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Showing 1 to 20 of 30 for “"Sm/Nd"”.
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Sm-Nd and C-isotope chemostratigraphy of Ordovician epeiric sea carbonates, midcontinent of North America
Interpreting and correlating epeiric sea sequences is key to understanding ancient marine environments. As a result, eNd, d13C and Sm/Nd profiles are developed as tools for interpreting epeiric sea carbonates. Previously, eNd and d13C profiles in epeiric sea carbonates have been used to study …
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A geochemical profile through the Uitkomst Complex on the farm Slaaihoek, with special reference to the platinum-group elements and Sm-Nd isotopes
… It is situated on the farms Uitkomst 541JT and Slaaihoek 540JT, about 25 km north of Badplaas and 50 km east of the eastern limb of the Bushveld Complex in the Mpumalanga province of South Africa. The intrusion plunges between 8 to 10º to the northwest with an established length of 12 km and …
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Oscillator strength measurements in singly-ionized, doubly-ionized and neutral lanthanides and transition elements (sm, nd, pr, gd, cu, and fe) using laser-induced breakdown spectroscopy.
… for stars in the Milky Way's galactic halo, and stellar chemical abundance determinations are dependent upon accurate atomic spectroscopic data to allow the correct interpretation of stellar absorption and emission spectra. It is well known that calculations of many astrophysically important …
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Investigating sediment size distributions and size-specific Sm-Nd isotopes as paleoceanographic proxy in the North Atlantic Ocean: reconstructing past deep-sea current speeds since Last Glacial Maximum
… in the North Atlantic can be related to modern and past Atlantic Meridional Overturning Circulation (AMOC) flow speed, particle size distributions (weight%, Sortable Silt mean grain size) and grain-size separated (0–4, 4–10, 10–20, 20–30, 30–40 and 40–63 µm) Sm-Nd isotopes and trace element …
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The isotopic evolution of the British lithosphere
A Sm-Nd mineral isochron obtained from an olivine gabbro yields an age of 375 +/- 34 Ma (M.S.W.D. = 0.006) and represents the formation age of the Lizard Igneous Complex. Two magmatic suites are recorded in the complex, an early trace element enriched (ENd<sub>375</sub> = + 8.9 - + 10.1) and a late …
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Tektonometamorphe Entwicklung von Scherzonen im präkambrischen Basement Südindiens
In the South Indian basement, several crustal-scale amphibolite facies shear zones occur between high-grade metamorphic units with a different geological history: the EW-trending Moyar Shear Zone (MSZ) is a zone of predominantly dip-slip transport separating the Archaean Dharwar Craton in the north …
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Mesozoic alkaline volcanism and mantle evolution of the southwestern São Francisco craton, Brazil
… the nature of the subcontinental lithosphere underlying the southwestern margin of the São Francisco craton and the relation of variations in the petrochemistry of kimberlites and related alkali igneous rocks to variations in age, thickness and thermodynamic history of their continental …
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Edelgase als Tracer für Wechselwirkungen von Krusten- und Mantelfluiden mit diamantführenden Gesteinen des östlichen Baltischen Schildes
In der vorliegenden Arbeit werden anhand der Edelgaszusammensetzung von Kimberliten und Lamproiten sowie ihrer gesteinsbildenden Minerale die Wechselwirkungen dieser Gesteine mit Fluiden diskutiert. Die untersuchten Proben stammen vom östlichen Baltischen Schild, vom Kola-Kraton (Poria Guba und …
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Geodynamic Development of the South China Block from Precambrian to Cretaceous: Constraints from Geology Geochemistry and Geochronology
… block is subject to debate. Most articles tend to subdivide the South China block into two sub-ordinate blocks (Yangtze and Cathaysia), with a central Sibao (Jiangnan) Orogen, although there are also suggestions for a separate eastern (Tolo) block. Debate primarily occurs around the timing of …
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A thermotectonic framework for the growth and stabilization of the eastern Kaapvaal craton, southern Africa
Continents are an amalgamation of crust and mantle lithosphere assembled over -4 Gyr and are therefore our best record of the early Earth. Exposures of rocks -3.0-3.7 Ga cover -20,000 km2 of eastern S. Africa and Swaziland, and provide a record of the continental assembly and subsequent …
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Large-shift Raman scattering in insulating cuprate materials
… the T' phase materials (R2Cu04, R=Gd, Eu, Sm, Nd, Pr), T phase La2Cu04, and 123 phase PrBa2Cu3Cu06 and YBa2Cu3Cu06+x· For all of these materials, several features are observed near 12000 cm-1 (-1.5 eV) with A2g, B1g, and A1g symmetry. At low temperatures, the largest feature with A2g …
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The evolution of the Archaean continental crust of Northern Zimbabwe
… clasts preserved in Late Archaean conglomerates indicate the presence of continental crust in Northern Zimbabwe prior to the"" 2.7 to "" 2.6Ga "event" which terminated with the stabilisation of the Zimbabwe Craton. The "Kober Technique" (Kober, 1986, 1987) of direct thermal ionisation of zircons …
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Saarisen ultramafisen intruusion petrografia, geokemia ja geokronologia
… kivistä. Lapinlahti sijaitsee Fennoskandian arkeeisen kratonin reuna-alueella ja geologiset rakenteet jakaantuvat sekä arkeeisiin että proterotsooisiin. Magmatismi on ollut alueella hyvin moninaista ja arkeeinen kallioperä on kokenut useita keski- ja korkean asteen metamorfisia …
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Mineralogy and geochemistry of the carbonaceous mudstones and coal petrogenesis of the Grootgeluk formation in the Waterberg coalfield, South Africa
… in the Waterberg Coalfield consists of coal and mudstone layers that were deposited during the Late Permian. In the south-central part of the Waterberg Basin rapid subsidence resulted in the formation of strata (-70 m thick) which consist of relatively thin coal beds interbedded with a …
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Magmatic-hydrothermal critical ore systems: identifying fluid sources and tracing fluid evolution
Critical metals are essential to the economy and national defense. However, many critical metal systems are not understood as well as traditional deposits (e.g. porphyry systems). Furthermore, their sources and formation processes are debated. This dissertation investigates how …
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Archean continental crust formation and the rise of atmospheric oxygen
… the establishment of the continental crust and the progressive rise of an oxygenated atmosphere. The volume of continental crust on the earliest Earth is a critical parameter for constraining the chemical evolution of major terrestrial reservoirs, and radiogenic isotope signatures document …
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Compositional Analysis of the Martian Meteorites Northwest Africa 6342 and Northwest Africa 10961
The most abundant type of meteorite that we have from Mars is the shergottite. This makes the study of shergottite samples invaluable to understanding the geological evolution of that planet. Electron microprobe analyses, bulk elemental composition calculation, and laser ablation-inductively …
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The timing of prograde metamorphism in the Garhwal Himalaya, India
… significant example of present-day orogenesis and consequently have been extensively studied to gain an understanding of the principle controls on the response of the crust to continental collision. However, our understanding of the prograde metamorphic evolution of the orogen remains poor. This …
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Geochemical and isotopic constraints on the source regions of phanerozoic carbonatites and associated alkaline rocks from the Zandkopsdrift complex of Namaqualand, South Africa, and the Marinkas Quellen, and Dicker Willem complexes in Namibia
This is a study of Phanerozoic carbonatites and related alkaline silicate rocks from Zandkopsdrift in Namaqualand, South Africa (55 Ma), and Marinkas Quellen (529 Ma), and Dicker Willem (49 Ma) in southern Namibia, all emplaced within the Proterozoic Namaqua Natal province. The aims of this thesis …
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From the Appalachians to the Alps: Constraints on the Timing, Duration, and Conditions of Metamorphism at Convergent Margins
The timing, duration, and pressure-temperature (P-T) conditions of metamorphism provide a direct record of the physical and chemical evolution of the crust and inform our knowledge and understanding of plate tectonics. The characteristic timescales and length-scales of metamorphism vary by orders …
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