Gabbro and pyroxenite from a deep-sea core in the Indian Ocean

Abstract

A sediment core was taken from a depth of 5,982 m in the Ob Trench bordering the Broken Ridge in the southeastern Indian Ocean. The core contained fragments of gabbros and pyroxenites embedded in “red clay”. It is concluded that partial melting and differentiation by crystal settling of mafic rocks gave rise to the sequence of interlayered gabbro and pyroxenite exposed on the southern flank of the Broken Ridge. After emplacement, these rocks suffered the effect of dynamic metamorphism as a result of a general faulting of the area.