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Abstract. Determining the timing and extent of Quaternary glaciations around the globe is critical to understanding the drivers behind climate change and glacier fluctuations. Evidence from the southern mid-latitudes indicates that local glacial maxima preceded the global Last Glacial Maximum (LGM), implying that feedbacks in the climate system or ice dynamics played a role beyond the underlying orbital forcings. To shed light on these processes, we investigated the glacial landforms shaped and deposited by the Lago Argentino glacier (50° S), an outlet lobe of the former Patagonian Ice Sheet, in southern Argentina. We mapped geomorphological features on the landscape and dated moraine boulders and outwash sediments using 10Be cosmogenic nuclides and feldspar infrared stimulated luminescence (IRSL) to constrain the chronology of glacial advance and retreat. We report that the Lago Argentino glacier lobe reached more extensive limits prior to the global LGM, advancing during the middle to late Pleistocene between 243–132 ka and during Marine Isotope Stage 3 (MIS 3), culminating at 44.5 ± 8.0 and at 36.6 ± 1.0 ka. Our results indicate that the most extensive advance of the last glacial cycle occurred during MIS 3, and we hypothesize that this was a result of longer and colder winters, as well as increased precipitation delivered by a latitudinal migration of the Southern Westerly Winds belt, highlighting the role of local and regional climate feedbacks in modulating ice mass changes in the southern mid-latitudes.
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This content will become publicly available on April 1, 2026
Palaeoenvironmental implications of Late Quaternary bioerosion traces in central Patagonia (Southern Atlantic, Argentina)
ABSTRACT Bioerosion is a valuable tool for inferring palaeoenvironmental and palaeoclimatic changes over time and across different regions. However, studies of bioerosion traces are scarce in the Southern Hemisphere. Most ichnological studies within Argentina are concentrated in San Jorge Gulf (Patagonia, Argentina) and little is known about deposits located north of the Gulf. Here, we focus on bioerosion traces on Quaternary mollusc shells. Samples were collected from Quaternary marine deposits at the Bahía Vera–Cabo Raso sites in northern San Jorge Gulf. To resolve age discrepancies reported in the literature, we use amino acid racemization and radiocarbon dating to confirm the presence of beach ridge deposits from Marine Isotope Stage (MIS) 5 and MIS 1. Fourteen ichnotaxa are recorded in the study area. Additionally, distinct variations in the pattern of bioerosion across different ages are observed, indicating that environmental changes occurred in the northern San Jorge Gulf between the MIS 5 interglacial and the Holocene. This reinforces the hypothesis that there is an association between bioerosion, productivity and circulation in the Southern Atlantic Ocean.
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- Award ID(s):
- 2317409
- PAR ID:
- 10626694
- Publisher / Repository:
- John Wiley & Sons, Ltd.
- Date Published:
- Journal Name:
- Journal of Quaternary Science
- Volume:
- 40
- Issue:
- 3
- ISSN:
- 0267-8179
- Page Range / eLocation ID:
- 481 to 499
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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