نتایج جستجو برای: volcanic areas
تعداد نتایج: 414965 فیلتر نتایج به سال:
Results are presented of a continued investigation of the infrared colorimetry of the Martian bright and dark areas. Laboratory comparisons indicate that the infrared color profile of the Martian deserts matches that of a naturally occurring limonite stain which forms and is preserved on igneous rocks in a terrestrial desert environment. The co]orimetry of the Martian dark regions is compared t...
Age-depth relations from internal layering reveal a large region of rapid basal melting in Greenland. Melt is localized at the onset of rapid ice flow in the large ice stream that drains north off the summit dome and other areas in the northeast quadrant of the ice sheet. Locally, high melt rates indicate geothermal fluxes 15 to 30 times continental background. The southern limit of melt coinci...
[1] Sintering and densification are ubiquitous processes influencing the emplacement of both effusive and explosive products of volcanic eruptions. Here we sinter ash-size fragments of a synthetic National Institute of Standards and Technology viscosity standard glass at temperatures at which the resultant melt has a viscosity of ∼108-109 Pa.s at 1bar to assess sintering dynamics under near-sur...
Mantling deposits on the Moon are considered to be pyroclastic units emplaced on the lunar surface as a result of explosive fire fountaining. These pyroclastic units are characterized as having low albedos, having smooth fine-textured surfaces, and consisting in part of homogeneous, Febearing volcanic glass and partially crystallized spheres. Mantling units exhibit low returns on depolarized 3....
Volcanic eruptions are major natural disturbances with varied and complex consequences. Recent studies of how plants colonize newly created volcanic surfaces already have begun to clarify our understanding of succession. Because volcanoes create disturbance mosaics, it is imperative that we more fully understand the biotic responses. The 1883 eruption of Krakatau captured the world’s imaginatio...
We analyze mass-flow tsunami generation for selected areas within the Aleutian arc of Alaska using results from numerical simulation of hypothetical but plausible mass-flow sources such as submarine landslides and volcanic debris avalanches. The Aleutian arc consists of a chain of volcanic mountains, volcanic islands, and submarine canyons, surrounded by a low-relief continental shelf above abo...
Interactions with volcanic gases in eruption plumes produce soluble salt deposits on the surface of volcanic ash. While it has been postulated that saturation-driven precipitation of salts following the dissolution of ash surfaces by condensed acidic liquids is a primary mechanism of salt formation during an eruption, it is only recently that this mechanism has been subjected to detailed study....
The Dongpan section in southern Guangxi Province records the influence of local volcanic activity on marine sedimentation at intermediate water depths (~200-500 m) in the Nanpanjiang Basin (South China) during the late Permian crisis. We analyzed ~100 samples over a 12-m-thick interval, generating palynological, paleobiological, and geochemical datasets to investigate the nature and causes of e...
Rifted continental margins are the product of stretching, thinning and ultimate break-up of a continental plate into smaller fragments, and the rocks lying beneath them store a record of this rifting process. Earth scientists can read this record by careful sampling and with remote geophysical techniques. These experimental studies have been complemented by theoretical analyses of continental e...
0019-1035/$ see front matter 2011 Published by doi:10.1016/j.icarus.2010.09.026 ⇑ Corresponding author. E-mail address: [email protected] (A.G. D Dark paterae on the jovian satellite Io are evidence of recent volcanic activity. Some paterae appear to be entirely filled with dark volcanic material, while others have only partially darkened floors. Dark paterae have area and heat flow lo...
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