Fredrik Høgaas , Anders Romundset , Katherine Aurand , Jacob Bendle , Mikis van Boeckel , Louise Hansen , Oddvar Longva
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引用次数: 0
Abstract
The final demise of the Scandinavian Ice Sheet in southern Norway was associated with partial glacial retreat in ice-dammed lakes, but how the subaqueous retreat affected glacial dynamics is largely unknown. Here, we present results from comprehensive mapping that demonstrate the existence and final catastrophic drainage of multiple ice-dammed lakes in southern Norway during the Early Holocene, as well as key landforms that detail the course of glacial retreat. We have identified several previously unknown ice-dammed lakes and described three hitherto unknown 15–80 km3-large glacial lake outburst floods. The floods formed mega dunes, large flood bars, canyons and other distinctive features in the impacted areas downstream. We present a relative chronology for the ice-dammed lakes and drainage events that, coupled with existing chronological constraints, allow detailed palaeoglaciology reconstructions in a period of rapid deglaciation. The ice-dammed lake record documents that the mountainous areas became ice-free first, whereas the large inland valleys in southern Norway were deglaciated last. The very last remnants of the Scandinavian Ice Sheet in southern Norway were probably located in the valleys around Jotunheimen. The ice-dammed lakes induced dynamic glacial retreat and probably caused a significant increase in ice-sheet drawdown and retreat rates compared to where glacial retreat was land-based, e.g. as indicated by a near tenfold increase in retreat rates when the Store Dølasjø ice-dammed lake formed, and the glacier became water-terminating. The study highlights the value of ice-dammed lakes for reconstructing palaeo-ice sheets, and the data serve as a relevant analogue for future ice mass loss in glacierized regions worldwide.
期刊介绍:
Quaternary Science Reviews caters for all aspects of Quaternary science, and includes, for example, geology, geomorphology, geography, archaeology, soil science, palaeobotany, palaeontology, palaeoclimatology and the full range of applicable dating methods. The dividing line between what constitutes the review paper and one which contains new original data is not easy to establish, so QSR also publishes papers with new data especially if these perform a review function. All the Quaternary sciences are changing rapidly and subject to re-evaluation as the pace of discovery quickens; thus the diverse but comprehensive role of Quaternary Science Reviews keeps readers abreast of the wider issues relating to new developments in the field.