Search Results - "Valley, John"

SIMS analyses of the oldest known assemblage of microfossils document their taxon-correlated carbon isotope compositions by Schopf, J. William, Kitajima, Kouki, Spicuzza, Michael J., Kudryavtsev, Anatoliy B., Valley, John W.

“…Analyses by secondary ion mass spectroscopy (SIMS) of 11 specimens of five taxa of prokaryotic filamentous kerogenous cellular microfossils permineralized in a…”
Get full text

Primordial oxygen isotope reservoirs of the solar nebula recorded in chondrules in Acfer 094 carbonaceous chondrite by Ushikubo, Takayuki, Kimura, Makoto, Kita, Noriko T., Valley, John W.

“…Highly precise and accurate ion microprobe analyses of oxygen three-isotope ratios in chondrules from the Acfer 094, one of the most primitive carbonaceous…”
Get full text

Perspectives on the origin of plagiogranite in ophiolites from oxygen isotopes in zircon by Grimes, Craig B., Ushikubo, Takayuki, Kozdon, Reinhard, Valley, John W.

“…The formation of oceanic plagiogranite has been attributed primarily to either 1) extreme fractional crystallization of a mantle melt, or 2) partial melting of…”
Get full text

Oxygen Isotope Variability within Nautilus Shell Growth Bands by Linzmeier, Benjamin J, Kozdon, Reinhard, Peters, Shanan E, Valley, John W

“…Nautilus is often used as an analogue for the ecology and behavior of extinct externally shelled cephalopods. Nautilus shell grows quickly, has internal growth…”
Get full text

Hadean age for a post-magma-ocean zircon confirmed by atom-probe tomography by Valley, John W., Cavosie, Aaron J., Ushikubo, Takayuki, Reinhard, David A., Lawrence, Daniel F., Larson, David J., Clifton, Peter H., Kelly, Thomas F., Wilde, Simon A., Moser, Desmond E., Spicuzza, Michael J.

“…The oldest minerals on Earth are thought to have formed in the Hadean eon, but the reliability of the dates has been questioned. Atom-probe tomography of an…”
Get full text

Bulk and grain-scale minor sulfur isotope data reveal complexities in the dynamics of Earth's oxygenation by Izon, Gareth, Luo, Genming, Uveges, Benjamin T, Beukes, Nicolas, Kitajima, Kouki, Ono, Shuhei, Valley, John W, Ma, Xingyu, Summons, Roger E

“…SignificanceThe permanent disappearance of mass-independent sulfur isotope fractionation (S-MIF) from the sedimentary record has become a widely accepted proxy…”
Get full text

Petrogenesis of Montana, USA Sapphires Inferred from Oxygen Isotopes and Zircon Inclusions by Turnier, Rachelle B, Berg, Richard B, Kitajima, Kouki, Palke, Aaron C, Valley, John W

“…Abstract Montana hosts the largest sapphire deposits in the US, but the genesis of and connection among the various secondary and primary sapphire occurrences…”
Get full text

Microscale Simultaneous Measurement of Carbon and Nitrogen Isotopes on Natural Diamond by Ishida, Akizumi, Kitajima, Kouki, Hashizume, Ko, Spicuzza, Michael J., Zaitsev, Alexander, Schulze, Daniel J., Valley, John W.

“…Simultaneous analysis of carbon and nitrogen isotope ratios by SIMS was applied for the first‐time to a natural diamond from the Kelsey Lake kimberlite, State…”
Get full text

Melt Origin across a Rifted Continental Margin: a Case for Subduction-related Metasomatic Agents in the Lithospheric Source of Alkaline Basalt, NW Ross Sea, Antarctica by Panter, Kurt S, Castillo, Paterno, Krans, Susan, Deering, Chad, McIntosh, William, Valley, John W, Kitajima, Kouki, Kyle, Philip, Hart, Stan, Blusztajn, Jerzy

“…ABSTRACT Alkaline magmatism associated with the West Antarctic rift system in the NW Ross Sea (NWRS) includes a north–south chain of shield volcano complexes…”
Get full text

Evolution of quartz cementation and burial history of the Eau Claire Formation based on in situ oxygen isotope analysis of quartz overgrowths by Hyodo, Ayumi, Kozdon, Reinhard, Pollington, Anthony D., Valley, John W.

“…Individual quartz overgrowths in siltstone of the late Cambrian Eau Claire Formation (Fm.) are systematically zoned in oxygen isotope ratio (δ18O). In situ…”
Get full text

The Origin of Plagiogranites: Coupled SIMS O Isotope Ratios, U–Pb Dating and Trace Element Composition of Zircon from the Troodos Ophiolite, Cyprus by Morag, Navot, Golan, Tzahi, Katzir, Yaron, Coble, Matthew A, Kitajima, Kouki, Valley, John W

“…U–Pb ages, trace element content and oxygen isotope ratios of single zircons from five plagiogranite intrusions of the Troodos ophiolite were measured to…”
Get full text

Comparison of δ 13 C analyses of individual foraminifer (Orbulina universa) shells by secondary ion mass spectrometry and gas source mass spectrometry by Wycech, Jody B, Kelly, Daniel Clay, Kozdon, Reinhard, Ishida, Akizumi, Kitajima, Kouki, Spero, Howard J, Valley, John W

“…The use of secondary ion mass spectrometry (SIMS) to perform micrometer-scale in situ carbon isotope (δ C) analyses of shells of marine microfossils called…”
Get full text

Comparison of δ13C analyses of individual foraminifer (Orbulina universa) shells by secondary ion mass spectrometry and gas source mass spectrometry by Wycech, Jody B., Kelly, Daniel Clay, Kozdon, Reinhard, Ishida, Akizumi, Kitajima, Kouki, Spero, Howard J., Valley, John W.

“…Rationale The use of secondary ion mass spectrometry (SIMS) to perform micrometer‐scale in situ carbon isotope (δ13C) analyses of shells of marine microfossils…”
Get full text

High precision SIMS oxygen three isotope study of chondrules in LL3 chondrites: Role of ambient gas during chondrule formation by Kita, Noriko T., Nagahara, Hiroko, Tachibana, Shogo, Tomomura, Shin, Spicuzza, Michael J., Fournelle, John H., Valley, John W.

“…We report high precision SIMS oxygen three isotope analyses of 36 chondrules from some of the least equilibrated LL3 chondrites, and find systematic variations…”
Get full text

Influence of radiation damage on Late Jurassic zircon from southern China: Evidence from in situ measurements of oxygen isotopes, laser Raman, U–Pb ages, and trace elements by Wang, Xiao-Lei, Coble, Matthew A., Valley, John W., Shu, Xu-Jie, Kitajima, Kouki, Spicuzza, Michael J., Sun, Tao

“…The influence of radiation damage on chemical alteration and in situ elemental and isotopic analyses in zircons is evaluated in three ~155Ma granites that are…”
Get full text

Ti-in-zircon thermometry: applications and limitations by Fu, Bin, Page, F. Zeb, Cavosie, Aaron J., Fournelle, John, Kita, Noriko T., Lackey, Jade Star, Wilde, Simon A., Valley, John W.

“…The titanium concentrations of 484 zircons with U-Pb ages of ∼1 Ma to 4.4 Ga were measured by ion microprobe. Samples come from 45 different igneous rocks (365…”
Get full text

Chondrulelike Objects in Short-Period Comet 81P/Wild 2 by Nakamura, Tomoki, Noguchi, Takaaki, Tsuchiyama, Akira, Ushikubo, Takayuki, Kita, Noriko T, Valley, John W, Zolensky, Michael E, Kakazu, Yuki, Sakamoto, Kanako, Mashio, Etsuko, Uesugi, Kentaro, Nakano, Tsukasa

“…The Stardust spacecraft returned cometary samples that contain crystalline material, but the origin of the material is not yet well understood. We found four…”
Get full text

Extreme 13C-depletions and organic sulfur content argue for S-fueled anaerobic methane oxidation in 2.72 Ga old stromatolites by Lepot, Kevin, Williford, Kenneth H., Philippot, Pascal, Thomazo, Christophe, Ushikubo, Takayuki, Kitajima, Kouki, Mostefaoui, Smaïl, Valley, John W.

“…The extreme 13C-depletions recorded in Neoarchean organic matter (OM) have commonly been interpreted as markers of methanotrophy. This methane oxidation…”
Get full text

Seasonal climate signals (1990–2008) in a modern Soreq Cave stalagmite as revealed by high-resolution geochemical analysis by Orland, Ian J., Burstyn, Yuval, Bar-Matthews, Miryam, Kozdon, Reinhard, Ayalon, Avner, Matthews, Alan, Valley, John W.

“…High-resolution isotopic and geochemical analyses in a modern (1990–2008) Soreq Cave stalagmite are compared to instrumental records of rainfall and dripwater…”
Get full text

Preservation and detection of microstructural and taxonomic correlations in the carbon isotopic compositions of individual Precambrian microfossils by Williford, Kenneth H., Ushikubo, Takayuki, Schopf, J. William, Lepot, Kevin, Kitajima, Kouki, Valley, John W.

“…Here we present techniques for, and new data from, in situ carbon isotope (δ13C) analysis of Precambrian permineralized microscopic fossils with a…”
Get full text