نتایج جستجو برای: zircon
تعداد نتایج: 3386 فیلتر نتایج به سال:
19 Detrital-zircon analysis of sandstones interbedded with ca 464 Ma ignimbrites in 20 the lower Mweelrea Formation of the South Mayo Trough, western Ireland, 21 suggests Ordovician source-rock provenance that corresponds to two distinct 22 volcanic-arc phases on the Laurentian margin. East-derived sandstones contain a 23 suite of zircons with a mean age of ca 487 Ma that suggests derivation fr...
Zan lateritic horizon is located about 25 km southeast of Damavand, Tehran Province. This horizon developed as stratiform in lower part of shales and sandstones of Shemshak Formation (Jurassic). Mineralogical investigations show that diaspore, hematite, goethite, anatase, and kaolinite are the principal minerals of this horizon accompanied by lesser amounts of accessory minerals like boehmite, ...
Al diffusion under anhydrous 1-atm conditions has been measured in natural zircon. Experiments used a source consisting of AlPO4-ZrSiO4 powder mixtures. were run air crimped Pt capsules. profiles with Nuclear Reaction Analysis (NRA) using the reaction 27Al(p, γ)28Si. For parallel to c, following Arrhenius relation is determined: D = 6.24 × 103 exp.(−774 ± 34 kJ mol−1 /RT) m2s−1 Diffusivities no...
Introduction: The Moon is believed to have formed from debris produced by a giant impact of a Mars sized body with the Earth (at around 4.51 Ga), forming a primitive body with a thick global layer of melt referred to as the Lunar Magma Ocean (LMO) [1]. The crystallization of LMO created internal strati-fication of the Moon forming main geochemical reservoirs. The surface features on the Moon we...
Surface samples have been collected from Kerala coast, Valapatanam-Azhikode deposit of northern Kerala coast. The average heavy minerals percentage shows 30.32 %. The heavy mineral assemblage of samples from area showed an appreciable percentage of opaque followed by sillimanite and zircon. The chemical analysis carried out for the present investigation, is detailed as Ferrian ilmenite. X-ray d...
The original version of this Article contained errors in the Supplementary Information files: Zircon U-Pb age results for sample 23, shown in Supplementary Fig. 3, are incorrect, and missing from Supplementary Data 1, while several identification labels relating to Yellow River Lanzhou terraces samples are missing from Supplementary Data 2. Supplementary Data 1 and 2 have now been updated to pr...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید