Talk:Unaweep Canyon

Theories of Origin

Glaciation in the Paleozoic (Permian Period) can not have cut the Unaweep Canyon. Triassic and younger formations were deposited in near-horizontal layers on the top of a fairly smooth granite surface, and could not have been deposited in such a manner if the canyon had already been cut. Glaciation, if it occurred at all, must have been post-Triassic and possibly Pleistocene. Sheer granite walls characterize the canyon. A number of cirque-like features occur high on the south side of the canyon and are suggestive of glacial action. However, if the canyon is actually V-shaped below the deep valley fill, then glaciation is unlikely.

Rivers much larger than the present-day Dolores and Gunnison flowing through a faulted and jointed terrain likely are most responsible for this spectacular canyon. Just as the Colorado River cut the Grand Canyon as the plateau around it arched and rose, the Unaweep rivers cut through the Uncompahgre Plateau. The granite-sediments contact as can be readily seen from the road that runs from Highway 140 north on to the Uncompahgre Plateau. Geraldtray--Geraldtray (talk) 03:24, 1 October 2008 (UTC)

In response to the above--The flat-lying nature of Triassic and younger does not refute a possible Permian age for the canyon, if the canyon was buried before Triassic time. Pleistocene glaciation is not tenable, owing to the overall low elevation of the canyon. The shape of the "bedrock" canyon bottom remains contested; e.g., recent gravity data suggest a U shape. The geometry of the tributaries is inconsistent with river incision. (DustRx (talk) 20:59, 26 February 2011 (UTC))

Recent edits to this page were made to correct some misstatements, and add references; see "View History" for specific edits. (DustRx (talk) 21:16, 26 February 2011 (UTC))