Altered rock type is strongly associated with intense silicification, pyritization, chloritization and illitization and its protolith
are commonly volcanic breccia and tuff (Fig.
 suggest that fluid flow in fractured chalk is especially influenced by the protolith
, in particular, the presence of interlayered marl horizons.
High abundances of [Al.sub.2][O.sub.3] ([greater than or equal to] 19 wt%) in an amphibolite-derived liquid are the result of high [H.sub.2]O (water-saturated) and/or high anorthite contents in the mafic protolith
In paper Study on Highly Weathered Phyllite Filling Subgrade Technical Highway , 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., 2002).
The profile material can be divided into regolith, saprock, weathered shale, and fresh shale (protolith
) according to the field investigation.
Based on field, petrographic, and geochemical evidences, the ore fluid may have been derived largely from fracturing, metamorphic dewatering  and crustal devolatilization  of sedimentary and gabbroic protolith
of the host rocks.
Epidote is an indication of mafic igneous protolith
, along with augite and hornblende.
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.