Mantle hotspot neon in basalts from the Northwest Lau Back-arc Basin

Abstract

The neon isotope compositions of basalts from the Northwest Lau Back-arc Basin reflect three-component mixing between an ocean island basalt (OIB) mantle hotspot component, mid-ocean ridge basalt (MORB) mantle, and atmosphere. Our study confirms that a mantle hotspot signature is present in the neon isotopes of both the Rochambeau Rifts and the Northwest Lau Spreading Center (NWLSC), just as it is in the helium isotopes. Furthermore, the Ne isotope signature in the Rochambeau Rifts lava having the highest 3 He/ 4 He ratio (28 R a) most closely resembles that observed previously in the highest 3 He/ 4 He lavas from Samoa. The coupled He-Ne isotope systematics are further evidence for incursion into this region of material derived from the Samoan mantle plume. Copyright 2012 by the American Geophysical Union.