Cobble imbrication as a sensitive indicator of subtle local changes in river flow direction

摘要: Imbrication of cobbles in Pleistocene terrace gravels along the Shoshone River near Powell, Wyoming, shows significant changes orientation from a lower set to an upper within gravel layer. The show mean 126°, with spreads s = 38° 56°. is 070°, 19° 26°. Change deposit abrupt, no noticeable variability contact. In fact, contact can easily be overlooked without close scrutiny cobble fabric. This suggests that imbrication may sensitive indicator subtle flow direction braided stream. Because earlier fabric was not disturbed by deposition younger unit, there every reason believe such fabrics and will preserved even consolidated rock record used for paleoenvironmental interpretations.