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.
Fornari, Daniel J.
MetadataShow full item record
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 imagery and visual observations. Volcano emplacement is rapid (<1 Myr), associated with focused eruptions, and with effusion rates feeding lava flows that bury tectonic features developed prior to and during volcano construction. This volcanic phase likely requires efficient melt pooling and a long-lived crustal magma chamber as a melt source. A reduction in melt supply triggers formation of an axial graben rifting the central volcano, and the onset of seafloor spreading may eventually split it. At Lucky Strike, this results in two modes of crustal construction. Eruptions and tectonic activity focus at a narrow graben that bisects the central volcano and contains the youngest lava flows, accumulating a thick layer of extrusives. Away from the volcano summit, deformation and volcanic emplacement is distributed throughout the rift valley floor, lacking a clear locus of accretion and deformation. Volcanic emplacement on the rift floor is characterized by axial volcanic ridges fed by dikes that propagate from the central axial magma chamber. The mode of rapid volcano construction and subsequent rifting observed at the Lucky Strike seamount is common at other central volcanoes along the global mid-ocean ridge system.
Author Posting. © American Geophysical Union, 2014. 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 15 (2014): 4157–4179, doi:10.1002/2014GC005477.
Showing items related by title, author, creator and subject.
Advanced geophysical studies of accretion of oceanic lithosphere in Mid-Ocean Ridges characterized by contrasting tectono-magmatic settings Xu, Min (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2012-02)The structure of the oceanic lithosphere results from magmatic and extensional processes taking place at mid-ocean ridges (MORs). The temporal and spatial scales of the variability of these two processes control the ...
Behn, Mark D.; Ito, Garrett T. (American Geophysical Union, 2008-08-02)We use 2-D numerical models to explore the thermal and mechanical effects of magma intrusion on fault initiation and growth at slow and intermediate spreading ridges. Magma intrusion is simulated by widening a vertical ...
Ito, Garrett T.; Behn, Mark D. (American Geophysical Union, 2008-09-30)We investigate the origin of mid-ocean ridge morphology with numerical models that successfully predict axial topographic highs, axial valleys, and the transition between the two. The models are time-dependent, simulating ...