نتایج جستجو برای: lava rock
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The rate at which lava emerges from a volcano is a fundamental property of the dynamics of the eruption. Intensive field measurements can capture this. However, for many, often cloud-covered, volcanoes with long-lived eruptions, spaceborne InSAR provides a potentially useful source of information. Repeated DEM creation at intervals allows the changing thickness of the lava flow field to be meas...
Catastrophic collapses of the flanks of stratovolcanoes constitute a major hazard threatening numerous lives in many countries. Although many such collapses occurred following the ascent of magma to the surface, many are not associated with magmatic reawakening but are triggered by a combination of forcing agents such as pore-fluid pressurization and/or mechanical weakening of the volcanic edif...
Chemical analyses conducted on the surface of rock slabs under a combination of two X-ray spectrometry methods, wavelength dispersive XRF and energy dispersive XRF, are used to establish a geochemical correlation between the studied samples. This proves to be an excellent method for the characterization of volcanic glasses, particularly when particles of exotic origin are present, because the e...
New high-precision ages, determined from palynomorph assemblages within intercalated sedimentary deposits, are presented for the Palaeogene lava fields (Skye, Mull and Antrim) of the British Province. These data reveal very rapid averaged eruption rates (1 m/200 years) and the non-synchronous formation of the lava fields. Eruption of the volumetrically dominant transitional to mildly alkaline l...
Introduction: It is known from previous studies that in principle, the dimensions of lava flows reflect rheologic properties such as yield strength, effusion rates and viscosity [1-17]. In a previous study, we reported on such derived rheologic properties of lava flows on Arsia Mons, Pavonis Mons, and Ascraeus Mons, which are located on the extensive Tharsis bulge [1,2]. Here, we expand on our ...
Bryophytes are ecologically essential to northern ecosystem restoration after disturbance. In this study, native bryophytes were used revegetate two Arctic sites. Different propagation types (small, medium, large fragments) and substrates (crushed rock, lake sediment, processed kimberlite in Canada; volcanic silt loam crushed lava rock Iceland) with erosion control treatments (with without chee...
Recent modeling studies of the early Mars climate predict a predominantly cold climate, characterized by the formation of regional ice sheets across the highland areas of Mars. Formation of the predicted “icy highlands” ice sheets is coincident with a peak in the volcanic flux of Mars involving the emplacement of the Late Noachian – Early Hesperian ridged plains unit. We explore the relationshi...
Soil-geomorphic studies indicate that six major allostratigraphic units occur in Crater Flat, Nevada, adjacent to Yucca Mountain. These units are, from youngest to oldest, Crater Flat, Little Cones, Late Black Cone, Early Black Cone, Yucca, and Solitario. Presence and degree of differentiation of Av, Ak, Bw, Bt, Btk, Btkq, and Bqkm genetic soil horizons characterize units, confirm relative ages...
Quantitative measurements of interactions between lava and ice/snow are critical for improving our knowledge of glaciovolcanic hazards and our ability to use glaciovolcanic deposits for paleoclimate reconstructions. However, such measurements are rare because the eruptions tend to be dangerous and not easily accessible. To address these diffi culties, we conducted a series of pilot experiments ...
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