Basalt magma sources during the opening of the North Atlantic
Atlantique ; Atlantique, Nord ; Basalte ; Ere tertiaire ; Géographie physique ; Magmatisme ; Origine ; Tectonique de plaques ; Tectonique globale ; Volcanisme
The mantle that supplied basalts to the North Atlantic Tertiary province at the time of continental breakup was isotopically similar to the present-day sub-oceanic mantle. There is no evidence for undepleted source regions beneath the continent
A preliminary study of typical profiles is reported together with data on their composition. These observations are used to comment on the origins of the sub-basaltic beds and to investigate the possibility that they may represent karst bauxites
comparable in their origin to the inter-basaltic bauxites found between the overlying basalts.
Radiocarbon dating was applied to carbon bearing, charred eolian sediment from beneath the lava flows. Twenty of the more than 60 lava flows of the Crater of the Moon lava field have been dated| their ages range from about 15,000 to about 2000 yr
Physiographically controlled allometry of specific sediment yield in the Canadian Cordillera : a lake sediment-based approach
Bassin-versant ; Bilan sédimentaire ; British Columbia ; Canada ; Charge en suspension ; Modèle ; Montagne ; Sédiment lacustre ; Sédimentologie ; Transfert sédimentaire
British Columbia ; Canada ; Lacustrine sediment ; Model ; Mountain ; Sediment budget ; Sediment transfer ; Sedimentology ; Suspended load ; Watershed
estimates of long-term sediment yield, sub-regional patterns of specific yield have been investigated for the Canadian Cordillera. The results suggest that no single model of sediment yield is adequate to describe sediment transfer processes in the Canadian
It is generally supposed that specific sediment yield declines as the drainage basin area increases, as part of the mobilized sediment becomes trapped in the downstream cascade of storage zones. Using a larger data set of lake sediment-based
and continental basalts, to radiogenic Sr/Sr values. These data are used to demonstrate the ancient enriched, grossly heterogeneous nature of the sub-continental mantle, which complements the predominantly depleted nature of the sub-oceanic mantle.
Glacial landform sediment associations are reported and the implications for glacigenic depositional sequences are discussed for areas that have experienced proglacial thrusting.
Détermination de la polarité magnétique de sédiments et de basaltes du Massif Central et du Midi méditerranéen français. Interprétation chronostratigraphique
Basalte ; Chronostratigraphie ; France ; Géochronologie ; Géographie physique ; Massif Central ; Midi méditerranéen ; Paléomagnétisme ; Polarité magnétique ; Quaternaire zones moyennes ; Stratigraphie ; Sédimentaire ; Technique de recherche
avec les conclusions dégagées de l'étude géochimique fine des basaltes. En fait ces enclaves peuvent parvenir en surface très modifiées chimiquement et minéralogiquement.
Using Be 10 and Al 26 to determine sediment generation rates and identify sediment source areas in an arid region drainage basin
Arid area ; Arizona ; Grain size distribution ; Isotope dating ; Model ; Sediment budget ; Sediment transport ; United States of America ; Watershed ; Weathering
In this work, the AA. apply the techniques developed for determining basin-wide sediment generation rates in small basins to both the entire Yuma Wash drainage and to smaller sub-basins of the Wash. Tracing nuclide concentrations in sediment along
the length of Yuma Wash, the AA. identify significant sediment source areas. Nuclide concentrations in upland basins represent the production rate of sediment from the weathering of bedrock (sediment generation). Nuclide concentrations in main stem samples
reflect both upland sediment generation and the long-term effects of sediment storage and reworking.
Weathering of basalt and sandstone by wetting and drying : a process isolation study
Afrique du Sud ; Antarctique ; Basalte ; Drakensberg ; Expérimentation ; Grès ; Humidité ; Marion Island ; Météorisation ; Porosité ; Propriétés de la roche ; Sub-Antarctique
Antarctica ; Basalt ; Experimentation ; Moisture ; Porosity ; Sandstone ; South Africa ; Weathering
Rock samples from Marion Island in the Sub-Antarctic and from the Drakensberg, South Africa were divided into sets and subjected to wetting and drying at 2 different moisture amplitudes to determine changes in physical rock properties. Rock porosity
Sediment yield and storage variations in the Négron River catchment (south western Parisian Basin, France) during the Holocene period
Agricultural land use ; Colluvium ; France ; Holocene ; Human impact ; Lithology ; Loess ; Periglacial features ; Poitou-Charentes ; Quaternary ; Sediment budget ; Vienne ; Watershed
by each approach. The mean sediment yield of the catchment will be compared to those of its various sub-basins. In the Négron catchment, the values of sediment yield differ widely according to the parameters used for calculation. Sediment yield varies
This study aims to attempt a sediment budget for the Holocene period using different approaches (quantification of present flux of solid material, of various sedimentary stores, and of rates of sedimentation), and to compare the values obtained
by a factor of 1 to 5 according to the lithology of the sub-basin studied. During the Holocene it has increased by a factor of 6 as a result of the growth of agricultural activities.
how basaltic particles weather both physically and chemically so that it will be possible to apply traditional sedimentological concepts, such as sediment maturity, to understanding aeolian processes on Venus and Mars. Here, 3 areas where Earth analogs
studies, along with wind tunnel experiments and theoretical modeling. However, an important difference is that unlike terrestrial dunes most dunes on Venus and Mars are composed primarily of basaltic particles. Additional research is needed to understand
are extremely relevant are discussed, including studies of basaltic dune fields, laboratory analyses, and the formation of linear dunes.
Point pattern analysis of eruption points for the Mount Gambier volcanic sub-province : a quantitative geographical approach to the understanding of volcano distribution
This paper examines the method of point pattern analysis, its potential and limitations, and discusses the patterns of volcano geography for the Mount Gambier volcanic sub-province of southeastern Australia. Two classes of point pattern measure were
spatially random, and offers through the exploration of point dispersion, orientation and pattern, a viewpoint on the geography of a low-volume, basaltic monogenetic volcanic system.
Accumulation rate ; Biogenic process ; British Columbia ; Canada ; Lacustrine sedimentation ; Lake ; Model ; Mountain ; Sedimentology ; Spatial variation ; Varves
processes, morphometric controls, and the extent of post-depositional mixing by bioturbation. Systematic variations in the model parameters are observed for different lake sub-regions and are associated with changing sediment transfer dynamics between
Spatial variability of recent lacustrine sedimentary structures and sedimentation rates are examined for Green Lake, a morphologically complex lake basin of the southern Coast Mountains. Spatial patterns are related to within-lake sediment transfer
Sill intrusions into highly porous sediments in the Guaymas Basin, Gulf of California, lead to low-grade metamorphism, thermal alteration and migration of organic compounds, marked changes in interstitial water chemistry, and large-scale expulsion
The spatio-temporal invariability of sediment concentration and the flow–sediment relationship for hilly areas of the Chinese Loess Plateau
China ; Concentrated flow ; Experimental catchment ; Flood ; Gansu ; Loess ; Model ; Plateau ; Sediment budget ; Sediment transport ; Soil erosion ; Water erosion ; Watershed
Ten experimental sites of entire slope and sub-watershed and 580 flood events at 3 locations in the hilly areas of the Chinese Loess Plateau are involved in this study. The analysis at the intra-event time scale shows that the instantaneous sediment
that a single proportional function is adequate to fit the flow–sediment relationship for any entire slope or sub-watershed, where eroded sediments are primarily sourced, over a considerable areal extent unless soil property has changed or check dams
concentrations in runoff can generally approach the detach-limited maximum sediment concentration since the active massing wasting ensures an abundant sediment supply. Consequently, the event mean sediment concentration does not only remain fairly constant among
Basalte ; British Columbia ; Canada ; Chronostratigraphie ; Glaciaire ; Glaciation ; Paléogéographie ; Paléomagnétisme ; Pléistocène ; Stratigraphie
Basalt ; British Columbia ; Canada ; Chronostratigraphy ; Glacial features ; Glaciation ; Palaeogeography ; Palaeomagnetism ; Pleistocene ; Stratigraphy
conclusion, il semble que les sédiments furent déposés durant la période glaciaire qui a précédé immédiatement la mise en place du basalte. Présentation d'arguments qui indiquent que les conditions glaciaires sont apparues entre 341 et 352 ka, ce qui
Dans la vallée de la rivière Stikine, au nord-ouest de la Colombie Britannique, étude stratigraphique et paléomagnétique des sédiments glaciaires et non-glaciaires préservés sous les vestiges des coulées basaltiques du Pléistocène moyen. En