Results 251 to 260 of about 7,803,272 (294)

Interpreting ages from Re–Os isotopes in peridotites

Lithos, 2009
Abstract Since the first application of the 187Re–187Os isotope system to determine the timing of melt extraction from peridotites twenty years ago, a plethora of studies have demonstrated its usefulness in dating melt depletion, hence, lithosphere formation in continental settings. However, these studies have also highlighted issues that affect this
Roberta L. Rudnick, Richard J. Walker
openaire   +1 more source

Re-Os isotope systematics of sediments of the Brahmaputra River system

Geochimica et Cosmochimica Acta, 2003
Re-Os analyses were performed on suspended loads and coarser grained bank sediments of the Brahmaputra River system. Re and Os concentrations of these sediments vary from 7 to 1154 ppt and from 3 to 173 ppt, respectively. 187Os/188Os ratios range from 0.178 to 6.8, and thus vary from nearly mantle to very radiogenic crustal values.
Singh, Sunil, Reisberg, Laurie, France-Lanord, Christian   +2 more
openaire   +2 more sources

Re-Os isotopic evidence for early differentiation of the Martian mantle

Geochimica et Cosmochimica Acta, 2000
Variations in the short-lived systems of 182Hf-182W and 146Sm-142Nd in the SNC meteorites indicate an early isolation of, and subsequent inefficient mixing between, mantle reservoirs in Mars. Correlations of eW and e142Nd with initial γOs are consistent with the Re-Os isotopic systematics of these meteorites being set during the earliest ...
A.D. Brandon, R.J. Walker, J.W. Morgan, G.G. Goles   +3 more
openaire   +1 more source

The Aguablanca Ni-Cu Deposit: A Re-Os Isotope Study

International Geology Review, 2008
The Aguablanca Ni-Cu ore deposit is hosted by subvertical magmatic breccia bodies in which fragments of pyroxenite are cemented by sulfides. It is located within the Aguablanca Stock, which includes diorite, gabbro, norite and gabbronorite. Re-Os isotope data of magmatic pyrrhotite, chalcopyrite, and pentlandite and hydrothermal pyrite show that the Os
Ryan Mathur, Fernando Tornos, Fernando Barra   +2 more
openaire   +1 more source

Re‐Os Isotopic Measurements at the Femtomole Level in Natural Samples

Geostandards Newsletter, 1997
Here we describe a new chemical separation method for Os and an improved mass spectrometric procedure for Re and Os. This technique is based on the selective extraction of OsO4 from aqueous solution in liquid bromine. Among other advantages, this procedure avoids the cumbersome distillation procedure for Os and uses only commercial “off the shelf” PFA ...
Jean Louis Birck, Matthieu Roy Barman, Françoise Capmas   +2 more
openaire   +1 more source

Re–Os isotopic evidence for a lower crustal origin of massif-type anorthosites

Nature, 2000
Massif-type anorthosites are large igneous complexes of Proterozoic age. They are almost monomineralic, representing vast accumulations of plagioclase with subordinate pyroxene or olivine and Fe-Ti oxides--the 930-Myr-old Rogaland anorthosite province in southwest Norway represents one of the youngest known expressions of such magmatism.
, Schiellerup, , Lambert, , Prestvik, , Robins, , McBride, , Larsen   +5 more
openaire   +2 more sources

Re-Os Isotope Geochemistry of Magmatic Sulfide Ore Systems

1999
Abstract The formation of magmatic Cu-Ni-Co-platinum-group element (PGE) sulfide deposits is dependent on mantlederived silicate magmas (komatiites and basalts) attaining sulfide saturation. Because the sulfur content of the upper mantle is considered to be low (250 ppm; McDonough and Sun, 1995), it is likely that, for moderate to ...
D. D. Lambert, J. G. Foster, L. R. Frick, E. M. Ripley   +3 more
openaire   +1 more source

High precision Re-Os isotopic dating of molybdenites

Molybdenite is an ideal mineral for Re-Os isotopic dating, and its Re-Os isotopic systematics are widely employed to constrain the timing of hydrothermal metal mineralization.
Xiaorui Fan, Jifeng Xu, Jie Li, Guiqin Wang, Yunchuan Zeng   +4 more
openaire   +1 more source

Re-Os Isotope ages of molybdenum deposits in East Qinling and their significance

Chinese Journal of Geochemistry, 1995
Dating of metallic ore deposits has been one of the problems concerned with by ore geologists for many years. The establishment of the Re-Os Isotope Laboratory at the Institute of Rock and Mineral Analysis, Chinese Academy of Geological Sciences, has provided us with a new technique to carry out geochronological studies of molybdenum ores.
Dianhao Huang, Chengyu Wu, Andao Du, Hongliao He   +3 more
openaire   +1 more source

Paragenesis, Stable Isotopes, and Molybdenite Re-Os Isotope Age of the Lala Iron-Copper Deposit, Southwest China

Economic Geology, 2012
The Lala Fe-Cu deposit in the Kangdian iron oxide copper-gold (IOCG) metallogenic province, SW China, is hosted in the Paleoproterozoic Hekou Group. This volcanic-sedimentary sequence has undergone upper greenschist-lower amphibolite facies metamorphism at ~850 Ma.
Chen, WT, Zhou, MF
openaire   +3 more sources