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Marange Diamonds

De Beers discovered the Marange fossil placer diamond deposit in 2003 during the tenure of their exploration licence (EPO 1523) covering the Marange area. The exploration was targeted at discovering kimberlitic diamonds, but the recovery of rounded diamonds in some heavy mineral samples collected from local streams led to suspicions of a secondary source for the diamonds. A search for the possible source led to the discovery of a mineralized conglomerate. 
 
The discovery attracted informal miners from all over the country and abroad.

Kariba porphyritic biotite granitoid gneiss

The Kariba porphyritic biotite granitoid gneiss is coarse-grained, with a weak gneissic fabric, and contains large K-feldspar phenocrysts, and numerous decimetric slab-like mafic xenoliths. It contains small garnets rimmed and replaced by biotite. The zircons dated have oscillatory zoning in the centre (of igneous origin), but the margins have been affected by metasomatic alteration zones, and in some cases have discrete overgrowth rims. The zircons have yielded ages of 1962.9 ± 8.5 Ma and 2.1-2.17 Ga.

Palaeoproterozoic (ca 2.07 Ga) granitoid , with complex (inherited) 3.4 and 2.7 Ga zircons

In this outcrop, there is a deformed granite with anastomosing subhorizontal fractures, which is weathered with brownish iron oxide staining. It has yielded a very complex set of zircons, with inherited cores as old as 3.4 Ga, with 2.7 Ga overgrowths, and a final overgrowth at 2.07 Ga, which is possibly the age of intrusion of the granite, which was subsequently deformed (Master et al., 2013a,b).

Manjeri Formation Type Section

This exposure is described in detail by Martin (1978) and Bickle et al. (1975) and only a summary is given here.
 
The sedimentary succession here is 130m thick with the lower part dominated by argillite and quartzite and ironstone and the other 80m by siltstone and argillite.

Kariba sillimanite quartzite Kariba Heights

The Kariba sillimanite quartzite Kariba Heights, Sample ZMB13/11 is an aluminous quartzite consisting mainly of quartz and sillimanite. The zircons have yielded concordant ages of 2.018 Ga, 2.172, 2.220 and 2.70 Ga (Master et al., 2015). The maximum age of the quartzite is 2.018 Ga, the age of the youngest concordant detrital zircon, while the other zircons reflect a provenance from older crust dated at 2.17, 2.22, and 2.70 Ga.

Pink paragneiss (meta-arkose) of the Malaputese Group

At this outcrop locality, about 10 km further NW from the previous stop, there are numerous roadside outcrops of strongly recrystallized pink paragneiss of the Malaputese Group. The gneisses are interpreted as meta-arkoses, and some show relict cross bedding. They have yielded a detrital zircon population that ranges in age from 2254 ± 18 to 2796 ± 17 Ma, with a strong age peak at ca. 2.7 Ga (Master et al., 2013a,b).

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). 

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