An Alternative Structural Model for the Development of the Cape Fold Belt Syntaxis and Groundwater Potential
The syntaxis separates the eastern and western branches of the Cape Fold Belt, South Africa. A satisfactory and holistic solution remains unresolved. This investigation is to develop an alternative hypothesis for the development of the syntaxis. Because macroscopic fold structures are considered most relevant in resolving a tectonic solution on subcontinental scale, the fold hinge traces of macroscopic structures were comprehensively compiled from published geological maps. The fold patterns of the eastern and western fold belt branches are separated across the hypothetical Ceres lineament without any identified interaction. The en echelon fold pattern of the western branch is interpreted as the result of northern movement of a lower crustal block. The eastern branch is dominated by north-verging over folding and thrusting in the east and westwards towards the Ceres lineament the folds are predominantly upright. It is suggested that differential basal slip causes the fold belt to terminate against the lineament with a sinistral rotation that is also accommodated by the sinistral Villiersdorp ductile shear zone. It appears that basal slip retardation increases from east to west. The two fold belt branches were developed in adjacent crustal blocks that reacted differently to northward tectonic transport driven by subduction and accretion further south along southern Gondwana. The hypothesis is testifiable. The structural investigation revealed the hitherto unknown existence of special structural situations with wellfield potential for groundwater that remains to be tested by drilling.
Blignault Hendrik Johan,
Theron Johannes Nicolaas,
An Alternative Structural Model for the Development of the Cape Fold Belt Syntaxis and Groundwater Potential, Earth Sciences.
Vol. 8, No. 5,
2019, pp. 277-284.
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