نتایج جستجو برای: lava rocks
تعداد نتایج: 24704 فیلتر نتایج به سال:
available online at http://meteoritics.org 1495 © Meteoritical Society, 2004. Printed in USA. Shocked rocks and impact glasses from the El’gygytgyn impact structure, Russia Eugene P. GUROV1 and Christian KOEBERL2* 1Institute of Geological Sciences, National Academy of Sciences of the Ukraine, 55b Oles Gontchar Street, Kiev 01054, Ukraine 2Department of Geological Sciences, University of Vienna,...
[1] We have used new compositional information on Martian basaltic rocks from the Mars Exploration Rover Spirit and data from new stereo imaging by the High Resolution Stereo Camera (HRSC) on the Mars Express orbiter to constrain an existing analyticalnumerical computer model to assess the potential of Martian lavas to form lava channels by erosion of substrate. The basaltic rocks studied in Gu...
Identifying the genes underlying adaptation is a major challenge in evolutionary biology. Here, we describe the molecular changes underlying adaptive coat color variation in a natural population of rock pocket mice, Chaetodipus intermedius. Rock pocket mice are generally light-colored and live on light-colored rocks. However, populations of dark (melanic) mice are found on dark lava, and this c...
Four bacterial species isolated from the rhizoplane of cacti growing in bare lava rocks were assessed for growth promotion of giant cardon cactus seedlings (Pachycereus pringlei). These bacteria fixed N(2), dissolved P, weathered extrusive igneous rock, marble, and limestone, and significantly mobilized useful minerals, such as P, K, Mg, Mn, Fe, Cu, and Zn in rock minerals. Cardon cactus seeds ...
Mesozoic strata in the Cowhole Mountains, eastern Mojave block California, include 200–800 m of eolian quartz arenite (Aztec Sandstone) overlain by more than 575 m of silicic ignimbrites, lava flows, and minor sedimentary rocks (Cowhole volcanics). U-Pb zircon geochronologic data on a crystal-rich dacite lava flow in the Aztec Sandstone indicate that the sandstone is Middle Jurassic and is ther...
late miocene–pliocene calc-alkaline volcanic rocks are exposed southeast of isfahan in the urumieh-dokhtar magmatic belt. volcanic rocks consist of lava flows and domes, chiefly basaltic andesites, andesites and dacites. minerals in the volcanic rocks exhibit degrees of disequilibrium features. plagioclase as dominant mineral in these rocks generally displays reverse and oscillatory zoning; sie...
The Mars Exploration Rover Spirit has traversed a fairly flat, rock-strewn terrain whose surface is shaped primarily by impact events, although some of the landscape has been altered by eolian processes. Impacts ejected basaltic rocks that probably were part of locally formed lava flows from at least 10 meters depth. Some rocks have been textured and/or partially buried by windblown sediments l...
The Yellowstone Plateau volcanic field, the site of some of the largest known silicic volcanic eruptions, is the present location of NE-migrating hotspot volcanic activity. Most volcanic rocks in the Yellowstone caldera (0.6 Ma), which formed in response to the climactic eruption of 1000 km3 of Lava Creek Tuff (LCT), have unusually low oxygen isotope ratios. Ion microprobe analysis of both U^Pb...
This paper reports on the thermal characterization, via the thermal conductivity, of natural materials, such as mulch and lava rock and their usefulness as building insulation. Experiments were carried out using a scale one monitored wall (i.e. heat flux and temperature sensors) exposed to a heating source on one side and to an air conditioned space on the other. The wall system was composed of...
The Cheheltan Mountain is located at south west of Bardsir, Kerman Province. It represents a part of the Eocene Hezar volcanic complex (Urumiyeh-Dokhtar volcanic belt) and consists of lava flows, pyroclastics, epiclastics and numerous intrusions. The lava flows comprise of basaltic-andesites and basalts and contain plagioclase and pyroxene phenocrysts that set in a vitreous or fine-grained matr...
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