# name
Ground ice degradation and thermokarst terrain formation in Canada over the past 16 000 years

# metadata.dc.description[].value
We examine the relationship between the modelled ground ice loss in permafrost terrain to thermokarst processes and landforms in Canada.

# metadata.dc.description[].value
Nous examinons la relation entre la perte de glace au sol modélisée dans le pergélisol et les processus thermokarstiques et les formes de relief au Canada.

# metadata.dc.description.abstract[].value
Thermokarst results from thawing of excess ground ice in permafrost sediments. Thermokarst processes and landforms are controlled by ground ice type, amount and distribution, as well as the patterns of ground ice loss over time. Recent acceleration of varied thermokarstprocesses across diverse Canadian permafrost terrains make for a challenging task in predicting landscape-scale thaw trajectories. Using existing ground ice models, we examined the modelled amounts and spatial extent of ground ice loss relative to ground ice maxima in the last ca. 16 ka BP forrelict, segregated and wedge ice. We relate observed thermokarst features to the nature of ground ice development and loss in different environments (cold continuous permafrost, discontinuous permafrost, and no current permafrost). In cold, continuous permafrost areas where ground ice loss has beenlimited over the last 16 ka BP, thermokarst processes include active layer detachments and slumps in segregated and relict ice, gullying and ponding in ice wedge troughs, and the cyclical development of shallow thermokarst ponds in segregated ice. With ground ice loss in discontinuous permafrost,thermokarst processes are wide-ranging. Slumps, subsidence, and collapse of lithalsas, palsas and peat plateaus occur from thawing of segregated ice, thermokarst ponds from melting wedge and segregated ice, and involuted terrain from melting and creep of relict or segregated ice. In formerpermafrost terrain, evidence of thermokarst includes former ice wedge polygons, collapsed lithalsas, and irregular hummocky terrain. The relations between modelled ground ice loss and observed thermokarst landscapes assist in understanding present-day processes and in predicting future thermokarstlandform evolution with a changing climate.

# metadata.dc.identifier.citation[].value
Wolfe, S. A., O'Neill, H. B., Duchesne, C., Froese, D., Young, J. M. & Kokelj, S. V. (2022). Ground ice degradation and thermokarst terrain formation in Canada over the past 16 000 years. Geological Survey of Canada, Scientific Presentation, 134, Natural Resources Canada. https://doi.org/10.4095/329668

# metadata.dc.relation.isrelatedto[].value
Ground ice map of Canada

# metadata.dc.relation.isrelatedto[].value
Ground ice map of Canada

# metadata.dc.relation.isrelatedto[].value
Ground ice map of Canada

# metadata.dc.relation.isrelatedto[].value
Ground ice map of Canada

# metadata.dc.title[].value
Ground ice degradation and thermokarst terrain formation in Canada over the past 16 000 years

# metadata.nrcan.serial.title[].value
Geological Survey of Canada, Scientific Presentation

# metadata.nrcan.sponsor.program[].value
GEM2: Geo-mapping for Energy and Minerals