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Variations of Upper Mantle Structure under the Pacific Ocean
Science (New York, N.Y.)
|October 11, 1974
Summary
Lithospheric thickness in the Pacific Ocean increases with seafloor age. The low-velocity channel
Area of Science:
- Geophysics
- Seismology
- Plate Tectonics
Background:
- Understanding oceanic lithosphere evolution is crucial for plate tectonics.
- Rayleigh wave dispersion is a key method for probing lithospheric structure.
- Previous studies have indicated variations in oceanic lithosphere with age.
Purpose of the Study:
- To investigate the relationship between lithospheric thickness and age in the Pacific Ocean.
- To characterize the structure of the low-velocity channel beneath the lithosphere.
- To determine how lithospheric structure changes from ridge crest to older oceanic regions.
Main Methods:
- Inversion of Rayleigh wave dispersion data.
- Analysis of seismic wave propagation across the Pacific Ocean basin.
- Modeling of lithospheric and upper mantle structure.
Main Results:
- A systematic increase in lithospheric thickness with increasing seafloor age was observed.
- The lid overlying the low-velocity channel is thin or absent near the ridge crest.
- The low-velocity channel may be absent in the oldest oceanic lithosphere.
Conclusions:
- Oceanic lithosphere thickens progressively as it ages away from the spreading center.
- The thermal and mechanical evolution of the lithosphere influences the presence and structure of the low-velocity channel.
- These findings provide insights into the long-term cooling and strengthening of oceanic plates.
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