Structure
The Narryer Gneiss Terrane has undergone many high-grade polyphase deformation events, with the most notable being at 2600 to 2700 Ma associated with granite-greenstone magmatism in the Yilgarn Craton, following an event at ~3350 Ma of amphibolite facies, resulting in widespread re-equilibration of geochronometers, preceded by a deformation loosely constrained to ~3680 Ma and another predating the Meeberrie Gneiss and postdating the Manfred Complex, between 3680 and 3730 Ma.
Older structural grain is preserved in areas of low stress in subsequent deformations; the 2700 to 2600 Ma Yilgarn Craton associated deformation has overprinted most other deformations, resulting in rotation of previous structures into parallelism with NE-trending upright folds and metamorphic banding.
Proximal to the Proterozoic orogens and thrust belts, the gneiss belt has become variably overprinted by later deformations. In the Bryah-Padbury Basin fold-thrust belt, Yarlarweelor Gneiss rafts exist as undeformed thrust plates of pelitic schist bounded by discrete mylonite zones, as well as deformed heavily overprinted gneiss blocks caught up within shear zones, some of which appear to preserve the unconformity surface.
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