Search Results - "Janney, P. E."

Hafnium Isotope and Trace Element Constraints on the Nature of Mantle Heterogeneity beneath the Central Southwest Indian Ridge (13°E to 47°E) by JANNEY, P. E., LE ROEX, A. P., CARLSON, R. W.

“…Hafnium isotope and incompatible trace element data are presented for a suite of mid-ocean ridge basalts (MORB) from 13 to 47°E on the Southwest Indian Ridge…”
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Sources and Effects of Fluids in Continental Retrograde Shear Zones: Insights from the Kuckaus Mylonite Zone, Namibia by Harris, C., Diener, J. F. A., Fagereng, A., Stenvall, C. A., Janney, P. E.

“…Midcrustal rocks in retrograde metamorphic settings are typically H2O-undersaturated and fluid-absent and have low permeability. Exhumed continental retrograde…”
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Age, Composition and Thermal Characteristics of South African Off-Craton Mantle Lithosphere: Evidence for a Multi-Stage History by Janney, P. E., Shirey, S. B., Carlson, R. W., Pearson, D. G., Bell, D. R., Le Roex, A. P., Ishikawa, A., Nixon, P. H., Boyd, F. R.

“…A mineral chemistry and whole-rock major element, platinum group element (PGE), and Re–Os isotope dataset is presented for a large suite of mantle xenoliths…”
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Precise titanium isotope compositions of refractory inclusions in the Allende CV3 chondrite by LA-MC-ICPMS by Williams, C.D., Janney, P.E., Hines, R.R., Wadhwa, M.

“…We present here analyses of mass-independent effects in the Ti isotope ratios of 17 coarse-grained (compact Type A and Type B) calcium–aluminum-rich inclusions…”
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A Chemical and Multi-Isotope Study of the Western Cape Olivine Melilitite Province, South Africa: Implications for the Sources of Kimberlites and the Origin of the HIMU Signature in Africa by JANNEY, P. E., LE ROEX, A. P., CARLSON, R. W., VILJOEN, K. S.

“…We present major and trace element and Sr–Nd–Pb–Hf–Os isotopic data for the 76–58 Ma Western Cape melilitite province, an age-progressive magmatic lineation in…”
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Nanoscale variations in 187Os isotopic composition and HSE systematics in a Bultfontein peridotite by Wainwright, A.N., Luguet, A., Schreiber, A., Fonseca, R.O.C., Nowell, G.M., Lorand, J.-P., Wirth, R., Janney, P.E.

“…Understanding the mineralogical controls on radiogenic chronometers is a fundamental aspect of all geochronological tools. As with other common dating tools,…”
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Geochemical evidence from the Pukapuka volcanic ridge system for a shallow enriched mantle domain beneath the South Pacific Superswell by Janney, P.E, Macdougall, J.D, Natland, J.H, Lynch, M.A

“…The South Pacific Superswell is characterized by shallow bathymetry and unusually slow upper mantle seismic velocities, and is also the largest volcanically…”
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Matrix effects in the analysis of Mg and Si isotope ratios in natural and synthetic glasses by laser ablation-multicollector ICPMS: A comparison of single- and double-focusing mass spectrometers by Janney, P.E., Richter, F.M., Mendybaev, R.A., Wadhwa, M., Georg, R.B., Watson, E.B., Hines, R.R.

“…We report composition-dependent matrix effects in the in-situ measurement of Mg and Si isotope ratios by laser ablation inductively coupled plasma mass…”
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Isotope geochemistry of the Darwin Rise seamounts and the nature of long-term mantle dynamics beneath the south central Pacific by Janney, Philip E., Castillo, Paterno R.

“…The Darwin Rise region in the west central Pacific Ocean contains an extraordinarily large number of Cretaceous seamounts with isotopic compositions spanning a…”
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The Early Differentiation History of Mars from W-182-Nd-142 Isotope Systematics in the SNC Meteorites by Foley, C. Nicole, Wadhwa, M., Borg, L. E., Janney, P. E., Hines, R., Grove, T. L.

“…We report here the results of an investigation of W and Nd isotopes in the SNC (Shergottite-Nakhlite-Chassignite (martian)) meteorites. We have determined that…”
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238U/235U Variations in Meteorites: Extant 247Cm and Implications for Pb-Pb Dating by BRENNECKA, G. A, WEYER, S, WADHWA, M, JANNEY, P. E, ZIPFET, J, ANBAR, A. D

“…The 238U/235U isotope ratio has long been considered invariant in meteoritic materials (equal to 137.88). This assumption is a cornerstone of the…”
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Geochemistry of the oldest Atlantic oceanic crust suggests mantle plume involvement in the early history of the central Atlantic Ocean by Janney, Philip E., Castillo, Paterno R.

“…Controversy has surrounded the issue of whether mantle plume activity was responsible for Pangaean continental rifting and massive flood volcanism (resulting…”
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Carbonatite, aillikite and olivine melilitite from Zandkopsdrift, Namaqualand, South Africa: Constraints on the origin of an unusual lamprophyre-dominated carbonatite complex and the nature of its mantle source by Ogungbuyi, P.I., Janney, P.E., Harris, C.

“…We present a chemical and stable and radiogenic isotope data set for carbonatite, aillikite (ultramafic lamprophyre) and olivine melilitite from the…”
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Geochemistry of Mesozoic Pacific mid-ocean ridge basalt: Constraints on melt generation and the evolution of the Pacific upper mantle by Janney, Philip E., Castillo, Paterno R.

“…We present major and trace element and Sr‐Nd‐Pb isotope results on Mesozoic (130–151 Ma) mid‐ocean ridge basalt (MORB) recovered from five Deep Sea Drilling…”
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Thermal and chemical evolution in the early solar system as recorded by FUN CAIs: Part I – Petrology, mineral chemistry, and isotopic composition of Allende FUN CAI CMS-1 by Williams, C.D., Ushikubo, T., Bullock, E.S., Janney, P.E., Hines, R.R., Kita, N.T., Hervig, R.L., MacPherson, G.J., Mendybaev, R.A., Richter, F.M., Wadhwa, M.

“…Detailed petrologic, geochemical and isotopic analyses of a new FUN CAI from the Allende CV3 meteorite (designated CMS-1) indicate that it formed by extensive…”
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Tungsten Nuclear Anomalies in Planetesimal Cores by Qin, Liping, Dauphas, Nicolas, Wadhwa, Meenakshi, Markowski, Agnès, Gallino, Roberto, Janney, Philip E, Bouman, Claudia

“…Use of the extinct super(182)Hf- super(182)W chronometer to constrain the timing of planetary accretion and differentiation rests on the assumption that the…”
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U/²³⁵ Variations in Meteorites: Extant ²⁴⁷ and Implications for Pb-Pb Dating by Brennecka, G. A., Weyer, S., Wadhwa, M., Janney, P. E., Zipfel, J., Anbar, A. D.

“…The 238 U/235 U isotope ratio has long been considered invariant in meteoritic materials (equal to 137.88). This assumption is a cornerstone of the…”
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238 U/ 235 U Variations in Meteorites: Extant 247 Cm and Implications for Pb-Pb Dating by Brennecka, G. A., Weyer, S., Wadhwa, M., Janney, P. E., Zipfel, J., Anbar, A. D.

“…How to Get a Date Radiometric dating relies on measuring the abundance of a radioactive isotope and/or its decay products. By knowing a decay rate and an…”
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Rapid accretion and differentiation of iron meteorite parent bodies inferred from super(1) super(8) super(2)Hf- super(1) super(8) super(2)W chronometry and thermal modeling by Qin, L, Dauphas, N, Wadhwa, M, Masarik, J, Janney, P E

“…New high-precision W isotope measurements are presented for 33 iron meteorites from 8 magmatic groups (IC, IIAB, IID, IIIAB, IIIE, IIIF, I VA and IVB), 2…”
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Clues from Fe Isotope Variations on the Origin of Early Archean BIFs from Greenland by Dauphas, Nicolas, van Zuilen, Mark, Wadhwa, Meenakshi, Davis, Andrew M., Marty, Bernard, Janney, Philip E.

“…Archean rocks may provide a record of early Earth environments. However, such rocks have often been metamorphosed by high pressure and temperature, which can…”
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