1. Introduction
The Neoproterozoic Pan African Belt of central southern Africa is an east – west trending transcon-
tinental orogenic belt located within central, southern Africa and is interpreted to transect the
cratonic assemblage of West Gondwana Shackle- ton, 1996. The belt is comprised of several oro-
genic systems which, from west to east include the Damara Orogenic Belt of western, southern
Africa; the Lufilian Arc of central, southern Africa; the Zambezi Belt of southern Zambia and
northern Zimbabwe and the north – south trending Mozambique Belt of eastern Africa Fig. 1. Like
other Proterozoic orogenic belts, the Pan African Belt and its many orogenic systems are comprised
of a mosaic of structurally and metamorphically contrasting terranes most of which invariably en-
train tracts of older, re-tectonised basement. Mapping
by Goscombe
et al.
1994, Goscombe et al., 1998, Oliver et al. 1998 and
Johnson 1999 in the Zambezi Belt of northern Zimbabwe has revealed such a region of re-mo-
bilised basement Fig. 2. The Chewore Inliers are a group of isolated horsts, comprised of four
lithologically contrasting, tectonically juxtaposed terranes, i.e. Granulite, Quartzite, Zambezi and
Ophiolite Terranes. The most southerly terrane of this basement tract, the Ophiolite Terrane, is
interpreted by Oliver et al. 1998 and Johnson 1999 to represent a relict, highly dismembered
oceanicmarginal basin the Chewore Ophiolite and island-arc complex the Kaourera Arc. The
discovery of the ophiolite-type lithologies were documented in brief by Oliver et al. 1998 and
are subsequently described in detail here and by Johnson 1999.
Fig. 1. Tectonic map of central, southern Africa showing the location of the Chewore Inliers CI in relation to the surrounding tectonic belts After Vinyu et al., 1999. Key to abbreviations: LK, Lake Kariba; MD, Mwembeshi Dislocation; MG, Makuti
Group; and RG, Rushinga Group. Box outlines the position of Fig. 2.
Fig. 2. Simplified geological map of the Chewore Inliers after Oliver et al. 1998. Box illustrates the position of Fig. 3.
Ophiolite Group that comprises lithologies associ- ated with the Chewore Ophiolite and the Kaour-
era Island Arc Group that comprises lithologies associated with the Kaourera Arc Fig. 3.
Rocks in both the Maunde and Kaourera groups have undergone lower to upper amphibo-
lite facies re-crystallisation, static annealing and intense deformation during the Pan African
Orogeny Goscombe et al., 1998, the peak of which is dated in the Chewore Inliers at 524 9 16
Ma from high precision, SHRIMP zircon ages Goscombe et al., 1998. This tectono-metamor-
phic event has altered the primary igneous miner- alogy and has obliterated most igneous textures.
Meta-basaltic lithologies have been altered to epi- dote-bearing amphibolites; ultramafics to tremo-
lite-
and talc-bearing
serpentinites and
the intermediate island-arc lithologies to biotite- and
hornblende-bearing quartzofeldspathic schists. All lithologies accommodate a tectonic fabric, both
foliation and lineation, of which the foliation is parallelsub-parallel to the boundaries of the dif-
fering lithologies. The foliation and tectonic boundaries dip moderately 30 – 50° toward
the southeast while the lineation plunges shal- lowly 10 – 20° toward the south Fig. 3.
These fabrics share a similar orientation to Pan African aged fabrics within northern margin of
the Zimbabwe Craton Barton et al., 1993 and are interpreted by Goscombe et al. 1994, 1998 to
be related to the same Pan African tectonother- mal cycle. This deformation episode has dismem-
bered
both the
ophiolite and
island-arc stratigraphy such that both lithological and map-
ping group contacts are tectonic Oliver et al., 1998; Johnson, 1999.
3. Lithostratigraphy of the Chewore Ophiolite
Kategori