inscription
PORTAIL D'INFORMATION GÉOGRAPHIQUE

Résultats de la recherche (581 résultats)

Affinez votre recherche

Par Collection Par Auteur Par Date Par Sujet Par Titre Par ville ? Par pays ? Par continent ?
  • Experimental weathering of sandstone by combinations of salts
  • Chemical erosion ; Experimentation ; Geochemistry ; Salt ; Sandstone ; Weathering
  • Laboratory experiments are described that examined the effectiveness of certain naturally occurring combinations of salts as weathering agents. Cubes of a highly quartzose sandstone were repeatedly soaked in one of a series of salt solutions
  • and then oven-dried to simulate natural weathering. The results indicate that is difficult to predict the weathering behaviour of combinations of salts from the weathering behaviour of the salts individually. Possible causes of enhanced weathering by some
  • combined salt solutions are discussed.
  • Surface features of the Salt Basin of Lancaster County, Nebraska
  • Duricrust ; Groundwater ; Humid environment ; Micromorphology ; Nebraska ; Pedogenesis ; Saline soil ; Salt ; United States of America
  • The purposes of this study are to : 1) examine the macromorphology and micromorphology of surface accumulations of salts in the Salt Basin; 2) describe the pedological, chemical, and biological features associated with surface accumulations of salt
  • ; 3) interpret the origin of salts crusts, salt flats, and saline wetlands using modern scientific data and historical accounts; and 4) compare pedological features of the Salt Basin with other soils in the surrounding area and with similar surface
  • salt occurences worldwide.
  • A szikes talajok elterjedésének foldrajzi és geokémiai torvényszerüségei. (Geographical and geochemical laws governing the location of salt-affected soils)
  • The salt cycle of soils and the types of salt-affected soils are presented. The environments favouring salt accumulation/salt-domes| salt-domes of marine origin| deluvial salt accumulation| river deltas in deserts an steppes| inland deltas| alluvial
  • plains and river terraces| salt lakes and swamps/are described in detail. (DLO).
  • Displacement of salt by the Laurentide Ice Sheet
  • Glacial features ; Ice sheet;Ice cap;Inlandsis ; Quaternary ; Salt tectonics ; United States
  • In most halokinesis, the dynamic factor is levitation of salt in an up-dip direction, because salt is less dense than overlying rock. This paper presents observations that suggest displacement of salt in a down-dip direction, where the up-dip part
  • of the salt-bearing bed has been overridden by massive ice sheets. From central New York through northeastern Ohio, southwestern Ohio, and the southern peninsula of Michigan, up-dip edges of salt basins are in areas covered by successive Pleistocene ice sheets.
  • Experimental frost and salt weathering of chalk. I.
  • This paper describes a series of experiments designed to isolate the effects of minimum temperature, rate of freezing, and salt concentration on the breakdown of rocks immersed in distilled water or salt solutions of varying strength. Discussion
  • Salt tectonics and geomorphology
  • Brief review of the geomorphological consequences of evaporites : the development of diapiric structures, the production of faults and folds, tectonic uplift and associated drainage modification, the creep of salt as salt glaciers , and widespread
  • The Mexican salt industry 1560-1980. A study in chance.
  • Mexico has not only developed the widest range of methods for recovering sodium chloride worldwide, it was also the first country to use salt on a large scale for industrial purposes. From about 1560 to the 20th century, Mexico refined its silver
  • ores with salt. Today, the country ranks first in the export of salt on the world market. Apart from presenting the diverses methods of salt production in their geographical and historical context, the book concentrates on the legal background changing
  • patterns of demand and supply, labour and the impact of salt on land and people. (HK).
  • Salt-marsh foraminifera in Ho Bugt, western Denmark, and their use as sea-level indicators
  • Denmark ; Estuary ; Foraminifera ; Holocene ; Hydrobiology ; Index ; Jylland ; North Sea ; Salinity ; Salt marsh ; Sea level
  • This paper presents the data of 27 surface samples, collected from the Kjelst Enge salt marsh in Ho Bugt, Jutland, to investigate the potential use of salt-marsh foraminifera as sea-level indicators in Holocene intertidal deposits. The results
  • confirm the usefulness of salt-marsh foraminifera as sea-level indicators in North Sea salt marshes.
  • Spatial distribution of salt efflorescence on brick walls in the Shimoren Kiln, central Japan
  • Building materials ; Chemical erosion ; Geotechnics ; Honshu ; Japan ; Salt ; Weathering
  • Salt weathering causes geomorphological changes and damages to man-made structures. The AA. investigated the detailed spatial distribution of salts in this kiln studied by Kawanobe and Kuchitsu (1998) and Kuchitsu (2000). The results show that more
  • than ten kinds of salts were observed and that each salt has an optimal height for efflorescing.
  • The origin and distribution of salts on alluvial fans in the Atacama Desert, northern Chile
  • Aeolian transport ; Alluvial cone ; Arid area ; Aridity ; Chile ; Desert ; Endoreic drainage ; Salt ; Volcanism
  • As part of an investigation into the relationship of salts and surface weathering features, the aim of this study was to determine the nature, quantity and distribution of salt minerals on the surface of 3 alluvial fans in salar basins representing
  • a transect of different environments in the Atacama Desert, such that the origin and distribution processes of the salts might be inferred. The pattern of salts that might be expected on each fan is first considered by examining regional sources and processes
  • of salt input onto the fans. The observed distribution of salts is subsequently discussed for each fan in a regional comparison.
  • Landscape evolution of the Five Islands of south Louisiana : scientific policy and salt dome utilization and management
  • Diapir ; Geological structure ; Geomorphology ; Hydrogeology ; Louisiana ; Mining activity ; Model ; Natural resources ; Quaternary ; Resource management ; Salt ; Tectonics ; United States of America ; Vertical movement
  • This paper reviews the geomorphic processes occurring on the Five Islands in conjunction with salt mining, oil extraction, and salt dome storage activities. It also illustrates the role of salt dome geomorphology as it relates to engineering
  • and environmental geology, salt tectonics and structure, Quaternaire stratigraphy, and ground water and surface water hydrology. The A. introduces a conceptual salt dome landscape model and outlines a strategy for salt dome utilization that has goals of both safe
  • Salt ramps: wind-induced depositional features on Tunisian playas
  • Beach ; Coastal environment ; Degradation ; Duricrust ; Geochemistry ; Geomorphometry ; Precipitation ; Salinity ; Salt ; Sebkha ; Tunisia ; Wind
  • Semicircular and crescent-shaped accumulations of salt crystals developed on salt crusts were measured on three Tunisian playas in September 1990. These features have been termed salt ramps. Their morphology and chemistry suggest
  • Salt weathering : influence of evaporation rate, supersaturation and crystallization pattern
  • Environment ; Evaporation ; Experimentation ; Lithology ; Microstructure ; Mineralogy ; Porosity ; Salt ; Weathering
  • Micro- and macroscale experiments which document the dynamics of salt damage to porous stone have yielded data which expose weakness in earlier interpretations. Salt damage due to crystallization pressure appears to be largely a function of solution
  • supersaturation ratio and location of crystallization. These key factors are related to solution properties and evaporation rates, which are constrained by solution composition, environmental conditions, substrate properties, and salt crystallisation growth
  • Salt dissolution features in saline lakes of the northern Great Plains, western Canada
  • Alberta ; Canada ; Carbonate dissolution ; Evaporite ; Lacustrine sediment ; Lake ; Manitoba ; Palaeo-environment ; Quaternary ; Salt lake ; Saskatchewan
  • Large-scale salt dissolution is an important process affecting the sediments of many of the saline lakes in the northern Great Plains region of western Canada. The most easily recognized features of this salt karst are water-filled chimneys
  • , vertical shafts, and collapse structures. Because these salt karst features can affect large vertical sections of the sediment fill in the lakes, their recognition is of fundamental importance in attempting to use the stratigraphic records of the basins
  • Experimental frost weathering of sandstone by various combinations of salts
  • Experimentation ; Freeze-thaw cycle ; Freezing ; Gypsum ; Salt ; Sandstone ; Weathering
  • Weathering experiments are reported combining frost and a range of salts that occur widely on sandstone rock outcrops in western and central Europe. The effects of alunogen, gypsum, halite and alum salts are examined, both singly and in combination
  • . The results confirm the destructiveness of halite in solution at sub-zero temperatures and demonstrate that alum salts are also capable of greatly increasing frost weathering, though not as markedly as halite.
  • The salt balance of the Aral Sea
  • The estimate of the salt balance of the Aral Sea is of general importance when considering the problem of the necessity and possibility to keep the Aral Sea in definite borders. The A. considers in detail every point of the salt balance before
  • the sea level dropped: surface (river and irrigation) drainage; underground discharge of dissolved salts to the Aral Sea; salts income with liquid and solid precipitation; deflation of salts to the atmosphere, from the sea surface; accumulation in the bays
  • ; alteration of the principal components of the sea salt budget during the last 30 years.
  • Salt weathering simulation-some comments and reply
  • Salt weathering simulation using a single-immersion technique
  • Arid land;Arid environment ; Atmospheric moisture ; Desert ; Experimentation ; Salt ; Temperature ; Weathering
  • Samples of concrete were subjected in an environmental cabinet to six different diurnal cycles of temperature and humidity change representative of desert surface conditions in the presence of a range of saturated salt solutions. The two most
  • Salt weathering
  • The purpose of this account is to bring together into one review the wide-ranging and disparate studies on salt weathering that have been published in recent years.
  • Rapid entrenchment of stream profiles in the salt caves of Mount Sedom, Israel
  • Arid area ; C 14 dating ; Dead Sea ; Diapir ; Fluvial erosion ; Groundwater ; Holocene ; Israel ; Karst ; Longitudinal section ; Rift ; Salt ; Stream
  • This paper focuses on downcutting rates and stream profile development measured in rock salt cave stream passages in the Mount Sedom salt diapir, Dead Sea rift valley, Israel. Although the area is very arid, the diapir contains extensive karst