Field observations, petrography and magnetic susceptibility fabrics are used to characterize the structure and evolution of the Nebo granite, forming part of the Bushveld Complex, in South Africa. The Nebo granite is the dominant component of the Lebowa granite suite, the largest known anorogenic granitoid complex. It is a composite tabular intrusion, comprising alkali feldspar granites and syenogranites. There are seven main petrographic units, defined by differences in modal content, crystallization sequence, magmatic water content, magnetic susceptibility and magnetic fabric. Each unit was emplaced independently and fed by vertical dykes. Anisotropy of magnetic susceptibility used to map magmatic fabrics within the granite shows that they are dominantly controlled by alignment of early-crystallizing magnetite and are similar in outcrop and pluton scale. Magnetic foliations and lineations are horizontal, reflecting vertical host-rock compression and horizontal magma flow during emplacement. Space was created by magma pressure which resulted in roof uplift and floor depression: displacements were accommodated by normal and reverse faulting and flexural-slip along bedding planes in host-rock metasediments.

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