scholarly journals Holocene Stratigraphy and Geomorphology of Flintstone Hill, Lauder Sandhills, Glacial Lake Hind Basin, Southwestern Manitoba

2004 ◽  
Vol 56 (2-3) ◽  
pp. 291-303 ◽  
Author(s):  
Garry L. Running ◽  
Karen G. Havholm ◽  
Matt Boyd ◽  
Dion J. Wiseman
Keyword(s):  
River Channel ◽  
Low Energy ◽  
Glacial Lake ◽  
Wind Regime ◽  
Wet Meadows ◽  
Dune Sands ◽  
Eolian Sand ◽  
Holocene Stratigraphy ◽  
Modern Landscape ◽  
Sand Sheets

Abstract Sediments exposed at Flintstone Hill in a Souris River cutbank provide the most complete postglacial stratigraphic section in the Glacial Lake Hind Basin (GLHB), southwestern Manitoba. Four lithologic units, A-D, are observed: A1 (~2 m thick), glaciolacustrine silts and clays that grade upward to peat and record final regression of Glacial Lake Hind (~10 500-9300 BP); A2 (~1.5 m thick), low energy fluvial marl and silts grading to O-horizon(s) (by 6700 BP); B (1.5 m thick), dune sands that migrated from the southwest, contrary to the modern wind regime (after ~6700 BP); C (1.0 m thick), thin fluvial deposit between eolian sand sheets (~5500-3200 BP); D (up to 7 m thick), parabolic dune on the modern landscape oriented consistent with the modern wind regime, blowouts suggest episodic dune reactivation (~3200 BP to present). Overall, Flintstone Hill deposits record draining of Glacial Lake Hind, establishment of the Souris River channel through the GLHB, mid-Holocene eolian activity / landscape instability greater than present, and a return to nearly modern conditions by ~5400 BP. Native inhabitants in the GLHB focused on exploiting wetlands and wet meadows before 9300 BP and a landscape similar to the present thereafter.

THE CAROLINA SANDHILLS OF THE SOUTHEASTERN UNITED STATES ARE EOLIAN SAND SHEETS AND DUNES THAT WERE ACTIVE DURING THE LAST GLACIATION

2016 ◽  
Author(s):  
Christopher S. Swezey ◽  
◽  
Bradley A. Fitzwater ◽  
G. Richard Whittecar ◽  
Christopher P. Garrity ◽  
...  
Keyword(s):  
United States ◽  
Southeastern United States ◽  
Last Glaciation ◽  
Eolian Sand ◽  
Sand Sheets

The Carolina Sandhills: Quaternary eolian sand sheets and dunes along the updip margin of the Atlantic Coastal Plain province, southeastern United States

2016 ◽  
Vol 86 (3) ◽  
pp. 271-286 ◽  
Author(s):  
Christopher S. Swezey ◽  
Bradley A. Fitzwater ◽  
G. Richard Whittecar ◽  
Shannon A. Mahan ◽  
Christopher P. Garrity ◽  
...  
Keyword(s):  
United States ◽  
Grain Size ◽  
Coastal Plain ◽  
Southeastern United States ◽  
Atlantic Coastal Plain ◽  
Laurentide Ice Sheet ◽  
Coarse Grain ◽  
Eolian Sand ◽  
Atlantic Coastal ◽  
Sand Sheets

AbstractThe Carolina Sandhills is a physiographic region of the Atlantic Coastal Plain province in the southeastern United States. In Chesterfield County (South Carolina), the surficial sand of this region is the Pinehurst Formation, which is interpreted as eolian sand derived from the underlying Cretaceous Middendorf Formation. This sand has yielded three clusters of optically stimulated luminescence ages: (1) 75 to 37 thousand years ago (ka), coincident with growth of the Laurentide Ice Sheet; (2) 28 to 18 ka, coincident with the last glacial maximum (LGM); and (3) 12 to 6 ka, mostly coincident with the Younger Dryas through final collapse of the Laurentide Ice Sheet. Relict dune morphologies are consistent with winds from the west or northwest, coincident with modern and inferred LGM January wind directions. Sand sheets are more common than dunes because of effects of coarse grain size (mean range: 0.35-0.59 mm) and vegetation. The coarse grain size would have required LGM wind velocities of at least 4-6 m/sec, accounting for effects of colder air temperatures on eolian sand transport. The eolian interpretation of the Carolina Sandhills is consistent with other evidence for eolian activity in the southeastern United States during the last glaciation.

scholarly journals Modeling the Glacial Lake Outburst Flood Process Chain in the Nepal Himalaya: Reassessing Imja Tsho's Hazard

2017 ◽  
Author(s):  
Jonathan M. Lala ◽  
David R. Rounce ◽  
Daene C. McKinney
Keyword(s):  
Human Life ◽  
River Channel ◽  
Glacial Lake ◽  
Process Chain ◽  
Outburst Flood ◽  
Worst Case ◽  
Site Specific ◽  
Lake Outlet ◽  
Wide Range ◽  
Glacial Lake Outburst Flood

Abstract. The Himalayas of South Asia are home to many glaciers that are retreating due to climate change and causing the formation of large glacial lakes in their absence. These lakes are held in place by naturally deposited moraine dams that are potentially unstable. Specifically, an impulse wave generated by an avalanche or landslide entering the lake can destabilize the moraine dam, thereby causing a catastrophic failure of the moraine and a glacial lake outburst flood (GLOF). Imja-Lhotse Shar glacier is amongst the glaciers experiencing the highest rate of mass loss in the Mount Everest region, which has contributed to the expansion of Imja Tsho. A GLOF from this lake may have the potential to cause catastrophic damage to downstream villages, threatening both property and human life. Therefore, it is essential to understand the processes that could trigger a flood and quantify the potential downstream impacts. The avalanche-induced GLOF process chain was modeled using the output of one component of the chain as input to the next. First, the volume and momentum of various avalanches entering the lake were calculated using RAMMS. Next, the avalanche-induced waves were simulated using BASEMENT and validated with empirical equations to ensure the proper transfer of momentum from the avalanche to the lake. With BASEMENT, the ensuing moraine erosion and downstream flooding was modeled, which was used to generate hazard maps downstream. Moraine erosion was calculated for two geomorphologic models: one site-specific using field data and another worst-case based on past literature that is applicable to lakes in the greater region. Neither case resulted in flooding outside the river channel at downstream villages. The worst-case model resulted in some moraine erosion and increased channelization of the lake outlet, which yielded greater discharge downstream but no catastrophic collapse. The site-specific model generated similar results, but with very little erosion and a smaller downstream discharge. These results indicated that Imja Tsho is unlikely to produce a catastrophic GLOF due to an avalanche in the near future, although some hazard exists within the downstream river channel, necessitating continued monitoring of the lake. Furthermore, these models were designed for ease and flexibility so that they can be adopted by a wide range of stakeholders and appropriated for other lakes in the region.

Wastewater Treatment of Greater Agadir (Morocco): An Original Solution for Protecting the Bay of Agadir by Using the Dune Sands

1992 ◽  
Vol 25 (12) ◽  
pp. 239-245 ◽  
Author(s):  
A. C. Bennani ◽  
J. Lary ◽  
A. Nrhira ◽  
L. Razouki ◽  
J. Bize ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Chemical Oxygen Demand ◽  
Suspended Matter ◽  
Oxygen Demand ◽  
Fecal Coliforms ◽  
Original Solution ◽  
Dune Sands ◽  
Eolian Sand ◽  
Series Of Experiments ◽  
Treated Effluents

The wastewater treatment by infiltration-percolation plant at Ben Sergao (a suburb of Agadir, Morocco) foreshadows the installation which will be able to be built for Greater Agadir (first fraction: 40,000 m3/d). The present plant treats 1,000 m3/d of highly concentrated raw effluents which after being decanted in an anaerobic stabilization pond are infiltrated into 5 infiltration basins of 1,500 m2 each, constituted by a bed 2 metres thick of eolian sand drained at its base. The decanted water infiltrates at the rate of one metre per day. With this process 100 % of the suspended matter, and 95 % of the chemical oxygen demand are removed, 85 % of the nitrogen is oxidized. The parasites are entirely eliminated and the number of fecal coliforms and streptococci is made 10,000 to 100,000 times smaller. A series of experiments of irrigation by the treated effluents is under way.

Origin of Eolian Sand Mobilization during the Past 2300 Years in the Mu Us Desert, China

2000 ◽  
Vol 53 (1) ◽  
pp. 78-88 ◽  
Author(s):  
Jimin Sun
Keyword(s):  
Sand Dunes ◽  
Field Investigation ◽  
Central China ◽  
Mu Us Desert ◽  
Archaeological Data ◽  
The Past ◽  
Eolian Sand ◽  
Land Cultivation ◽  
Historical Times ◽  
Sand Sheets

AbstractEolian sand dunes and sand sheets are extensive in the semiarid regions of northern-central China. Previous studies indicated that these eolian sands mainly formed during historical times. However, the sand sources and their reworking processes have not been well studied, and even the reasons for their occurrence are still controversial. Field investigation and sedimentary evidence indicate that both the inner Mu Us Desert and its southern marginal region, both sources of modern eolian sand, are largely associated with reworking of sands of the last glaciation. Based on geological, documentary, and archaeological data, three phases of land cultivation during the past 2300 years, together with historical droughts, high wind energy, and the easily reworked sand sources, largely account for the occurrence of active sand dunes and sand sheets in the Mu Us Desert.

scholarly journals Unusual thick eolian sand sheet sedimentary succession: Paleoproterozoic Bandeirinha Formation, Minas Gerais

2015 ◽  
Vol 45 (suppl 1) ◽  
pp. 3-11 ◽  
Author(s):  
Fábio Simplicio ◽  
Giorgio Basilici
Keyword(s):  
Saline Water ◽  
Near Surface ◽  
Accommodation Space ◽  
Eolian Sand ◽  
Sand Supply ◽  
Sedimentary Succession ◽  
Sand Sheet ◽  
Stabilizing Factors ◽  
Sand Sheets ◽  
Main Factor

ABSTRACTSome present-day eolian sand sheets have small and width dunes, called zibars, as common type of depositional morphology. Their formation is related to different stabilizing factors, which reduce the availability of clastic materials for eolian processes. In fact, zibars are dunes which do not have time to develop a larger dune with slipface (proto-dune). Dunes in sands sheet areas generally are constructed by wind ripple laminations and commonly generate sedimentary succession less than 20 m thick, which are the consequence of low sand supply. This study deals with an uncommon eolian sand sheet sedimentary succession more than 50 m thick, Proterozoic in age, known as Bandeirinha Formation. This paper tries to explain the anomalous thick of this sand sheet sedimentary succession. High thickness was probably the result of a high input of sand material, combine with low availability of sand, thus allowing the only construction of proto-dunes (zibars). Early cementation, due to near-surface evaporation of saline water, has been proposed as main factor that reduced the sand availability into this eolian system. Finally, the subsidence processes related to the first stage of rift Espinhaço Basin must have generated the accommodation space to preserve the sand sheet succession.

Vertebrate Tracks in Pleistocene Eolian Sand-Sheet Deposits of Alaska

1996 ◽  
Vol 45 (2) ◽  
pp. 226-240 ◽  
Author(s):  
Peter D. Lea
Keyword(s):  
Cross Sections ◽  
Silty Sand ◽  
Large Herbivores ◽  
Deformation Structures ◽  
Eolian Sand ◽  
Vertebrate Tracks ◽  
Central Ridge ◽  
Eolian Deposits ◽  
Sand Sheet ◽  
Sand Sheets

AbstractDeformation structures interpreted as vertebrate hoof- and foot-tracks occur within upper-Pleistocene eolian sand-sheet deposits in the stabilized Kantishna sand sea of central Alaska and in the Nushagak lowland of southwestern Alaska. Exposures of tracks are generally limited to cross sections, which reveal concave-up deformation structures in which displacement of preexisting strata diminishes downward. Deposits in both areas contain tracks that are 6 to 16 cm in diameter and are divided by a central ridge, reflecting formation by artiodactyl (even-toed) ungulates. Larger (21–34 cm) tracks without a central ridge, observed in the Nushagak lowland, were formed by proboscideans, probably woolly mammoth. Large vertebrate tracks occur within irregularly stratified sand and silty sand that accumulated upon partially vegetated sand sheets, and within thin, even wind-ripple laminae of unvegetated sand sheets. The presence of tracks at multiple stratigraphic levels and preservation of roots and rhizocretions within the eolian deposits suggest that vegetated sand sheets may have formed a locally important grazing habitat for large herbivores during at least part of the last glaciation. Recognition that vertebrate tracks are preserved in eolian sand-sheet deposits, and in deposits of other environments as well, opens a new source of stratigraphic and paleoecological data to aid reconstruction of the vanished ecosystems of Beringia.

Paleoecological Studies of a Holocene Lacustrine Record from the Kangerlussuaq (Søndre Strømfjord) Region of West Greenland

1995 ◽  
Vol 43 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Wendy R. Eisner ◽  
Torbjörn E. Törnqvist ◽  
Eduard A. Koster ◽  
Ole Bennike ◽  
Jacqueline F.N. van Leeuwen
Keyword(s):  
Subsequent Development ◽  
Vegetation Density ◽  
Final Phase ◽  
West Greenland ◽  
Sediment Stratigraphy ◽  
Pollen Accumulation Rates ◽  
Environmental Deterioration ◽  
Pollen Zone ◽  
Eolian Sand ◽  
Sand Sheets

AbstractA lacustrine sediment record from the Kangerlussuaq region, West Greenland, has resulted in a pollen, macrofossil, and sediment stratigraphy that encompasses the last 5000 14C yr. Deglaciation of the area and subsequent development of a nearby floodplain occurred before 5000 yr B.P. Since that time eolian sand and silt deposition appear to have been continuous, with a significant increase ca. 1000 14C yr B.P. Pollen analysis shows little change in the character of the vegetation throughout the record. Fluctuations in herb pollen taxa indicate changes in the extent and development of eolian sand sheets. The oldest pollen zone records relatively little pollen accumulation and low taxa diversity. This is followed by a zone of high pollen accumulation, presumably a phase of highest vegetation density, from 4400 to 3400 14C yr B.P. Thereafter, declining pollen accumulation rates reveal a gradual environmental deterioration. Macrofossil analyses record significant limnological changes, with an early eutrophic phase followed by a masotrophic phase and a reversal to more eutrophic conditions in the final phase. The preserved record illustrates the interactions of deglaciation, eolian activity, regional vegetation, and limnological change.

Evolution of Holocene Eolian Landscapes in the Glacial Lake Hind Basin, Manitoba

2004 ◽  
Vol 56 (2-3) ◽  
pp. 305-313 ◽  
Author(s):  
Woody G. Wallace
Keyword(s):  
Great Plains ◽  
Black Shale ◽  
Soil Profile ◽  
Depositional Environments ◽  
Low Energy ◽  
Glacial Lake ◽  
Soil Profiles ◽  
Lake Basin ◽  
Buried Soils ◽  
Buried Soil

Abstract Stratigraphic investigations into dune fields in Glacial Lake Hind basin reveal three lithologic units: a lake basin unit, a lower eolian unit, and an upper eolian unit. The lake basin unit contains gleyed silty clays representing a low energy lake environment, and coarse sands and black shale gravels representing higher energy depositional environments. The lower eolian unit contains sedimentary and organic laminations and no buried soils. The upper eolian unit does not have laminations, but contains multiple buried soil profiles. Preservation of organic laminations and presence of redoximorphic colouring in the lower eolian unit suggest that it has been preserved by groundwater. The upper eolian unit contains four soil profile types that appear in sequence with an interdunal profile at the bottom and a dune profile at the top. Radiocarbon ages of soils in the upper eolian unit (2350 ± 50 and 1100 ± 40 BP) indicate regional synchronicity with soil forming periods across the northeastern Great Plains. However, the morphology of a buried soil profile depended on the site’s location on the paleolandscape during development.

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