GEOL 306 Lecture Notes - Lecture 3: The Mantle, Liquidus, Partial Melting
22 Jan 2020
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Vei 8 is big as it gets. Ex: vei 1-hawaii: kilauea; vei 8-supervolcano: yellowstone, toba. Molten core is not rising through the mantle. Liquidus: marking the boundary between that crystal-liquid mush (s + l) and complete liquid (l) = total melting. Solidus: marking the boundary between a complete solid (s) and a partial- solid/partial-liquid. The melting curve is higher temp than the geotherm at all depths through the mantle. Decompression melting- upward movement of the earth"s mantle to an area of lower pressure. The reduction in overlying pressure enables the rock to melt, leading to magma formation. Partial melting: no movement of material, no increase in temperature or pressure. Incorporating new rock types that have water in them. Compressing sediments, driving water out of the. All the water has been squeezed out. Adding another substance lowers the melting temperature. Ex: hawaii oldest volcanoes to the southeast. Age progression later extended by radiometric dating.
