| Popis: |
Recently Cant and Stockmal (1999) published new structural observations and interpretations, and a revision of sedimentological interpretations of Hamblin and Walker (1979) on the Trans-Canada Highway outcrop section at Banff, formerly known as the Banff Traffic Circle section. This frequently visited outcrop has been described several times in the past, including by ourselves (Hamblin, 1978a, b; Hamblin and Walker, 1979; Hamblin, 1983), but highway improvement has altered the upper portion (50 m of a 350 m section) since that time. We thank Cant and Stockmal for the important structural observations and interpretations; something we admittedly minimized at the time of our original work. However, as portions of the paper by Cant and Stockmal discuss and comment on our original sedimentological interpretations, we wish to reply here to several points they make. Although there are additional minor aspects of their paper which we dispute, we will focus on the two most important points of disagreement: 1) their questioning of our use of the word “turbidite”, and 2) their interpretation of the upper, modified exposure of the outcrop. We will discuss these by referring to the subtitle headings of Cant and Stockmal’s paper. ### Observations Cant and Stockmal (1999) discuss the applicability of the word “turbidite” to the Fernie-Kootenay transition beds exposed, and suggest that it may be inappropriate. We disagree and contend that our original interpretation is reasonable. This part of the outcrop (~0–225 m on their Fig. 4) comprises a thick succession of bioturbated mudstone with thin beds of coarse siltstone to very fine sandstone. These latter beds are characterized by great lateral extent in spite of their thinness, sharp bases with abundant and well preserved sole marks, high flow regime flat bedding, consistent unidirectional paleoflow (as manifest by the sole marks, the oriented wood fragments and the ripple … |
