نتایج جستجو برای: sr and nd isotopes
تعداد نتایج: 16837175 فیلتر نتایج به سال:
The isotope effects of neodymium in Nd-glycolate ligand exchange system were studied by using ion exchange chromatography. The separation coefficients of neodymium isotopes, ε's, were calculated from the observed isotopic ratios at the front and rear boundaries of the neodymium adsorption band. The values of separation coefficients of neodymium isotopes, ε's, for the Nd-glycolate ligand exchang...
محدوده دامن قر در شمال بردسکن، استان خراسان رضوی، واقع شده و به لحاظ ساختاری بخشی از زون تکنار است. زمین شناسی منطقه شامل سنگهای رسوبی دگرگون شده و متاریولیت های سازند تکنار است که مورد نفوذ دیابازهایی به شکل استوک و دایک قرار گرفته اند. بافت متاریولیتها پورفیری و شامل کوارتز و فلدسپار و بافت دیابازها افتیک و شامل پلاژیوکلاز، پیروکسن و هورنبلند است. سن متاریولیتها و دیابازها با استفاده از رو...
r a 200 .015 : +1 570 qu.edu Summary Stable isotopes, radiogenic isotopes, and major ion chemistry are used to constrain flow paths in a fracture-controlled regional groundwater flow system in far west Texas. The flow system occurs in Permian and Cretaceous sedimentary rocks and Cenozoic alluvial basin fill. Samples from springs and wells in the study area were analyzed for major ions and hydro...
Abstract The Dupal anomaly has attracted widespread attention since being discovered and is regarded as the most direct manifestation of mantle inhomogeneity at present. From initially defined anomalies limited to southern hemisphere global scale, criteria for identifying by Pb isotopes have also been adjusted, providing an important method reference study evolution. Pearce Peate (1995) propose...
Abstract Geochemical similarities between the continental crust and arc magmas have led to inference that subduction zones may be primary sites of crustal growth. Thus, it is necessary unravel petrogenetic mechanism(s) granitoid generation in subduction-related settings understand growth through magmatic differentiation processes. In this study, we focused on oceanic-continental zones. We analy...
Four crustal xenoliths from Scotland have been dissected in order to evaluate the effects of magma-xenolith interaction on Rb-Sr and Sm-Nd isotopic systematics, and hence the use of the xenoliths for accurate determination of source compositions. Each xenolith was sampled from the edge to the center, The Nd isotopic compositions are virtually uniform across each xenolith; however, there are sig...
Introduction: It has long been recognized that lunar mantle is chemically, isotopically, and lithologically heterogeneous. The heterogeneities are ancient and were formed during large-scale differentiation events, such as the solidification of a globally distributed lunar magma ocean (LMO) and subsequent lunar cumulate mantle overturn [1-3]. Mixing of distinct early and late LMO cumulates resul...
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