Between Dec 19, 2024 and Jan 2, 2025, datasets can be submitted to DRUM but will not be processed until after the break. Staff will not be available to answer email during this period, and will not be able to provide DOIs until after Jan 2. If you are in need of a DOI during this period, consider Dryad or OpenICPSR. Submission responses to the UDC may also be delayed during this time.
 

Estimating The Sliding Velocity Of The Rainy Lobe Using Intermediate Clast Size In Lodgement Tills

Loading...
Thumbnail Image

Persistent link to this item

Statistics
View Statistics

Journal Title

Journal ISSN

Volume Title

Title

Estimating The Sliding Velocity Of The Rainy Lobe Using Intermediate Clast Size In Lodgement Tills

Published Date

2018-08

Publisher

Type

Thesis or Dissertation

Abstract

Lodgement tills are important in glacier reconstruction because their properties can be used to infer parameters such as glacier sliding velocity, ice thickness, and hydrology. These tills provide important calibration parameters for mass balance studies and numerical simulation. In Minnesota, lodgement tills of the Rainy lobe of the Late Wisconsinan glaciation exhibit significant changes in sedimentology between tills associated with the Last Glacial Maximum (LGM) and those deposited late during ice retreat. These changes include a small, but systematic increase in the intermediate size of clasts in the tills from the LGM to final ice retreat. Clast size in lodgement tills directly relates to the basal sliding velocity of ice. Small clasts drag on the bed and “lodge”, whereas large clasts simply plow into the basal sediment, but the stresses on them are too large for deposition. Therefore, we can use the size of clasts in lodgement tills to estimate sliding velocity at various times in a glacial advance. This investigation uses field-based measurements of intermediate clast size in lodgement tills, along with the analyses of Weertman (1959, 1964), Iverson and Hooyer (2004), and Hooke (1977) to estimate sliding velocity. Clast size is determined photogrammetrically from field exposures along the path of the Rainy Lobe. Calculated sliding velocity is compared with independent calculation of the velocity based on mass balance profiles. Preconsolidation pressures of these lodgement tills and the shear strength of the subglacial sediment are also considered. These calculations provide an important calibration parameter for comparison to balance velocity calculations from mass balance studies of numerical simulation.

Description

University of Minnesota M.S. thesis. August 2018. Major: Geological Sciences. Advisor: Howard Mooers. 1 computer file (PDF); v, 61 pages.

Related to

Replaces

License

Series/Report Number

Funding information

Isbn identifier

Doi identifier

Previously Published Citation

Other identifiers

Suggested citation

Kotrapu, Kristi. (2018). Estimating The Sliding Velocity Of The Rainy Lobe Using Intermediate Clast Size In Lodgement Tills. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/200997.

Content distributed via the University Digital Conservancy may be subject to additional license and use restrictions applied by the depositor. By using these files, users agree to the Terms of Use. Materials in the UDC may contain content that is disturbing and/or harmful. For more information, please see our statement on harmful content in digital repositories.