Title: Macrofossil, peat composition, LOI, radiocarbon, and permafrost data from a drained thermokarst lake, Old Crow Flats, Yukon
Citation: Chiasson, Danielle; Roy-Léveillée, Pascale; Bhiry, Najat; Lantz, Trevor, 2026, "Macrofossil, peat composition, LOI, radiocarbon, and permafrost data from a drained thermokarst lake, Old Crow Flats, Yukon", https://doi.org/10.5683/SP3/YZ35V6, Borealis
Study Site: Old Crow Flats, Yukon
Purpose: Drained thermokarst lake basins (DTLBs) are extremely dynamic and create complex landscapes marked by repeated cycles of permafrost degradation through thermokarst lake formation, and permafrost aggradation following lake drainage. The age of DTLBs can range from decades to thousands of years old and have different morphologies and vegetation depending on their age. In terms of morphology, young basins have raised margins and depressed centres with remnant ponds, and show uncertain permafrost aggradation in the decades following drainage. Whereas old basins are the opposite, with depressed margins and raised centres. The vegetation of young basins is characterized by a rapid development and mortality of tall willow thickets in its margins, representing an intermediate stage of succession. The vegetation in older basins is either dominated by dwarf shrubs, tussock tundra, or mosses. While contemporary conditions in DTLBs have been well documented, little is known about the evolution of young basins to old, and there are few paleo-environmental reconstructions of post-drainage basin evolution prior to anthropogenic climate warming. Luckily, DTLBs and their thick peat covers are excellent paleo-archives.
Abstract: Peat and soil samples were collected at the end of August 2022 from the margin and centre of a drained thermokarst lake basin in Old Crow Flats, Yukon, Canada. Samples were collected to reconstruct local vegetation histories based on macrofossil records, with selected samples from specific stratigraphic levels subjected to radiocarbon dating. Peat samples were collected as vertical profiles down to the basal layer. These included peat monoliths and frozen peat cores if the basal layer was below the permafrost table. Soil samples were also collected below the basal layer to characterize the pre-drainage conditions. The dataset includes macrofossil counts, peat matrix composition, loss-on ignition (LOI), radiocarbon ages, calibrated ages, age-depth models, accumulation rates, and simulated permafrost aggradation depth.
Supplemental Information Summary:
Research:
Further Info: Post-drainage vegetation succession and basin floor evolution of a large thermokarst lake, Old Crow Flats, Yukon (Catena, Submitted 2025)
Status: Complete
Keywords:
peat properties,
effects of disturbance,
vegetation,
radiocarbon dating,
Permafrost,
drainage,
Geographical coordinates: North: 67.55, South: 67.55 East: -139.91 West: -139.91
Bounding Temporal Extent: Start Date: 2022-08-25, End
Date: 2022-08-26
