UNDERSHOOTING the East Pacific Rise

The UNDERSHOOT experiment was designed to image the pattern of magma delivery from the mantle to the crust beneath the East Pacific Rise near 9ºN.

Nature Podcast

Our research was featured in the March 22, 2007 Nature Podcast


Toomey, D.R. and E. E. E. Hooft, Mantle upwelling, magmatic differentiation, and the meaning of axial depth at fast-spreading ridges, Geology, 36, doi:10.1130/G24834A.1, 679-682, 2008.

Toomey, D. R., D. Jousselin, R. A. Dunn, W. S. D. Wilcock and R. S. Detrick, Skew of mantle upwelling beneath the East Pacific Rise Governs Segmentation, Nature, 444, doi:10.1038/nature05679, 409-414, 2007.

Canales, J. P., R. S. Detrick, D. R. Toomey and W. S. D. Wilcock, Segment-scale variations in crustal structure of 150- to 300-k.y.-old fast spreading oceanic crust (East Pacific, 8°15'N-10°15°N) from wide-angle seismic refraction profiles, Geophys. J. Int., 152, 766–794, 2003.

Jousselin, D., R. A. Dunn and D. R. Toomey, Modeling the seismic signature of structural data from the Oman Ophiolite: Can a mantle diapir be detected beneath the East Pacific Rise?, Geochem. Geophys. Geosyst., 4(7), 8610, doi:10.1029/2002GC000418, 2003.

Tian, T., W. S. D. Wilcock, D. R. Toomey and R. S. Detrick, Seismic heterogeneity in the upper crust near the 1991 eruption site on the East Pacific Rise, 9° 50'N, Geophys. Res. Lett.,27, 2369-2373, 2000.


(Click on image for larger view)

Perspective view of East Pacific Rise and the seismic velocity structure of the underlying mantle. Surprisingly, regions of magma storage in the mantle (shown as orange and red colors) are in many places not centered beneath the plate plate boundary [Toomey et al., 2007]

(Click on image for larger view)

Vestimentiferan tubeworms Riftia pachyptila occur near deep sea hydrothermal vents found along the East Pacific Rise. Sites of intense hydrothermal activity, and their related ecosystems, rely upon upwelling magma from Earth's mantle for their energy. (Credit: Dr. James Childress, UCSB)

(Click on image for larger view)

The northern East Pacific Rise near 9ÂșN is an Integrated Study Site of the NSF-funded RIDGE 2000 program. The East Pacific Rise is a fast-spreading ridge characterized by rapid creation of oceanic crust and intense seafloor volcanic and hydrothermal activity.(Credit: Dr. Donna Blackman, UCSD/SIO).


(Click to see the movie; high resolution)

(Click to see movie; low resolution)

Fly in to the Northern East Pacific Rise near 9ºN. Topographic data from GeoMapApp. (13.4 MB; high res). Requires Quick Time 7.0 to view.


Toomey's Site

DEPARTMENT OF Geological Sciences, University of Oregon

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