نتایج جستجو برای: stable oxygen and carbon isotope

تعداد نتایج: 16944832  

2005
YAO-HUA LUO LEONEL DA SILVEIRA LOBO STERNBERG

Hydrogen and oxygen isotopic fractionation relative to medium water for two different carbohydrate metabolic pathways leading to cellulose synthesis were measured. This was accomplished by analysing stable hydrogen and oxygen isotope ratios of water and cellulose for seedlings. The seedlings had been germinated and heterotrophically grown in closed vessels from species having starch (Triticum a...

Journal: :Global and planetary change 1990
J C Walker

Climate is an important environmental parameter of the early Earth, likely to have affected the origin and evolution of life, the composition and mineralogy of sedimentary rocks, and stable isotope ratios in sedimentary minerals. There is little observational evidence constraining Precambrian climates. Most of our knowledge is at present theoretical. Factors that must have affected the clima...

2015
Micha Horacek Karin Hansel-Hohl Kornel Burg Gerhard Soja Walter Okello-Anyanga Silvia Fluch

The indication of origin of sesame seeds and sesame oil is one of the important factors influencing its price, as it is produced in many regions worldwide and certain provenances are especially sought after. We joined stable carbon and hydrogen isotope analysis with DNA based molecular marker analysis to study their combined potential for the discrimination of different origins of sesame seeds....

Journal: :Mineral resource reviews 2023

Abstract Orogenic gold deposits formed in various terranes of most ages since the Paleoarchean and generally consist quartz veins hosted shear zones at ductile brittle transition under greenschist to lower amphibolite metamorphic conditions. Vein mineralogy is dominated by with amounts silicates, carbonates, phyllosilicates, borates, tungstates, sulfides, oxides. The isotopic composition these ...

2005
Michael P. Richards Paul B. Pettitt Mary C. Stiner Erik Trinkaus

New carbon and nitrogen stable isotope values for human remains dating to the mid-Upper Paleolithic in Europe indicate significant amounts of aquatic (fish, mollusks, and/or birds) foods in some of their diets. Most of this evidence points to exploitation of inland freshwater aquatic resources in particular. By contrast, European Neanderthal collagen carbon and nitrogen stable isotope values do...

Journal: :FEMS microbiology ecology 2004
Annette Summers Engel Megan L Porter Libby A Stern Sarah Quinlan Philip C Bennett

Filamentous microbial mats from three aphotic sulfidic springs in Lower Kane Cave, Wyoming, were assessed with regard to bacterial diversity, community structure, and ecosystem function using a 16S rDNA-based phylogenetic approach combined with elemental content and stable carbon isotope ratio analyses. The most prevalent mat morphotype consisted of white filament bundles, with low C:N ratios (...

Journal: :journal of sciences islamic republic of iran 0

about 35 samples were collected from lower and upper parts of the proposed frasnianamennian boundary in three sections of upper devonian marine sediments of the kerman province. the biostratigraphical and geochemical studies indicate that about 45% extinction of brachiopods probably caused by the frasnian-famennian bioevents, which is slightly higher than thr rate of devonian-carboniferous exti...

Journal: :Analytical chemistry 2014
Robert van Geldern Martin E Nowak Martin Zimmer Alexandra Szizybalski Anssi Myrttinen Johannes A C Barth Hans-Jürg Jost

A newly developed isotope ratio laser spectrometer for CO2 analyses has been tested during a tracer experiment at the Ketzin pilot site (northern Germany) for CO2 storage. For the experiment, 500 tons of CO2 from a natural CO2 reservoir was injected in supercritical state into the reservoir. The carbon stable isotope value (δ(13)C) of injected CO2 was significantly different from background val...

2010
Peter Molnar

Although geomorphic observations suggest that the Sierra Nevada has tilted so that the crest has risen 1–2 km since late Miocene time, deuterium and oxygen-18 isotope concentrations in Cenozoic geologic materials decrease eastward across California and Nevada similarly to those in modern, orographically induced precipitation, as if little change in Sierra Nevadan elevations has occurred since E...

2012
C. Fontanier

The paper entitled “Variation in stable carbon and oxygen isotopes of individual benthic foraminifera: tracers for quantifying the vital effect” by Ishimura San et al. deals with the applicability of inter-individual delta13C and delta18O distributions (Standard Deviation within species) to reconstruct the bottom water isotopic signatures. This work is based on live and dead (assumed as modern)...

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