Photogeologic Study of Periglacial Talus Glaciers in Northwestern Canada
| Autor: | H. T. U. Smith |
|---|---|
| Rok vydání: | 1973 |
| Předmět: |
010506 paleontology
geography geography.geographical_feature_category 010504 meteorology & atmospheric sciences Mass movement Frost weathering Geography Planning and Development Rock glacier Geology Glacier Escarpment 01 natural sciences Paleontology Cliff Glacial period Geomorphology 0105 earth and related environmental sciences Chronology |
| Zdroj: | Geografiska Annaler: Series A, Physical Geography. 55:69-84 |
| ISSN: | 1468-0459 0435-3676 |
| DOI: | 10.1080/04353676.1973.11879881 |
| Popis: | In the Norman Wells area, precipitous escarpments at two localities are flanked by fossil composite talus glaciers of unusual size, extent, con- figuration, and topographic setting. The term, pied- mont talus glacier is proposed as descriptive. Talus is supplied by the disintegration of massive Silurian limestone, and merges downward into broad continuous aprons of rubble marked by transverse and longitudi- nal ridges and furrows in varied patterns. Outward extent is up to 1000 m, and the outer margin is ir- regular to strongly scalloped. Lateral extent is up to 14 km, with a few gaps. Volume of material is esti- mated to represent cliff recession on the order of 60 m. The surface now is entirely stabilized, except for an upper fringe of new, active talus overlapping the older talus. Occurrence in an area of former continental gla- ciation excludes ice of valley glaciers as a genetic factor. Pseudo-glacial movement by gradual, differen- tial mass movement, conditioned by a former peri- glacial environment, is the only satisfactory basis for explanation. Ensuing stabilization is attributed to cli- matic amelioration, with diminution or cessation of frost weathering which supplied talus. Present size and extent is interpreted provisionally to represent the cumulative effects of two episodes of formation, one pre-Hypsithermal and one early Neo- glacial. Observed stabilization is assigned to the ensu- ing part of Neoglacial time until interrupted in latest Neoglacial time by reneval of talus building still in progress, reflecting another climatic shift toward con- ditions more favorable for frost weathering. These relationships provide new data for interpretation of Postglacial climatic chronology in the area. |
| Databáze: | OpenAIRE |
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