Failure of plume theory to explain midplate volcanism in the southern Austral islands

Article Abstract:

Radiometric dating indicates that the volcanoes making up the southernmost part of the Austral volcanic line are made up of three separate volcanic chains. Their age progressions are not consistent. It appears that stress in the lithosphere is the controlling factor for the volume and location of volcanism in this region, rather than the location of narrow plumes linked with deep Earth. It is possible that there is a plume underneath the Macdonald seamount, but this would account for only a very small part of the very high volume of off-ridge volcanism.

Volcanoes, Seamounts

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Two-way exchange between the Easter mantle plume and the Easter microplate spreading axis

Article Abstract:

There is a bidirectional movement of material between the spreading axis and the volcanic plume in the Easter seamount chain. This is consistent with geophysical and fluid-dynamical models of the flow of the mantle material. The isotopic composition of the lavas in the East Rift near the Easter Island is identical to those of the volcanic-field lavas. Geological, geochemical, and geochronological data indicate that the plume volcanism is near the Easter Island.

Easter Island

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Diachronous uplift of the Tibetan plateau starting 40 Myr ago

Article Abstract:

The Tibetan plateau covers an area of over one million sq km, all of which lies above 5,000 mt high. It has been widely assumed that the plateau's uplift occurred concurrently, but new findings suggest potassium-rich volcanism some 35 million years ago in the northeastern part of the Tibetan plateau, which may have risen about 15 million years before the southern area.

Tibet

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