Investigating the Magnetic Susceptibility of Cornish Loess as a Tool for Understanding the Palaeoclimate of SW England

Loess is a silty material produced via glacial grinding and its deposition is usually associated with colder periods when there is a considerable increase in atmospheric dust transport. The magnetic susceptibility of loess-palaeosol sequences has been the subject of extensive research within palaeoc...

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Bibliographic Details
Main Author: Tingdal, Love
Format: Bachelor Thesis
Language:English
Published: Uppsala universitet, Institutionen för geovetenskaper 2020
Subjects:
Online Access:http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-417794
Description
Summary:Loess is a silty material produced via glacial grinding and its deposition is usually associated with colder periods when there is a considerable increase in atmospheric dust transport. The magnetic susceptibility of loess-palaeosol sequences has been the subject of extensive research within palaeoclimatology as it has proven to be reliable climate proxy. Most research on magnetic susceptibility has been focused on thick deposits found in Europe and Asia, in particular the Chinese Loess Plateau where it is possible to discern more than 2.5 million years of climate variation in deposits several hundred meters thick. The climate development throughout the Quaternary has been characterized by glacials where there has been a significant ice growth, and interglacials where ice sheets have retreated. The Last Glacial Maximum was the most recent time of ice sheets reaching their maximum extent, occurring at some point between 26.5 and 18 ka BP. Aeolian reworking of material produced in conjunction with the Irish Sea Ice Stream (ISIS) occurred approximately 5000 years after the LGM. The ISIS limit were located just north of the Lizard Peninsula, and impinged on the Isles of Scilly. Loess deposits in SW England has largely been ignored in previous research in favour of the previously mentioned Chinese loess, but may be important climate archives in understanding the climate development of the North Atlantic. As such, the scope of this thesis is investigating the magnetic susceptibility of loess deposits in Cornwall and the Isles of Scilly in the far SW England. This is done by analyzing 36 samples from Lowland Point and 24 samples from Chynhalls Point, both located at the Lizard Peninsula in Cornwall, as well as 20 samples from Porthcressa and 14 samples from Gimble Porth, both located at the Isles of Scilly. The instruments used for analysis are the Bartington MS2B and the Agico MFK-1 FA Kappabridge, where all 96 samples were analyzed on the former while the 36 Lowland Points samples and the 20 Porthcressa samples were ...