Syngenetic dynamic of permafrost of a polar desert solifluction lobe, Ward Hunt Island, Nunavut

Arctic Science

article

Manuel Verpaelst¹  Daniel Fortier¹  Mikhail Kanevskiy³  Michel Paquette¹  Yuri Shur³ 

[1] Department of Geography, University of Montreal;Centre for Northern Studies, Université Laval;Institute of Northern Engineering, University of Alaska Fairbanks

关键词: solifluction lobe;    cryostratigraphy;    syngenetic permafrost;    ground ice;    polar desert.;   

DOI  :  10.1139/as-2016-0018

学科分类：地球科学(综合)

来源: NRC Research Press

【 摘 要 】

Repeated freeze–thaw cycles on slopes trigger sorting and solifluction mass movements, while subsequent displacement of material modifies the geomorphology of slopes as well as permafrost dynamics. This study focuses on the geomorphology and the cryostratigraphy of a polar desert stone-banked solifluction lobe with the objective to clarify the impact of slow mass movements on ground ice aggradation. The morphology of the solifluction lobe was characterized by peripheral ridges of coarse gravel, partially surrounding a depression filled with finer sediments saturated with water and covered by organics. Cryostratigraphic analysis demonstrated that the solifluction lobe’s formation led to the development of a syngenetic layer of permafrost with an ice content that varied according to the location in the lobe. The ice-rich cryofacies formed in the central depression of the lobe should act as a buffer to potential active layer deepening, slowing down its thawing, whereas the ice-poor cryofacies formed under the ridges is expected to thaw faster than the central depression under climate warming scenarios. Thawing of the ice-rich zone in the future will result in differential thaw subsidence between the ridges and the central depression of solifluction lobes, along with increased drainage through the ridges and subsequent changes in hydrology.

【 授权许可】

CC BY