A new lake in Italy (Southwestern Sardinia) : a maar ?
Applied geomorphology ; Italy ; Lacustrine sediment ; Lake ; Maar ; Oligocene ; Sardegna
This study of a small lake basin located near the southwestern coast of Sardinia has allowed individualisation of this morphology as this lake is linked to the volcanic outcrops of the Oligo-Miocene that constitute the basement of this territory
. The historical, physical and geological characteristics of this lake, known as «Stagno’e Forru» («stagno» means «pond», so it has always been considered as such), allow us to hypothesise to a possible origin as a maar formed during the final activity of the calc
be established, making drilling of the lacustrine deposits necessary for further investigation. However, knowledge of this lake is significant because it is the confirmation of another lake existence in Sardinia ; until now, Sardinia is known to have only one
natural lake, which was formed by an aeolian obstruction. - (NF)
Thermokarst lakes on the Arctic coastal plain of Alaska : geomorphic controls on bathymetry
Alaska ; Arctic Region ; Bathymetry ; Bedrock ; Coastal plain ; Geomorphometry ; Lake ; Permafrost ; Thermokarst
Detailed bathymetric data were collected for 28 thermokarst lakes across the Arctic Coastal Plain (ACP) of northern Alaska from areas with distinctly different surficial sediments and topography. Based on the variety of lakes that were surveyed
in the 3 study areas, these data suggest that thermokarst lake morphometry largely depends on the characteristics of the substrate beneath the lake and the availability of sediments eroded at the lake margin.
Recharge sources and chemical composition types of groundwater and lake in the Badain Jaran Desert, northwestern China
Arid area ; China ; Cluster analysis ; Desert ; Hydrochemistry ; Infiltration ; Lake ; North-Western China ; Precipitation ; Spatial variation ; Underground water ; Water
Based on the analysis of ion chemical composition of lake water and shallow groundwater in the Badain Jaran Desert, this paper discussed the characteristics of ion chemical composition, spatial variation of lake water, and possible supply sources
of lake water and groundwater in the desert areas. The results show that the pH, salinity, TDS and electrical conductivity of the lake water are greater than those of groundwater. The ion chemical composition of the lake water reveals that the flow
direction of lake water is from southeast to northwest in the Badain Jaran Desert. The ion chemical composition, moisture content of sand layer water level height and hierarchical cluster analysis of the lake water and groundwater demonstrate that the lake
Water quality changes in lake McKenzie, Fraser Island, Australia : a palaeolimnological approach
Australia ; Climatic variation ; Diatom ; Grain size distribution ; Lake ; Palaeo-ecology ; Palaeolimnology ; Queensland ; Water quality
This study uses a palaeoecological approach to identify biological and sediment changes in Lake McKenzie, Fraser Island, Australia. A sediment core was extracted from the lake and the fossil diatom assemblage and sediment particle size analysed
of detected environmental change at Lake McKenzie.
Using ice-scars as indicators of exposure to physical lakeshore disturbances, Corvette Lake, northern Québec, Canada
Canada ; Cold area ; Dendrochronology ; Dendrology ; Ice ; Impact ; Lake ; Lake hydrology ; Lake level ; Lake shore ; Landscape structure ; Quebec ; Space time ; Vegetation ; Wave
segment located at the extreme east of Corvette Lake, situated in the high-boreal climatic zone of northern Quebec. A significant relationship was found between ice-scar chronology and wave exposure index, which indicates that the mechanical action
Holocenic proxies of sedimentary organic matter and the evolution of Lake Arari-Amazon Region
Brazil ; Fresh water ; Holocene ; Humid environment ; Island ; Isotope analysis ; Lacustrine sediment ; Lake ; Palaeo-environment ; Palynology ; Pará ; Phytoplankton ; Pollen diagram ; Sea level ; Sea water
Four sediment cores were sampled from Lake Arari, located on Marajó Island at the mouth of the Amazon River in Northern Brazil. The island's vegetation cover is composed mainly of Amazon coastal forest, herbaceous and varzea vegetation
. The integration of data on sedimentary structures, pollen, carbon and nitrogen isotope records, C/N ratios and radiocarbon ages allowed the identification of changes in vegetation and the sources of organic matter accumulated in the lake during the Holocene
. This study identified an influence between marine and freshwater with 3 development stages of Lake Arari : presence of mangroves during the lagoon phase; then, the mangroves were replaced by herbaceous vegetation with the increase in freshwater river
discharge; finally, Lake Arari was established in association with the expansion of herbaceous vegetation and the dominance of freshwater algae.
The impact of permafrost disturbances and sediment loading on the limnological characteristics of two High Arctic Lakes
Arctic Region ; Canada ; Geochemistry ; Lake ; Limnology ; Periglacial features ; Permafrost ; The 2000's ; Turbidity ; Watershed
The physical and chemical characteristics of two High Arctic lakes were investigated at the Cape Bounty Arctic Watershed Observatory on Melville Island, in response to large active-layer detachments generated by extreme summer temperatures in 2007
. In the two years following the permafrost disturbances, there was an elevated loading of total dissolved solids into both lakes, but no concomitant increase in suspended sediment levels. The physical dynamics of one lake were significantly altered
by an internal sediment input, which was not directly related to watershed processes. The results indicate that localised permafrost disturbance in the watersheds resulted in changes to chemical conditions in these relatively deep, large lakes, while increased
Culturel ; Développement économique ; Economie du jeu ; Environnement ; Etats-Unis ; Lake Tahoe ; Nevada ; Paysage culturel ; Zonage
Transcendent lake Tahoe landscapes and a fervent gambling economy were first conjoined in an odd mid-20th century partnership. After 1947 Tahoe's residents attempted to limit change brought by easier access. The resultant political alliance
recognized a need for throttling development near southeastern Lake Tahoe. The outcome was an interdiction of gambling, with ensuing zoning ordinances that restricted heavy commercial and gambling establishments to the Stateline area.
Thermokarst lakes on the Arctic coastal plain of Alaska : spatial and temporal variability in summer water temperature
Alaska ; Arctic Region ; Coastal plain ; Cold area ; Lake ; Spatial variation ; Summer ; Thermokarst ; Water temperature ; Weather type
In summer 2010, water temperature profile measurements were made in 12 thermokarst lakes along a 150-km long north–south transect across the Arctic Coastal Plain of northern Alaska. Based on the variety of lakes that was monitored in the 3 study
areas, the results demonstrate that climatic gradients, meteorological conditions and basin characteristics impact lake temperature dynamics.
Fluvial response to an historic lowstand of the Great Salt Lake, Utah
Années 1960 ; Années 2000 ; Avulsion ; Cours d'eau ; Dynamique fluviale ; Etats-Unis ; Great Salt Lake ; Géométrie hydraulique ; LiDAR ; Méandre ; Photo-interprétation ; Photographie aérienne ; Transport sédimentaire ; Télédétection ; Utah
the most influential factor causing the meandering form of Lee Creek and the braiding channel of the Goggin Drain, 2 streams that are part of the Jordan River drainage into the endorheic Great Salt Lake of northern Utah. Although Lee Creek has not recently
2012
[b1] Dep. of Geology and Geophysics, Univ. of Utah, Salt Lake City, Etats-Unis
[b2] Dep. of Geography, Univ. of Utah, Salt Lake City, Etats-Unis
Sediment and nutrient deposition in Lake Volta in Ghana due to Harmattan dust
Aeolian dust ; Aeolian features ; Aeolian transport ; Eutrophication ; Fluvial deposit ; Ghana ; Lacustrine sedimentation ; Lake ; Nutrient ; Reservoir
In this study, the AA. determine the amount of sediment and nutrients that are deposited by the Harmattan wind in big water bodies, exemplified by the dust deposition in the Harmattan period in the man-made Lake Volta. These depositions are compared
with similar inputs by the rivers. If the amount of readily available nutrients coming from the Harmattan dust is held against the influx of readily available (dissolved) Ca, Mg and P from the rivers to Lake Volta, it appears that the Harmattan dust accounts
for only 0.7‰ Mg, 4.8‰ Ca, and 2.1% P. It must therefore be concluded that the contribution of nutrients to Lake Volta by the Harmattan dust is very limited.
Data from a lake sediment core was used to reconstruct changes in vegetation and fire frequencies over the last 7000 cal yr : Bear Lake is a high-elevation lake surrounded by subalpine vegetation in Rocky Mountain National Park, Colorado. The pollen
Modelling open-talik Formation and permafrost lateral thaw under a thermokarst lake, Beiluhe Basin, Qinghai-Tibet Plateau
Using in situ data and information from monitoring of a representative thermokarst lake in the Beiluhe Basin, this study simulates the rate of talik development beneath the lake, the time taken for an open talik to form, and the rate of permafrost
the lake and that the talik thickness increases substantially over time.
Assessing the impacts of climate variability and human activities on streamflow in the water source area of Baiyangdian Lake
China ; Climatic variability ; Human impact ; Hydrology ; Impact ; Lake ; Model ; Northern China ; Stream flow ; Time series
In this study, the AA. quantified the impacts of climate variability and human activities on streamflow in the water source area of the Baiyangdian Lake, based on analyses of hydrologic changes of the upper Tanghe river catchment (a sub-basin
a dominant role on the decline of the streamflow in the water source area of the Baiyangdian Lake.
Aeolian features ; C 14 dating ; Climatic variation ; Dune ; Eemian ; Holocene ; Lacustrine sediment ; Lake level ; Mongolia ; Optically stimulated luminescence ; Palaeo-environment ; Palaeoclimate ; Western Mongolia
relations in the past. The floodplain is locally covered by lacustrine sediments representing an Early to Mid-Holocene lake only a few meters deep. This can be deduced from several 14C and OSL dates and tachymetric measurements, and is in accordance
with high stands of other lakes in Western Mongolia. Relics of a lake sediment on top of an old dune 17 m above the floodplain have been OSL-dated,indicative of an Eemian age. At that time a large and deep lake must have covered the plain. The transition
The role of geographic expertise in international border disputes : a study of the middle of Lake Erie through historical and cartographic perspectives
Quartz weathering in freeze-thaw cycles : experiment and application to the El'Gygytgyn crater lake record for tracing Siberian permafrost history
the results of laboratory tests to a Quaternary sediment record. The combination of silt production, relative quartz enrichment in the silt fraction, and quartz grain micromorphology is traced in a multi-100-kyr lake sediment archive as indicator data
for cryogenic weathering. Constant cryogenic weathering conditions are inferred for at least the last 220 000 years from a lake sediment core of El'gygytgyn Crater, northeast Russia.
Proxy evidence for easterly winds in glacial Lake Algonquin, from the Black River Delta in Northern Lower Michigan
Aeolian features ; Delta ; Dune ; Geographical information system ; Glacial lake ; Michigan ; Palaeo-environment ; Palaeoclimate ; Pleistocene ; Sediment transport ; Soil properties ; United States of America
The AA. examined a large, Late Pleistocene delta in northern Lower Michigan, formed by the Black River in Glacial Lake Algonquin. Their subsurface data, taken at 153 sites across the delta, show trends in sediment texture across the delta surface
Concept ; Epistemology ; Geomorphology ; Glacial erosion ; Glacial features ; Glacial lake ; Nineteenth Century ; Theory
visit when he knew about glaciation he then saw it all around him. Glacial theorists such as Ramsay and Bonney discussed the relationship between glacial erosion and lake formation, arguing by analogy and comparison, but Bonney refused to be swayed