Publications [#221825] of Emily M. Klein

Papers Published

  1. Waters, Christopher L. and Sims, Kenneth W. W. and Klein, Emily M. and White, Scott M. and Reagan, Mark K. and Girard, Guillaume, 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 (May, 2013), pp. 59-70, ISSN 0012-821X [doi]
    (last updated on 2013/12/27)

    Abstract:
    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 U-238-Th-230-Ra-226-Pb-210 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 Pb-210 excesses in axial basalts and basaltic andesites, which we suggest results from gas-magma fractionation of Rn-222 from Ra-226 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 8 ka, and likely as young as 1 ka, despite being located on crust that has a spreading age of similar to 75 ka. 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. (C) 2013 Elsevier B.V. All rights reserved.

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