Reactivation of basement faults: interplay of ice-sheet advance, glacial lake formation and sediment loading

2011 ◽  
Vol 23 (1) ◽  
pp. 53-64 ◽  
Author(s):  
Christian Brandes ◽  
Ulrich Polom ◽  
Jutta Winsemann
Keyword(s):  
Ice Sheet ◽  
Glacial Lake ◽  
Sediment Loading ◽  
Basement Faults ◽  
Lake Formation

Reconstruction of Early Holocene jokulhlaups along the Hvita River and Gullfoss waterfall, Iceland

2020 ◽  
Author(s):  
Greta Wells ◽  
Þorsteinn Sæmundsson ◽  
Sheryl Luzzadder-Beach ◽  
Timothy Beach ◽  
Andrew Dugmore
Keyword(s):  
Ice Sheet ◽  
Hydraulic Modeling ◽  
Early Holocene ◽  
Glacial Lake ◽  
Exposure Dating ◽  
Alpine Regions ◽  
Outburst Floods ◽  
Lake Formation ◽  
Geothermal Activity ◽  
Downstream Communities

<p>Glacial lake outburst floods (GLOFs) have occurred across the planet throughout the Quaternary and are a significant geohazard in Arctic and alpine regions today. Iceland experiences more frequent GLOFs—known in Icelandic as jökulhlaups—than nearly anywhere on Earth, yet most research focuses on floods triggered by subglacial volcanic and geothermal activity. However, floods from proglacial lakes may be a better analogue to most global GLOFs.</p><p>As the Icelandic Ice Sheet retreated across Iceland in the Late Pleistocene-Early Holocene, meltwater pooled at ice margins and periodically drained in jökulhlaups. Some of the most catastrophic floods drained from ice-dammed Glacial Lake Kjölur, surging across southwestern Iceland from the interior highlands to the Atlantic Ocean. These floods left extensive geomorphologic evidence along the modern-day course of the Hvítá River, including canyons, scoured bedrock, boulder deposits, and Gullfoss—Iceland’s most famous waterfall. The largest events reached an estimated maximum peak discharge of 300,000 m<sup>3</sup> s<sup>-1</sup>, ranking them among the largest known floods in Iceland and on Earth.</p><p>Yet, all our evidence for the Kjölur jökulhlaups comes from only one publication to date (Tómasson, 1993). My research employs new methods to better constrain flood timing, routing, magnitude, and recurrence interval at this underexplored site. This talk presents new and synthesized jökulhlaup geomorphologic evidence; HEC-RAS hydraulic modeling results of flow magnitude and routing; and ongoing geochronological analyses using cosmogenic nuclide exposure dating and tephrochronology. It also situates these events within Icelandic Ice Sheet deglaciation chronology and environmental change at the Pleistocene-Holocene transition. Finally, it examines the Kjölur floods as an analogue to contemporary ice sheet response, proglacial lake formation, and jökulhlaup processes and landscape evolution in Arctic and alpine regions worldwide, where GLOFs pose an increasing risk to downstream communities due to climate-driven meltwater lake expansion.  </p><p>Citation: Tómasson, H., 1993. Jökulstífluð vötn á Kili og hamfarahlaup í Hvítá í Árnessýslu. Náttúrufræðingurinn 62, 77-98.</p>

scholarly journals The pattern and style of deglaciation at the Late Wisconsinan Laurentide and Cordilleran ice sheet limits in northeastern British Columbia

2017 ◽  
Vol 54 (1) ◽  
pp. 52-75 ◽  
Author(s):  
David H. Huntley ◽  
Adrian S. Hickin ◽  
Olav B. Lian
Keyword(s):  
British Columbia ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Yukon Territory ◽  
Glacial Lake ◽  
Glacial Lakes ◽  
Lake Formation ◽  
Late Wisconsinan ◽  
Cordilleran Ice Sheet ◽  
Lake Deposits

This paper reports on the landform assemblages at the northern confluence of the Late Wisconsinan Laurentide and Cordilleran ice sheets with montane and piedmont glaciers in the northern Rockies and southern Mackenzie Mountains. Recent observations in northeastern British Columbia refine our knowledge of the pattern and style of ice sheet retreat, glacial lake formation, and meltwater drainage. At the onset of deglaciation, confluent Laurentide and Cordilleran terminal ice margins lay between 59°N, 124°30′W and 60°N, 125°15′W. From this terminal limit, ice sheets retreated into north-central British Columbia and Yukon Territory, with remnant Cordilleran ice and montane glaciers confined to mountain valleys and the Liard Plateau. Distinctive end moraines are not associated with the retreat of Cordilleran ice in these areas. Laurentide ice retreated northeastward from uplands and the plateaus; then separated into lobes occupying the Fort Nelson and Petitot river valleys. Ice-retreat landforms include recessional end moraines (sometimes overridden and drumlinized), hill–hole pairs, crevasse-fill deposits, De Geer-like ribbed till ridges, hummocky moraines, kames, meltwater features, and glacial lake deposits that fall within the elevation range of glacial Lake Liard and glacial Lake Fort Nelson (ca. 840–380 m). Meltwater and sediment transport into glacial lakes Fort Nelson, Liard, Nahanni, and Mackenzie was sustained by remnant ice in the Liard River and Fort Nelson River drainage basins until the end of glaciation. Optical dating of sand from stabilized parabolic dunes on the Liard Plateau indicates that proglacial conditions, lake formation, and drainage began before 13.0 ± 0.5 ka (calendar years). The Petitot, Fort Nelson, and Liard rivers all occupy spillways incised into glacial deposits and bedrock by meltwater overflow from glacial lakes Peace and Hay.

scholarly journals Identification of Locations for Potential Glacial Lakes Formation using Remote Sensing Technology

2013 ◽  
Vol 12 ◽  
pp. 10-16
Author(s):  
P Yagol ◽  
A Manandhar ◽  
P Ghimire ◽  
RB Kayastha ◽  
JR Joshi
Keyword(s):  
Remote Sensing ◽  
Glacial Lake ◽  
Glacial Lakes ◽  
Outburst Flood ◽  
Remote Sensing Technology ◽  
Sensing Technology ◽  
Lake Formation ◽  
Significant Area ◽  
Glacial Lake Outburst Flood

In past Nepal has encountered a number of glacial lake outburst flood (GLOF) events causing loss of billions of rupees. Still there are a number of glacial lakes forming and there are chances of new glacial lake formation. Hence there is intense need to monitor glaciers and glacial lakes. The development on remote sensing technology has eased the researches on glacier and glacial lakes. Identification of locations of potential glacial lakes through the use of remote sensing technology has been proven and hence is opted for identification of locations of potential glacial lake in Khumbu Valley of Sagarmatha Zone, Nepal. The probable sites for glacial lake formation are at Ngojumpa, Lobuche, Khumbu, Bhotekoshi, Inkhu, Kyasar, Lumsumna, etc. As per study, the biggest glacial lake could form at Ngozumpa glacier. Even in other glaciers potential supra-glacial lakes could merge together to form lakes that occupy significant area. Nepalese Journal on Geoinformatics -12, 2070 (2013AD): 10-16

Periodic JöKulhlaups from Pleistocene Glacial Lake Missoula—New Evidence from Varved Sediment in Northern Idaho and Washington

1984 ◽  
Vol 22 (1) ◽  
pp. 46-58 ◽  
Author(s):  
Richard B. Waitt
Keyword(s):  
Ice Sheet ◽  
Glacial Lake ◽  
Gravel Beds ◽  
Varved Sediment ◽  
Cordilleran Ice Sheet ◽  
Northern Idaho ◽  
New Evidence ◽  
Stratigraphic Succession ◽  
Conventional Idea ◽  
Sand Beds

Newly examined exposures in northern Idaho and Washington show that catastrophic floods from glacial Lake Missoula during late Wisconsin time were repeated, brief jökulhlaups separated by decades of quiet glaciolacustrine and subaerial conditions. Glacial Priest Lake, dammed in the Priest River valley by a tongue of the Purcell trench lobe of the Cordilleran ice sheet, generally accumulated varved mud; the varved mud is sharply interrupted by 14 sand beds deposited by upvalley-running currents. The sand beds are texturally and structurally similar to slackwater sediment in valleys in southern Washington that were backflooded by outbursts from glacial Lake Missoula. Beds of varved mud also accumulated in glacial Lake Spokane (or Columbia?) in Latah Creek valley and elsewhere in northeastern Washington; the mud beds were disrupted, in places violently, during emplacement of each of 16 or more thick flood-gravel beds. This history corroborates evidence from southern Washington that only one graded bed is deposited per flood, refuting a conventional idea that many beds accumulated per flood. The total number of such floodlaid beds in stratigraphic succession near Spokane is at least 28. The mud beds between most of the floodlaid beds in these valleys each consist of between 20 and 55 silt-to-clay varves. Lacustrine environments in northern Idaho and Washington therefore persisted for two to six decades between regularly recurring, colossal floods from glacial Lake Missoula.

Catastrophic glacial-lake outburst flooding of the Patagonian Ice Sheet

2020 ◽  
Vol 200 ◽  
pp. 102996 ◽  
Author(s):  
Gerardo Benito ◽  
Varyl R. Thorndycraft
Keyword(s):  
Ice Sheet ◽  
Glacial Lake

scholarly journals Mechanism of Till Deposition Related to Thermal Conditions in a Pleistocene Glacier

1971 ◽  
Vol 10 (60) ◽  
pp. 363-373
Author(s):  
John Shaw
Keyword(s):  
Environmental Conditions ◽  
Lacustrine Sediments ◽  
Ice Sheet ◽  
Thermal Conditions ◽  
Basal Part ◽  
Glacial Lake ◽  
Depositional Processes ◽  
Polar Type ◽  
Lake Deposits ◽  
The Relationship

AbstractA record of sedimentation from pro-glacial sandur deposits through pro-glacial lake deposits to final deposition of till is used to interpret changing environmental conditions, and depositional processes, during the development of the “Little Welsh Advance” in the Shrewsbury area, England. The relationship between lacustrine sediments and till establishes till deposition by flowage. However, the most important conclusions are derived from the deduction that lacustrine sediments were incorporated into the basal part of the ice sheet and transported across previously deposited end moraines. A discussion of this deduction, based on the findings of Weertman (1961), establishes that during the advancing phase the ice sheet was of the polar type. Final melting is thought to have occurred by both top-melt and under-melt as a result of climatic amelioration.

scholarly journals A conceptual model of supra-glacial lake formation on debris-covered glaciers based on GPR facies analysis

2016 ◽  
Vol 42 (6) ◽  
pp. 903-914 ◽  
Author(s):  
Jordan R. Mertes ◽  
Sarah S. Thompson ◽  
Adam D. Booth ◽  
Jason D. Gulley ◽  
Douglas I. Benn
Keyword(s):  
Conceptual Model ◽  
Facies Analysis ◽  
Glacial Lake ◽  
Lake Formation
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