Open AccessEvidence of a recent magma dike intrusion at the slow spreading Lucky Strike segment, Mid‐Atlantic Ridge
Author(s) -
Dziak Robert P.,
Smith Deborah K.,
Bohnenstiehl DelWayne R.,
Fox Christopher G.,
Desbruyeres Daniel,
Matsumoto Haru,
Tolstoy Maya,
Fornari Daniel J.
Publication year - 2004
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2004jb003141
Subject(s) - geology , dike , seafloor spreading , seismology , magma , earthquake swarm , volcano , ridge , volcanism , crust , intrusion , mid ocean ridge , mid atlantic ridge , oceanic crust , hydrothermal circulation , geophysics , geochemistry , tectonics , paleontology , basalt , induced seismicity , subduction
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, seismological, and biological evidence of a magmatic dike intrusion at the Lucky Strike segment, the first detected from the deeper sections (>1500 m) of the MAR. The dike caused the largest teleseismic earthquake swarm recorded at Lucky Strike in >20 years of seismic monitoring, and one of the largest ever recorded on the northern MAR. Hydrophone records indicate that the rate of earthquake activity decays in a nontectonic manner and that the onset of the swarm was accompanied by 30 min of broadband (>3 Hz) intrusion tremor, suggesting a volcanic origin. Two submersible investigations of high‐temperature vents located at the summit of Lucky Strike Seamount 3 months and 1 year after the swarm showed a significant increase in microbial activity and diffuse venting. This magmatic episode may represent one form of volcanism along the MAR, where highly focused pockets of magma are intruded sporadically into the shallow ocean crust beneath long‐lived, discrete volcanic structures recharging preexisting seafloor hydrothermal vents and ecosystems.