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Schmidt-hammer exposure-age dating (SHD) was applied to similar to 180 medium- to large-scale solifluction features on the northern edge of Juyflye, Jotunheimen (southern Norway) using an electronic Schmidt-hammer (RockSchmidt) and an improved local SHD age-calibration equation. Age estimates from four different types of solifluction landforms were analysed and compared with those from recalibrated estimates from patterned ground previously investigated on Juvflye. Average SHD-age estimates are c. 9.8 and 9.3 ka for the two dominant morphological types of solifluction features ('type A' boulder tongues and 'type B' stone-banked solifluction lobes) and c. 8.6 ka for sorted stripes and circles. Our results indicate that active formation of all investigated types of solifluction features, sorted stripes, and sorted circles ceased in the Early Holocene, prior to the onset of the regional Holocene Thermal Maximum (HTM) at c. 7.7 ka. Formation of all of these periglacial landforms appears to have commenced shortly after local deglaciation (c. 11.4 ka) in water-saturated till. Alternative origins are rejected, including the possibility of development before the last glaciation, survival beneath cold-based glaciers, and exhumation in the Early Holocene. Cessation of activity is attributed to changing ground conditions affecting active layer processes, particularly reduced soil moisture and pore water pressure. Temporal variations of the altitudinal permafrost limits had little or no impact on the timing of either the Early Holocene climax in activity or subsequent stabilisation. Caution is therefore urged in the utilisation of large-scale solifluction and patterned ground landforms as palaeoclimatic indicators.

期刊论文 2024-08-01 DOI: 10.1016/j.geomorph.2024.109247 ISSN: 0169-555X

Recent Canadian research on permafrost is reviewed, concentrating on permafrost-climate relations, the processes of thermokarst, ice-wedge development, frost heave and soil convection, and ground ice studies. This field of geomorphology is often of direct interest to engineers and managers of northern resource development. While industrial activity in the Arctic is currently slow, concern for the effects of permafrost stability of global climate warming has stimulated research. Much of the work on the potential consequences to permafrost of climate change is by modelling: there are yet few relevant field data, although this is crucial for model evaluation. Studies of permafrost processes usually rely on geotechnical or geophysical theory too: the review concentrates on the use of field evidence in support of analytical models of landform development. Current research on ground ice is of a more geological nature: we examine approaches to the delineation and origin of massive ice.

期刊论文 1993-01-01 DOI: 10.1177/030913339301700204 ISSN: 0309-1333
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