Compatibility of rhenium in garnet during mantle melting and magma genesis
Measurements of the partitioning of rhenium (Re) between garnet and silicate liquid from 1.5 to 2.0 gigapascals and 1250 degrees to 1350 degreesC show that Re is compatible in garnet. Oceanic island basalts (OIBs) have lower Re contents than mid-ocean ridge basalt, because garnet-bearing residues of deeper OIB melting will retain Re. Deep-mantle garnetite or eclogite may harbor the missing Re identified in crust-mantle mass balance calculations. Oceanic crust recycled into the upper mantle at subduction zones will retain high Re/Os (osmium) ratios and become enriched in radiogenic 187Os. Recycled eclogite in a mantle source should be easily traced using Re abundances and Os isotopes.
Righter
K
K. Righter, Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA. E. H. Hauri, Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USA.
Hauri
EH