title: Experimental constraints on the damp peridotite solidus and oceanic mantle potential temperature.
abstract: Decompression of hot mantle rock upwelling beneath oceanic spreading centers causes it to exceed the melting point (solidus), producing magmas that ascend to form basaltic crust ~6 to 7 kilometers thick. The oceanic upper mantle contains ~50 to 200 micrograms per gram of water (H2O) dissolved in nominally anhydrous minerals, which-relative to its low concentration-has a disproportionate effect on the solidus that has not been quantified experimentally. Here, we present results from an experimental determination of the peridotite solidus containing known amounts of dissolved hydrogen. Our data reveal that the H2O-undersaturated peridotite solidus is hotter than previously thought. Reconciling geophysical observations of the melting regime beneath the East Pacific Rise with our experimental results requires that existing estimates for the oceanic upper mantle potential temperature be adjusted upward by about 60°C.
authors.affiliation: Massachusetts Institute of Technology-Woods Hole Oceanographic Institution Joint Program in Oceanography/Applied Ocean Science and Engineering, Cambridge, MA 02139, USA. etursack@whoi.edu.|Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
authors.forename: Emily
authors.identifier: 0000-0001-7780-6932
authors.initials: E
authors.lastname: Sarafian
authors.affiliation: Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
authors.forename: Glenn A
authors.identifier: 0000-0002-6026-2534
authors.initials: GA
authors.lastname: Gaetani
authors.affiliation: Department of Terrestrial Magnetism, Carnegie Institute for Science, 5241 Broad Branch Road, NW, Washington, DC 20015, USA.
authors.forename: Erik H
authors.identifier: 0000-0002-7449-4774
authors.initials: EH
authors.lastname: Hauri
authors.affiliation: Massachusetts Institute of Technology-Woods Hole Oceanographic Institution Joint Program in Oceanography/Applied Ocean Science and Engineering, Cambridge, MA 02139, USA.|Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
authors.forename: Adam R
authors.identifier: 0000-0002-5032-4383
authors.initials: AR
authors.lastname: Sarafian