نتایج جستجو برای: volcanic rock
تعداد نتایج: 52326 فیلتر نتایج به سال:
The precise location and relative elevation of Spirit during its traverses from the Columbia Memorial station to Bonneville crater were determined with bundle-adjusted retrievals from rover wheel turns, suspension and tilt angles, and overlapping images. Physical properties experiments show a decrease of 0.2% per Mars solar day in solar cell output resulting from deposition of airborne dust, co...
miocene silisiclastic sediments in binalood zone consist of three lithofacies group including gravelly (gmm, gcm, gci, gh, gt, gp), sandy (st, sm, sh, sp, ss, sl) and muddy (fm, fl). gravelly lithofacies are generally massive and mainly consist of volcanic and sedimentary lithic in different size. sandy lithofacies are composed of litharenite and feldespathic volcanicarenite and rock fragments ...
The toxic element arsenic is widespread in New Zealand’s aquatic and terrestrial environments. Arsenic is ubiquitous in all of the geothermal areas and waterways that fall within or pass-through the Taupo Volcanic Zone, an area in the central North Island that stretches from Mt Ruapehu to White Island (Figure 1). On its way to the surface, super-heated geothermal water dissolves appreciable amo...
The weathering of volcanic rocks contributes significantly to the global silicate weathering budget, effecting carbon dioxide drawdown and long-term climate control. The rate of chemical weathering is influenced by the composition of the rock. Rock-dwelling micro-organisms are known to play a role in changing the rate of weathering reactions; however, the influence of rock composition on bio-we...
Chemical analyses conducted on the surface of rock slabs under a combination of two X-ray spectrometry methods, wavelength dispersive XRF and energy dispersive XRF, are used to establish a geochemical correlation between the studied samples. This proves to be an excellent method for the characterization of volcanic glasses, particularly when particles of exotic origin are present, because the e...
Introduction: NWA 7034 is a monomict breccia of volcanic [1] or impact [2,3] origin. Interestingly, the oldest zircon ages in the paired NWA7533 meteorite point at an ancient formation age (~4.43 Gyr, [3]), while disturbed younger zircon ages are observed [3], and the Rb/Sr age of NWA7034 is ~2.1 Gyr [1]. According to the initial study by Agee and co-workers [1], NWA7034 shares features with th...
rocks of the Stuhuni and King Salmon Groups; a pre-.Middlm: Triassic unconformity is found througbmt the North American Cordillera (Read and Okulitch, 1977, Siberling, 1973:. In the Stikine Terrane, late Triassic volcanic rocks ar: dominantly fragmental andcommonly alkalic. Based on bul:: rock chemistry, both extensional, ba:k-arc, and Fore-ar: tectonic settings have been suggested tor these r...
[1] We collected 56 marine gravity cores from the Pacific seafloor offshore Central America which contain a total of 213 volcanic ash beds. Ash-layer correlations between cores and with their parental tephras on land use stratigraphic, lithologic, and compositional criteria. In particular, we make use of our newly built database of bulk-rock, mineral, and glass major and trace element compositi...
The Microscopic Imager on the Spirit rover analyzed the textures of the soil and rocks at Gusev crater on Mars at a resolution of 100 micrometers. Weakly bound agglomerates of dust are present in the soil near the Columbia Memorial Station. Some of the brushed or abraded rock surfaces show igneous textures and evidence for alteration rinds, coatings, and veins consistent with secondary minerali...
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