Nature and distribution of frozen salinesediment on the Russian Arctic coast
Arctique ; Gel ; Littoral ; Pergélisol ; Propriétés du sol ; Périglaciaire ; Russie ; Salinisation ; Sol salin ; Zone froide
Arctic Region ; Coastal environment ; Cold area ; Freezing ; Periglacial features ; Permafrost ; Russia ; Saline soil ; Salinisation ; Soil properties
This paper examines frozen fine-grained soils, mainly of Pleistocene and Holocene age, that are distributed along the Arctic coast at the surface and which contain soluble salts. Salinization is determined by both the conditions at formation
, and subsequent processes at cryogenic temperatures. An increase in salinization with depth is observed. This is most likely caused by moving of salts from the upper permafrost layers as the result of the migration of pore water. Salinization in general increases
with an increase in ice content. An important feature of the saline soils of the Russian Arctic coast is their heterogeneity.
Salinity of marshes along the James Bay coast, Ontario, Canada
The salinities of tide water and sediments from the northern and the southern sectors of the coastal marshes are compared. In the north, Bay water of relatively high salinity is introduced to the marsh by tides, as is generally found in coastal
marshes elsewhere. The tidewater in southern James Bay has low salinity and the salt in the marsh is released by molecular diffusion from relict salt deposited with the post-glacial Tyrrell sea sediments. This study demonstrates that the salt in coastal
Argile ; Diffractométrie ; Evaporite ; Géographie physique ; Milieu salin ; Mode de dépôt ; Sédimentation ; Sédimentologie ; Technique de recherche
Etude expérimentale du comportement des fines en suspension lors de leur dépôt dans un milieu salin. L'effet de floculation est illustré par les courbes de fréquence de répartition des différents diamètres. Les analyses ont été réalisées à l'aide
Influence des sédiments des eaux sous-marines sur le bilan hydrique et salin des océans
Bilan hydrique ; Eau de mer ; Géochimie ; Océan ; Océan mondial ; Sédiment marin ; Sédimentation marine
Geochemistry ; Marine sediment ; Marine sedimentation ; Ocean ; Sea water ; Water budget ; World ocean
Méthode de calcul des eaux lors de la lithogenèse des sédiments marins argileux. Evaluation régionale de la quantité d'eaux sédimentées sous-marines pour la partie supérieure des sédiments de l'Océan mondial.
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
The AA. compare alkenone unsaturation ratios measured on recent sediments from the Indian Ocean (20°N-45°S) with modern sea oceanographic parameters. For each of the core sites they estimate average seasonal cycles of sea surface temperature (SST
) and salinity, which they then weight with the seasonal productivity cycle derived from chlorophyll satellite imagery.
Climatic oscillations 10,000-155,000 yr B.P. at Owens Lake, California reflected in glacial rock flour abundance and lake salinity in core OL-92
California ; Carbonate ; Clay mineral ; Climatic variation ; Core sampling ; Geochemistry ; Glacier advance ; Lacustrine sediment ; Lake ; Quaternary ; Salinity ; United States of America
Chemical analyses of the acid-soluble and clay-size fractions of sediment samples (1500-yr resolution) reveal oscillations of lake salinity and of glacial advances in core OL-92 back to 155,000 yr B.P. The AA. found that the mineralogy and chemistry
Les efflorescences salines, dont on connaît l'efficacité haloclastique, se rencontrent dans les zones arides, chaudes et froides. La vitesse d'accrétion à partir de l'atmosphère est de l'ordre de 10 à 100 kg par ha et par an. Les feuilles des
plantes peuvent également jouer un rôle dans l'alcalinisation. Dans les régions froides, la baisse de température peut aussi causer un dépôt saisonnier. Les croûtes salines les plus développées du Namib et du désert d'Atacama sont dues non seulement à leur
A 200,000-year record of change in oxygen isotope composition of sulfate in a salinesediment core, Death Valley, California
Arid area ; California ; Carbonate ; Geochemistry ; Lacustrine sediment ; Lake level ; Oxygen 18 ; Palaeo-environment ; Quaternary ; Salinity ; United States of America
Carbon-isotope, diatom, and pollen evidence for Late Holocene salinity change in a brackish marsh in the San Francisco estuary
C 14 dating ; California ; Diatom ; Estuary ; Geochemistry ; Holocene ; Palaeo-ecology ; Palaeo-environment ; Palynology ; Salinity ; San Francisco ; Sedimentation ; United States of America
California ; Datation C 14 ; Diatomée ; Estuaire ; Etats-Unis ; Géochimie ; Holocène ; Palynologie ; Paléo-environnement ; Paléo-écologie ; Salinité ; San Francisco ; Sédimentation
Analysis of diatoms, pollen, and the carbon-isotopic composition of a sediment core from a brackish marsh in the northern part of the San Francisco Estuary has provided a paleosalinity record that covers the past 3000 yr. Changes in marsh
Diagenetic transformations and silcrete–calcrete intergrade duricrust formation in palaeo-estuary sediments
Botswana ; Diagenesis ; Duricrust ; Geochemistry ; Paleo-estuary ; Phreatic ground water ; Pool ; Salinity ; Sedimentology
of microcrystalline silcrete–calcrete intergrade deposits while developing insight into pene-contemporaneous silica and calcite matrix formation. General precursor conditions require the presence of cyclical endoreic freshwater inflow into a saline pan. The pan should
be deep enough to sustain a permanent watertable under climatic conditions sufficient to cause carbonate fractionation within the groundwater. Freshwater inflow into a saline pan drives the geochemistry of the system (from freshwater to saline, from
neutral to high pH). The geochemistry is controlled by the periodicity of inflow relative to salinity levels of phreatic groundwater in the receptor saline pan.
Etude stratigraphique des sédiments tardiglaciaires de la Mer de Champlain. Mise en évidence de 2 séquences d'écozones à foraminifères. Les résultats obtenus concernant les paléosalinités ne permettent pas de détecter le détournement de l'exutoire
Tidal variation in field settling velocities of suspended sediment in a tidal channel
In this study, field settling velocities of the suspended sediment have been measured during two tidal periods, in Ho Bugt, on October 17, 1989 and July 24, 1990. During both periods, the current velocity, salinity, water temperature and suspended
sediment concentration were measured together with the field settling velocities of the fine-grained suspended sediment. Discussion of the results and study of the flocculation process.
Coastal environment ; Crustacea ; Ecosystem ; Fauna ; Fish ; Heavy metals ; Lacustrine sediment ; Martinique ; Nature park ; Pollution ; Pond ; Sampling
Ce rapport présente en 3 parties les travaux préliminaires de cette étude sur la présence et la genèse de quelques métaux lourds (cadmium, plomb, zinc, mercure, arsenic, etc) dans le bassin versant de l'étang des Salines : 1) Recherche de métaux
) Recherche de métaux lourds dans la chair des poissons et des crustacés de l'étang des Salines, résultats des campagnes d'analyses de 2006. Conclusions sur les pollutions de Cd et Pb localisées principalement dans la partie sud de l'étang, hypothèses pour
The diatom stratigraphy of a 23-m sediment core from Lake Tilo, a maar lake in the Ethiopan Rift Valley, provides a 10,000-yr record of lake salinity and trophic status. The results show that the lake remained relatively fresh throughout the early
Holocene arid intervals, due to high rates of geothermal groundwater discharge. Palaeoclimatic interpretation of palaeosalinity proxies from the sediments of volcanic crater lakes should be approached with caution.
Plusieurs problèmes d'ordre géomorphologique sont à prendre en compte dans la croissance des agglomérations en domaine aride: gravillons et agrégats, inondations, sédimentation, terres salines et processus éoliens. Exemples de problèmes régionaux ou
High abundances of Fragilaria in Belgian coastal deposits are described. These occur mainly in slightly brackish salt-marsh sediments, especially in areas with strong fresh-water influence. Species succession within them is influenced
by a differential salinity response. Environmental instability stimulates mass development of Fragilaria.