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Basic decompression theory and use of decompression tables is part of the theory component of training for commercial divers, [130] and dive planning based on decompression tables, and the practice and field management of decompression is a significant part of the work of the diving supervisor.
Haldane's decompression model is a mathematical model for decompression to sea level atmospheric pressure of divers breathing compressed air at ambient pressure that was proposed in 1908 by the Scottish physiologist, John Scott Haldane (2 May 1860 – 14/15 March 1936), [1] who was also famous for intrepid self-experimentation.
Partial melting is the phenomenon that occurs when a rock is subjected to temperatures high enough to cause certain minerals to melt, but not all of them. Partial melting is an important part of the formation of all igneous rocks and some metamorphic rocks (e.g., migmatites), as evidenced by a multitude of geochemical, geophysical and petrological studies.
Decompression melting happens when solid material from deep beneath the body rises upwards. Pressure decreases as the material rises upwards, and so does the melting point. So, a rock that is solid at a given pressure and temperature can become liquid if the pressure, and thus melting point, decreases even if the temperature stays constant.
In decompression theory, the solubility of gases in liquids is of primary importance, as it is the formation of bubbles from these gases that causes decompression sickness. [4] [5] [6] Solubility of gases in liquids is influenced by three main factors: The nature of the solvent liquid and the solute [7]
Further decompression and cooling at a slow rate (Stage 2 retrograde metamorphism) [2] One might expect that the rock reaches its peak metamorphism at the peak temperature and pressure at similar time, and near-isothermal decompression P-T-t path is observed at its stage 1 metamorphism. [2]
[13] [14] The theory predicts mushroom-shaped mantle plumes with heads of about 2000 km diameter that have a critical time (time from onset of heating of the lower mantle to formation of a plume) of about 830 million years for a core mantle heat flux of 20 mW/m 2, while the cycle time (the time between plume formation events) is about 2000 ...
This suggests that decompression melting may contribute, as this, too, is expected to increase with lithospheric thickness. The significant increase in magmatism during the last 2 million years indicates a major increase in melt availability, implying that either a larger reservoir of pre-existing melt or an exceptionally fusible source region ...