Welded tuffs deformed into megarheomorphic folds during collapse of the McDermitt caldera, Nevada-Oregon.

The Montana Mountains contain part of a resurgent dome complex within the SW sector of the McDermitt caldera. Exposed intracaldera units consist of welded tuffs, lavas, domes and epiclastic deposits. A deformed series of comenditic welded tuffs occur in a strongly folded rheomorphic zone >500m thick. Although superficially resembling a series of intrusive domes, detailed examination of relationships suggests that their large-scale folds in the deformed sequence developed shortly after caldera collapse.-after Authors