نتایج جستجو برای: zircon
تعداد نتایج: 3386 فیلتر نتایج به سال:
Granitic rocks related to 1.18 to 1.13 Ga anorthosite-mangerite-charnockitegranite plutonism stitch three terranes in the southwestern Grenville Province (Adirondack Highlands–Morin terrane, Frontenac terrane, Elzevir terrane). Because of the refractory nature of zircon (Zrn), analysis of oxygen-isotope ratios of dated igneous zircon from these rocks allows calculation of δ18O values of origina...
Isotopic characterization of aerosol mineral particles (atmospheric dust) of varying sizes is essential in classifying source areas, and for determining the source of dust deposited over oceans and icesheets. However, the effect of atmospheric transport on radiogenic isotopic compositions is not well constrained, making provenance interpretation difficult. In order to investigate the isotopic v...
Zircons are crucial to understanding the first 500 Myr of crustal evolution of Earth. Very few zircons of this age (>4050 Ma) have been found other than from a ~300 km diameter domain of the Yilgarn Craton, Western Australia. Here we report SIMS U-Pb and O isotope ratios and trace element analyses for two ~4100 Ma detrital zircons from a Paleozoic quartzite at the Longquan area of the Cathaysia...
This in vitro study evaluated the marginal gap, cement thickness, and microleakage of glass-ionomer cement (GIC) and phosphate monomer-containing resin cement (MDP-RC) under 2 zirconia crown systems (Cercon and DC-Zirkon). Forty human premolars were prepared for all-ceramic zirconia crowns with a 1 mm circumferential finish line and a 1.5 mm occlusal reduction. The crowns (n = 10 per group) fro...
Zircon is widely used to simulate melt generation, migration and evolution within the crust mantle. The achievable performance of modelling generally depends on availability reliable trace element partition coefficients (D). However, a large range DREE values for zircon from natural samples experimental studies has been reported, with spanning up 3 orders magnitude. Unfortunately, gap knowledge...
Ophiolitic belt of Northern Sabzevar is invaded by basic, intermediate and acidic post-ophiolitic magmtism as dome, dyke and cone. Microscopically, the texture of the studied samples is porphyric and trachytic. Phenocryst mostly consists of amphibole, feldspar and clinopyroxene. All researchers that have investigated basic to acidic post ophiolitic magmatism of northern Sabzevar have consensus ...
Recognition of heavy minerals in Oman continental shelf sediments and their application for interpretation of sediments sourc rock is the purpose of this study. Seven core samples of sea sediment and three surface samples from tidal flat area have been examined. Heavy minerals are dense grains, wich are found not only in rocks, but also in different types of sand and sediments. Separation of he...
Abstract: Auto-ignited gel combustion process has been used for producing a red hematite-zircon based pigment. The combustible mixtures contained the metal nitrates and citric acid as oxidizers and fuel, respectively. Sodium silicate (water glass) was used as silica source for producing zircon phase. X-Ray Diffractometery, Electron Microscopy and Simultaneous Thermal Analysis were used for ...
Introduction: Zircons are difficult to destroy yet can bear witness to the occurrence and sometimes age of major impact events [e.g. 1]. The zirconium mineral record consequently has implications for the tempo and nature of early bombardment and ultimately the evolution of planetary crusts, hydrospheres and life. Recent models that rescale impactor flux according to a saw-tooth decay in lunar i...
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