Asynchronous glaciations in arid continental climate

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dc.contributor.authorBatbaatar, Jen_AU
dc.contributor.authorGillespie, ARen_AU
dc.contributor.authorFink, Den_AU
dc.contributor.authorMatmon, Aen_AU
dc.contributor.authorFujioka, Ten_AU
dc.date.accessioned2021-12-16T20:59:08Zen_AU
dc.date.available2021-12-16T20:59:08Zen_AU
dc.date.issued2018-02-15en_AU
dc.date.statistics2021-11-16en_AU
dc.description.abstractMountain glaciers at ∼26–19 ka, during the global Last Glacial Maximum near the end of the last 105 yr glacial cycle, are commonly considered on the basis of dating and field mapping in several well-studied areas to have been the largest of the late Quaternary and to have advanced synchronously from region to region. However, a numerical sensitivity model (Rupper and Roe, 2008) predicts that the fraction of ablation due to melting varies across Central Asia in proportion to the annual precipitation. The equilibrium-line altitude of glaciers across this region likely varies accordingly: in high altitude, cold and arid regions sublimation can ablate most of the ice, whereas glaciers fed by high precipitation cannot ablate completely due to sublimation alone, but extend downhill until higher temperatures there cause them to melt. We have conducted field studies and 10Be dating at five glaciated sites along a precipitation gradient in Mongolia to test the Rupper/Roe model. The sites are located in nearby 1.875 × 1.875° cells of the Rupper/Roe model, each with a different melt fraction, in this little-studied region. The modern environment of the sites ranges from dry subhumid in the north (47.7° N) to arid in the south (45° N). Our findings show that the maximum local advances in the dry subhumid conditions predated the global Last Glacial Maximum and were likely from MIS 3. However, we also found that at ∼8–7 ka a cirque glacier in one mountain range of the arid Gobi desert grew to a magnitude comparable to that of the local maximum extent. This Holocene maximum occurred during a regional pluvial period thousands of years after the retreat of the Pleistocene glaciers globally. This asynchronous behavior is not predicted by the prevailing and generally correct presumption that glacier advances are dominantly driven by temperature, although precipitation also plays a role. Our findings are consistent with and support the Rupper/Roe model, which calls for glaciation in arid conditions only at high altitudes of sub-freezing temperatures, where the melt fraction in ablation is low. We expect a heterogeneous pattern of glacial responses to a changing modern climate in cold arid regions; an individual glacier advance should not be necessarily interpreted as evidence of cooling climate.© 2017 Elsevier Ltd.en_AU
dc.identifier.citationBatbaatar, J, Gillespie, A. R., Fink, D., Matmon, A., & Fujioka, T. (2018). Asynchronous glaciations in arid continental climate. Quaternary Science Reviews, 182, 1-19. doi:10.1016/j.quascirev.2017.12.001en_AU
dc.identifier.issn0277-3791en_AU
dc.identifier.journaltitleQuaternary Science Reviewsen_AU
dc.identifier.pagination1-19en_AU
dc.identifier.urihttps://doi.org/10.1016/j.quascirev.2017.12.001en_AU
dc.identifier.urihttps://apo.ansto.gov.au/dspace/handle/10238/12502en_AU
dc.identifier.volume182en_AU
dc.language.isoenen_AU
dc.publisherElsevieren_AU
dc.subjectGlaciersen_AU
dc.subjectMountainsen_AU
dc.subjectAsiaen_AU
dc.subjectBeryllium 10en_AU
dc.subjectAge estimationen_AU
dc.subjectQuaternary perioden_AU
dc.subjectMongoliaen_AU
dc.subjectClimatesen_AU
dc.subjectDesertsen_AU
dc.subjectArid landsen_AU
dc.titleAsynchronous glaciations in arid continental climateen_AU
dc.typeJournal Articleen_AU
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