نتایج جستجو برای: غنی‌شدگی LREE

تعداد نتایج: 951  

2004
D. J. CHERNIAK J. PYLE JOHN RAKOVAN

(REE,Y) phosphates were synthesized in a 1 atm furnace by ß ux-growth methods involving Pb-free ß uxes. Microcrystalline (REE,Y) phosphate was precipitated from a solution of (REE,Y) chlorides or nitrates plus ammonium dihydrogen phosphate, and mixed with a M2CO3 (M = Li or Na)-MoO3 ß ux (75:25:2 molar ratio M2CO3:MoO3:REEPO4). Crystal growth was achieved over the temperature range 1350–870 °C,...

2018
Kaori Jogo Motoo Ito Tomoki Nakamura Sachio Kobayashi Jong Ik Lee

We measured the abundances of Sr and rare earth elements (REEs) in the matrices of five CV3 carbonaceous chondrites: Meteorite Hills (MET) 00430, MET 01070, La Paz ice field (LAP) 02206, Asuka (A) 881317 and Roberts Massif (RBT) 04143. In the MET 00430 and MET 01074 matrices, the Sr/CI and light REE (LREE, La–Nd)/CI ratios positively correlate with the amounts of Ca-rich secondary minerals, whi...

2017
Giovanna Della Porta Gregory E. Webb Iain McDonald

Marine microbialites serve as robust seawater rare earth element and yttrium (REE+Y) proxies through many intervals of Earth history, but questions remain about the partitioning of REEs into different coeval carbonate phases, potential syn-depositional contaminants and elemental redistribution during diagenesis. Microbial carbonates, cements and background sediments were analysed for stable iso...

2017
J S. Beard S S. Sorensen Reto Gieré

Allanite is present in most samples of the tonalitic Bell Island Pluton, with an average mode near 0.05 wt.%. Allanite occurs as cores in igneous epidote-clinozoisite and exhibits characteristic and consistent zoning patterns. REE-rich cores (All40–70) grade out towards epidote-clinozoisite with REE below electron microprobe detection limits. La, Ce and Pr contents are highest in the REE-rich c...

2010
ROSEMARY LOUISE HICKEY

Boninites are unusual island arc volcanic rocks with high MgO (>9%), high Si0 2 (>55%) contents, and exceptionally low TiO 2 (<0.4%) contents. High MgO contents, MgO/(MgO + EFeO), Ni, Cr and Co contents indicate that boninites have equilibrated with mantle peridotite. Experimental petrologic studies and high Cr/(Cr + Al) in spinels in boninites suggest that they have separated from extremely re...

Journal: :European Physical Journal C 2021

We obtain the left-right entanglement entropy (LREE) for a D$p$-brane with tangential motion in presence of $U(1)$ gauge potential, Kalb-Ramond field and an open string tachyon field. Thus, at first we extract R\'{e}nyi then by taking special limit it acquire entropy. shall investigate behavior LREE under condensation phenomenon. observe that deformation LREE, through this process, reveals coll...

2002
Victoria C. Bennett Allen P. Nutman Malcolm T. McCulloch

3870 Ma to 3760 Ma metadiorites and tonalites, and older mafic inclusions contained within these rocks from southern West Greenland, have a range of initial end values from + 4.5 to --4.5. The extremely positive initial values determined for nine of the fourteen early Archean samples demonstra te that they were derived from a LREE depleted mantle reservoir which had an end value of ~ + 4 prior ...

ژورنال: :علوم محیطی 0
حمیدرضا پاکزاد دانشگاه اصفهان مهرداد پسندی دانشگاه اصفهان اردشیر رومیانی دانشگاه اصفهان مهدی کمالی دانشگاه اصفهان

تالاب انزلی از لحاظ شرایط خاص اکولوژیک، اقتصادی و اجتماعی اهمیت زیادی دارد. رودخانه های متعددی با عبور از جنگل، شهر و روستاهای اطراف این تالاب، انواع گوناگونی از آلاینده ها را در آن تخلیه میکنند. برای تعیین غلظت فلزات سنگین و عوامل فیزیکوشیمیایی و رسوبی موثر بر تمرکز نسبی آنها در رسوبات تالاب انزلی از 22 نقطه واقع در رودخانه های ورودی به تالاب و کانال های ارتباطی تالاب با دریا نمونهبرداری صورت ...

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