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  • Comparison of conventional K-Ar and Ar40/Ar39 dating of young mafic volcanic rocks
  • Dating ; Geochronology ; K/Ar dating ; Methodology ; Pleistocene ; Quaternary ; United States of America ; Volcanic rock ; Western United States
  • The objective of this study was to compare the results using both Ar techniques on Quaternary volcanic rocks from 3 areas of the western United States : the Snake River Plain, Idaho, Mount Adams, Washington, and Crater Lake, Oregon. The samples
  • selected for comparison are representative of the rock types in the 3 areas.
  • New evidence of Pre-Hercynian volcanics from Southern Sulcis (Southwestern Sardinia)
  • Italy ; Palaeozoic ; Regional geology ; Sardegna ; Sedimentary ; Structural geomorphology ; Volcanic rock
  • Several occurrences of metamorphosed pre-Hercynian volcanic rocks crop out in the Paleozoic basement of Southern Sulcis (SW Sardinia), hosted in Cambrian-Early carboniferous sedimentary sequences belonging to two different structural units. - (NF)
  • Volcanic activity in Taiwan
  • Cenozoic ; Dating ; Fault ; Geothermics ; K/Ar dating ; Plate tectonics ; Quaternary ; Taiwan ; Volcanic eruption ; Volcanism
  • A group of Ar-K dating data of volcanic rocks in Taiwan Island is listed in this paper, which clarifies the data of volcanic activity. This volcanic activity is closely related with plate movement since Mesozoic. Now there are still manifestations
  • of volcanic actions such as hot springs or fumaroles or solfataras.
  • Etude géologique et géomorphologique des « beehive rocks » dans le massif de Bükk, Nord-Est de la Hongrie
  • Erosion ; Escarpment ; Geomorphogenesis ; Geomorphology ; Hungary ; Mountain ; Rock ; Slope ; Volcanic rock ; Volcanism
  • This paper examines the geological and geomorphological conditions under wich the special riolith-tuff cliffs, the so-called « beehive rocks » south from the Bükk Mountains (NE-Hungary) were formed. - (JS)
  • Hungary ; Mountain ; Structural geomorphology ; Volcanism
  • The Tokaj Mountains differ from the other volcanic mountains of Hungary by strike, heavy dissection, (a younger) age of volcanism, a great diversity of volcanic rocks, paleogeographic circumstances (frequent marine transgressions). The paper deals
  • with the volcanic forms in detail, with their types, with erosional and derasional valleys and their development. - (ZK)
  • In-situ gamma-ray spectrometric study of weathered volcanic rocks in Hong Kong
  • Chemical erosion ; Geochemistry ; Geotechnics ; Hong Kong ; Volcanic rock ; Weathering
  • In this study, an integrated geochemical and in-situ GRS survey was conducted at 2 sites in Hong Kong where tuffs of varying weathering states were exposed. Field description of rock materials and sampling for elemental analyses were conducted at 57
  • Tertiary silicic rocks in the area of the Koekjuskord rhyolitic volcano, Eastern Iceland
  • Dacite ; Géographie de l'Europe ; Ignimbrite ; Islande ; Islande de l'Est ; Magma ; Pyroclastique ; Rhyolite ; Volcan central ; Volcanisme
  • A propos des volcans centraux de l'Islande orientale. Etude minitieuse de l'un d'entre eux, considéré comme un volcan parasite. - (JCB)
  • Comparative geochemistry of volcanics from rift valleys, transform faults and aseismic ridges
  • It is suggested that transform faults have, by faulting, exposed more fractioned types of basaltic rocks (may be as intrusives) than the rift valley volcanics. While aseismic ridges have undergone a greater degree of differentiation than both
  • transform faults and rift valley volcanics.
  • Chemical erosion ; Geochemistry ; Island ; Japan ; Microstructure ; Mineralogy ; Porosity ; Rock ; Rock mechanics ; Volcanic rock ; Weathering
  • To examine the mechanism of rock-strength reduction due to weathering, temporal changes in microstructure of 4 porous rhyolite were investigated at Kozu-shima Island in the western Pacific. With the results of mineralogical investigations
  • and laboratory tests of pore structure of the rocks, the AA. conclude that the microstructural changes due to chemical weathering strongly influence the reduction of rock strengths.
  • Formation of silica glaze rock coatings through water vapor interactions
  • Basalte ; Domaine aride ; Désert ; Enduit ; Géochimie ; Hawaii ; Humidité ; Mars ; Météorisation ; Silice ; Vapeur d'eau ; Vernis ; Volcan ; Zone subtropicale
  • Arid area ; Basalt ; Desert ; Geochemistry ; Hawaii ; Mars planet ; Moisture ; Rock coatings ; Rock varnish ; Silica ; Subtropical zone ; Volcano ; Water vapor ; Weathering
  • Basalto ; Campo árido ; Desierto ; Geoquímica ; Hawaii ; Humedad ; Meteorización ; Sílice ; Vapor de agua ; Volcán ; Zona subtropical
  • A two decade-long laboratory experiment tested importance of high water vapor content in silica glaze formation. Twenty years of exposing basalt rock chips to 80% and 90% levels of relative humidity revealed that water vapor alone can generate
  • silica glaze and may be an important factor in explaining why silica glaze is the dominant rock coating in humid warm drylands. In addition to adding a new dimension to the formation of terrestrial rock coatings, these findings may have importance
  • Composition and age of Law Bassin and Ridge volcanic rocks: implications for evolution of an interarc basin and remnant arc
  • Paleomagnetism of the Flores volcanics, Vancouver Island, in place by Eocene time
  • The purpose of this paper is to describe paleomagnetic data from Eocene rocks of the Insular Belt, the westernmost element of the Canadian Cordillera. The possibility of using their paleomagnetism to reconstruct their attitude is considered
  • Geomorphological, hydrological and climatic significance of rock glaciers in the Andes of Central Chile (33-35°S)
  • Air temperature ; Andes ; Chile ; Hydrology ; Moisture ; Mountain ; Periglacial features ; Permafrost ; Rock glacier ; Spatial distribution ; Volcanism
  • of the mean annual air temperature of at least c. 5.5°C. South of Santiago, active rock glacier distribution ends at 35° 15'S due to lower topography, young volcanism and increased humidity.
  • Rock glaciers in the Andes of Santiago de Chile occupy c. 10% of the total land surface between 3500 and 4250m ASL.. An estimated water equivalent of 0.3 km3 per 1000 km2 of mountain area is stored within them; this value is one order of magnitude
  • higher than in the Swiss Alps. Climate data indicate that the lowest occurences of active rock glaciers in the Andes of Santiago are not in equilibrium with modern climate. Relict features are found as low as at 2630 m ASL, implying a depression
  • Measurement of tectonic rock strain in Iceland
  • The AA. applied the overcoring method to determine in-situ rock deformation by means of strain gage rosettes at 20 sites located within the area of active rifting. They determined numerous changes in the amount and the orientation of the maximum
  • and minimum horizontal crustal strain and consider these stress fluctuations to be caused by the pulsation of the Krafla volcanic centre.
  • Volcanic soils of the High Börzsöny and their relationship with geomorphological conditions
  • Hungary ; Pedogenesis ; Soil classification ; Soil properties ; Typology ; Volcanic rock ; Volcanic soil
  • Heretofore very little research has been done on a specific soil type in Hungary called „erubáz”, which develops on volcanic rocks. Its largest uniform and unbroken spot is located in the central part of Börzsöny Mountains (High Börzsöny
  • Chemical erosion ; Erosion rate ; Field experiment ; Freeze-thaw cycle ; Island ; Japan ; Volcanic rock ; Weathering
  • To examine the rate of weathering, field experiments using microweight-loss techniques were carried out. Two kinds of porous rhyolite forming lava domes in Kozushima Island were selected : a younger rock and an older rock. Results show
  • that the younger rock has a lower weight loss, and the older rock a higher weight loss, and the rates of weight loss for both rocks on the ground surface is larger than that under the saturated grus layer. The first result shows that older rock has a higher rate
  • of chemical weathering than younger rock. The second result suggests that in addition to chemical weathering, physical weathering such as freeze-thaw weathering occurs on the ground surface.
  • Geomorphogenesis ; Hungary ; Mountain ; Periglacial features ; Volcanism
  • The range of Tokaj Mountains is not only different from the rest of our volcanic mountains because of its N-S direction, but also the duration and extent of its volcanism, its volcanic material ; and the paleogeographical circumstances were
  • different too. As a result of all this, the mountain is very rich in morphological forms. In Hungary, these mountains are the richest in periglacial forms thanks to the varied collection of rocks and their settlement characteristics. - (ZK)
  • Soil-elevation relationships on a volcanic plateau in the Southern Cascade Range, northern California, USA
  • Altitude ; California ; Chronosequence ; Pedogenesis ; Precipitation ; Soil ; Soil properties ; Temperature ; United States ; Vegetation ; Volcanic rock
  • This paper presents the main features of an altitudinal sequence. They were determined from mapping soils on a late cenozoic volcanic plateau west-southwest of Lassen Peak, and from the analyses of 27 pedons sampled from 270 to 2 030 m above sea
  • Genesis and diagenesis of paleosols from Pliocene volcanics on the Golan Heights
  • Basalt ; C 14 dating ; Carbonate ; Clay mineral ; Diagenesis ; Geochemistry ; Israel ; Palaeoclimate ; Palaeogeography ; Palaeosol ; Pedogenesis ; Pliocene ; Precipitation ; Vertisol ; Volcanic rock
  • the paleosols formed, the impacts of burial by volcanic flows and the nature of post-burial diagenetic processes on the paleosols.
  • Spatial variability of soils developing on basalt flows in the Potrillo volcanic field, southern New Mexico : prelude to a chronosequence study
  • Aquifer ; Arid area ; Basalt ; Chronosequence ; Natural recharge ; New Mexico ; Soil ; Soil properties ; Spatial variation ; United States of America ; Volcanic rock
  • This study seeks to improve the accuracy of a future soil chronosequence study in the Potrillo volcanic field by : further evaluating the evolution of basalt flow surface topography with time; identifying the systematic variability of soils