@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 {2797,
	title = {Analysis of multiple cosmogenic nuclides constrains Laurentide Ice Sheet history and process on Mt. Mansfield, Vermont{\textquoteright}s highest peak},
	journal = {Quaternary Science Reviews},
	volume = {205},
	year = {2019},
	month = {Jan-02-2019},
	pages = {234 - 246},
	abstract = {Constraining glacial history and process on Mt Mansfield, the highest peak in Vermont (1339 m a.s.l.), provides insight into how the Laurentide Ice Sheet shaped the underlying landscape, when latest Pleistocene ice retreated, and how upland and lowland glacial histories relate. Here, we quantify in situ cosmogenic 10Be in 20 bedrock and boulder surfaces, as well as in situ cosmogenic 14C in three of those surfaces, to assess subglacial erosion and exposure history. Isotopic concentrations indicate that Mt. Mansfield{\textquoteright}s lower elevations (\~{}400{\textendash}1200 m a.s.l.) were deeply eroded by at least several meters during the last glaciation and then deglaciated rapidly; 10Be ages across this elevation span are indistinguishable and average 13.9 {\textpm} 0.6 ka (n = 15), suggesting that 800 m of ice thinning occurred within at most about a millennium. Conversely, the higher elevations (>1200 m a.s.l.) preserve a more complex geomorphic history. Mt. Mansfield{\textquoteright}s summit surfaces contain 10Be from previous periods of exposure, indicating that the mountaintop landscapes were likely preserved beneath cold-based, weakly-erosive glacial ice. Exposure ages from the shorter-lived isotope, 14C, are younger (9.7 and 11.7 ka), suggesting that Mt. Mansfield{\textquoteright}s summit was covered until the early Holocene, perhaps by snowfields, ice carapaces, and/or till. Our findings, in context of previous work, suggest that thinning Laurentide ice flowed through the valleys for at most hundreds of years following deglaciation of the uplands, but that the summit remained shielded by ice or sediment for millennia after the valleys became ice-free.},
	keywords = {Cosmogenic isotopes, erosion, Geochronology, Glaciation, Last glacial maximum, North America, Pleistocene},
	issn = {02773791},
	doi = {10.1016/j.quascirev.2018.12.014},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0277379118307145},
	author = {Corbett, Lee B. and Bierman, Paul R. and Wright, Stephen F. and Shakun, Jeremy D. and Davis, P. Thompson and Goehring, Brent M. and Halsted, Christopher T. and Koester, Alexandria J. and Caffee, Marc W. and Zimmerman, Susan R.}
}
