@article {2964,
	title = {Ice-sheet expansion from the Ross Sea into McMurdo Sound, Antarctica, during the last two glaciations},
	journal = {Quaternary Science Reviews},
	volume = {278},
	year = {2022},
	month = {Jan-02-2022},
	pages = {107379},
	abstract = {An understanding of Antarctic Ice Sheet (AIS) behavior is important for future sea-level predictions. Here, we examine past ice-sheet history in the McMurdo Sound region of the western Ross Sea over the last two glacial-interglacial cycles in order to gain insight into the drivers of ice-sheet change. Surficial mapping, along with radiocarbon dates of lacustrine algae and uranium-thorium disequilibrium dates of lacustrine carbonates from ice-dammed lakes, allow reconstruction of the timing and origin of grounded ice in McMurdo Sound during the last glacial maximum (LGM) and penultimate glaciation. During the LGM, ice-surface elevation profiles and distribution of erratics indicate ice flow into southern McMurdo Sound from the Ross Sea, rather than seaward expansion of local glaciers from the Royal Society Range. The grounded ice in McMurdo Sound flowed westward to block the mouths of valleys in the Royal Society Range and to dam proglacial lakes. In Marshall Valley, maximum ice extent during what is termed the Ross Sea glaciation, was achieved by 18 ka and remained close to this position until after 14 ka. The pattern of surficial deposits suggests that ice during the penultimate glaciation, locally named the Marshall glaciation, was slightly more extensive than that of the LGM but had a similar Ross Sea origin. Maximum ice extent in Marshall Valley occurred at \~{}145{\textendash}150 ka; the grounded ice may have receded from the valley mouth shortly after 138 ka. Both ice expansions occurred broadly during times of low Antarctic air temperatures, which have been linked to insolation minima. However, the lack of widespread surface melting ablation zones on the AIS indicates that the link between ice expansion and orbital forcing is likely to be indirect and possibly driven through the ocean. Closer examination of the precise timing of the glacial maxima in Marshall Valley shows that the Marshall glaciation occurred synchronously with the penultimate global maximum; ice recession took place during Termination II. In contrast, maximum ice extent during the Ross Sea glaciation along the Royal Society Range occurred after the global LGM, during Termination I. Deglaciation was primarily an early Holocene event. We attribute this delayed maximum and deglaciation (relative to global events) to the effect of rising accumulation on ice-sheet mass balance.},
	issn = {02773791},
	doi = {10.1016/j.quascirev.2022.107379},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0277379122000105},
	author = {Heath, Stephanie and Hall, Brenda L. and Denton, George H. and Henderson, Gideon M. and Hendy, Chris H.}
}
@article {denton_zealandia_2021,
	title = {The Zealandia Switch: Ice age climate shifts viewed from Southern Hemisphere moraines},
	journal = {Quaternary Science Reviews},
	volume = {257},
	year = {2021},
	month = {04/2021},
	pages = {106771},
	abstract = {Two fundamental questions about the ice-age climate system await satisfactory resolution. First, if summer solar radiation intensity truly controls the orbital signature of the last glacial cycle, then why were major climatic shifts, including the last termination, globally synchronous? Second, what caused the millennial-scale climate oscillations superimposed on this cycle? We address these questions from a Southern Hemisphere perspective focused on mid-latitude mountain ice fields. We put particular emphasis on the last glacial termination, which involved both orbital-scale and millennial-scale climate elements and has generally well-resolved chronological control. Sustained retreat of mountain glaciers, documented by detailed mapping and chronology of glacial landforms in the Southern Alps and southern Andes, marked the termination of the last ice age, beginning \~{}18 kyrs ago and involved a change from glacial to near-interglacial atmospheric temperature within a millennium or two. A rapid poleward shift of the Subtropical Front, delineating the northern margin of the Southern Ocean, \~{}18 kyrs ago implies a concurrent poleward shift of the austral westerlies and leads us to hypothesize a southern origin for the dominant phase of the last glacial termination. Together with interhemispheric paleoclimate records and with results of coupled ocean-atmosphere climate modeling, these findings suggest a big, fast, and global end to the last ice age in which a southern-sourced warming episode linked the hemispheres. We posit that a shift in the Southern Ocean circulation and austral westerly wind system, tied to southern orbital forcing, caused this global warming episode by affecting the tropical heat engine and hence global climate. Central to this hypothesis, dubbed the {\textquoteleft}Zealandia Switch{\textquoteright}, is the location of the Australia and Zealandia continents relative to Southern Hemisphere oceanic and atmospheric circulation. Coupled ocean-atmosphere climate modeling shows that the locus of the austral westerlies, whether in a more equatorward position representing a glacial-mode climate or in a poleward-shifted position marking interglacial-mode climate, has profound effects on oceanic and associated atmospheric linkages between the tropical Pacific and the Southern Ocean. Shifts in the austral westerlies have global climatic consequences, especially through resulting changes in the greenhouse gas content of the atmosphere and altered heat flux from the tropical Pacific into the Northern and Southern Hemispheres. We suggest that the last glacial termination was a global warming episode that led to extreme seasonality in northern latitudes by stimulating a flush of meltwater and icebergs into the North Atlantic from adjoining ice sheets. This fresh-water influx resulted in widespread North Atlantic sea ice that caused very cold boreal winters, thus amplifying the annual southward shift of the Intertropical Convergence Zone and the monsoonal rain belts. We further suggest that muted manifestations of the Zealandia Switch mechanism were responsible for smaller, recurring millennial-scale climate oscillations within the last glacial cycle.},
	keywords = {Climate dynamics, Climate modeling, Cosmogenic isotopes, Geomorphology, Glacial, Glaciation, paleoclimatology, Quaternary, South Pacific Ocean, Southern Hemisphere westerlies, Southern Ocean},
	issn = {0277-3791},
	doi = {10.1016/j.quascirev.2020.106771},
	url = {https://www.sciencedirect.com/science/article/pii/S0277379120307332},
	author = {Denton, George H. and Putnam, Aaron E. and Russell, Joellen L. and Barrell, David J. A. and Schaefer, Joerg M. and Kaplan, Michael R. and Strand, Peter D.}
}
@article {2801,
	title = {Asynchronous behavior of the Antarctic Ice Sheet and local glaciers during and since Termination 1, Salmon Valley, Antarctica},
	journal = {Earth and Planetary Science Letters},
	volume = {482},
	year = {2018},
	month = {Jan-01-2018},
	pages = {396 - 406},
	abstract = {The stability of the Antarctic Ice Sheet under future warming remains an open question with broad implications for sea-level prediction and adaptation. In particular, knowledge of whether the ice sheet has the capacity for rapid drawdown or collapse, or whether it can remain stable during periods of warming, is essential for predicting its future behavior. Here we use 55 radiocarbon dates, coupled with geomorphologic mapping, to reconstruct the timing of changes in ice extent and elevation during the last ice-age termination in Salmon Valley, adjacent to McMurdo Sound in the western Ross Sea Embayment. Results indicate that a grounded ice sheet in the Ross Sea Embayment achieved its maximum elevation and extent along the headlands of Salmon Valley at \~{}18,000 yr BP, during a period of increasing temperatures and accumulation over the Antarctic continent. This ice remained at or near its maximum on the headlands near the valley mouth until after \~{}14,000 yr BP. Removal of grounded Ross Sea ice from Salmon Valley was complete shortly after \~{}7900 yr BP, indicating that the grounding line had retreated through southern McMurdo Sound by that time. We suggest the primary driver of Ross Sea ice removal from McMurdo Sound was marine-based, either through basal melting or calving due to sea-level rise. When combined with regional data, the Salmon Valley record suggests that this sector of the Antarctic Ice Sheet did not contribute in a significant way to deglacial meltwater pulses, such as meltwater pulse 1a. In contrast to the Ross Sea ice, our work also shows that local, independent alpine glaciers in Salmon Valley have advanced through the Holocene. Land-terminating glaciers such as these elsewhere in the region show a similar pattern, and may reflect the continued influence of increased accumulation following the termination of the last ice age.},
	keywords = {Antarctic Ice Sheet, glacial geomorphology, ice sheet stability, Termination I},
	issn = {0012821X},
	doi = {10.1016/j.epsl.2017.11.038},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0012821X1730674X},
	author = {Jackson, Margaret S. and Hall, Brenda L. and Denton, George H.}
}
@article {39,
	title = {Holocene glacier history of the Lago Argentino basin, Southern Patagonian Icefield},
	journal = {Quaternary Science Reviews},
	volume = {101},
	year = {2014},
	pages = {124-145},
	abstract = {We present new geomorphic, stratigraphic, and chronologic data for Holocene glacier fluctuations in the Lago Argentino basin on the eastern side of the southern Patagonian Andes. Chronologic control is based on 14C and surface-exposure 10Be dating. After the Lateglacial maximum at 13,000 cal yrs BP, the large ice lobes that filled the eastern reaches of Lago Argentino retreated and separated into individual outlet glaciers; this recession was interrupted only by a stillstand or minor readvance at 12,200 cal yrs BP. The eight largest of these individual outlet glaciers are, from north to south: Upsala, Agassiz, Onelli, Spegazzini, Mayo, Ameghino, Perito Moreno, and Grande (formerly Fr{\'\i}as). Holocene recession of Upsala Glacier exposed Brazo Cristina more than 10,115 {\textpm} 100 cal yrs BP, and reached inboard of the Holocene moraines in Agassiz Este Valley by 9205 {\textpm} 85 cal yrs BP; ice remained in an inboard position until 7730 {\textpm} 50 cal yrs BP. Several subsequent glacier readvances are well documented for the Upsala and Fr{\'\i}as glaciers. The Upsala Glacier readvanced at least seven times, the first being a relatively minor expansion {\textendash} documented only in stratigraphic sections {\textendash} between 7730 {\textpm} 50 and 7210 {\textpm} 45 cal yrs BP. The most extensive Holocene advances of Upsala Glacier resulted in the deposition of the Pearson 1 moraines and related landforms, which are divided into three systems. The Pearson 1a advance occurred about 6000{\textendash}5000 cal yrs BP and was followed by the slightly less-extensive Pearson 1b and 1c advances dated to 2500{\textendash}2000 and 1500{\textendash}1100 cal yrs BP, respectively. Subsequent advances of Upsala Glacier resulted in deposition of the Pearson 2 moraines and corresponding landforms, also separated into three systems, Pearson 2a, 2b, and 2c, constructed respectively at \~{}700, >400, and <300 cal yrs BP to the early 20th century. Similar advances are also recorded by moraine systems in front of Grande Glacier and herein separated into the Fr{\'\i}as 1 and Fr{\'\i}as 2a, 2b, and 2c. The Onelli and Ameghino glacier valleys also preserve older Holocene moraines. In the Agassiz, Spegazzini, and Mayo valleys, ice of the late-Holocene advances appears to have overridden landforms equivalent in age to Pearson 1. Perito Moreno Glacier is an extreme case in which ice of historical (Pearson 2c) advances overrode all older Holocene moraines. Based on the distribution and number of moraines preserved, we infer that the response to climate differed among the Lago Argentino outlet glaciers during the Holocene. This led us to examine the effects of climatic and non-climatic factors on individual glaciers. As a consequence, we detected an important effect of the valley geometry (hypsometry) on the timing and magnitude of glacier response to climate change. These results indicate that caution is needed in correlating moraines among glacier forefields without firm morpho-stratigraphic and age control. Finally, we note important similarities and differences between the overall moraine chronology in the Lago Argentino basin and that in other areas of southern South America and elsewhere in the Southern Hemisphere.},
	issn = {0277-3791},
	doi = {10.1016/j.quascirev.2014.06.026},
	url = {http://www.sciencedirect.com/science/article/pii/S0277379114002558},
	author = {Strelin, Jorge A. and Kaplan, Michael R. and Vandergoes, Marcus J. and Denton, George H. and Schaefer, Joerg M.}
}
@article {104,
	title = {Extensive recession of Cordillera Darwin glaciers in southernmost South America during Heinrich Stadial 1},
	journal = {Quaternary Science Reviews},
	volume = {62},
	year = {2013},
	note = {id: 2331},
	pages = {49-55},
	abstract = {The geographic expression and phasing of events during the last termination are important for isolating mechanisms that caused Earth to emerge from the last ice age. Heinrich Stadial 1 (HS1; 14,600{\textendash}18,000 yr BP) is a key because of the central role that its far-field effects had on the last termination in the Southern Hemisphere. Here, we present new data from Cordillera Darwin that show rapid glacier recession in southern South America during HS1. This retreat was coeval with ice recession elsewhere in South America and New Zealand, with increased upwelling in the Southern Ocean, with warming of SSTs offshore of Chile, and with a rise in atmospheric CO2. Together, these data indicate a coherent and rapid response to the effects of HS1 in the middle and high latitudes of the Southern Hemisphere.},
	issn = {0277-3791},
	doi = {10.1016/j.quascirev.2012.11.026},
	url = {http://www.sciencedirect.com/science/article/pii/S0277379112005057},
	author = {Hall, Brenda L. and Porter, Charles T. and Denton, George H. and Lowell, Thomas V. and Bromley, Gordon R. M.}
}
@article {92,
	title = {Late Holocene expansion of Istorvet ice cap, Liverpool Land, east Greenland},
	journal = {Quaternary Science Reviews},
	volume = {63},
	year = {2013},
	note = {id: 2290},
	pages = {128-140},
	abstract = {The Greenland Ice Sheet is undergoing dynamic changes that will have global implications if they continue into the future. In this regard, an understanding of how the ice sheet responded to past climate changes affords a baseline for anticipating future behavior. Small, independent ice caps adjacent to the Greenland Ice Sheet (hereinafter called {\textquotedblleft}local ice caps{\textquotedblright}) are sensitive indicators of the response of Greenland ice-marginal zones to climate change. Therefore, we reconstructed late Holocene ice-marginal fluctuations of the local Istorvet ice cap in east Greenland, using radiocarbon dates of subfossil plants, 10Be dates of surface boulders, and analyses of sediment cores from both threshold and control lakes. During the last termination, the Istorvet ice cap had retreated close to its maximum Holocene position by \~{}11,730 cal yr BP. Radiocarbon dates of subfossil plants exposed by recent recession of the ice margin indicate that the Istorvet cap was smaller than at present from AD 200 to AD 1025. Sediments from a threshold lake show no glacial input until the ice cap advanced to within 365 m of its Holocene maximum position by \~{}AD 1150. Thereafter the ice cap remained at or close to this position until at least AD 1660. The timing of this, the most extensive of the Holocene, expansion is similar to that recorded at some glaciers in the Alps and in southern Alaska. However, in contrast to these other regions, the expansion in east Greenland at AD 1150 appears to have been very close to, if not at, a maximum Holocene value. Comparison of the Istorvet ice-cap fluctuations with Holocene glacier extents in Southern Hemisphere middle-to-high latitude locations on the Antarctic Peninsula and in the Andes and the Southern Alps suggests an out-of-phase relationship. If correct, this pattern supports the hypothesis that a bipolar see-saw of oceanic and/or atmospheric circulation during the Holocene produced asynchronous glacier response at some localities in the two polar hemispheres.},
	issn = {0277-3791},
	doi = {10.1016/j.quascirev.2012.11.012},
	url = {http://www.sciencedirect.com/science/article/pii/S0277379112004830},
	author = {Lowell, Thomas V. and Hall, Brenda L. and Kelly, Meredith A. and Bennike, Ole and Lusas, Amanda R. and Honsaker, William and Smith, Colby A. and Levy, Laura B. and Travis, Scott and Denton, George H.}
}
