Thermokarst lakes forming in yedoma (organic-rich permafrost containing massive syngenetic Pleistocene ice wedges) play an important role in periglacial landscape evolution. These lakes alter landscape elevation and topography, as well as redistribute upland sediment into lower basins. However, sediment deposition within yedoma thermokarst lakes is not well understood. Sedimentological, biogeochemical and macrofossil analyses enabled identification of five prominent fades in yedoma thermokarst lakes in my study region on the northern Seward Peninsula, Alaska. These include a Yedoma Taberal Silt facies situated below a sub-lacustrine unconformity, three types of basal facies and a Lacustrine Silt facies. A preliminary geomorphological model based on sediment cores from mature yedoma thermokarst lakes illustrates how fades distribution changes through the different stages of lake development. First-generation lakes (those forming in undisturbed upland) and later-generation lakes (those forming in thermokarst-affected lowland) were present on the northern Seward Peninsula. A comparison between these two lake types indicates that the depositional environments of later-generation lakes are much more variable than first-generation lakes. Understanding the depositional history and development of yedoma thermokarst lakes is critical to understanding their role in landscape evolution and the carbon cycle.
Thesis (M.S.) University of Alaska Fairbanks, 2012
The export option will allow you to export the current search results of the entered query to a file. Different
formats are available for download. To export the items, click on the button corresponding with the preferred download format.
By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.
To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export.
The amount of items that can be exported at once is similarly restricted as the full export.
After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.