A Karst Lake System in the High Arctic: A Case Study at Linnédalen, Svalbard
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The island of Spitsbergen, which makes up the largest portion of the Svalbard archipelago, is located in the high arctic, between 74° and 81° north. This high latitude Arctic environment provides the means for widespread permafrost formation. Currently, Svalbard is 60% glaciated, leaving 40% and approximately 25,000km as a permafrost and periglacial environment (Humlum, 2003: 199). Glaciers, permafrost, and periglacial features can all be widely observed on Svalbard. This study will look at a system of karst lakes found in an active and continuous permafrost zone on Svalbard. Karst is a globally spread phenomena which commonly occurs in regions consisting of carbonate rocks and evaporites when weathering and erosion occurs (Ritter et al, 2006: 407). Although karst is found in every region on earth, it is mostly found in temperate or tropical climates, because moderate temperatures, humidity, high precipitation, free flowing water, and high vegetation levels are all seen as favorable factors for formation (Ritter et al, 2006: 412). Karst is not nearly as frequently found in Arctic climates, due to the typical Arctic conditions of extremely low temperature, low precipitation, frozen water, and low vegetation being unfavorable for the formation of karst features. There have been relatively few studies of karst features occurring in High-Arctic environments. These studies have been mostly concentrated in Canada, the United States, Russia, and Svalbard. It was originally thought that only thermokarst features could form in the arctic, and true karst could not exist, because the chemical weathering needed to form karst was prevented by permafrost (French, 2007: 69). Thermokarst is not related to karst, and has nothing to do with the solubility and weathering of limestone or evaporites. The relationship of the two names can be explained, because the thaw of permafrost leads to thermokarst features, including the collapse, subsidence, erosion, and instability of the ground surface, which would appear similar to the results of true karst (French, 2007: 186.). It is now known that true karst can exist in the High-Arctic. Studies by D. C. Ford have resulted in the development of a model for karst existing in permafrost zones, with the groundwater circulation and solution being limited to the active-layer, allowing for shallow karst terrain (French, 2007: 69). The previous studies of karst systems in the High-Arctic have been done on karst systems in Svalbard, the United States, Canada, and Russia. In a study done by I. D. Clark and B. Lauriol at the Firth river basin, in the Yukon, Canada, the drainage of water from karst systems is proven to flow through taliks, and then resurface in the growth of an aufeis. In Svalbard, Northeast of the study area, a karst system has been studied by O. Salvigsen, Ø. Lauritzen, and J Mangerud. Here, the authors have only been able to conclude that the water must drain below the active layer of two meters, but cannot determine the mechanisms which make this drainage possible. A study by O. Salvigsen and A. Elgersma in Svalbard focuses on the same area as this study. They were able to determine that the lakes in the study area were true karst, but did not attempt to date Sara Cohen: AG-212 Term Report 4 the formation of the karst. They did, however, try to determine how the water drained through the karst system, by performing dye tests and digging pits in the area, but were unsuccessful. In order to further the understanding of karst systems in High-Arctic climates consisting of active permafrost zones, this report will take a comprehensive look at a karst lake system located in Linnédalen, Svalbard. The report will include a geomorphological map created after a month long period of observations in the study area which aims to catalogue the periglacial features and processes occurring in the area. The report will also attempt to come up with an explanation of when and under what conditions the karst lake system was formed. Finally, the report will include an interpretation of how the water in the lakes drains vertically through the permafrost. This report is meant to be the first part of a continuing study of the karst lakes in Linnédalen. At the end of the report there will be a plan for the continuation of the study.