Steeply plunging folds in the sealy range, southern Alps

Abstract Large steeply plunging folds are very clearly exposed in rugged country near Mt Cook, New Zealand. The axes of abundant minor folds are roughly parallel to those of the major folds. The strata consist of metagreywacke, belonging to the prehnite‐pumpellyite mineralogical facies, and of associated quartzo‐feldspathic schist, the latter concentrated within a belt some 4,000 ft wide bordered on both sides by less metamorphosed greywacke. Along one boundary of the schist belt a fault follows a narrow zone of greenschist, probably metamorphosed tuff, and separates an overturned anticline of moderate axial plunge from overturned folds of very steep plunge, in places exceeding 90°