Glacial landscape evolution in the Uummannaq region, West Greenland

Abstract

Citation for published item:vneD FF nd oertsD hFrF nd ¡ y gofighD gF nd eD fFF nd ieliD eF @PHITA 9qlil lndspe evolution in the ummnnq regionD est qreenlndF9D foresFD RS @PAF ppF PPHEPQRF Further information on publisher's website: httpXGGdxFdoiForgGIHFIIIIGorFIPISH Publisher's copyright statement: his is the epted version of the following rtileX vneD F FD oertsD hF rFD ¡ y gofighD gFD eD fF F ieliD eFX qlil lndspe evolution in the ummnnq regionD est qreenlndF foresD RS@PAX PPHEPQRD whih hs een pulished in (nl form t httpXGGdxFdoiForgGIHFIIIIGorFIPISHF his rtile my e used for nonEommeril purposes in ordne ith iley erms nd gonditions for selfErhivingF Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. The Uummannaq region is a mosaic of glacial landsystems, consistent with hypothesised landscape distribution resulting from variations in subglacial thermal regime. The region is dominated by selective linear erosion which has spatially and altitudinally partitioned the landscape. Low altitude areas are dominated by glacial scour, with higher elevations are dominated by plateaux or mountain valley and cirque glaciers. The appearance and nature of each landscape type varies locally with altitude and latitude, as a function of bedrock geology and average glacial conditions. Selective linear erosion has been a primary control on landscape distribution throughout Uummannaq, leading to plateau formation and the growth of a coalescent fjord system in the Uummannaq region. This has allowed the development of the Uummannaq ice stream's (UIS) onset zone during glacial periods.Fjord development has been enhanced by a down-stream change in geology to less-resistant lithologies, increasing erosional efficiency and allowing a single glacial channel to develop, encouraging glacier convergence and the initiation of ice streaming. The landscape has been affected by several periods of regional uplift from 33 Ma to present, and has been subject to subsequent fluvial and glacial erosion. Uplift has removed surfaces from the impact of widespread warm-based glaciation, leaving them as relict landsurfaces. The result of this is a regional altitude-dependant continuum of glacial modification, with extreme differences in erosion between high and low elevation surfaces.This study indicates that processes of long-term uplift, glacial erosion/protection, and spatial variability in erosion intensity have produced a highly partitioned landscape.Timothy P. Lane

The Impact of Lithology on Fjord Morphology

“…The scaling between fjord width and drainage area (or ice discharge) varies with lithology, with broader valleys associated with softer rocks (i.e., sedimentary rocks); consistent with previous observations (Swift et al., 2008). The influence of lithology on fjord morphology has also been described for a variety of lithologies in West Greenland (Lane et al., 2016), Iceland (Brook et al., 2004), Scotland (Brook et al., 2004; Krabbendam & Glasser, 2011), New‐Zealand (Augustinus, 1992a), Norway (Nesje & Whillans, 1994), and Patagonia (Glasser & Ghiglione, 2009), thus supporting our results. To test whether our results strongly depend on the reference elevation, we performed the same morphological analyses but considering sea‐level as an absolute reference elevation from where to measure fjord width and depth following Augustinus (1992b).…”

“…The scaling between fjord width and drainage area (or ice discharge) varies with lithology, with broader valleys associated with softer rocks (i.e., sedimentary rocks); consistent with previous observations (Swift et al, 2008). The influence of lithology on fjord morphology has also been described for a variety of lithologies in West Greenland (Lane et al, 2016), Iceland (Brook et al, 2004), Scotland (Brook et al, 2004;Krabbendam & Glasser, 2011), New-Zealand (Augustinus, 1992a), Norway (Nesje & Whillans, 1994), and Patagonia (Glasser 4) and (e and f) varying by an order of magnitude k 1 for abrasion (Equation 1). (c and g) Cross-sectional views of the resulting fjords shown along one transect downstream.…”

“…Determining the controlling factors of fjord development is required to reconstruct or predict the evolution of ice sheets, as the amount of ice drained by fjords strongly depends on their size and morphology. In some regions, fjords display contrasting morphologies at the boundary between different lithologies (Lane et al, 2016;Swift et al, 2008), or along structural weaknesses (Glasser & Ghiglione, 2009;Nesje & Whillans, 1994). However, it is unclear how the erosion processes interact with different lithological properties to produce these variable shapes.It is well recognized that the pace and mechanics of glacial erosion depend on bedrock properties (Augusti-…”

Arctic tsunamis threaten coastal landscapes and communities – survey of Karrat Isfjord 2017 tsunami effects in Nuugaatsiaq, western Greenland

“…Bendixen et al, 2017;Strzelecki et al, 2018) or rocky coast interaction with coastal permafrost (e.g. Strzelecki et al, 2017;Lim et al, 2020). At the same time little attention was paid to cold-region tsunami hazards whose effects are devastating to both human and natural coastal environments.…”

The impact of lithology on fjord morphology

“…Determining the controlling factors of fjord development is required to reconstruct or predict the evolution of ice sheets, as the amount of ice drained by fjords strongly depends on their size and morphology. In some regions, fjords display contrasting morphologies at the boundary between different lithologies (Lane et al, 2016;Swift et al, 2008), or along structural weaknesses (Glasser & Ghiglione, 2009;Nesje & Whillans, 1994). However, it is unclear how the erosion processes interact with different lithological properties to produce these variable shapes.…”