Interdisciplinary Studies of the 8° 20'N Seamount Chain, EPR

Posted on 08.25.2015
Map of the East Pacific Rise between the Clipperton and Siqueiros Transform Faults showing the location of the 8 20’ Seamounts. We will be conducting a field experiment here in the winter of 2016 to better understand crustal accretion at mid-ocean ridges.

Understanding how melts are generated and focused across hundreds of kilometers through the upper mantle to the narrow mid-ocean ridge (MOR) axis is fundamental to understanding how most of Earth’s lithosphere is formed. Significant advancements have been made in the use of geodynamic models to investigate mantle melting and melt transport in 3D. However, the lack of comprehensive off-axis geophysical and correlative geochemical data presents a critical information gap that needs to be filled before progress can be made in refining these models. Our collaborative project proposes to fill these data gaps through a multidisciplinary field program to survey and sample the 8 20’N Seamount Chain which extends 200 km westward from the East Pacific Rise (EPR) / Siqueiros ridge-transform intersection (RTI). Seamounts provide a unique opportunity to test hypotheses of off-axis melt distribution and source variation, as melts delivered through the crust to build these seamounts provide geochemical ‘probes’ into the upper mantle. The ~200 km long continuous 8 20’N Seamount Chain will provide an ideal location for a systematic, spatial analysis of off-axis melting.

This project utilizes a comprehensive geophysical and geochemical field and modeling study of off-axis volcanic construction to directly test hypotheses for 3D melt generation and transport. Petrologic and geochemical analyses of dredged samples will be used in conjunction with morphological and geophysical data analyses to develop new, integrated models for upper lithosphere structure, deformation, and melt distribution at a fast-spreading center. The goal of this work is to investigate specific hypotheses for the dynamics of off-axis melting. Our strategy is to utilize an interdisciplinary approach where spatially and temporally related geophysical and geochemical data analyses inform each other and are linked by geodynamic modeling.

This work is funded by NSF OCE and includes a field expedition to the 8 20’N Seamount Chain off of the East Pacific rise. The field mission will involve a full geophysical survey (magnetics, gravity, and bathymetry), 15 AUV Alvin dives, 20+ dredges, and 5-10 Camera Tows. Projected expedition date is Winter 2016.

We are looking for graduate students to participate in this project both on land and at sea! Please click on the link for prospective students for more information about graduate studies at UIUC.

COLLABORATORS: Dan Fornari (WHOI), Mike Perfit (U Florida)

FUNDING: This work is funded by the National Science Foundation