DOI: 10.1016/j.palaeo.2013.09.019
论文题名: Mountain building and the initiation of the greenland ice sheet
作者: Solgaard A.M. ; Bonow J.M. ; Langen P.L. ; Japsen P. ; Hvidberg C.S.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2013
卷: 392 起始页码: 161
结束页码: 176
语种: 英语
英文关键词: Atmosphere ice sheet interaction
; Ice sheet initiation
; Mountain building
; Pliocene
英文摘要: The effects of a new hypothesis about mountain building in Greenland on ice sheet initiation are investigated using an ice sheet model in combination with a climate model. According to this hypothesis, low-relief landscapes near sea level characterised Greenland in Miocene times until two phases of km-scale uplift in the late Miocene and in the latest Miocene-Pliocene (beginning at 10 and ~. 5. Ma, respectively) initiated the formation of the present-day mountains. The topography of Greenland, prior to these uplift events is reconstructed from the present-day, isostatically compensated bedrock by mapping the two main steps in the landscape that resulted from the two uplift phases. Ice sheet initiation is studied using the topography before uplift and after each phase of uplift by applying different forcing conditions relevant for the late Cenozoic, which was characterised by long-term cooling superimposed by cold and warm excursions. The modelling results show that no ice initiates in the case of the low-lying and almost flat topography prior to the uplifts. However, the results demonstrate a significant ice sheet growth in response to the orographically induced increase in precipitation and the cooling of surface temperatures accompanying the uplift. Large amounts of ice are able to form after the first uplift event, but the ice sheet is sensitive to changes in climate. The results show that the second phase of uplift facilitates ice sheet build-up further and increases the stability of the ice sheet by providing anchoring points which are not available to the same extent in the lower topographies. However, the results also reveal a Föhn effect that inhibits ice sheet expansion into the interior Greenland and thus shifts the threshold of formation of inland ice towards colder temperatures. Under conditions that are colder than the present, the ice can overcome the Föhn effect, flow into the interior and form a coherent ice sheet. The results thus indicate that the Greenland Ice Sheet of today is a relict formed under colder conditions. The modelling results are consistent with the observed climatic variability superimposed on the general cooling trend in the late Cenozoic: e.g., ice rafted debris in late Miocene deposits off southeast Greenland and the mid-Pliocene Warmth. The late Cenozoic mountain building in Greenland augments the effects of the climatic deterioration leading to the Northern Hemisphere glaciations, and without the second phase of uplift, the Greenland Ice Sheet would have been more sensitive to the changes in climate over the past millions of years. © 2013 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69563
Appears in Collections: 过去全球变化的重建
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作者单位: Centre for Ice and Climate, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen Ø, Denmark; Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, 1350 Copenhagen K, Denmark; Danish Meteorological Institute (DMI), Lyngbyvej 100, 2100 Copenhagen Ø, Denmark; School of Natural Sciences, Technology and Environmental Studies, Södertörn University, SE-14189 Huddinge, Sweden
Recommended Citation:
Solgaard A.M.,Bonow J.M.,Langen P.L.,et al. Mountain building and the initiation of the greenland ice sheet[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2013-01-01,392