A STRUCTURAL SEQUENCE IN LOW STRAIN SEDIMENTARY-ROCKS IN THE BEAUFORTGROUP OF THE SOUTH-WESTERN KAROO AND ITS BEARING ON SYNGENETIC AND EPIGENETIC MINERALIZATION
Iw. Halbich, A STRUCTURAL SEQUENCE IN LOW STRAIN SEDIMENTARY-ROCKS IN THE BEAUFORTGROUP OF THE SOUTH-WESTERN KAROO AND ITS BEARING ON SYNGENETIC AND EPIGENETIC MINERALIZATION, Journal of African earth sciences, and the Middle East, 18(3), 1994, pp. 197-208
Several sets of planar and linear structures are described from the ve
ry gently folded Karoo strata of the northern-most tectonic zone of th
e Permo-Triassic Cape Fold Belt. The superposition of these structures
reveals a time sequence. Horizontal compression occurred before compa
ction was complete. After compaction further horizontal compression de
veloped a sequence of structures that are readily interpreted in terms
of visco-elastic strain in multilayers. This analysis reveals that a
set of mainly antithetic kinks in the form of monoclines developed out
of earlier incipient sinusoidal macrofolds during the final stages of
horizontal N-S compression. The model is in agreement with evidence f
or synsedimentary folding that controlled the sites for erosion channe
ls as well as the direction of sedimentary transport. Exploration effo
rts for syngenetic and/or fluid controlled epigenetic mineralization i
n permeable strata of this fluviatile sedimentary sequence should be d
irected along certain structural lines.