Koviesberg
Kaiser (1926) depicts on a geological map and describes a number of north to north-northwest-trending tinguaite/bostonite dykes in the Koviesberg area.
There are four major provinces of alkaline rocks and carbonatites in Namibia three of which comprise linear distributions of occurrences defining northeast-southwest-trending lines. The Damaraland Province is the most northerly while the Luderitz and Kuboos-Bremen provinces are in the south, the latter extending into South Africa. Marsh (1973) correlated these linear distributions with transform faults in the South Atlantic and concentrations of similar rocks in South America, a theme that is also discussed by Prins (1981). Reviews of the Damaraland Province will be found in Martin et al. (1960) and Prins (1981) and of geochemistry in Prins (1978). Age determinations on Damaraland Province complexes are listed by Marsh (1973) and Prins (1981). Descriptions of the principal Luderitz Province occurrences will be found in Marsh (1975a, 1975b and 1976) and an outline of the Kuboos-Bremen province will be found in Smithies and Marsh (1996). Pirajno (1994) has reviewed the mineral resources of each of the provinces. Very full accounts of the carbonatites of Namibia will be found in reviews by Verwoerd (1966, 1967 and 1993).
Kaiser (1926) depicts on a geological map and describes a number of north to north-northwest-trending tinguaite/bostonite dykes in the Koviesberg area.
This is a poorly exposed complex an estimated 85% of which is obscured by sand and calcrete. It intrudes quartzites, schists and granites of Late Precambrian age and comprises a series of syenite intrusions that may form rings (Marsh, 1976, Fig. 5).
This is an occurrence of nephelinite located west of the Klinghardt Mountains (No. 116-00-037).
The rock at this locality is referred to as 'limburgite' by Lock and Marsh (1981) and as melilite basalt by Kaiser (1926).
This is a small plug situated in the Diamond Area north of the mouth of the Orange River, which is normally inaccessible. The plug is about 100x50 m in plan, 30 m high and forms an eastward-facing escarpment. It has an irregular outline sending numerous apophyses into the country rocks.
This locality is an intense, point source, reversed magnetic anomaly which may be an alkaline intrusion. It has not, however, been drilled.
Like No. 116-00-039, this is an intense, point source, reversed magnetic anomaly. It has been drilled and appears to be an altered phonolite.
Karingarub is a dolomitic carbonatite intrusion which forms a subdued koppie. Other details not found.
These two complexes are in contact and define a northeast-southwest-trending 14 km long line which appears to end at the Orange River. (Smithies and Marsh, 1996). The line continues to the southwest in the form of the Tatasberg complex (see South Africa No. 116-00-037).
This 3x2 km intrusion lies to the northeast of, and in line with, the Grootpenseiland and Marinkas Kwela complexes (No. 116-00-042). Kanabeam consists of a series of ring dykes and circular plugs of nepheline syenite, quartz syenite, granite, phonolitic breccia and late dykes (Reid, 1991).