Solr Search · GéoProdig, portail d'information géographique

Aminostratigraphic relations and age of Quaternary deposits, Northern Española Basin, New Mexico

Aminostratigraphic relations and age of Quaternary deposits, Northern Española Basin, New Mexico
Amino acid ratios of gastropods provide a useful basis for correlation and approximate dating of middle to late Quaternary fluvial deposits from the northern Española basin, New Mexico. The AA. correlate deposits using amino acid data and elevation
; age estimates are derived using 14C ages, the age of Lava Creek B tephra, and minimum ages for erosion surfaces.

Quaternary shelf deposits and drainage patterns off the French and Belgian coasts in The Quaternary and Tertiary geology of the Southern Bight, North Sea.

Quaternary shelf deposits and drainage patterns off the French and Belgian coasts in The Quaternary and Tertiary geology of the Southern Bight, North Sea.
High-resolution reflection seismic data recorded in the Southern Bight of the North Sea have allowed to draw a first general reconstruction of the topography of the base of the Quaternary deposits. The morphological aspects of this erosion surface
have been confronted with the knowledge of the Quaternary history of the Belgian coastal plain, yielding a hypothesis about the origin of the palaeolandforms and of the present-day offshore morphology. The evolution of this erosion surface is also

Surface erosion associated with tephra deposition on Mt. Usu and other volcanoes

Surface erosion associated with tephra deposition on Mt. Usu and other volcanoes
The 1977-1978 eruptions of Mt. Usu, Hokkaido, altered erosion regime of its summit atrio through destruction of pre-existing vegetation, new tephra deposition and crustal deformation, resulting in heavy relling and gullying. The pattern, initial

Techniques to measure the dry aeolian deposition of dust in arid and semi-arid landscapes : a comparative study in West Niger

Techniques to measure the dry aeolian deposition of dust in arid and semi-arid landscapes : a comparative study in West Niger
Seven techniques designed to measure the dry aeolian deposition of dust on a desert surface were tested during field experiments in Niger. The results show that the crude (unconverted) deposition fluxes of the 5 experimental techniques were similar
, while the crude deposition fluxes calculated by the 2 theoretical techniques were substantially higher. The measurements illustrate the need to include a grain shape factor in theoretical dust deposition models. The paper also discusses the advantages

Trend surface analysis of glacially buried Pleistocene organic deposits in central Michigan

Trend surface analysis of glacially buried Pleistocene organic deposits in central Michigan
; Surface d'érosion ; Surfaces de tendance ; Technique de recherche
Etablissement de surfaces de tendances pour déterminer la surface du socle à partir de la topographie actuelle et de 42 forages dans des horizons carbonés enfouis sous les dépôts morainiques dans la partie centrale du Michigan. A partir des données
, les AA. sont à peu près sûrs que les dépôts organiques pléistocènes constituent au moins deux paléosurfaces pré-woodfordiennes. L'analyse des surfaces de tendance permet de reconnaître les paléosurfaces et de séparer les différentes couches du drift

A model of pollen source area for an entire lake surface

A model of pollen source area for an entire lake surface
This paper describes a model for pollen deposition integrated over an entire lake surface, and it estimates the source area of major pollen types for various lake sizes. It is a modification of Prentice's (1985, 1988) model, which estimates
the source area of pollen deposited at a point in the center of a sedimentary basin. Comparison of the results from the two models displays the potential differences in pollen source areas when a bog and a lake of similar size are considered.

Seasonal inorganic nitrogen release in alpine lakes on the Colorado western slope

Bassin-versant ; Colorado ; Eau de fonte ; Eau de surface ; Ecosystème ; Etats-Unis ; Hydrochimie ; Lac ; Montagne ; Nitrate ; Pollution ; Rocky Mountains ; Saisonnalité
Colorado ; Ecosystem ; Hydrochemistry ; Lake ; Meltwater ; Mountain ; Nitrate ; Pollution ; Rocky Mountains ; Seasonality ; Surface water ; United States of America ; Watershed
In the Rocky Mountains, the association of increases in acidic deposition with increased loading of sulfate and direct changes in surface water chemistry has been reported by several AA. In alpine areas of the Colorado Front Range, modest loadings
of N in deposition have been associated with leakage of N to surface waters. The question remains of whether NO3 is being exported to surface waters on the Colorado western slope during snowmelt runoff. Landscape type appears to be important in leakage
of N to surface waters, which is associated with basins having steep slopes, thin soils, and large amounts of exposed bedrock.

A new chronology for the age of Appalachian erosional surfaces determined by cosmogenic nuclides in cave sediments

A new chronology for the age of Appalachian erosional surfaces determined by cosmogenic nuclides in cave sediments
Aplanissement ; Appalachian Mountains ; Cours d'eau ; Datation ; Datation isotopique ; Etats-Unis ; Grotte ; Géochronologie ; Incision ; Kentucky ; Surface d'érosion ; Sédimentologie ; Tennessee
Appalachian Mountains ; Cave ; Dating ; Downcutting ; Erosion surface ; Geochronology ; Isotope dating ; Kentucky ; Planation ; Sedimentology ; Stream ; Tennessee ; United States of America
in place of terrace deposits. Multilevel caves linked hydrologically to the incision history of the Cumberland River contain in situ sediments equivalent to fluvial deposits found scattered across the Eastern Highland Rim erosional surface. This method has
Constraining the timing of river incision into the Appalachian uplands was difficult in the past due to unsuitable dating methods and poorly preserved surface materials. The problem of erosional loss is solved in this study by using cave sediments

An evaluation of the use of size distribution of sediment in runoff as a measure of aggregate breakdown in the surface of a cracking clay soil under rain

An evaluation of the use of size distribution of sediment in runoff as a measure of aggregate breakdown in the surface of a cracking clay soil under rain
Two rainfall simulators of different plot size were used to test whether sediment in runoff could be used to measure aggregate breakdown in the surface of a cracking clay soil under rain. Size distributions of deposited sediment were similar
to those of the surface of adjacent furrow ridges exposed to raindrop impact. This provides evidence that sampling the soil surface with a spatula gives a representative sample of the material available for rainflow transport.

Fedőüledékes depressziók típusai és kialakulásuk

Carbonate rock ; Closed depression ; Geomorphology ; Hungary ; Karst ; Sedimentary basin ; Stratigraphy ; Surface deposits ; Topography ; Weathering
The A. presents closed features of the superficial deposit on karst. The study areas were the following : karst areas in Hungary, a few karst areas of the Alps and the Padis Plateau (Apuseni Mountains, Romania). The A. investigated the morphology
of the depressions of superficial deposit (by topographical mapping, morphological mapping) and the morphology of the bedrock (by Vertical Electrical Sounding). He analysed the denudation types of superficial deposit found at the bottom of depressions of bedrock
(on the topographical map using slope angle class data). In the paper the depressions of superficial deposit were classified. - (AM)

Middle-Late Pleistocene evolution of the Adriatic coastline of Southern Apulia (Italy) in response to relative sea-level changes

Messapica”, is also present. This area shows the effects of different phases of coastal evolution. During the Middle Pleistocene, north of the Soglia Messapica, thin coastal deposits accumulated and abrasion surfaces were cut whereas, to the south, marine
The Adriatic coastal area stretching from Monopoli to Brindisi in Apulia is characterised by landforms and marine/coastal deposits of Middle-Upper Pleistocene age. An E-W striking fault system, roughly corresponding to the geographic “Soglia
sediments were deposited. During the last interglacial period, two thin transgressive beach deposits formed along with a dune belt and backdune deposits. - (NF)

Novye dannye o stroenii donnyh osadkov Aral'skogo morja. (Données nouvelles sur la structure des sédiments benthiques de la mer d'Aral)

It was opened the following: the salt deposition (mirabilite) within the western deep depression, sea deposits carbonate clays underlaid by continental ones (quartz sands), much more wide distribution of deltaic deposits as compared with surface
layer and reduction of sea deposits, the availability of 2 to 36 sm intermediate layer enriched by plant organic laying among bottom deposits of the southern aquatic area at a depth of 40 to 140 sm. (Ed.).

Depositional processes and particle characteristics on fans in the Southern Alps, New Zealand

Depositional processes and particle characteristics on fans in the Southern Alps, New Zealand
Characteristics of surface particles on 4 fans dominated by different depositional processes are investigated in the sedimentary ranges of the Aoraki-Mount Cook area. Statistical testing shows that on 3 of the fans all indices of particle size
and roundness differ significantly according to the depositional process : snow avalanches produce the largest and most angular particles, streamflows the smallest and most rounded, with debris flows in between. On the fourth fan affected by all
of these depositional processes, particle size and roundness indicate that snow avalanches are presently dominant with streamflow playing a secondary role.

Loessic silt deposits in the Western Himalayas : their sedimentology, genesis and age

Loessic silt deposits in the Western Himalayas : their sedimentology, genesis and age
Asia ; Clay mineral ; Dating ; Grain size distribution;Granulometry ; Himalaya ; Karakoram ; Loess ; Microstructure ; Pedogenesis ; Sedimentology ; Surface deposits ; Thermoluminescence

Loess accumulation and soil formation in central Kansas, United Sates, during the past 400 000 years

Aeolian features ; Isotope dating ; Kansas ; Loess ; Mineralogy ; Palaeo-environment ; Pedogenesis ; Stratigraphy ; Surface deposits ; United States
The AA. present here the stratigraphical, chemical, physical and mineralogical records from the loess deposits of central Kansas. The records show a strong correlation with the Louchuan record and the oxygen isotope curve, indicating continuous
deposition of loess in central Kansas. The Kansas loess sections provide an important proxy for central Northern American climate over the last 400 000 years.

Post-eruption erosion and deposition in the 1980 crater of Mount St Helens, Washington, determined from digital maps

Post-eruption erosion and deposition in the 1980 crater of Mount St Helens, Washington, determined from digital maps
Crater ; Earth surface processes ; Erosion ; Geographical information system ; Mass movement ; Numerical model ; Sedimentation ; Topography ; United States ; Volcanism ; Volcano ; Washington State
The purposes of this paper are to describe briefly the mass movements in the crater, to document post-eruption changes in the topography of the crater, and to estimate the volume of erosion and deposition in the crater between 1980 and 1988.

Eolian transport and deposition in a partially vegetated linear sand dune area (northwestern Negev, Israel)

Eolian transport and deposition in a partially vegetated linear sand dune area (northwestern Negev, Israel)
The AA. present results of bulk and net sand and dust deposition above and at the surface along a cross-dune transect in order to quantify sediment transport and input in mobile and stable eco-geomorphic units. Furthermore, the role of higher

Particle motion and the theory of charcoal analysis : source area, transport, deposition, and sampling

Particle motion and the theory of charcoal analysis : source area, transport, deposition, and sampling
The A. presents a theory of charcoal transport from fires and recently burned areas, and of charcoal deposition in lakes. It is a first approximation, this theory is not intended to be predictive for any particular fire. Rather, the A. seeks
of the physics of particle motion. He focuses on eolian processes, because surface runoff is not an important process for charcoal transport to lakes.

Grèzes litées as a spacial type of periglacial slope sediments in the German Highlands

by a complex of geomorphic processes involving frost weathering, episodic or periodic aquatic transport and deposition in connection with surface runoff, slopewash and active layer interflow. (l'A.).
Field and laboratory investigations into the sedimentology and geomorphology of thick stratified slope deposits (grèzes litées) in the Rothaargebirge, in the northeastern part of the Rhenish Slate Mountains show that these deposits were formed

Age calibration of carbonate rind in thickness in late Pleistocene soils for surficial deposit age estimation, Southwest USA

Age calibration of carbonate rind in thickness in late Pleistocene soils for surficial deposit age estimation, Southwest USA
Carbonate ; Chronosequence ; Dating ; Palaeosol ; Pleistocene ; Soil ; Soil properties ; Surface deposits ; United States of America ; Western United States

Résultats de la recherche (2887 résultats)

Affinez votre recherche