protolith


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protolith

[′prōd·ə‚lith]
(petrology)
The original, unmetamorphosed rock from which a given metamorphic rock is formed.
References in periodicals archive ?
On the other hand, the methods and dated materials (whole rock, mineral) are very diverse and, therefore, may reveal different ages the age of the protolith, the age of emplacement, the age of metamorphism, the age of metamorphic post-peak or the age of collision/accretion.
In paper Study on Highly Weathered Phyllite Filling Subgrade Technical Highway [3], and under the basis of intense weathered phyllite protolith basic physical mechanical test and packing engineering characteristic test, Mao Xuesong, et al conducted improvement on padding whose bearing ratio does not meet the highway roadbed filling mechanical properties.
Depleted-mantle model ages (Tdm) are useful to estimate the crustal residence age for the granite protolith (Andersen et al.
Epidote is an indication of mafic igneous protolith, along with augite and hornblende.
For example, plutonic rocks can remain above their blocking temperature for millions of years and metamorphic rocks can have their radiometric clocks reset by subsequent reheating, which means that the protolith of these rocks can form long before the radiometric clock begins (Berger and York, 1981).
In less deformed specimens, the protolith of in-situ ore can locally be seen to be deformed transported ore, thereby suggesting the possibility that much or all of the known in-situ ore is actually deformed clastic ore.
The graphite is generally believed to have been derived from the protolith of the host rock, a black shale rich in carbonaceous sedimentary organic matter that was deposited in a geosynclinal environment around 1.
One of them, Medellin Amphibolites, is an extensive amphibolitic body that shows no relics of its metavolcanic protolith and is frequently associated with metasediments.
Whole-rock isotopic data from the Riga, Marjamaa, Naissaare, Neeme, and Abja plutons indicate an approximately chondritic source for Nd in the mafic rocks of the Riga batholith and the Abja intrusion, and a Palaeoproterozoic (Svecofennian) protolith for the felsic rocks--the [T.
The differences between the two thermometers are very probably connected with significant quantities of inherited zircon in metasedimentary protolith.
Pell SD, Williams IS, Chivas AR (1997) The use of protolith zircon-age fingerprints in determining the protosource areas for some Australian dune sands.