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Reliance Formation Type Section

The petrography of the Type Section rocks (Martin 1978) and their chemistry (Nisbet et al., 1977) are described elsewhere and detailed information on some of the more magnesian rocks are given by Nisbet et al (1987).

The Kariba Dam Observation Point

The steps ascending to the interpretive centre (beneath the crochet work) at the Observation Point, and those beyond, reveal banded Kariba Quartzite, with apparent biotite gneiss interleaved in either bedded or thrust relationship.  It is in this situation where weathering is deep and where the dip corresponds with the hill slope, landslip took place threatening to disrupt the tailraces on the south bank.  Extensive drainage, rock bolting and slope sculpture has aleviated this threat.

Tourmalinised amphibolite schists of the Malaputese Group

This is an outcrop on the main Bulawayo to Victoria Falls road, about 3 km NW from the turnoff to Gwaai River Mine (i.e., Mabale Store).  Here there are schistose amphibolites which are strongly impregnated with tourmaline which occurs in the form of black acicular or prismatic crystals. This is one of many examples of tourmalinization in the schist belts of the Dete-Kamativi Inlier, often associated with quartz-muscovite and tin-bearing pegmatites that are of late Mesoproterozoic ca. 1.03 Ga age (Master et al., 2013b). 

Zeederbergs Formation

The outcrop shows a pavement of pillow lavas with spherulites, some patches of pillow breccia and a tuff band. The pillows are generally about 1-2m in cross-section and some 3-D exposures suggest lengths of 3-4m. The spherulites tend to be concentrically arranged, with some flow units consisting almost wholly of coalesced spherulites. In some pillows the spherulites appear to be located around cooling cracks.

Makuti Marble

Outcrop of Matuki Marble in the roadside cutting on the Zambezi escarpment

Archaean (2.71 Ga) migmatitic granitoid gneisses

These are variegated inhomogeneous, polydeformed migmatitic gneisses, with leucocratic quartzo-feldspathic leucosomes and biotitic melanosomes. These migmatitic gneisses are the westernmost dated Archaean rocks of the Zimbabwe Craton. They have zircons which an age of ca. 2.71 Ga (Master et al., 2013a,b)- and they appear to be the source of the 2.7 Ga detrital zircons in the Malaputese Formation meta-arkoses (pink paragneisses), as well as the source of inherited zircons in the Palaeoproterozoic granites intruding the western Magondi Belt.

Hokonui Formation Volcanic Vent

An outcrop interpreted as a volcanic vent is exposed in the bed of the Mtshingwe River. The outline of the “megabreccia” approximates to the river bed and finer-grained sulphidic tuffs occur along the regional strike to the north and south. However, detailed mapping has not been done. The clasts in the breccia of finer-grained, grey tuffaceous rocks (not unlike the surrounding tuffs) and larger fragments of tonalite which are lithologically and isotopically very similar to the Chingezi tonalite which intrudes the Hokonui Formation to the east.

 

Nickel laterite -View of Mvukwe Hill

A road-side stop on the Mazowe – Mutorashanga road to view the topography of the Great Dyke from the east side in the vicinity of Mvukwe hill. 
Note the following:
1. This stop is on the Miocene Post-African erosion surface, here a mature granitic plain and inselberg landscape on the east side of the Great Dyke.
2. To the west is Mvukwe hill (1752m) on the P5 and P6 Pyroxenites of the Pyroxenite Succession.

Isoclinally infolded remnant of amphibolite schists, intruded by unmetamorphosed Kamativi Dyke Swarm dolerite dyke

At the sign that marks 40 km to Gwayi River, there is a roadcut exposure of isoclinally folded amphibolite and biotite schists which was mapped by Lockett (1979a), who regarded it as a tightly infolded remnant of the Malaputese supracrustal sequence, surrounded by basement granitoid gneisses. It may possibly be a large raft or xenolith, or even a roof pendant, of the Palaeoproterozoic post-Magondi biotite granodiorites that are found close by (Stop 8), containing numerous biotite-rich schlieren.

Hokonui Formation Agglomerates

Narrow, fine-grained pyroclastic layers show graded bedding and flame structures.

 

These give way to a thick sequence of agglomerates with the dominant clasts having a similar composition to the matrix. In thin section the clasts consist of albite phenocrysts set in a dirty saussuritic groundmass containing feldspar microlites and minute quartz grains. The clast margins are very fine-grained and almost opaque except for random feldspar microlites.

 

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