DOI: 10.1016/j.quascirev.2016.07.024
Scopus记录号: 2-s2.0-84979895505
论文题名: The timing and cause of glacial advances in the southern mid-latitudes during the last glacial cycle based on a synthesis of exposure ages from Patagonia and New Zealand
作者: Darvill C.M. ; Bentley M.J. ; Stokes C.R. ; Shulmeister J.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2016
卷: 149 起始页码: 200
结束页码: 214
语种: 英语
英文关键词: Cosmogenic nuclide exposure dating
; Glacial advances
; Last glacial cycle
; New Zealand
; Patagonia
Scopus关键词: Climate change
; Isotopes
; Oceanography
; Sea ice
; Cosmogenic nuclides
; Glacial advances
; Last glacial cycles
; New zealand
; Patagonia
; Glacial geology
; atmosphere-ocean coupling
; cosmogenic radionuclide
; glacial erosion
; ice sheet
; Last Glacial Maximum
; Northern Hemisphere
; oceanic front
; sea ice
; seasonality
; westerly
; New Zealand
; Patagonia
; Southern Ocean
英文摘要: Glacier advances in the southern mid-latitudes during the last glacial cycle (ca. 110–10 ka) were controlled by changes in temperature and precipitation linked to several important ocean-climate systems. As such, the timing of glacial advance and retreat can yield important insights into the mechanisms of Southern Hemisphere climate change. This is particularly important given that several recent studies have demonstrated significant glacial advances prior to the global Last Glacial Maximum (gLGM) in Patagonia and New Zealand, the cause of which are uncertain. The recent increase in chronological studies in these regions offers the opportunity to compare regional trends in glacial activity. Here, we compile the first consistent10Be exposure-dating chronologies for Patagonia and New Zealand to highlight the broad pattern of mid-latitude glacial activity over the last glacial cycle. Our results show that advances or still stands culminated at 26–27 ka, 18–19 ka and 13–14 ka in both Patagonia and New Zealand and were broadly synchronous, but with an offset between regions of up to 900 years that cannot be explained by age calculation or physically plausible erosion differences. Furthermore, there is evidence in both regions for glacial advances culminating from at least 45 ka, during the latter half of Marine Isotope Stage (MIS) 3. Glacial activity prior to the gLGM differed from the large Northern Hemisphere ice sheets, likely due to favourable Southern Hemisphere conditions during late MIS 3: summer insolation reached a minimum, seasonality was reduced, winter duration was increasing, and sea ice had expanded significantly, inducing stratification of the ocean and triggering northward migration of oceanic fronts and the Southern Westerly Winds. Glacial advances in Patagonia and New Zealand during the gLGM were probably primed by underlying orbital parameters. However, the precise timing is likely to have been intrinsically linked to migration of the coupled ocean-atmosphere system, which may account for the small offset between Patagonia and New Zealand due to differences in oceanic frontal migration. During deglaciation, advances or still stands occurred in both regions during the southern Antarctic Cold Reversal (ca. 14.5–12.9 ka) rather than the northern Younger Dryas (ca. 12.9–11.7 ka). Our findings suggest that major rearrangements of the Southern Hemisphere climate system occurred at various times during the last glacial cycle, with associated impacts on the position and intensity of the Southern Westerly Winds and oceanic fronts, as well as wind-driven upwelling and degassing of the deep Southern Ocean. Thus, reconstructing the timing of glacial advance/retreat using our compilation is a powerful way to understand the mechanisms of past interhemispheric climate change. © 2016 Elsevier Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59475
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Geography, Durham University, South Road, Durham, United Kingdom; School of Geography Planning and Environmental Management, University of Queensland, Brisbane, QLD, Australia
Recommended Citation:
Darvill C.M.,Bentley M.J.,Stokes C.R.,et al. The timing and cause of glacial advances in the southern mid-latitudes during the last glacial cycle based on a synthesis of exposure ages from Patagonia and New Zealand[J]. Quaternary Science Reviews,2016-01-01,149