Intermittent upwelling of asthenosphere beneath the Gregory Rift, Kenya
- Univ. of Tasmania (Australia) Kyoto Univ. (Japan)
- Kyoto Univ. (Japan)
- Okayama Univ. of Science (Japan)
- Kumamoto Univ. (Japan)
- Nagoya Univ. (Japan)
K-Ar dates and chemical compositions of basalts in the Gregory Rift, Kenya, demonstrate marked secular variation of lava chemistry. Two magmatic cycles characterized by incompatible element relative depletion are recognized; both occurring immediately after the peak of basaltic volcanism and coeval with both trachyte/phonolite volcanism and domal uplift of the region. These cycles may be attributed to increasing degree of partial melting of mantle source material in association with thinning of the lithosphere by thermal erosion through contact with hot upwelling asthenospheric mantle. Cyclic variation in asthenosphere upwelling may be considered an important controlling process in the evolution of the Gregory Rift.
- OSTI ID:
- 5558823
- Journal Information:
- Geophysical Research Letters (American Geophysical Union); (United States), Vol. 18:6; ISSN 0094-8276
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
KENYA
RIFT ZONES
MAGMATISM
AGE ESTIMATION
ARGON ISOTOPES
BASALT
CHEMICAL COMPOSITION
EARTH MANTLE
ISOTOPE RATIO
LAVA
POTASSIUM ISOTOPES
SAMPLING
VOLCANISM
AFRICA
ALKALI METAL ISOTOPES
DEVELOPING COUNTRIES
GEOLOGIC STRUCTURES
IGNEOUS ROCKS
ISOTOPES
ROCKS
VOLCANIC ROCKS
580000* - Geosciences