نتایج جستجو برای: lava

تعداد نتایج: 2954  

2009
T.

Observations of terrestrial examples of lava and ice interaction have been combined with laboratory simulations to provide a framework for investigating lava and ice interaction on Mars. Identification of largeand small-scale characteristic features will indicate whether large quantities of meltwater were trapped or whether lava flow confinement occurred. These features should also enable the d...

2017
S. F. Jenkins S. J. Day B. V. E. Faria J. F. B. D. Fonseca

Fast-moving lava flows during the 2014–2015 eruption of Fogo volcano in Cape Verde engulfed 75% (n = 260) of buildings within three villages in the Chã das Caldeiras area, as well as 25% of cultivable agricultural land, water storage facilities and the only road into the area. The eruption had a catastrophic impact for the closeknit communities of Chã, destroying much of their property, land an...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1998
G B Dalrymple W K Hamblin

At least 13 times during the Pleistocene Epoch lava flowed into the inner gorge of the Grand Canyon and formed lava dams, as high as 600 m, that temporarily blocked the flow of the Colorado River. K-Ar ages on these lava dams indicate that the seven youngest formed within a short period of time between about 0.6 and 0.4 mega-annum (Ma). The physiography of the lava dam remnants within the canyo...

2003
Scott M. White Ken C. Macdonald Rachel M. Haymon

Meter-scale DSL-120 sonar mapping and coregistered Argo II photographic observations reveal changes in eruptive style that closely follow the third-order structural segmentation of the ridge axis on the southern East Pacific Rise, 17°11’-18°37’S. Near segment ends we observe abundant basaltic lava domes which average 20 m in height and 200 m in basal diameter and have pillow lava as the dominan...

Journal: :Geomicrobiology journal 2014
Jennifer J Marshall Hathaway Robert L Sinsabaugh Maria De Lurdes N E Dapkevicius Diana E Northup

Lava caves are an understudied ecosystem in the subterranean world, particularly in regard to nitrogen cycling. The diversity of ammonia oxidation (amoA) and nitrogen fixation (nifH) genes in bacterial mats collected from lava cave walls on the island of Terceira (Azores, Portugal) was investigated using denaturing gradient gel electrophoresis (DGGE). A total of 55 samples were collected from 1...

2003
Harry Pitt

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...

1997
B. R. BELL D. W. JOLLEY

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...

2015
H. Hiesinger J. H. Pasckert D. Reiss

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 ...

2016
James P. Cassanelli James W. Head

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...

2013
Benjamin R. Edwards Jeffrey Karson Robert Wysocki Einat Lev Ilya Bindeman Ulrich Kueppers

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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