Zobrazeno 1 - 10
of 42
pro vyhledávání: '"R. Keith O'Nions"'
Publikováno v:
Earth and Planetary Science Letters. 272:513-522
Hydrogenous ferromanganese crust deposits on seafloor and volcanic seamounts are archives of past isotopic compositions of the ocean. Isotopic compositions of long-life radiogenic isotopes that are dissolved in the ocean such as Nd and Pb, are mixtur
Publikováno v:
Biochemical and Biophysical Research Communications. 323:79-85
The natural variation of Mg and Ca stable isotopes of carbonates has been determined in carbonate skeletons of perforate foraminifera and reef coral together with Mg/Ca ratios to assess the influence of biomineralisation processes. The results for co
Publikováno v:
Journal of Analytical Atomic Spectrometry. 18:296-301
A technique for separation of Mg, with 100% yield from low-Mg biogenic carbonates has been developed suitable for high precision analysis of Mg isotopes by multiple-collector inductively coupled plasma mass spectrometry. Two separate stages of ion-ex
Publikováno v:
Journal of Analytical Atomic Spectrometry. 17:1290-1294
A new separation method of Ti from silicate materials is presented that is suitable for the determination of natural Ti isotope variations using multi-collector inductively coupled plasma source mass spectrometry (MC-ICP-MS). This method makes possib
Publikováno v:
Earth and Planetary Science Letters. 201:105-115
Simultaneous high-precision measurement of 24 Mg, 25 Mg and 26 Mg isotopic compositions were made by multiple collector inductively coupled mass spectrometry (MC-ICP-MS) relative to the international standard SRM980. Data are presented on low-Mg calc
Publikováno v:
International Journal of Mass Spectrometry. 208:89-98
Multiple-collector inductively coupled plasma mass spectrometry has been used for the precise measurement of variations in the isotopic composition of Mg in a range of materials. The contributions of CC, CN, and MgH molecular species to the mass spec
Publikováno v:
Journal of Analytical Atomic Spectrometry. 14:1835-1838
Multi-collector ICP-MS has been used for the precise measurement of natural variations in the isotopic composition of Ca. The interference of Ar in the Ca mass region is assessed and the repeatability of the 44Ca/42Ca ratio of a sample calcium soluti
Autor:
R. Keith O'Nions, Dan McKenzie
Publikováno v:
Physics of the Earth and Planetary Interiors. 107:143-182
Ocean island basalts are well-known to have distinctive isotopic signatures whose origin is not yet understood. It is, however, clear that these signatures impose important constraints on models of mantle circulation and melt generation. Large number
Publikováno v:
Chemical Geology. 144:305-312
The calibration of U–Pb and Th–Pb ratios in Th–U-rich minerals measured by SIMS usually assumes that there are no matrix effects arising from the compositional difference between standard and sample. Matrix effects have been observed during att
Closure of the Central American Isthmus and its effect on deep-water formation in the North Atlantic
Publikováno v:
Nature. 386:382-385
Modern ocean thermohaline-driven circulation influences global climate by transporting heat to high latitudes1,2 and by affecting the exchange of CO2 between ocean and atmosphere3. North Atlantic Deep Water (NADW) plays a key role in this circulation