نتایج جستجو برای: fractional crystallization

تعداد نتایج: 82382  

1996
Ian S.E. Carmichael

The Aurora volcanic field, located along the northeastern margin of Mono Lake in the Western Great Basin, has erupted a diverse suite of high-K and shoshonitic lava types, with 48 to 76 wt% SiO2, over the last 3.6 million years. There is no correlation between the age and composition of the lavas. Three-quarters of the volcanic field consists of evolved (,4 wt% MgO) basaltic andesite and andesi...

Journal: :Geochimica et Cosmochimica Acta 2022

Zircon is often used to study granites (sensu lato) and continental crust because it very resistant can be analyzed for various isotope systems that provide time source information about their parental melts. Granites with different petrological histories have distinct bulk-rock silicon compositions but unclear if these differences are also detectable in zircon of superimposed fractionation eff...

2005
Y. Katzir

The central pluton within the Neoproterozoic Katharina Ring Complex (area of Gebel Mussa, traditionally believed to be the biblical Mt. Sinai) shows a vertical compositional zoning: syenogranite makes up the bulk of the pluton and grades upwards to alkalifeldspar granites. The latters form two horizontal subzones, an albite–alkali feldspar (Ab–Afs) granite and an uppermost perthite granite. The...

2004
EDWARD R. D. SCOTT

We have analyzed metallic and silicate phases in the IVA iron meteorites and two related stony irons, Steinbach and Sgo JoHo Nepomuceno. Analyses of bulk metal phases in the two stony irons using INAA show that they plot as close to the chemical trends within group IVA as most IVA irons, indicating a common source. Our fractional crystallization models for the IVA chemical trends suggest that t...

2004
P. C. Buchanan W. U. Reimold C. Koeberl F. J. Kruger

The Rooiberg Group is a 6-km-thick sequence of mostly volcanic rocks, which represent the first phase of magmatic activity associated with the Bushveld Complex. These strata include, in ascending stratigraphic order, the Dullstroom, Damwal, Kwaggasnek, and Schrikkloof Formations. Units of the lower Dullstroom Formation range from basalts to andesites and comprise two compositional suites: high ...

2006
E. Médard T. L. Grove

Introduction: Deconvolution of thermal emission spectra from Mars orbiting spacecraft, in-situ analysis of martian rocks by Mars Pathfinder, Spirit and Opportunity rovers, as well as investigation of martian meteorites, all point towards a wide magmatic diversity at the surface of the planet. Compositions varying from olivine-rich basalt to high-silica granite / rhyolite through basaltic andesi...

Journal: :Chemical Geology 2022

Extremely light and highly variable δ60Ni values have been observed in komatiite-associated magmatic sulfides recent studies. In this study, we examine the mechanisms of Ni isotope fractionation between silicate sulfide liquids Hart Fe-Ni-Cu-sulfide system. We assess petrogenetic significance these using concentration data. The bulk rock varies from 774 to 2690 ppm komatiite samples with no min...

2006
A. K. Schmitt J. A. Vazquez

Rhyolite lavas and xenoliths from the Salton Sea geothermal field (Southern California) provide insights into crustal compositions and processes during continental rupture and incipient formation of oceanic crust. Salton Buttes rhyolite lavas contain xenoliths that include granophyres, fine-grained altered rhyolites (“felsite”), and amphibole-bearing basalts. Zircon is present in lavas and xeno...

2017
Xiaodong Wang Jie Ouyang Ying Liu

A multi-scale phase-field approach, which couples the mesoscopic crystallization with the microscopic orientation of chain segments and macroscopic viscoelastic melt flow, is proposed to study how the crystal growth of semi-crystalline polymers is affected by flows. To make the simulation feasible, we divide the problem into three parts. In the first part, a finitely extensible nonlinear elasti...

Journal: :iranian journal of pharmaceutical sciences 0
maryam maghsoodi school of pharmacy and drug applied research center, tabriz university of medical sciences, tabriz, iran sara esmaeilzadeh school of pharmacy and drug applied research center, tabriz university of medical sciences, tabriz, iran

in this study, the effect of recrystallization of naproxen in the presence of hydroxypropyl cellulose (hpc) on the release rate of drug was investigated. crystals were generated by the anti-solvent approach using the hpc solution in water as the anti-solvent. the samples were subjected to various physicochemical evaluations such as crystal size, scanning electron microscopy, fourier transform i...

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