Evidence for plagioclase-lherzolite intrusion in the Mid-Atlantic Ridge, DSDP Leg 37

Author(s): Girardeau, Jacques; Mercier, Jean-Claude C.
Author Affiliation(s): Primary:
Institut de Physique du Globe, Laboratoire de Petrologie Physique, Paris, France
Other:
University of Bristol, United Kingdom
Volume Title: Ophiolites and their modern oceanic analogues
Volume Author(s): Parson, L. M., editor; Murton, B. J.; Browning, P.
Source: Ophiolites and their modern oceanic analogues, edited by L. M. Parson, B. J. Murton and P. Browning. Geological Society Special Publications, Vol.60, p.241-250. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0305-8719
Note: In English. 57 refs.; illus., incl. sketch map
Summary: Plagioclase lherzolites, interpreted as cumulate rocks, were drilled at site 334 at approx 36 degrees 50'N. They display poikilitic textures with oikocrysts of clinopyroxene and interstitial plagioclase that include strained and partly annealed olivine and subidiomorphic spinel; the olivines display weak lattice fabrics which may have resulted from high-T plastic flow. Mineral compositions resemble those of ophiolitic and oceanic rocks interpreted as residues from partial melting, except for clinopyroxenes which have a slight Ti enrichment. It is considered that these plagioclase lherzolites represent residual harzburgites which have been pervasively impregnated by a melt from which plagioclase and clinopyroxene crystallized. These peridotites may have been locally sufficiently lubricated by interstitial melt that they behaved as a crystal mush that had intruded the high- level crustal gabbros of the MAR.
Year of Publication: 1992
Research Program: DSDP Deep Sea Drilling Project
Key Words: 05 Petrology, Igneous and Metamorphic; Atlantic Ocean; Cumulates; DSDP Site 334; Deep Sea Drilling Project; Feldspar group; Framework silicates; Harzburgite; Igneous rocks; Intrusions; Leg 37; Lherzolite; Mid-Atlantic Ridge; Ocean floors; Peridotites; Plagioclase; Plutonic rocks; Silicates; Ultramafics
Coordinates: N370208 N370208 W0342452 W0342452
Record ID: 1997025040
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom