نتایج جستجو برای: volcanic rock

تعداد نتایج: 52326  

2008
William I. Rose Adam J. Durant

This retrospective study focuses on the fine silicate particles (\62 lm in diameter) produced in a large eruption that was otherwise well studied. Fine particles represent a potential hazard to aircraft, because as simple particles they have very low terminal velocities and could potentially stay aloft for weeks. New data were collected to describe the fine particle size distributions of distal...

2016
James Hickey Joachim Gottsmann Haruhisa Nakamichi Masato Iguchi

Ground deformation often precedes volcanic eruptions, and results from complex interactions between source processes and the thermomechanical behaviour of surrounding rocks. Previous models aiming to constrain source processes were unable to include realistic mechanical and thermal rock properties, and the role of thermomechanical heterogeneity in magma accumulation was unclear. Here we show ho...

2010
LUZ M. CISNEROS-DOZAL JEFFREY M. HEIKOOP JULIANNA FESSENDEN R. SCOTT ANDERSON PHILIP A. MEYERS CRAIG D. ALLEN MARCEY HESS TOTI LARSON GEORGE PERKINS MICHAEL REARICK

Elemental (C, N, Pb) and isotopic (dC, dN) measurements of cored sediment from a small bog in northern New Mexico reveal changes in climate during the Late Pleistocene and Holocene. Abrupt increases in Pb concentration and dC values ca. 14 420 cal. YBP indicate significant runoff to the shallow lake that existed at that time. Weathering and transport of local volcanic rocks resulted in the deli...

2014
Francesco Italiano Angelo De Santis Paolo Favali Mario Luigi Rainone Sergio Rusi

Italy has a strong geothermal potential for power generation, although, at present, the only two geothermal fields being exploited are Larderello-Travale/Radicondoli and Mt. Amiata in the Tyrrhenian pre-Apennine volcanic district of Southern Tuscany. A new target for geothermal exploration and exploitation in Italy is represented by the Southern Tyrrhenian submarine volcanic district, a geologi...

2017
Craig Magee Ian D. Bastow Benjamin van Wyk de Vries Christopher A.-L. Jackson Rachel Hetherington Miruts Hagos

Shallow-level sill emplacement can uplift Earth’s surface via forced folding, providing insight into the location and size of potential volcanic eruptions. Linking the structure and dynamics of ground deformation to sill intrusion is thus critical in volcanic hazard assessment. This is challenging, however, because (1) active intrusions cannot be directly observed, meaning that we rely on trans...

2009
R. Lena

Introduction: Lunar domes are smooth low features similar to low terrestrial shield volcanoes. They were formed during the terminal phases of lunar eruptions and mostly occur in the maria. A few domes have been reported in the highlands, but these are usually difficult to observe because of the brightness and ruggedness of the surrounding terrain. According to [1,2], constructional volcanic fea...

2005
P. F. Dobson S. Maruyama

An Eocene submarine boninite series volcanic center is exposed on the island of Chichi-jima, Bonin Islands, Japan. Five rock types, boninite, bronzite andesite, dacite, quartz dacite, and rhyolite, were distinguished within the boninite volcanic sequence on the basis of petrographic and geochemical observations. Boninite lavas contain high magnesium, nickel, and chromium contents indicative of ...

2014
Emma C Marcucci Brian M Hynek

We have completed laboratory experiments and thermochemical equilibrium models to investigate secondary mineral formation under conditions akin to volcanic, hydrothermal acid-sulfate weathering systems. Our research used the basaltic mineralogy at Cerro Negro Volcano, Nicaragua, characterized by plagioclase, pyroxene, olivine, and volcanic glass. These individual minerals and whole-rock field s...

Journal: :Journal of human evolution 2003
F J Gathorne-Hardy W E H Harcourt-Smith

Lake Toba, Sumatra, Indonesia, is the site of the largest volcanic explosion in the late Pleistocene, which occurred about 73,500 ( 2000) years ago (Chesner et al., 1991, Bühring & Sarnthein 2000). It has been asserted by Ambrose (1998) and others (Rampino & Self 1992, Rampino & Ambrose 2000, Rampino 2002) that the eruption gave rise to a “volcanic winter” of such a catastrophic scale that it c...

2008
Mariek E. Schmidt Steven W. Ruff Timothy J. McCoy William H. Farrand Jeffrey R. Johnson Ralf Gellert Douglas W. Ming Richard V. Morris Nathalie Cabrol Kevin W. Lewis Christian Schroeder

[1] In the Inner Basin of the Columbia Hills, Gusev Crater is Home Plate, an 80 m platform of layered clastic rocks of the Barnhill class with microscopic and macroscopic textures, including a bomb sag, suggestive of a phreatomagmatic origin. We present data acquired by the Spirit Mars Exploration Rover by Alpha Particle X-Ray Spectrometer (APXS), Mössbauer Spectrometer, Miniature Thermal Emiss...

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