge recovered basaltic lavas from fracture zones and ridge segments between 25°E and 48°E. In terms of petrography and major element variations the samples are unremarkable for ocean ridge basalts and range from aphyric to highly plagioclase phyric and from primitive (mg-number = 70) to moderately evolved (mg-number = 40) in composition. Multiply saturated (i.e., olivine, plagioclase, and clinopyroxene) basalts are common within this region. There is no systematic difference in compositional characteristics between basalts dredged from fracture zone walls and those dredged from ridge segments, and fractional crystallization has played an important role in controlling the overall range in lava composition in both tectonic environments.

Notes:

n/a

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DOI:

10.1093/petrology/30.4.947