Regional variability of volcanicash soils in south Ecuador : the relation with parent material, climate and land use
Agricultural land use ; Andes ; Ecuador ; High mountain ; Organic materials ; Soil ; Soil properties ; Spatial variation ; Volcanic soil
the soil properties, and to relate the spatial variability of these properties to the major trends in parent material, volcanicash deposits and climate. The impact of human activities on the soil properties is assessed in a case study in the Machangara
Rates of stream incision in the middle part of the Arkansas River basin based on late Tertiary to mid-Pleistocene volcanicash
Arid area ; Arkansas ; Fluvial erosion ; Lithology ; Pleistocene ; Pliocene ; River bed ; Stream ; Tephrochronology ; United States of America ; Volcanism ; Watershed
Ages and elevations of ash layers correlated with late Tertiary and Pleistocene eruptions in the western US and present stream elevations are used to calculate net rates of incision by streams in the middle reaches of the Arkansas River basin
Mechanical consolidation in volcanicash soils in Impact of water and external forces on soil structure. Selected papers of the 1st Workshop on soilphysics and soilmechanics, Hannover 1986.
Europe ; Greece ; Italy ; Mediterranean area ; Pleistocene ; Quaternary ; Stratigraphy ; Tephrochronology ; Volcanic eruption
This paper reports the discovery of an exceptionally thick ash deposit of Middle Pleistocene age in western Epirus, Greece. This ash layer has not been reworked and has a chemical composition that links it to an Italian volcanic source 750 km
La zone de dispersion des poussières émises par une des dernières éruptions du volcan du Laachersee (Eifel)
Based upon a study of the heavy minerals in the recent soils between the Eifel, the Maine (France) and the Massif Central, the writer shows that the major part of the ash distributed by one of the last eruptions of the Laachersee volcano
was in the southerly direction. We have extended our knowledge of the ash distribution to the West, showing that it reached the Vosges and the region of Paris.
Cet ouvrage présente la beauté diabolique des volcans avec 200 magnifiques photos en couleurs, qui révèlent la force destructrice des volcans, mais aussi la fascination qu'ils exercent sur les hommes. Le texte est clair, vivant et bien documenté. Il
Occurrence and hydrological effects of water repellency in different soil and land use types in Mexican volcanic highlands
Ecosystem ; Forest ; Land use ; Mexico ; Michoacán ; Permeability ; Pyroclastic ; Soil erosion ; Soil properties ; Vegetation ; Volcanicash ; Volcanic soil ; Water erosion
soils developed from lavas, [2] soils developed from volcanicashes and pyroclastic sediments under sparse fir, pine and oak forest and shrubland, [3] pine and oak forested soils developed from lavas and pyroclastic sediments, and [4] bare soils
In this study the occurrence and hydrological effects of water repellency were investigated at a plot scale for different types of land use and volcanic soils in Mexican volcanic highlands from Michoacan, Mexico: [1] fir, pine and oak mixed forest
on recent ash sediments in plain surfaces. Shallow and irregular wetting fronts were observed at water-repellent zones, reducing the soil water storage capacity. The implications of soil water repellency in soil hydrology and erosion risk in the area shed
In Manizales (Colombia) a hydrological study was carried out to find zones with positive pore-water pressures (potential failure zones) in volcanic soils with significant vertical changes in hydraulic conductivity. The locations of potential failure
Volcanicash layers from three major Holocene eruptions are found throughout southern British Columbia and are useful stratigraphic markers. Here the AA. show that energy dispersive X-ray fluorescence analysis and alpha counting are useful
techniques for the rapid identification of these ashes.
. This is the main volcanic structure of peninsula and phreatomagmatic activity probably began here. The lapilli and coarse ashes in the pyroclastites are generally mud-coated, accretionary lapilli are common, and the tuffs are frequently light brownish, suggesting
The eruptive history of the Tihany Peninsula (Lake Balaton, Hungary) has been studied in detail to understand the evolution of volcanic and tectonic structures. Tectonic and depositional features indicate a maar-type origin of the Outer Lake
Asian part of Russia ; Caldera ; Geochemistry ; Holocene ; Kamchatka ; Mineralogy ; Quaternary ; Stratigraphy ; Tephrochronology ; Volcanic eruption ; Volcanism
This paper presents the first detailed account of most Holocene key-marker ash layers in Kamchatka, which form a detailed timescale for its stratigraphy. The dated tephra layers provide a record of the most voluminous explosive events from 11
[b1] Institute of Volcanic Geology and Geochemistry, Russian Academy of Sciences, Petropavlosk-Kamchatsky, Russie, Federation de
This paper examines the literature on research into the effects of burial by deposition of blown sand, volcanic deposits (tephra, lavas and lahars) or fluvial sediment on vegetation and the subsequent capacity of the vegetation for survival
is then demonstrated by reference to macahir sand dune stratification in the Outer Hebrides and vegetation damage and burial following proximal volcanic impacts in New Zealand.
California ; Dating ; Geochronology ; Isotope dating ; Nevada ; Pleistocene ; Quaternary ; Stratigraphic correlation ; Tephrochronology ; United States of America ; Volcanicash
The age of the Rockland tephra, which includes an ash-flow tuff south and west of Lassen Peak in northern California and a widespread ash-fall deposit that produced a distinct stratigraphic marker in western North America, is constrained to 565,000