Magmatic plumbing at Lucky Strike volcano based on olivine-hosted melt inclusion compositions
Wanless, V. Dorsey
Shaw, Alison M.
Behn, Mark D.
Soule, Samuel A.
Escartin, Javier E.
MetadataShow full item record
Here we present volatile, major, and trace element concentrations of 64 olivine-hosted melt inclusions from the Lucky Strike segment on the mid-Atlantic ridge. Lucky Strike is one of two locations where a crustal melt lens has been seismically imaged on a slow-spreading ridge. Vapor-saturation pressures, calculated from CO2 and H2O contents of Lucky Strike melt inclusions, range from approximately 300–3000 bars, corresponding to depths of 0.5–9.9 km below the seafloor. Approximately 50% of the melt inclusions record crystallization depths of 3–4 km, corresponding to the seismically imaged melt lens depth, while an additional ∼35% crystallize at depths > 4 km. This indicates that while crystallization is focused within the melt lens, significant crystallization also occurs in the lower crust and/or upper mantle. The melt inclusions span a range of major and trace element concentrations from normal to enriched basalts. Trace element ratios at all depths are heterogeneous, suggesting that melts are not efficiently homogenized in the mantle or crust, despite the presence of a melt lens. This is consistent with the transient nature of magma chambers proposed for slower-spreading ridges. To investigate the petrogenesis of the melt inclusion compositions, we compare the measured trace element compositions to theoretical melting calculations that consider variations in the melting geometry and heterogeneities in the mantle source. The full range of compositions can be produced by slight variations in the proportion of an Azores plume and depleted upper mantle components and changes in the total extent of melting.
Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 16 (2015): 126–147, doi:10.1002/2014GC005517.
Showing items related by title, author, creator and subject.
Lucky Strike seamount : implications for the emplacement and rifting of segment-centered volcanoes at slow spreading mid-ocean ridges Escartin, Javier E.; Soule, Samuel A.; Cannat, Mathilde; Fornari, Daniel J.; Dusunur, D.; Garcia, Rafael (John Wiley & Sons, 2014-11-07)The history of emplacement, tectonic evolution, and dismemberment of a central volcano within the rift valley of the slow spreading Mid-Atlantic Ridge at the Lucky Strike Segment is deduced using near-bottom sidescan sonar ...
Evidence of a recent magma dike intrusion at the slow spreading Lucky Strike segment, Mid-Atlantic Ridge Dziak, Robert P.; Smith, Deborah K.; Bohnenstiehl, DelWayne R.; Fox, Christopher G.; Desbruyeres, Daniel; Matsumoto, Haru; Tolstoy, Maya; Fornari, Daniel J. (American Geophysical Union, 2004-12-04)Mid-ocean ridge volcanic activity is the fundamental process for creation of ocean crust, yet the dynamics of magma emplacement along the slow spreading Mid-Atlantic Ridge (MAR) are largely unknown. We present acoustical, ...
Heat flow variations on a slowly accreting ridge : constraints on the hydrothermal and conductive cooling for the Lucky Strike segment (Mid-Atlantic Ridge, 37°N) Lucazeau, Francis; Bonneville, Alain; Escartin, Javier E.; von Herzen, Richard P.; Gouze, Philippe; Carton, Helene; Cannat, Mathilde; Vidal, Valerie; Adam, Claudia (American Geophysical Union, 2006-07-27)We report 157 closely spaced heat flow measurements along the Lucky Strike segment in the Mid-Atlantic Ridge (MAR) for ages of the ocean floor between 0 and 11 Ma. On the eastern flank of a volcanic plateau delimiting ...