Abe, Natsue (2011): Rutile included in the podiform chromitite from ocean floor at MAR 15 degrees 20'N FZ, Site 1271, ODP Leg 209

ODP 209
ODP 209 1271

Abe, Natsue
Japan Agency for Marine-Earth Science and Technology, Institute for Research on Earth Evolution, Yokosuka, Japan

Rutile included in the podiform chromitite from ocean floor at MAR 15 degrees 20'N FZ, Site 1271, ODP Leg 209
In: Anonymous, Goldschmidt 2011 abstract volume
Mineralogical Society, London, United Kingdom
Several podiform chromitites includes rutile grains in abyssal peridotite are recovered from Site 1271 at Mid- Atlantic Ridge (MAR) 15 degrees 20' N fracture zone (FZ) during an ocean drilling cruise, ODP Leg 209 [1]. Only chromian spinel is preserved as the primary mantle mineral and all other primary minerals in the chromitite samples are completely altered. The primary chromian spinel has comparable Cr0.5) with it in the chromitite "minipod" sampled from Hess Deep [2]. The samples associated with chromitites from the drilling site consist of mainly dunite, some amphibole-bearing gabbros and troctolite, and rare in harzburgite. Therefore, the chromitites from this site are included in the rock series that composes the Moho transition zone as same in the ophiolites. It implies that a mass of melt existed, but was consumed in the uppermost mantle beneath the area. This means that the area is not magma-starved, although it is unclear when and where did interaction occurred. Some grains of the chromian spinel in the samples have thick rims of Cr-magnetite or completely replaced by magnetites. Cr content increases in the Cr-magnetite rim accompanied with Fe-enrichment. The chemical modification of the chromian spinel suggests that the chromitite from Site 1271 were metamorphosed at high temperature condition up to the upper greenschist facies because significant Al-missing from spinel cores is taken place at high temperature as a result equilibration with fluids in equilibrium with chlorite.
Coverage:Geographic coordinates:
West:-44.5700East: -44.5700

Igneous and metamorphic petrology; Mineralogy of non-silicates; Atlantic Ocean; chrome spinel; chromitite; high temperature; igneous rocks; Leg 209; metamorphic rocks; metamorphism; metaplutonic rocks; Mid-Atlantic Ridge; North Atlantic; Ocean Drilling Program; ODP Site 1271; oxides; plutonic rocks; podiform deposits; rutile; temperature; ultramafics;