Palaeoenvironmental record of glacial lake evolution during the early Holocene at Sokli, NE Finland

Boreas ◽  
2013 ◽  
Vol 43 (2) ◽  
pp. 362-376 ◽  
Author(s):  
Shyhrete Shala ◽  
Karin F. Helmens ◽  
Krister N. Jansson ◽  
Malin E. Kylander ◽  
Jan Risberg ◽  
...  
Keyword(s):  
Early Holocene ◽  
Glacial Lake ◽  
Lake Evolution

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>

Early Holocene dune activity linked with final destruction of Glacial Lake Minong, eastern Upper Michigan, USA

2010 ◽  
Vol 74 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Henry M. Loope ◽  
Walter L. Loope ◽  
Ronald J. Goble ◽  
Timothy G. Fisher ◽  
Harry M. Jol ◽  
...  
Keyword(s):  
Lake Level ◽  
Lake Huron ◽  
Early Holocene ◽  
Glacial Lake ◽  
Radiocarbon Age ◽  
Lake Sediment Core ◽  
Littoral Sediment ◽  
Dune Activity ◽  
Lake Minong ◽  
Water Level Decline

AbstractThe early Holocene final drainage of glacial Lake Minong is documented by 21 OSL ages on quartz sand from parabolic dunes and littoral terraces and one radiocarbon age from a lake sediment core adjacent to mapped paleoshorelines in interior eastern Upper Michigan. We employ a simple model wherein lake-level decline exposes unvegetated littoral sediment to deflation, resulting in dune building. Dunes formed subsequent to lake-level decline prior to stabilization by vegetation and provide minimum ages for lake-level decline. Optical ages range from 10.3 to 7.7 ka; 15 ages on dunes adjacent to the lowest Lake Minong shoreline suggest final water-level decline ∼ 9.1 ka. The clustering of optical ages from vertically separated dunes on both sides of the Nadoway–Gros Cap Barrier around 8.8 ka and a basal radiocarbon date behind the barrier (8120 ± 40 14C yr BP [9.1 cal ka BP]) support the hypothesis that the barrier was breached and the final lake-level drop to the Houghton Low occurred coincident with (1) high meltwater flux into the Superior basin and (2) an abrupt, negative shift in oxygen isotope values in Lake Huron.

scholarly journals Early Holocene glacial lake meltwater injections into the Labrador Sea and Ungava Bay

2004 ◽  
Vol 19 (1) ◽  
pp. n/a-n/a ◽  
Author(s):  
Krister N. Jansson ◽  
Johan Kleman
Keyword(s):  
Early Holocene ◽  
Glacial Lake ◽  
Labrador Sea

scholarly journals Chronology and Stratigraphy of the Imlay channel in Lapeer County, Michigan, USA

2021 ◽  
Author(s):  
Jonathan N. Luczak ◽  
Timothy G. Fisher ◽  
Kenneth Lepper
Keyword(s):  
Cross Sections ◽  
Lake Erie ◽  
Early Holocene ◽  
Glacial Lake ◽  
Sedimentation Rates ◽  
Alluvial Fans ◽  
Radiocarbon Age ◽  
The Past ◽  
Water Well ◽  
A Current

The Imlay channel in Lapeer County, Michigan was one of two outlets for the glacial Lake Maumee phase of ancestral Lake Erie. Fifteen new radiocarbon and optical ages from within and adjacent to the Imlay channel constrain sedimentation rates within the channel and the timing of regional deglaciation. For nearly 50 years the deglaciation of this region of Michigan has been based on a single age from the Weaver Drain site located near the Imlay channel, and a new radiocarbon age of 16.7–17.0 cal ka BP from 3 km east of the Imlay channel supports this long-standing deglacial age. On average there is a 14 m thick sediment fill within the channel. Radiocarbon and OSL ages reveal that much of the alluvial fill was deposited by 14.9 ka, and alluvial fans building into the channel stabilized in the early Holocene. Cross-sections along and perpendicular to the Imlay channel, built from geotechnical borings and water-well records, reveal a current-day bedrock sill elevation at 235 masl that would have permitted drainage of all stages of glacial Lake Maumee in the past.

scholarly journals Reply to comments by on: “Glacial lake evolution and Atlantic-Pacific drainage reversals during deglaciation of the Patagonia Ice Sheet”

2019 ◽  
Vol 213 ◽  
pp. 171-177 ◽  
Author(s):  
Varyl R. Thorndycraft ◽  
Jacob M. Bendle ◽  
Ian P. Matthews ◽  
Adrian P. Palmer ◽  
Gerardo Benito ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Glacial Lake ◽  
Lake Evolution

Geomorphology, hydrology, and chronology of Early Holocene jökulhlaups along the Hvítá River and Gullfoss waterfall, Iceland

2021 ◽  
Author(s):  
Greta Wells ◽  
Sheryl Luzzadder-Beach ◽  
Timothy Beach ◽  
Thorsteinn Saemundsson ◽  
Andrew Dugmore
Keyword(s):  
Source Region ◽  
Ice Sheet ◽  
Flood Frequency ◽  
Early Holocene ◽  
Glacial Lake ◽  
Quarter Century ◽  
Alpine Regions ◽  
Outburst Floods ◽  
Geothermal Activity ◽  
Glacial Outburst Floods

<p>Glacial outburst floods (jökulhlaups) have occurred across Earth throughout the Quaternary, often leaving a geomorphologic, sedimentological, and climatic legacy that extends far beyond the source region and can persist for millennia. Furthermore, they pose an increasing geohazard in glaciated landscapes worldwide due to climate-driven ice retreat. Iceland experiences more frequent jökulhlaups than nearly anywhere on Earth, though most research focuses on floods triggered by subglacial volcanic and geothermal activity. However, abundant evidence also exists for non-volcanogenic floods from proglacial lakes, which may serve as a better analogue for most global jökulhlaups.</p><p>As the Icelandic Ice Sheet retreated across Iceland in the Late Pleistocene-Early Holocene, meltwater lakes formed 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 canyon systems, scoured bedrock, boulder deposits, and Gullfoss—Iceland’s most famous waterfall. The largest events reached an estimated peak discharge on the order of 10<sup>5 </sup>m<sup>3</sup> s<sup>-1</sup>, ranking them among the largest known floods in Iceland and on Earth. Yet, all our evidence for the Kjölur jökulhlaups comes from only one publication from a quarter-century ago.</p><p>This project employs a combination of field, modelling, and laboratory methods to better constrain flood timing and dynamics at this underexplored site. This talk synthesizes geomorphologic field mapping, HEC-RAS hydraulic simulations and paleohydraulic calculations, and cosmogenic nuclide exposure dates to reconstruct Kjölur jökulhlaup routing, hydrology, and chronology. It situates these events within the context of Pleistocene-Holocene Icelandic Ice Sheet retreat and paleoenvironmental change, presenting a series of scenarios of ice margin position, glacial lake extent, and jökulhlaup drainage. Finally, it assesses the Kjölur jökulhlaups as an analogue to contemporary glacial outburst floods in other Arctic and alpine regions in terms of flood frequency, dynamics, and landscape impact.</p>

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