Late Pleistocene rock glaciers in the western part of the Capitan Mountains, Lincoln County, New Mexico: Description, age and climatic significance
John W. Blagbrough

Abstract:

Seventy-six tongue-shaped rock glaciers of probable late Wisconsin age occur below talus at the heads of canyons and ravines at an average elevation of about 2485 m in the western part of the Capitan Mountains. They have abrupt fronts and steep sides often delineated by lateral ridges which curve to form transverse ridges at the crests of the fronts. Longitudinal and transverse ridges and furrows are common surface features. Their debris is stable and lichen covers 20-90% of exposed faces. A dark brown, weakly developed soil formed by decomposed organic material has a maximum thickness of 15 cm and occurs as isolated pockets that cover 10-15% of the surfaces. The rock-glaciers have surface features that indicate they are ice-cemented (permafrost) forms that moved by the flow of interstitial ice. They denote a climate with a mean annual temperature below freezing, characterized by much diurnal freezing and thawing which resulted in the generation of large volumes of talus. The average elevation of the fronts (2430 m) delineates the approximate lower limit of Late Wisconsin alpine permafrost and the upper periglacial (subnival) zone.


Citation:

  1. Blagbrough, John W., 1991, Late Pleistocene rock glaciers in the western part of the Capitan Mountains, Lincoln County, New Mexico: Description, age and climatic significance, in: Geology of the Sierra Blanca, Sacramento and Capitan Ranges, New Mexico, Barker, James M.; Kues, Barry S.; Austin, George S.; Lucas, Spencer, G., New Mexico Geological Society, Guidebook, 42nd Field Conference, pp. 333-338.

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