نتایج جستجو برای: basaltic composition
تعداد نتایج: 261472 فیلتر نتایج به سال:
The Rare Earth Elements (REEs) have been widely used to investigate marine biogeochemical processes as well as the sources and mixing of water masses. However, there are still important uncertainties about the global aqueous REE cycle with respect to the contributions of highly reactive basaltic minerals originating from volcanic islands and the role of Submarine Groundwater Discharge (SGD). He...
The Proterozoic eon is characterized by an unusual abundance of ferroan feldspathic rocks that range in composition from granite to quartz syenites to feldspathoid-bearing syenites. Three associations of ferroan rocks may be recognized on the basis of major element compositions: (1) metaluminous alkalic to alkali-calcic syenites and granites associated with anorthosites and iron-rich basaltic r...
The Campanian Ignimbrite is a 4200 km trachyte^phonolite pyroclastic deposit that erupted at 39 3 0 1ka within the Campi Flegrei west of Naples, Italy. Here we test the hypothesis that Campanian Ignimbrite magma was derived by isobaric crystal fractionation of a parental basaltic trachyandesitic melt that reacted and came into local equilibrium with small amounts (5^10 wt%) of crustal rock (ska...
[1] Axial valleys are found along most slow-spreading mid-ocean ridges and are one of the most prominent topographic features on Earth. In this paper, we present the first deep-tow swath bathymetry for the axial valley walls of the Mid-Atlantic Ridge. These data allow us to analyze axial valley wall morphology with a very high resolution (0.5 to 1 m compared to ≥ 50 m for shipboard multibeam ba...
[1] The uppermost 2 km of oceanic crust created near the southern end of the Juan de Fuca Ridge ( 60 mm/yr, full spreading rate) is exposed in a ‘‘tectonic window’’ created along the north wall of the Blanco Transform Fault. A total of 27 submersible dives transect this escarpment over a distance of >30 km, corresponding to 1 m.y. of spreading history. In this exposure, weakly deformed basaltic...
Kepsut-Dursunbey volcanic field (KDVF) is located in NW Turkey and contains various products of the post-collisional Neogene magmatic activity. Two distinct volcanic suites have been recognized; the Kepsut volcanic suite (KVS) and the Dursunbey volcanic suite (DVS). The KVS includes basaltic trachyandesitebasaltic andesite-andesite lavas and associated pyroclastic rocks. The DVS consists of dac...
Savanna soil samples were taken from 5 cm depth at different locations along the granitic (GI-GIV) and the basaltic (BI-BIII) catena.
Penicillium simplicissimum solubilized up to 80% of the titanium in granitic rocks but less than 2% of the titanium in basaltic rocks.
Article history: Monogenetic basaltic cinde Received 14 September 2007 Received in revised form 27 February 2008 Accepted 1 March 2008 Available online xxxx Editor: R.W. Carlson
[1] The Mössbauer (MB) spectrometer on Opportunity measured the Fe oxidation state, identified Fe-bearing phases, and measured relative abundances of Fe among those phases at Meridiani Planum, Mars. Eight Fe-bearing phases were identified: jarosite (K,Na,H3O)(Fe,Al)(OH)6(SO4)2, hematite, olivine, pyroxene, magnetite, nanophase ferric oxides (npOx), an unassigned ferric phase, and metallic Fe (k...
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