Variation in young oceanic crust and upper mantle structure
Abstract
Seismic refraction and single-channel reflection data taken along 0.5-, 2.5-, and 4.5-m.y.-age isochrons near the East Pacific Rise during Project ROSE are used to determine if a systematic change in the P velocity-depth function with age can be resolved. Inversion of these data suggests that any change in crustal P velocity structure related to age is smaller than variability in the seismic velocity-depth function along an isochron. The emergence of a `normal' crust-mantle transition by 4.5-m.y.-age is seen in these data. Crust and crust-mantle transition zone heterogeneity along these isochrons may be related to the along strike variability in processes at the ridge crest. The velocity-depth functions for the three split profile refraction lines are compared with velocity-depth functions for the Samail ophiolite, which is thought to represent oceanic crust of similar age. The velocity-depth functions for the ROSE data are bounded by different velocity-depth models for the Samail ophiolite; this suggests that those models are not in disagreement but represent the lateral heterogeneity that can be expected in young oceanic crust.
- Publication:
-
Journal of Geophysical Research
- Pub Date:
- October 1982
- DOI:
- 10.1029/JB087iB10p08435
- Bibcode:
- 1982JGR....87.8435G
- Keywords:
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- Seismology: Structure of the crust and upper mantle;
- Tectonophysics: Convection currents