anatexis


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anatexis

[‚an·ə′tek·səs]
(geology)
A high-temperature process of metamorphosis by which plutonic rock in the lowest levels of the crust is melted and regenerated as a magma.
References in periodicals archive ?
The production and redistribution of the gas phase was considered as the analogue of magma generation during crustal anatexis, with gas batches formed by the accumulation and transport processes representing the melt-rich domains or leucosomes in migmatites.
These observations suggest a three-stage model for emplacement, namely (i) generation of a composite magma, here assumed to be due to mafic underplating of the crust with subsequent crustal anatexis, (ii) buoyant rise of the composite magma followed by gravitational differentiation to produce the sill-like mass, and (iii) a late influx of mafic magma.
Large scale emplacement of mafic magma eventually caused anatexis of surrounding crustal host rocks, initially producing a gravitationally stable system with light salic magma above dense mafic magma.
As a consequence, [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] may remain close to unity, and anatexis of crustal rocks in arc environments generally proceeds at lower temperatures, and is more voluminous than in continental rifts, and spans longer periods of geologic time, routinely tens of millions of years.
1977, Model systems for anatexis of pelitic rocks I: Theory of melting reactions in the system KA1[O.
Peak temperatures in excess of 800[degrees]C in the lower and middle crust, which led to anatexis and widespread emplacement of granitoid plutons during and immediately following the metamorphic peak, are unlikely to have been achieved by crustal thickening alone.
From sediment to granite: timescales of anatexis in the upper crust.