Here the concentrations are as high as 70% and felsic rock
units underlie some parts of the Jordan Mountain area.
However, contacts between coarse and fine-grained to aphanitic felsic rocks
are always sharp where exposed, and where intrusive relations can be determined, the coarse-grained phase invariably cuts the fine-grained one.
Higher LREE/HREE ratios and negative Eu anomalies are generally found in felsic rocks
, whereas mafic rocks have lower LREE/ HREE ratios and no or small Eu anomalies (Cullers, 1995).
Additionally and importantly the new drill intervals are close to intrusive felsic rocks
that have potential to increase the graphite flake size in adjacent rocks.
range from dacitic to rhyolitic in composition, and normally contain quartz and plagioclase phenocrysts; felsic rocks
are commonly coarsely fragmental and are characterized by a considerable array of fragment types and sizes within and among units, as well as by variable amounts of juvenile volcanic material in the matrix.
Several igneous rapakivi subprovinces of a similar association of mafic and felsic rocks
from deep infracrustal intrusive to supracrustal volcanic facies have been distinguished (Ahall et al.
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.sub.DM] model ages of the felsic rocks
range from 2.10 to 1.89 Ga (Ramo et al.
Milling increased exchangeable alkali cations of mafic and felsic rocks
for use as fertilisers, with greater increases being due to dry milling than to wet milling (Priyono et al.
Francois Mountains has been reset to the same extent as in the older rocks of the Butler Hill Caldera and to thereby further constrain the extent and timing of the process(es) or event(s) responsible for resetting the K-feldspar structural state in the felsic rocks
of the St.
At higher temperature Ca in hydrothermal solution replaces K-feldspar in felsic rocks
which results into the production of calcium rich plagioclase and quartz.Equation
6), anda gap in Si[O.sub.2] separates those rocks from intermediate to felsic rocks
, which vary from 58 to 78 wt.
Gold mineralisation at the project is associated with quartz veins and carbonate-pyrite alteration along a north-east dipping contact between felsic rocks
to the west, and mafic dominated rocks to the east.