Early and Middle Pleistocene glaciation of the southern Patagonian plain

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dc.contributor.authorGriffing, Corinne Y.
dc.contributor.authorClague, John J.
dc.contributor.authorBarendregt, René W.
dc.contributor.authorErcolano, Bettina
dc.contributor.authorCorbella, Hugo
dc.contributor.authorRabassa, Jorge
dc.contributor.authorRoberts, Nicholas J.
dc.date.accessioned2022-01-13T01:12:11Z
dc.date.available2022-01-13T01:12:11Z
dc.date.issued2022
dc.descriptionOpen access article. Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0) appliesen_US
dc.description.abstractEvidence of at least three Early to Middle Pleistocene glaciations is recorded in the stratigraphic exposures near the outer limit of glaciation in southern Patagonia. At Cabo Vírgenes, at the mouth of the Strait of Magellan, up to 70 m of till, gravel, sand, and stony silt were deposited in a grounding-line environment at the front of the Magellan lobe along a front several tens of kilometres wide. Accommodation space for the sediments was produced by glacio-isostatic depression resulting from the advance of the Magellan lobe to the Atlantic coast. At that time, the ‘moat’ in which the sediments accumulated may have been seaward of the modern Atlantic shoreline because the continental shelf is shallow and sea level was much lower than it is today. The sediments at Cabo Vírgenes are normally magnetized, carry no reversed overprints, and thus probably date to the Brunhes Chron (<0.774 Ma). Seacliff exposures south of the Strait of Magellan along the Atlantic coast of northern Tierra de Fuego expose two tills separated by glaciofluvial sediments. Although not dated, the tills record two advances of the Magellan lobe onto the Atlantic continental shelf. The location of the exposures relative to Cabo Vírgenes indicates that the upper of the two tills may correlate with the Cabo Vírgenes drift. The Tres de Enero highway cut, 90 km northwest of Cabo Vírgenes, exposes lodgement tills deposited during the Great Patagonian glaciation (GPG) – two stacked, normally magnetized tills overlie a reversely magnetized till. Truncated sand wedges separate each of the three tills, indicating that the tills record three separate Early to Middle Pleistocene glaciations. The younger of the two normally magnetized tills, and perhaps both, were deposited in the Brunhes Chron; the lowest, reversely magnetized till records extensive glaciation late during the Matuyama Chron (2.608–0.780 Ma). At Bella Vista in the Río Gallegos valley, a 0.89-Ma-old basalt flow caps a thick unit of normally magnetized glaciofluvial gravel, which was probably deposited during the Jaramillo Subchron (1.075–0.991 Ma), but certainly not later. Sediments at Tres de Enero and Bella Vista show that the GPG is not a single event as originally thought, but rather at least three glaciations, perhaps spanning several hundred thousand years.en_US
dc.description.peer-reviewYesen_US
dc.identifier.citationGriffing, C. Y., Clague, J. J., Barendregt, R. W., Ercolano, Bettina, Corbella, H., Rabassa, J., & Roberts, N. J. (2022). Early and Middle Pleistocene glaciation of the southern Patagonian plain. Journal of South American Earth Sciences, 114, E103687. https://doi.org/10.1016/j.jsames.2021.103687en_US
dc.identifier.urihttps://hdl.handle.net/10133/6130
dc.language.isoen_USen_US
dc.publisherElsevieren_US
dc.publisher.departmentDepartment of Geography and Environmenten_US
dc.publisher.facultyArts and Scienceen_US
dc.publisher.institutionSimon Fraser Universityen_US
dc.publisher.institutionDouglas Collegeen_US
dc.publisher.institutionUniversity of Lethbridgeen_US
dc.publisher.institutionUniversidad Nacional de la Patagonia Australen_US
dc.publisher.institutionMuseo-Argentino de Ciencias Naturales CONICETen_US
dc.publisher.institutionCADIC-CONICETen_US
dc.publisher.institutionMineral Resources Tasmaniaen_US
dc.publisher.urlhttps://doi.org/10.1016/j.jsames.2021.103687en_US
dc.subjectCabo vírgenes glaciationen_US
dc.subjectGreat patagonian glaciationen_US
dc.subjectMiddle pleistoceneen_US
dc.subjectPaleomagnetismen_US
dc.subjectPatagoniaen_US
dc.subjectArgentinaen_US
dc.subjectGlaciation
dc.subjectEarly Pleistocene
dc.subject.lcshVirgins, Cape (Argentina)
dc.subject.lcshPaleomagnetism--Argentina
dc.subject.lcshGlaciology--Argentina
dc.subject.lcshDrift--Argentina
dc.subject.lcshGeology, Stratigraphic--Pleistocene
dc.subject.lcshPatagonia (Argentina and Chile)
dc.titleEarly and Middle Pleistocene glaciation of the southern Patagonian plainen_US
dc.typeArticleen_US
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