Structural evolution of a section along the base of the St. Anthony Complex, northwest Newfoundland

• Published in: Canadian Journal of Earth Sciences
• Main Author: Craw, D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1983
• Subjects: General Earth and Planetary Sciences; St. Anthony; Newfoundland
• Online Access: http://dx.doi.org/10.1139/e83-161; http://www.nrcresearchpress.com/doi/pdf/10.1139/e83-161

The basal portion of the St. Anthony Complex is made up of structural slices 10–30 m thick, with unknown amounts of relative movement between them. The lowest rocks are variably deformed pillow lavas and related rocks with one pervasive foliation. These rocks are overlain by greenschists, phyllonites, and mylonites with up to three planar structural elements developed. At least one of these latter surfaces (the earliest) had formed before the schists were thrust over the underlying pillow lavas. The overthrusting event resulted in deformation of underlying pillow lavas. All deformation occurred under lower greenschist facies conditions. Fold axes in the least deformed rocks have variable orientations, and this variation decreases up-section until axes are parallel and plunge gently eastwards, parallel to the stretching lineation. Parallelism between fold axes and stretching lineation implies rotation of fold axes during progressive deformation and is consistent with the rocks being part of a high-strain zone developed during regional overthrusting from east to west.