Premium
The Donegal ice dome, northwest Ireland: dimensions and chronology
Author(s) -
Ballantyne Colin K.,
McCarroll Danny,
Stone John O.
Publication year - 2007
Publication title -
journal of quaternary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.142
H-Index - 94
eISSN - 1099-1417
pISSN - 0267-8179
DOI - 10.1002/jqs.1116
Subject(s) - geology , dome (geology) , glacial period , wisconsin glaciation , ice sheet , antarctic sea ice , seabed gouging by ice , ice shelf , oceanography , ice stream , physical geography , ice caps , arctic ice pack , geomorphology , cryosphere , sea ice , glacier , geography
Geomorphological evidence indicates that Donegal was formerly occupied by an ice dome that extended offshore to the west, northwest and north and was confluent with adjacent ice masses to the east and south. Erosive warm‐based ice over‐rode almost all the highest mountains, implying an ice‐divide altitude greater than 700 m. Only six peripheral summits escaped glacial modification, implying either that they remained above the ice surface as nunataks or supported a thin cover of protective cold‐based ice. Gibbsite, a pre‐last glacial weathering product, is preferentially represented on summits that escaped glacial modification. Cosmogenic 10 Be exposure ages of 18.6 ± 1.4 to 15.9 ± 1.0 k yr for coastal sites confirm that Donegal ice extended offshore at the last glacial maximum. Reconstruction of the form of the Donegal ice dome suggests a former minimum ice thickness of ∼500 m close to the present coastline in the west and northwest, and ∼400 m near the coast of the Inishowen Peninsula in the north, with the ice extending at least 20 km across the adjacent shelf to the west and northwest. Copyright © 2007 John Wiley & Sons, Ltd.