Results 261 to 270 of about 163,795 (290)

U-Pb geochronology of grossular-andradite garnet

Chemical Geology, 2017
Abstract This study presents a new laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) based U-Pb geochronometric method for dating grossular-andradite (grandite) garnet. Grandite is a primary skarn mineral, therefore dating its growth directly dates hydrothermal activity.
S. Seman, D.F. Stockli, N.M. McLean
openaire   +1 more source

U-Pb ?????????????????? ?????? ???? ?????????????????? ?????????? ???????????? ???????????????? ?????????????????????????? ?????????? ???????????????????? ?????????? ?????????? ????????????

2015
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openaire   +2 more sources

Bastnaesite: a promising U-Pb geochronological tool

Doklady Earth Sciences, 2010
One of the most complex problems in geochrono logical studies is dating endogenous ore processes. The application of the U–Pb method in solving this prob lem is constrained by the sufficiently narrow range of traditional mineral geochronometers, which, if present in ores, are strongly altered.
E. B. Sal’nikova, S. Z. Yakovleva, A. V. Nikiforov, A. B. Kotov, V. V. Yarmolyuk, I. V. Anisimova, A. M. Sugorakova, Yu. V. Plotkina   +7 more
openaire   +1 more source

The three-dimensional UPb method: Generalized models and implications for UPb two-stage systematics

Chemical Geology, 1992
Four forms of the three-dimensional UPb method established so far are physically generalized within the framework of a UPb two-stage evolution. Such a generalization provides an explicit insight into the principle of conventional UPb discordia dating. Its implications for both UPb geochronology and Pb isotopic geology are illustrated for whole-rock
openaire   +1 more source

Does U–Pb date Earth's core formation?

Nature, 2006
Arising from: B. J. Wood & A. N. Halliday Nature 437, 1345–1348 (2005); Wood & Halliday reply Constraining the timing of the formation of Earth's core, which defines the birth of our planet, is essential for understanding the early evolution of Earth-like planets.
Qing-zhu Yin, Stein B. Jacobsen
openaire   +1 more source

Ion microprobe U–Pb dating of apatite

Chemical Geology, 1999
Abstract To illustrate in situ Sensitive High Resolution Ion MicroProbe (SHRIMP) analysis of apatites, Pb isotopes and Pb/U ratios of five apatite samples with different ages have been measured using SHRIMP II ion microprobe at Hiroshima University.
Yuji Sano, Takayuki Oyama, Kentaro Terada, Hiroshi Hidaka   +3 more
openaire   +1 more source

U–Pb SHRIMP dating of uraniferous opals

Chemical Geology, 2006
Abstract U–Pb and U-series analyses of four U-rich opal samples using sensitive high-resolution ion microprobe (SHRIMP) demonstrate the potential of this technique for the dating of opals with ages ranging from several tens of thousand years to millions of years.
Nemchin, Alexander, Neymark, L., Simons, S.   +2 more
openaire   +2 more sources

Staurolite as an isotopic U–Pb geochronometer

Geology of Ore Deposits, 2016
A new approach is suggested for measuring the real U–Pb and Pb–Pb ages of rock-forming metamorphic staurolite. Previously, two approaches have been used for this purpose: (1) measurement of the lead isotopic compositions, uranium and lead contents in leach substance as a product of the step-leaching technique; age is calculated by plotting the Pb–Pb ...
L. K. Levskii, A. F. Lobikov
openaire   +1 more source

U-Pb AGE OF THE CHATTANOOGA SHALE

Geological Society of America Bulletin, 1960
An attempt was made to date the upper black unit of the Gassaway member of the Chattanooga shale which carries the maximum U/Pb ratio. Three samples were analyzed by isotopic dilution techniques. The U238-Pb206 ages on all 3 samples agreed within their experimental errors. The average of the two samples with reasonably small errors gave an apparent age
J. C. COBB, J. L. KULP
openaire   +1 more source

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2014
???????????????? ???????????????????? U-Pb ???? ???????????????? ?????????????????? ??????????????????, ???? ?????????????????????????? ?? ???????????? ??. ?????????? ?? ?????????????????? ???????? ???? ?????????????????????? ????????????. ??????????????????????, ???? ???? ???????????? ???????????????????????????????? 1996 ?? 13 ?????? ????. ????????, ?
openaire   +3 more sources