Upper-mantle seismic reflections beneath the East Pacific Rise
Barth, G.A.; Mutter, J.C.; Madsen, J.A. (1991). Upper-mantle seismic reflections beneath the East Pacific Rise. Geology (Boulder Colo.) 19(10): 994-996
In: Geology. Geological Society of America: Boulder. ISSN 0091-7613; e-ISSN 1943-2682, more
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| Keywords |
ISE, East Pacific Rise
Measurement > Depth measurement > Bathymetry
Records > Analog records > Seismic profiles > Seismic reflection profiles
Seafloor spreading
Seismic discontinuities > Moho
Topographic features > Submarine features > Ridges > Submarine ridges > Mid-ocean ridges
East Pacific Rise [Marine Regions]
Marine/Coastal |
| Authors | | Top |
- Barth, G.A.
- Mutter, J.C.
- Madsen, J.A.
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| Abstract |
Multichannel seismic reflection profiles from the East Pacific Rise show distinctive patterns of reflecting events immediately below the reflection Moho in the axial region. These events begin at the reflection Moho horizon between 2 and 12 km from the ridge axis. They dip inward, in two-way traveltime, by 0.2 to 0.4 s over horizontal distances of similar to 1 to 3 km; depth conversion indicates that their dip is between 30 degree and 45 degree . The events terminate or fade away down dip and are not observed beneath the ridge crest itself. They are observed individually or in pairs about the ridge axis and have only been identified in the axial region. We favor the hypothesis that the sub-Moho events are directly related to the accumulation of melt in the upper mantle. If this interpretation is correct, the distribution of events implies that melt arriving at the base of the crust is not always centered with respect to the ridge axis or any imaged crustal features. |
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