Prospecting for hotspot roots
Article Abstract:
Seismologists Helmberger and colleagues and Russel and colleagues claimed to have identified the roots of Iceland and Hawaiian hotspots at the core-mantle boundary, 2,900 km below the Earth's surface. Helmberger and colleagues have shown that the ultra-low velocity zone can be detected below Iceland, which may reflect the hot source of the Iceland mantle plume. Russell and colleagues analyzed ScS and S phases to identify an area of lateral gradients in the lower mantle, suggesting the source region of the Hawaiian hotspot.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1998
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Mineralogy and dynamics of a pyrolite lower mantle
Article Abstract:
The Earth's upper and lower mantles are thought to be broadly similar in composition, consisting of a mixture of minerals called pyrolite. New diamond-anvil cell experiments simulate depths of 1,500 and 2,900 km at the lower mantle and show that pyrolite consists of only three types: magnesiowustite, magnesian-silicate perovskite and calcium-silicate perovskite. It is suggested that the lithology of subducting slabs in the lower mantle will make them buoyant before thermal equilibrium is attained.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1998
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The elusive coldfinger
Article Abstract:
In the Earth sciences, a concept explaining some features of continents, is that they are cooler and less dense than the mantle surrounding them. However Li and colleagues report that the features of the continental coldfinger are absent, following studies in continental North America. They measured seismic waves and monitored changes corresponding to mineralogical transitions in the mantle. The mantle transitions created echoes of the main seismic waves.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1998
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