| Title | Reviewing geological and numerical evidence on the extent of the Laurentide Ice Sheet during Marine Isotope Stage 3 |
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| Author | Dalton, A S; Pico, T; Thayananthan, T; Gowan, E J; Clague, J J; Forman, S L; McMartin, I ; Sarala, P; Helmens, K F |
| Source | 2022, 1 pages |
| Image |  |
| Year | 2022 |
| Alt Series | Natural Resources Canada, Contribution Series 20220186 |
| Publisher | Geological Society of America |
| Meeting | Geological Society of America Annual Meeting 2022; Denver; US; October 9-12, 2022 |
| Document | serial |
| Lang. | English |
| Media | paper; digital; on-line |
| File format | pdf |
| Subjects | Science and Technology; Nature and Environment; stratigraphy; ice sheets; chronostratigraphy; Laurentide Ice Sheet; North American ice sheet complex; Climate change |
| Program | GEM-GeoNorth: Geo-mapping for Energy and Minerals GEM Program Coordination |
| Released | 2022 10 09 |
| Abstract | The evolution of the North American ice sheet complex (consisting of the Laurentide, Innuitian and Cordilleran ice sheets) prior to the last glacial maximum (~25 ka) has been the subject of intense
research because this interval offers a critical long-term perspective from which to study the response of continental ice sheets to climatic change. Here, we review a suite of geological and numerical evidence that constrain the extent of the
largest North American ice sheet, the Laurentide, during Marine Isotope Stage 3 (MIS 3; ~57 ka to ~29 ka). We discuss hemispheric-scale inferences from the d18O and atmospheric records, along with more local evidence from the chronostratigraphic
record in the glaciated and unglaciated region. We also discuss recent modelling efforts to ascertain ice sheet dynamics and sea level during this interval. Overall, there is conflicting evidence for the extent of the Laurentide Ice Sheet during MIS
3: some studies provide evidence of a large ice sheet; others argue for severely reduced ice over central Canada, and; other studies support a highly dynamic configuration to the ice sheet during MIS 3. Our goal is to facilitate a discussion on these
key pieces of evidence and develop pathways for future collaborative research on this critical time interval. Key areas for future research include improved geochronological dating methods on stratigraphic records in the glaciated region, development
of additional proxies to track ice extent in the unglaciated region, as well as additional study of the causes and mechanisms behind Henrich Events. |
| Summary | (Plain Language Summary, not published)
Isotopic composition of marine organisms and seawater are commonly used to infer changes in global sea level and continental ice volume. However the
translation from the marine record to sea level estimates prior to last glacial maximum remains uncertain. This invited keynote presentation summarizes the results recently published as a collaborative paper by researchers from international science
institutes, universities and governments that reviews the geological and numerical evidence on the extent of the Laurentide Ice Sheet prior to the last glacial maximum. The Geological Survey of Canada contributed key data to the study collected as
part of the GEM and GEM-GeoNorth Programs in Nunavut. This study provides a critical long-term perspective from which to study the response of continental ice sheets to climatic change. |
| GEOSCAN ID | 330449 |
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