Abstract
A suite of garnet‐bearing xenoliths that is dominantly composed of olivine, clinopyroxene, and garnet, from Oahu, Hawaii is discussed. All the minerals are in Mg# equilibrium with each other. High Fe/Mg of constituent minerals, high TiO2, Al2O3, Na2O of cpx, and low Cr‐garnet preclude these xenoliths from being residues of partial melting. Combined petrography, mineral chemistry, and high‐pressure liquidus phase equilibria indicate that these xenoliths are high pressure cumulates and originated as products of magma fractionation at a depth of >100 km, corresponding to the uppermost part of the asthenosphere. These depth constraints are about 15 km more than the seismically detected lithosphere‐asthenosphere boundary. It is proposed here that the top of the asthenosphere beneath Oahu, Hawaii is a network of magma chambers where considerable amount of magma ponding and subsequent fractionation takes place.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
