Paleoflood marks in sandur morphometry as the result of the glacier surge (NW Poland)

2012 ◽  
Vol 44 (2) ◽  
pp. 264-280 ◽  
Author(s):  
Joanna E. Szafraniec
Keyword(s):  
Drainage System ◽  
Indirect Evidence ◽  
Outlet Glacier ◽  
Terminal Moraine ◽  
Outburst Floods ◽  
Morphometric Features ◽  
Scandinavian Ice Sheet ◽  
The Individual ◽  
Moraine Ridge ◽  
Weichselian Glaciation

In the Pomeranian marginal zone of the last Pleistocene glaciation specific morphometric features are found. They represent indicators of surging events affecting the individual outlet glacier lobes of the Scandinavian Ice Sheet margin. They are assumed to have been active during the climate warming of the Weichselian glaciation decay. Many tunnel valleys deep-rooted in the proximal slopes of the terminal moraine ridge with incised gorges and wide extramarginal sandur fans spread from the mouths to the forefield. The relatively low relief intensity factor, the fluvioglacial sediments covering distal slopes of the terminal moraines and ‘washed out’ older forms may be considered as indirect evidence of outburst floods caused by a re-canalization of the subglacial drainage system. The morphometry of the palaeochannels in the gorge profiles are used to calculate estimates of extreme discharges (c. 5 × 103–105m3s–1).

scholarly journals Reconstructing the History of Glacial Lake Outburst Floods (GLOF) in the Kanchenjunga Conservation Area, East Nepal: An Interdisciplinary Approach

2020 ◽  
Vol 12 (13) ◽  
pp. 5407
Author(s):  
Alton C. Byers ◽  
Mohan Bahadur Chand ◽  
Jonathan Lala ◽  
Milan Shrestha ◽  
Elizabeth A. Byers ◽  
...  
Keyword(s):  
Interdisciplinary Approach ◽  
Debris Avalanche ◽  
Field Investigation ◽  
Glacial Lake ◽  
High Mountain ◽  
Lateral Moraine ◽  
Conservation Area ◽  
Terminal Moraine ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods

An interdisciplinary field investigation of historic glacial lake outburst floods (GLOFs) in the Kanchenjunga region of Nepal was conducted between April and May, 2019. Oral history and field measurements suggested that at least six major GLOFs have occurred in the region since 1921. A remote sensing analysis confirmed the occurrence of the six GLOFs mentioned by informants, including two smaller flood events not mentioned that had occurred at some point before 1962. A numerical simulation of the Nangama GLOF suggested that it was triggered by an ice/debris avalanche of some 800,000 m3 of material, causing a surge wave that breached the terminal moraine and released an estimated 11.2 × 106 m3 ± 1.4 × 106 m3 of water. Debris from the flood dammed the Pabuk Khola river 2 km below the lake to form what is today known as Chheche Pokhari lake. Some concern has been expressed for the possibility of a second GLOF from Nangama as the result of continued and growing landslide activity from its right lateral moraine. Regular monitoring of all lakes and glaciers is recommended to avoid and/or mitigate the occurrence of future GLOF events in the region. Collectively, the paper demonstrates the benefits and utility of interdisciplinary research approaches to achieving a better understanding of past and poorly documented GLOF events in remote, data-scarce high mountain environments.

scholarly journals Englacial drainage structures in an East Antarctic outlet glacier

2019 ◽  
Vol 66 (255) ◽  
pp. 166-174 ◽  
Author(s):  
Thomas Schaap ◽  
Michael J. Roach ◽  
Leo E. Peters ◽  
Sue Cook ◽  
Bernd Kulessa ◽  
...  
Keyword(s):  
Drainage System ◽  
Austral Summer ◽  
Greenland Ice Sheet ◽  
Radar Data ◽  
The Arctic ◽  
Outlet Glacier ◽  
Near Surface ◽  
Surface Mass ◽  
Hydrological System ◽  
Englacial Drainage

AbstractGround-penetrating radar data acquired in the 2016/17 austral summer on Sørsdal Glacier, East Antarctica, provide evidence for meltwater lenses within porous surface ice that are conceptually similar to firn aquifers observed on the Greenland Ice Sheet and the Arctic and Alpine glaciers. These englacial water bodies are associated with a dry relict surface basin and consistent with perennial drainage into an interconnected englacial drainage system, which may explain a large englacial outburst flood observed in satellite imagery in the early 2016/17 melt season. Our observations indicate the rarely-documented presence of an englacial hydrological system in Antarctica, with implications for the storage and routing of surface meltwater. Future work should ascertain the spatial prevalence of such systems around the Antarctic coastline, and identify the degree of surface runoff redistribution and storage in the near surface, to quantify their impact on surface mass balance.

Extent and Dynamics of the Scandinavian Ice Sheet during Oxygen Isotope Stage 3 (65,000–25,000 yr B.P.)

2002 ◽  
Vol 57 (1) ◽  
pp. 38-48 ◽  
Author(s):  
Neil S. Arnold ◽  
Tjeerd H. van Andel ◽  
Vidar Valen
Keyword(s):  
Sea Ice ◽  
Oxygen Isotope ◽  
Ice Sheet ◽  
Ice Cover ◽  
Glacial Maximum ◽  
Oxygen Isotope Stage ◽  
Free Interval ◽  
Scandinavian Ice Sheet ◽  
Weichselian Glaciation ◽  
Low Precipitation

AbstractThe climate of the middle Weichselian Glaciation, Marine Oxygen Isotope Stage 3 (OIS-3), a relatively mild period compared to the glacial maxima of OIS-4 and OIS-2, consisted of long warm interstades punctuated by brief cold excursions that grew colder and more frequent with time. The OIS-4 ice sheet is generally thought to have persisted throughout OIS-3, but evidence from dated OIS-3 interstadial deposits suggests that it was swiftly reduced to small remnants which only briefly expanded and retreated. Only 30,000 years ago the deteriorating climate initiated a sustained ice advance leading toward the final glacial maximum of OIS-2. Dynamic ice-sheet models support the existence of a prolonged ice-free interval during OIS-3 induced, perhaps, by low precipitation due to extensive sea-ice cover offshore.

Subglacial water pressure records from a fast-flowing outlet glacier in Greenland

2020 ◽  
Author(s):  
Samuel Doyle ◽  
Bryn Hubbard ◽  
Poul Christoffersen ◽  
Marion Bougamont ◽  
Robert Law ◽  
...  
Keyword(s):  
Water Pressure ◽  
Drainage System ◽  
Greenland Ice Sheet ◽  
Distinct Component ◽  
Outlet Glacier ◽  
Diurnal Cycles ◽  
Close Proximity ◽  
Hydrological System ◽  
Discharge Pressure ◽  
Glacier Motion

<p>Glacier motion is resisted by basal traction that can be reduced significantly by pressurised water at the ice-bed interface. Few records of subglacial water pressure have been collected from fast-flowing, marine-terminating glaciers despite such glaciers accounting for approximately half of total ice discharge from the Greenland Ice Sheet.  The paucity of such measurements is due to the practical challenges in drilling and instrumenting boreholes to the bed, in areas that are often heavily-crevassed, through rapidly-deforming ice that ruptures sensor cables within weeks. Here, we present pressure records and drilling observations from two sites located 30 km from the calving front of Store Glacier in West Greenland, where ice flow averages ~600 m yr<sup>-1</sup>.  In 2018, boreholes were drilled 950 m to the bed near the margin of a large, rapidly-draining supraglacial lake. In 2019, multiple boreholes were drilled ~1030 m to the bed in the centre of the drained supraglacial lake, and in close proximity to a large, active moulin. All boreholes drained rapidly when they intersected or approached the ice-bed interface, which is commonly interpreted as indicating connection to an active subglacial drainage system. Neighbouring boreholes responded to the breakthrough of subsequent boreholes demonstrating hydrological or mechanical inter-connection over a distance of ~70 m. Differences in the time series of water pressure indicate that each borehole intersected a distinct component of the subglacial hydrological system. Boreholes located within 250 m of the moulin reveal clear diurnal cycles either in phase or anti-phase with moulin discharge. Pressure records from boreholes located on the lake margin, however, show smaller amplitude, and less distinct, diurnal cycles superimposed on longer-period (e.g. multiday) variability. We compare these datasets to those in the literature and investigate consistencies and inconsistencies with glacio-hydrological theory.</p>

Glacial meltwater microbes: are there seasonal trends in exported assemblages over different catchment sizes?

2020 ◽  
Author(s):  
Kristýna Jachnická ◽  
Tyler J. Kohler ◽  
Lukáš Falteisek ◽  
Petra Vinšová ◽  
Marie Bulínová ◽  
...  
Keyword(s):  
Drainage System ◽  
Greenland Ice Sheet ◽  
Assemblage Structure ◽  
Rrna Gene ◽  
Outlet Glacier ◽  
Efficient System ◽  
Microbial Life ◽  
Sediment Bed ◽  
Catchment Size ◽  
Subglacial Drainage

<p>Glaciers and ice sheets host diverse microbial life within the hydrologically connected supraglacial, englacial, and subglacial habitats. Microbial cells are collected from the entire glacial ecosystem by seasonally-generated meltwater and exported by proglacial streams. Over the course of the melt season, a subglacial drainage system develops beneath outlet glaciers from the Greenland Ice Sheet (GrIS). This system evolves from an inefficient distributed network to a more efficient channelized pathway. The extent and interconnectivity of the subglacial drainage system with the surface and sediment bed is hypothesized to differ with catchment size.</p><p>In this study, we ask whether microbial export from GrIS outlet glacier systems depend on catchment size and whether they evolve with subglacial hydrology over time. We hypothesize that larger catchments will have proportionally greater subglacial drainage, which may be reflected in a greater proportion of subglacial microbes compared to smaller catchments, where the supraglacial inputs might have a higher influence on the exported meltwater. We also expect that changes in assemblage structure are likely to coincide with the evolution of the subglacial drainage system of larger catchments as the season progresses, with supraglacial inputs increasing in importance as the channelized efficient system fully develops. To test these hypotheses, we sampled three outlet glaciers of the GrIS with different catchment sizes (from biggest to smallest: Isunnguata Sermia, Leverett and Russell glaciers) over the 2018 summer. Meltwater samples were taken at the same time each day over a period of three weeks to catch temporal patterns of microbial assemblages. DNA was extracted from samples, and 16S rRNA gene amplicons sequenced to characterize assemblage structure.</p><p>This study will help us better understand the meltwater hydrology of the GrIS by describing patterns in its microbial export and the degree of influence from supra- and subglacial systems. In this current age of glacier recession, it is furthermore important to make these characterizations as we might not have opportunity in near future to investigate them in the same unchanged environment.</p>

THE CESTODA OF CANADIAN FISHES: II. THE HUDSON BAY DRAINAGE SYSTEM

1932 ◽  
Vol 7 (1) ◽  
pp. 377-403 ◽  
Author(s):  
ROBERT ARNOLD WARDLE
Keyword(s):  
New Species ◽  
North American ◽  
Drainage System ◽  
North American Species ◽  
Hudson Bay ◽  
Lota Lota ◽  
European Species ◽  
Two New Species ◽  
The Individual

The results are given of a survey of the cestode fauna of several thousand fishes representing thirty species common in the Hudson bay drainage system, particularly in the Hudson bay and in the larger lakes of Manitoba and Saskatchewan. The survey yielded twelve species of adult and seven species of larval cestodes, ten of which were identical with European species, while seven were purely North American. The incidence of infection was high and the individual intensity was heavy. The highest incidence and heaviest intensity occurred among nektonic types such as Hiodon, Leucichthys, Esox, Lucioperca and Salvelinus. Benthonic forms such as Catostomus, Ameiurus, Lota, Acipenser and Coregonus, were found relatively free from infection.The North American species of Cyathocephalus and Diplocotyle are regarded as identical with the European species C. truncatus and D. Olrikii; the species C. americanus Cooper, and Bothrimonus intermedius Cooper are rejected. The triaenophorid common in the area is regarded as Triaenophorus tricuspidatus (Bloch), and two morphae are recognized, microdentatus and megadentatus, the latter equivalent to T. robustus (Olsson). Bothriocephalus cuspidatus Cooper is regarded as comprising three sub-species, cuspidatus, hiodontos and luciopercae. The eubothriid cestode in Lota lota maculosa is regarded as identical with the European E. rugosum, but comprising two morphae, conformatus and deformatus. Two new species of Proteocephalus are described, namely coregoni from Coregonus atikameg, and luciopercae from Lucioperca vitreum.

Recent catastrophic landslide lake outburst floods in the Himalayan mountain range

2016 ◽  
Vol 41 (1) ◽  
pp. 3-28 ◽  
Author(s):  
Virginia Ruiz-Villanueva ◽  
Simon Allen ◽  
Manohar Arora ◽  
Narendra K Goel ◽  
Markus Stoffel
Keyword(s):  
Large Scale ◽  
Drainage System ◽  
Mountain Range ◽  
The Tibetan Plateau ◽  
Remotely Sensed Data ◽  
Discharge Data ◽  
Outburst Floods ◽  
High Resolution Satellite Images ◽  
Hydrometeorological Conditions ◽  
Landslide Lake

Among the more complex and devastating interactions between climate and hydromorphological processes in mountain environments are landslide lake outburst floods (LLOFs), resulting from mass movements temporarily blocking a drainage system. This work reviews these processes in the Himalayas and highlights the high frequency of this type of phenomenon in the region. In addition, we analyse two recent catastrophic trans-national LLOFs occurring in the Sutlej river basin during 2000 and 2005. Based on high resolution satellite images, Tropical Rainfall Measuring Mission (TRMM), Moderate-Resolution Imaging Spectroradiometer (MODIS) derived evolution of snowline elevation and discharge data we reconstruct the timing and hydrometeorological conditions related to the formation and failure of landslide dams. Results showed that the 2005 flood, originating from the outburst of the Parchu Lake, was not related to heavy precipitation, but was likely enhanced by the rapid and late snowmelt of an unusually deep and widespread snowpack. The flood in 2000 was triggered by the outburst of an unnamed lake located on the Tibetan plateau, identified here for the first time. In this case, the outburst followed intense precipitation in the lake watershed, which raised the level of the lake and thus caused the breaching of the dam. As stream gauges were damaged during the events detailed discharge data is not available, but we estimated the peak discharges ranging between 1100 m3 s−1 and 2000 m3 s−1 in 2005, and 1024 m3 s−1 and 1800 m3 s−1 in 2000. These events caused significant geomorphic changes along the river valleys, with observed changes in channel width exceeding 200 m. Results also demonstrate that remotely-sensed data enables valuable large-scale monitoring of lake development and related hydrometeorological conditions, and may thereby inform early warning strategies, and provide a basis for flood risk reduction measures that focus on disaster preparedness and response strategies.

scholarly journals An analysis of instabilities and limit cycles in glacier-dammed reservoirs

2019 ◽  
Author(s):  
Christian Schoof
Keyword(s):  
Limit Cycle ◽  
Limit Cycles ◽  
Water Storage ◽  
Drainage System ◽  
Stable Limit Cycle ◽  
Stable Limit ◽  
Outburst Floods ◽  
The World ◽  
The Stability ◽  
Glacial Hazards

Abstract. Glacier lake outburst floods are common glacial hazards around the world. How big such floods can become (either in terms of peak discharge or in terms of total volume released) depends on how they are initiated: what causes the runaway enlargement of a subglacial or other conduit to start, and how big can the lake get before that point is reached? Here we investigate how the spontaneous channelization of a linked-cavity drainage system controls the onset of floods. In agreement with previous work, we show that floods only occur in a band of water throughput rates, and identify stabilizing mechanisms that allow steady drainage of an ice-dammed reservoir. We also show how stable limit cycle solutions emerge from the instability, a show how and why the stability properties of a drainage system with spatially spread-out water storage differ from those where storage is localized in a single reservoir or lake.

Subglacial Constructions and Investigations At Bondhusbreen, Norway

1979 ◽  
Vol 23 (89) ◽  
pp. 363-379 ◽  
Author(s):  
B. Wold ◽  
G. Østrem
Keyword(s):  
Drainage System ◽  
Hot Water ◽  
Electric Power Station ◽  
Water Drainage ◽  
Diversion Tunnel ◽  
Glacier Surface ◽  
Outlet Glacier ◽  
Ice Cap ◽  
System A ◽  
Tunnel System

Abstract For the construction of a hydro-electric power station in western Norway, a diversion tunnel was made to collect subglacial melt water under an outlet glacier from the Folgefonni ice cap. Many investigations were carried out by glaciologists and engineers before the project could begin, and several unexpected problems arose during the completion of the project. This paper deals with some of the problems and how they were solved. To avoid coarse glacier-carried material from being flushed into the water-collecting tunnel system, a large sedimentation chamber was constructed in the bedrock under the glacier. The dimensions of this huge chamber were decided from sediment-transport studies in the glacier stream and from studies of old bottom deposits in a lake close to the glacier front. Ice-velocity measurements were made on the glacier surface and similar studies were attempted in sub-glacial ice caves made by spraying hot water near the glacier bed, where the ice is 170 m thick. The subglacial water-drainage system was studied from a horizontal tunnel constructed in the bedrock under the glacier. Some preliminary conclusions are drawn from these studies. In future, it will still be possible to undertake subglacial studies because inspection tunnels have been left in the bedrock, and the accessibility is relatively good.

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