The mantle's lava lamp
Article Abstract:
It has been possible to reproduce the essential features of superswells and hotspots in laboratory experiments of convection scaled to Earth-like conditions. This research involved observing the modes of convection that developed in viscous fluids stratified in density, heated from below, and cooled from above. It is suggested that Earth could have originally formed in the layered-convection regime, with gradual mixing of the two layers by plume-type upwellings and sheet-type downwellings attenuating the chemical layering to the point that the buoyancy ratio is now under 0.5.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1999
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Th restless heart of a spiral
Article Abstract:
The property of excitability is shared by all two-dimensional rotating spiral waves, the motion of which is called a meander. Disturbances in the mammalian heart, such as fibrillation or flutter, are caused by the same excitation wave continually reinvading the same piece of tissue. Such arrhythmias can be stopped by artificially controlling the meander and propelling the wave tip from the heart. The availability of an accurate, three-dimensional mathematical model of excitations could help control disturbances of the heart.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1997
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Wrestling with restless calderas and fighting floods of lava
Article Abstract:
A symposium on volcanic systems has reinterpreted certain volcanic mechanisms. Eruptive volcanic deposits are a result of incremental accumulations over a long period of time and not due to an instant accumulation from a huge bulk of fast-moving lava or from a single dense mass of ash. Similarly, thick basalt flows arise from thin sheets of lava spread over flat areas that are later expanded through a deposit of slow-moving molten lava beneath the sheets. Large caldera-forming eruptions have a role in shifting climate.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1995
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