Rare gas systematics on Lucky Strike basalts (37 degrees N, North Atlantic): Evidence for efficient homogenization in a long-lived magma chamber system? | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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  Rare gas systematics on Lucky Strike basalts (37 degrees N, North Atlantic): Evidence for efficient homogenization in a long-lived magma chamber system?

Publication Type:

Journal Article

Source:

{GEOPHYSICAL RESEARCH LETTERS}, Volume {38} (0)

Abstract:

{We present rare gas data in fresh glasses from the Lucky Strike segment located on the Mid Atlantic Ridge (similar to 37.3 degrees N), close to the Azores plateau. We analyzed the helium and neon isotopes in 28 samples by melting as well as He-Ne-Ar-Kr-Xe isotopes in 9 samples by crushing. Samples were collected during the Graviluck06, MOMAR08, and Bathyluck09 cruises over a ridge length of similar to 13 km (mean sample spacing of similar to 500 m), and at depths ranging from 1550 m to 2174 m. The helium isotopic ratio varies between 84,410 and 88,235 (R/Ra between 8.19 and 8.56). The samples having the ``most{''} primitive helium isotopic ratio are the enriched samples (e. g. high K(2)O/TiO(2)) although the difference to the depleted samples is small. It appears that all of our samples derive from the same and well-homogenized magma chamber. Neon isotopes clearly show the influence of the Azores hotspot, which is not seen with helium because of lower (3)He/(22)Ne in the plume source compared to the MORB source. Citation: Moreira, M., J. Escartin, E. Gayer, C. Hamelin, A. Bezos, F. Guillon, and M. Cannat (2011), Rare gas systematics on Lucky Strike basalts (37 degrees N, North Atlantic): Evidence for efficient homogenization in a long-lived magma chamber system?, Geophys. Res. Lett., 38, L08304, doi:10.1029/2011GL046794.}