Partial melting

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.[1]

The parameters that influence partial melting include the composition of the source rock, the pressure and temperature of the environment, and the availability of water or other fluids.[2][1] As for the mechanisms that govern partial melting, the main are decompression melting and flux melting. Decompression melting occurs when rocks are brought from higher to lower pressure zones in the Earth's crust, lowering the melting point of its mineral components, thus generating a partial melt. Flux melting, on the other hand, occurs when water and other volatiles get in contact with hot rock, reducing the melting point of minerals, leading to partial melting.[2] With a few exceptions (e.g., Yellowstone[3]), conduction of heat is considered a mechanism too slow and inefficient to partially melt large bodies of rock.[2]

Partial melting is also linked to the formation of ores. Magmatic and hydrothermal ore deposits, such as chromite, Ni-Cu sulfides, rare-metal pegmatites, kimberlites, volcanic-hosted massive sulfide deposits are some examples of valuable natural resources closely related to the conditions of the origin, migration and emplacement of partial melts.[4]

  1. ^ a b Kilinc, Attila (1989-12-01). "Partial melting of crustal rocks". Engineering Geology. 27 (1): 279–299. Bibcode:1989EngGe..27..279K. doi:10.1016/0013-7952(89)90036-7. ISSN 0013-7952.
  2. ^ a b c Asimow, Paul D. (2016), "Partial Melting", in White, William M. (ed.), Encyclopedia of Geochemistry: A Comprehensive Reference Source on the Chemistry of the Earth, Encyclopedia of Earth Sciences Series, Cham: Springer International Publishing, pp. 1–6, doi:10.1007/978-3-319-39193-9_218-1, ISBN 978-3-319-39193-9, retrieved 2023-02-13
  3. ^ Huang, H.-H.; Lin, F.-C.; Schmandt, B.; Farrell, J.; Smith, R. B.; Tsai, V. C. (2015-05-15). "The Yellowstone magmatic system from the mantle plume to the upper crust". Science. 348 (6236): 773–776. Bibcode:2015Sci...348..773H. doi:10.1126/science.aaa5648. ISSN 0036-8075. PMID 25908659. S2CID 3070257.
  4. ^ Ridley, John (2013). Ore Deposit Geology. Cambridge: Cambridge University Press. doi:10.1017/cbo9781139135528. ISBN 978-1-107-02222-5.

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