Kilometre-scale folding in the Teslin zone, northern Canadian Cordillera, and its tectonic implications for the accretion of the Yukon–Tanana terrane to North America: Discussion1

Dicussions 882 Despite the often divergent opinions regarding the evolution of the Teslin suture zone (TSZ), previous tectonic models broadly agree that the TSZ comprises a ductile shear zone that constitutes a fundamental crustal boundary (e.g., Tempelman-Kluit 1979; Erdmer 1985; Hansen 1989; Stevens and Erdmer 1996; Hansen and Dusel-Bacon 1998). In contrast, de Keijzer et al. (1999) offer a radical model in which the TSZ is a rootless polydeformed nappe obducted onto North America. According to their interpretation the TSZ does not represent a shear zone. Although the influx of new ideas in science is always commendable, the methodology by which de Keijzer et al. (1999) arrive at their interpretation is scientifically flawed; they ignore or arbitrarily dismiss published TSZ data, and they fail to present evidence in support of key elements of their model. Although their data may be valid, we question: (1) their interpretation of linear fabric elements, (2) the existence of kilometre-scale folding, and (3) evidence for North American rocks in the western TSZ.