Journal article
Sill to surface: Linking young off-axis volcanism with subsurface melt at the overlapping spreading center at 9[degrees]03'N East Pacific Rise
Earth and planetary science letters, Vol.369-370, pp.59-70
05/01/2013
DOI: 10.1016/j.epsl.2013.03.006
Abstract
Byline: Christopher L. Waters, Kenneth W.W. Sims, Emily M. Klein, Scott M. White, Mark K. Reagan, Guillaume Girard No young, off-axis, mid-ocean ridge lavas have yet been directly linked to underlying off-axis melt bodies. In this study, we present new measurements of.sup.238U-.sup.230Th-.sup.226Ra-.sup.210Pb isotope compositions for a suite of lavas from the overlapping spreading center (OSC) at 9[degrees]03'N on the East Pacific Rise (EPR). These lavas span a large range of compositions, from basalt to dacite, and include both axial and off-axis samples recovered from a prominent, axis-parallel pillow ridge and a flat-topped seamount that overlie the westernmost extent of a 4-km-wide melt lens (Kent et al., 2000). We report.sup.210Pb excesses in axial basalts and basaltic andesites, which we suggest results from gas-magma fractionation of.sup.222Rn from.sup.226Ra beneath dacite magmas. In addition, our U-series ages agree with visual observations, indicating that while most recent volcanic activity occurs at the spreading axis, active volcanism also occurs away from the axis. Specifically, the off-axis pillow ridge and seamount samples overlying the off-axis subsurface melt body have eruption ages of less than 8ka, and likely as young as 1ka, despite being located on crust that has a spreading age of ~75ka. The young ages of these lavas, combined with existing geological, geochemical and geophysical constraints, provide evidence for a genetic link between the pillow ridge and seamount lavas and the seismically imaged, underlying off-axis melt lens. This link demonstrates that off-axis volcanism does not necessarily come from a sub-axial magma body and can be sourced directly from off-axis magma bodies. Author Affiliation: (a) Department of Geology and Geophysics, University of Wyoming, Laramie, WY 82072, USA (b) Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA (c) Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, NC 27708, USA (d) Department of Earth and Ocean Sciences, University of South Carolina, Columbia, SC 29208, USA (e) Department of Geoscience, University of Iowa, Iowa City, IA 52242, USA Article History: Received 10 April 2012; Revised 26 February 2013; Accepted 5 March 2013 Article Note: (miscellaneous) Editor: T. Elliott
Details
- Title: Subtitle
- Sill to surface: Linking young off-axis volcanism with subsurface melt at the overlapping spreading center at 9[degrees]03'N East Pacific Rise
- Creators
- Christopher L Waters - University of WyomingKenneth W.W Sims - Woods Hole Oceanographic InstitutionEmily M Klein - Duke UniversityScott M White - University of South CarolinaMark K Reagan - University of IowaGuillaume Girard - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Earth and planetary science letters, Vol.369-370, pp.59-70
- Publisher
- Elsevier B.V
- DOI
- 10.1016/j.epsl.2013.03.006
- ISSN
- 0012-821X
- eISSN
- 1385-013X
- Language
- English
- Date published
- 05/01/2013
- Description audience
- Academic
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984229175502771
Metrics
1 Record Views