Remote Sensing and GIS Based Quantification of Thermokarst in North Siberian Yedoma Deposits and Implications for Holocene Landscape and Carbon Dynamics

• Main Authors: Grosse, Guido, Schirrmeister, Lutz, Romanovsky, V. E.
• Format: Conference Object
• Language: unknown
• Published: 2007
• Subjects: laptev; Laptev Sea; Thermokarst; Siberia
• Online Access: https://epic.awi.de/id/eprint/18290/; https://hdl.handle.net/10013/epic.32598

Ice Complex deposits, also known as yedoma, are widely distributed in the North Siberian coastal lowlands. These Late Pleistocene terrestrial accumulations of up to several tens of meters in thickness are characterised by fine to medium grained clastic sediments, a very high ground ice content up to 90 vol-%, and mean total organic carbon (TOC) contents of 2-4%. Ground ice content includes large ice wedges and segregated ground ice in the form of small ice lenses and ice bands. Degradation of the Ice Complex in the form of thermokarst and thermo-erosion during the course of the Holocene produced massive landscape changes degenerating the existing accumulation plains to a complex system of thermokarst basins, lakes, and thermo-erosive valleys. Thermokarst triggered several feedback mechanisms that involve hydrology, vegetation and energy and matter fluxes. Thermokarst was a major agent in the partial transformation of the stored TOC into greenhouse gases. To evaluate the past and possible future impacts of thermokarst and related environmental feedbacks, the assessment of the current distribution and characteristics of Ice Complex deposits and thermokarst features is an important task. Field data, remote sensing, and terrain modelling within a geographical information system (GIS) are used to characterize Ice Complex deposits and thermokarst for a variety of sites in the Laptev Sea region, North Siberia. Field data consists of Ice Complex distribution, thickness, ice content, and TOC. Remote sensing was applied for the mapping of Ice Complex extent and distribution of thermokarst surface features in this area. Terrain modelling was used to quantify the volume of Ice Complex deposits based on digital elevation models, stratigraphical information, and satellite image mapping. Subsequently, terrain modelling was also applied to characterize thermokarst in this area. An assessment of the original, eroded, and remaining volume for the Ice Complex in the study area is provided.