Ultramafic and mafic rocks from the Garret Transform Fault near 13°30'S on the East Pacific Rise: igneous petrology

Details Ultramafic and mafic rocks from the Garret Transform Fault near 13°30'S on the East Pacific Rise: igneous petrology Ultramafic and mafic rocks from the Garret Transform Fault near 13°30'S on the East Pacific Rise: igneous petrology

Oct 1983

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1983e%26psl..65..107h&link_type=abstract

Earth and Planetary Science Letters, Volume 65, Issue 1, p. 107-125.

Mathematics

Logic

44

Scientific paper

Serpentinized peridotites, metagabbros and fresh basaltic rocks were dredged from the Garret Transform Fault near 13°S on the East Pacific Rise. Two dredge hauls taken on the northern wall (from about 3100-3600 m) consisted of aphyric and picritic basalts; while peridotites, gabbros and moderately phyric basalts were recovered in a single dredge located near the deepest part (4616-4820 m) of the transform valley. Well preserved igneous textures and mineralogical assemblages enable us to differentiate between tectonites (including harzburgites and clinopyroxene-bearing harzburgites) and cumulates (consisting of plagioclase-dunite, troctolites, olivine-gabbros and ilmenite-gabbros). The harzburgites are likely to represent deep-seated peridotites left after extraction of basaltic melt during upper mantle partial melting of a lherzolite. The ultramafic cumulates underwent some deformation and show textural and mineralogical evidences which suggest formation at a minimum depth corresponding to the very lower crust. It is also inferred that the composition of the coexisting liquid along with early cumulus crystals has a ratio Mg/(Mg + Fe2+) of 0.7, high CaO/Na2O ratios and a low Ni content (about 150 ppm) when compared to similar rock types from Atlantic fracture zones. Subsequent uplift during rifting of the oceanic lithosphere enhanced plastic deformation, subsolidus recrystallization and retrogressive metamorphism of the gabbros and the ultramafics.

Affiliated with

Also associated with

No associations

Rating

Ultramafic and mafic rocks from the Garret Transform Fault near 13°30'S on the East Pacific Rise: igneous petrology does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Ultramafic and mafic rocks from the Garret Transform Fault near 13°30'S on the East Pacific Rise: igneous petrology, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ultramafic and mafic rocks from the Garret Transform Fault near 13°30'S on the East Pacific Rise: igneous petrology will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1192988