1965/01/01 by G. D. Nicholls · 1 citation
Earth and Planetary Sciences · #Geological and Geochemical Analysis #High-pressure geophysics and materials #earthquake and tectonic studies #Basalt #Amphibole #Geology #Mantle (geology) #Geochemistry #Olivine #Partial melting #Seabed #Mineralogy #Oceanography #Paleontology #Quartz
paper · doi:10.1180/minmag.1965.034.268.32
openalex publication_date 1965/01/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/05/21
Summary Basalts dredged from the floor of the deep ocean show general tholeiitic affinities. Some samples are rich in aluminium and of very similar composition to the Warner high-alumina basalt from California. Both olivine tholeiite and high-alumina basalt have been found in the form of glass in dredgings from the Mid-Atlantic Ridge, indicating that liquid magmas of both compositions have been erupted on to the sea bed in this area. In explanation of this association a tentative hypothesis of fractional melting of hydrated upper mantle material is proposed. It is suggested that under the mid-ocean ridges the ‘basaltic fraction’ of the mantle is locally in the form of an amphibole. Fractional incongruent melting of this amphibole appears to be a possible explanation of the range of composition encountered in dredged glass samples.