schist, quartz-mica schist, calcareous schist, schistose marble, hornblende bearing quartz mica schist and micaceous marble.
The soil at the Kpong site is an alluvial material derived from the weathering of garnetiferous
hornblende gneiss (Table 1).
1): Bocabec Gabbro--greyish green, locally layered, medium-grained gabbro and minor associated granitic rocks; Utopia Granite--typically red, leucocratic, medium--to coarse-grained, equigranular, biotite granite; Welsford, Jake Lee Mountain, and Parks Brook granites--beige to pink, mediumgrained and equigranular to fine-grained and porphyritic, amphibole-bearing, peralkaline granites; Magaguadavic Granite--greyish pink, coarse-grained, megacrystic granite; John Lee Brook Granite--light grey, medium-grained, equigranular, garnetiferous
, two-mica granite; and Mount Douglas Granite--light pink, medium-to-coarse-grained and equigranular to fine-grained and porphyritic, rapakivitextured, biotite granite.
The formations include mainly garnetiferous
amphibolites and pelitic schist of Nellore schist belt, granitic gneiss and Cuddapahs (quartzites and shales) of Pre-cambrian period.
The highest values of the compression and sudar wave velocities were registered in the sample of banded garnetiferous
amphibolite (Hample h010, [V.sub.P] = 6.15 km/s, [V.sub.S] = 3.69 km/s), the lowest--in the sample of chloritized garnet amphibolite (sample h030, [V.sub.P] = 3.19 km/s, [V.sub.S] = 2.16 km/s).
biotite gneisses (khondalites) and the associated layered complex of garnetiferous
quartzo-felspathic granulites (leptynites) and non-garnetiferous quartzo-felspathic granulites (alaskites) constitute an assemblage of metasediments injected by granitic materials, and recrystallised under deep-seated palingenetic conditions into a migmatite complex.
The newly exposed, less weathered garnetiferous
rock consists mostly of vuggy, coarsely crystalline, reddish brown to deep molasses-colored grossular-andradite interspersed with irregular areas of amphibole.
Country rocks include charnockite mafic and felsic granulite, garnetiferous
granulite, biotite gneiss, migmatite, mylonite and pegmatite.
3a), and minor biotite- and muscovite-bearing granite, garnetiferous
aplite, and pegmatite.
These rocks comprise mylonitic peridotite and sub-ophiolitic metamorphic rocks that range from garnetiferous
amphibolites facies to amphibolite facies to greenschist facies and un- metamorphosed sediments.
The northern one, called the Olovi block, consists of a monotonous sequence of muscovite, garnetiferous
and two-mica shists (Mlcoch et al., 1997).