Abstract

A geological map of part of the western Namaqua mobile belt, 3200 km 2 in extent (scale of 1:100 000), has been compiled with the aid of a sequence mapping technique. The map shows the distribution of the lithostratigraphic units and the macroscopic structural development, including the thrust fault boundaries between four Proterozoic structural terranes. Most of the study region is in the Pofadder terrane, which is characterized by the metamorphic equivalents of 2.0 Ga calc-alkaline eruptive rocks (Haib Subgroup), granites (Vioolsdrif and Little Namaqualand Suites), and metasedimentary sequences (Pella Subgroup). The intense deformation and metamorphism of the region is ascribed to the Namaqua Orogeny (1.4-1.1 Ga), which largely overprinted the effects of an earlier regional deformation. Progressive ductile shear deformation was responsible for the production of a regional subhorizontal fabric comprising coplanar and colinear elements. The map represents part of the root zone of a region of Proterozoic crustal thickening, illustrating the deformational style of the Kibaran belts. Collectively, the facts presented in this paper provide a window into mid-crustal features during compressional tectonics in the Mesoproterozoic.

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