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High-Resolution Stratigraphy with Strontium Isotopes
Science, 1985The isotopic ratio of strontium-87 to strontium-86 shows no detectable variation in present-day ocean water but changes slowly over millions of years. The strontium contained in carbonate shells of marine organisms records the ratio of strontium-87 to strontium-86 of the oceans at the time that the shells form. Sedimentary rocks composed of accumulated
D J, Depaolo, B L, Ingram
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Strontium Isotopes in Deep-Sea Sediments
Science, 1966Recent deep-sea sediments, leached of carbonate, have Sr 87 : Sr 86 ratios ranging from 0.7044 to 0.7394. Strontium in the detrital sediment has not equilibrated isotopically with seawater strontium. Amounts of strontium-bearing authigenic material in the clay-mineral assemblage are not great
E J, Dasch, F A, Hills, K K, Turekian
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Ground-state properties of strontium isotopes
Physical Review C, 1995We present systematic constrained Hartree-Fock calculations of ground-state properties of even strontium isotopes ({ital A}=76--100) with the Skyrme interaction. Approximate projection of angular momentum is done after variation by explicit inclusion of the rotational energy {minus}{l_angle}{ital {cflx j}}{sup 2}{sub {ital x}}{r_angle}/J.
, Baran, , Höhenberger
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Strontium isotope stratigraphy
Palaeogeography, Palaeoclimatology, Palaeoecology, 1986The 87Sr/86Sr ratio of sea water has changed significantly with time in response to the input of varying proportions of Sr derived from continental crust and upper mantle sources, as moderated and buffered by carbonate recycling. Because of these fluctuations, the marine Sr isotope record can be used for stratigraphic correlation and absolute dating ...
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Strontium Isotopic Composition of Mid-Cretaceous Seawater
Science, 1994The 87 Sr/ 86 Sr ratio in fish teeth separated from mid-Cretaceous marl and black shale from the northeastern Apennines and Venetian Alps (Italy) define three periods of low 87 Sr/ 86 Sr ratio at 121 to 124 million years ago (Ma), 110 to 115 Ma,
INGRAM B. LYNN +3 more
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Strontium and Neodymium Isotopes
2019The chapter presents data on Rb–Sr and Sm–Nd TIMS analysis of pyroxenes, plagioclases, gross samples of igneous rocks and sulphide ores. In most Sm–Nd analyses of minerals, the isotope system (pyroxene–plagioclase) does not reflect the age of intrusions and shows a rejuvenated or aged isochronous age.
Yevgeny Bogomolov +3 more
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Dating phosphogenesis with strontium isotopes
Geochimica et Cosmochimica Acta, 1990Authigenic and replacement francolites in modern phosphorite have values of {sup 87}Sr/{sup 86}Sr within error of that of modern marine Sr (0.70916 {plus minus} 2). During the phosphatisation of carbonate, Sr is not inherited from the carbonate but is totally exchanged with Sr in ambient water. The {sup 87}Sr/{sup 86}Sr in shallow marine pore waters is
J.M McArthur +4 more
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Strontium Isotopes In Seawater Through Time
Annual Review of Earth and Planetary Sciences, 1989where pis the p-particle, v is an antineutrino, and Q represents the decay energy (0.275 MeV). The recommended decay constant for 87Rb is 1.42 x 10-11 yr-I (Steiger & Jager 1977), and its half-life T is therefore 48.8 Gyr. On geological time scales, the isotopes 84, 86, and 88 are stable, in contrast to 87Sr, and their abundance ratios are therefore ...
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