These metasedimentary rock is a metamorphosed extrusive mafic volcanic of calc alkaline affinity distinct from what has been deduced for amphibolitic
rocks of other parts of the Schist belt of Nigeria.
The most common facies is one of lit-par-lit amphibolitic
gneiss, hosting well developed ptygmatic folds, accompanied by amphibolitic
The composition of rocks and their metamorphic grade change rapidly from granulitic or high-grade amphibolitic
in the PPZ to mainly medium-grade amphibolitic
metasediments and intermediate to felsic metavolcanics, migmatites, and late-orogenic microcline granites in the Tallinn and Alutaguse zones.
The underlying geological setting appears to include large-scale zoned, S-type granitic intrusions and extensive pegmatite dike networks within amphibolitic
The prehnite deposit is enclosed in a north-south strip of amphibolitic
rocks (amphibolite and amphibolite gneiss).
Massive mineralisation is mostly associated with norite and layers of pyroxenite and peridotite, whereas pyroxene and amphibolitic
gabbros contain irregularly distributed mineralisation, either disseminated or semi-massive.
Although amphibole-poor soapstone was quarried at BRQ, artifacts from CW were made of a very amphibolitic
The Nagar Parkar Igneous complex comprises a series of late Proterozoic granitic rocks emplaced in a basement of amphibolitic
An indirect link to underlying basement rocks is provided by massive and schistose amphibolitic
dykes that intrude the Neoproterozoic granites of the Pull and Be Damned Complex as described by Currie (1988).