The “Missing Glaciations” of the Middle Pleistocene

• Published in: Quaternary Research
• Main Authors: Hughes, Philip, Gibbard, Philip, Ehlers, Jürgen
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2020
• Subjects: Illinoian; Quaternary stratigraphy; Saalian; Wolstonian; glacial cycles; ice ages; orbital forcing; Antarctic; Patagonia; West Antarctic Ice Sheet; Antarc*; Ice Sheet
• Online Access: https://research.manchester.ac.uk/en/publications/d36eb014-1242-4ec6-9ae1-fb674fd4394a; https://doi.org/10.1017/qua.2019.76; https://pure.manchester.ac.uk/ws/files/144687057/Hughesetal_MissingGlaciations_FINAL_withFigs.pdf

Global glaciations have varied in size and magnitude since the Early-Middle Pleistocene transition (~773 ka), despite the apparent regular and high-amplitude 100 kyr pacing of glacial-interglacial cycles recorded in marine isotopic records. The evidence on land indicates that patterns of glaciation varied dramatically between different glacial-interglacial cycles. For example, MIS (Marine Isotope Stages) 8, 10 and 14 are all noticeably absent from many terrestrial glacial records in North America and Europe. However, globally, the patterns are more complicated with major glaciations recorded in MIS 8 in Asia and in parts of the Southern Hemisphere, such as Patagonia for example. This spatial variability in glaciation between glacial-interglacial cycles is likely to be driven by ice volume changes in the West Antarctic Ice Sheet and associated interhemispheric connections through ocean-atmosphere circulatory changes. The weak global glacial imprint in some glacial-interglacial cycles is related to the pattern of global ice build-up. This is caused by feedback mechanisms within glacier systems themselves which partly result from long-term orbital changes driven by eccentricity.