نتایج جستجو برای: lava rock

تعداد نتایج: 41494  

Journal: :Geomicrobiology journal 2014
Jennifer J Marshall Hathaway Matthew G Garcia Monica Moya Balasch Michael N Spilde Fred D Stone Maria DE Lurdes N E Dapkevicius Isabel R Amorim Rosalina Gabriel Paulo A V Borges Diana E Northup

Worldwide, lava caves host colorful microbial mats. However, little is known about the diversity of these microorganisms, or what role they may play in the subsurface ecosystem. White and yellow microbial mats were collected from four lava caves each on the Azorean island of Terceira and the Big Island of Hawai'i, to compare the bacterial diversity found in lava caves from two widely separated ...

2004
Jeffrey Taylor

Some meteorites are pieces of lava flows. They have the expected minerals present and the crystals are intertwined in a characteristic way indicative of crystallization in a lava flow. This shows that lavas erupted on at least some asteroids. Age dating indicates that the eruptions took place 4.5 billion years ago. Planetary scientists have recognized three main groups of asteroidal lava flows,...

2015
M. J. Heap J. I. Farquharson P. Baud Y. Lavallée T. Reuschlé

The failure mode of lava-dilatant or compactant-depends on the physical attributes of the lava, primarily the porosity and pore size, and the conditions under which it deforms. The failure mode for edifice host rock has attendant implications for the structural stability of the edifice and the efficiency of the sidewall outgassing of the volcanic conduit. In this contribution, we present a syst...

Journal: :Molecular ecology 2003
H E Hoekstra M W Nachman

Identifying the genes responsible for adaptation has been an elusive goal in evolutionary biology. Rock pocket mice (Chaetodipus intermedius) provide a useful system for studying the genetics of adaptation: most C. intermedius are light-coloured and live on light-coloured rocks, but in several different geographical regions, C. intermedius are melanic and live on dark-coloured basalt lava, pres...

2011
Jerry W. Fried

Mt. Etna Erupts CATANIA I~ Explosive Ml. Etna which the ancients called the Forge 01 Vulcan. thundered Thursday in increasing eruption. Two blood-red rivers 01 molten rock poured almost a mile dow~ the mountainside. Some of Europe's most famous vul· canologists who came to watch said Iherc was no imminent danger to the lourist-crowded seafront towns 10 to 12 miles away at the root of the volcan...

2017
Mark Edwards

Introduction Ocean island basalts (OIB) are thought to sample the Earth’s deep mantle, whereby thermochemical plumes entrain lower mantle material and bring it to the surface where it erupts. By measuring the isotopic compositions of global OIB—which record the isotopic compositions of OIB mantle sources—geochemists can “map” the isotopic heterogeneity of the Earth’s deep mantle (e.g., Gast et ...

Journal: :Remote Sensing 2015
Neil Slatcher Mike R. James Sonia Calvari Gaetana Ganci John Browning

During volcanic eruptions, measurements of the rate at which magma is erupted underpin hazard assessments. For eruptions dominated by the effusion of lava, estimates are often made using satellite data; here, in a case study at Mount Etna (Sicily), we make the first measurements based on terrestrial laser scanning (TLS), and we also include explosive products. During the study period (17–21 Jul...

2006
D. G. Macfarlane G. Wadge D. A. Robertson M. R. James H. Pinkerton

[1] A ground-based millimetre wave radar, AVTIS (Allweather Volcano Topography Imaging Sensor), has been developed for topographic monitoring. The instrument is portable and capable of measurements over ranges up to 7 km through cloud and at night. In April and May 2005, AVTIS was deployed at Arenal Volcano, Costa Rica, in order to determine topographic changes associated with the advance of a ...

2013
Anssi Karvonen Bjarni K Kristjánsson Skúli Skúlason Maiju Lanki Christian Rellstab Jukka Jokela

Parasite communities of fishes are known to respond directly to the abiotic environment of the host, for example, to water quality and water temperature. Biotic factors are also important as they affect the exposure profile through heterogeneities in parasite distribution in the environment. Parasites in a particular environment may pose a strong selection on fish. For example, ecological diffe...

2004
J. B. GARVIN

Characteristics of rock populations on the surfaces of Mars and Venus can be derived from analyses of rock morphology and morphometry data. We present measurements of rock sizes and sphericifies made from Viking lander images using an interactive digital image display system. The rocks considered are in the gravel size range (16-256 mm in diameter). Mean sphericities, form ratios, and roundness...

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