Greenstone‐up shear sense at the margin of the Mt Edgar dome, East Pilbara Terrane: Implications for dome and keel formation in the early Earth

Abstract The Paleoarchean Mt Edgar dome in the East Pilbara Terrane has long been studied as an archetypal within Archean dome‐and‐keel terranes, but history of its formation is debated. Kinematic data presented this study provide new insights into late‐stage development and Terrane. Quartz crystallographic preferred orientation (CPO), optical microstructures, field structures all indicate that granite‐greenstone contact experienced reverse (greenstone‐up, dome‐down) sense shear after dominant schistosity. This observed at localities along entire extent sheared margin rings most dome, best documented southwest Warrawoona Greenstone Belt. Additionally, quartz CPO from a triple junction outside dominantly constrictional strain geometry, consistent with previous interpretation area represents zone vertical foundering buoyancy‐instability driven system. However, models do not necessarily predict occurrence greenstone‐up preserved solid‐state fabrics margin. Several geologic explanations are considered, including expansion or post‐doming deformation. directly relate to formation, especially when considered tandem recently published structural dome. These kinematic suggest late occurred near‐static crustal environment rather than extensional contractional setting.