238U/235U Systematics in Terrestrial Uranium-Bearing Minerals

被引：648

作者：

Hiess, Joe ^{[1
]}

Condon, Daniel J. ^{[1
]}

McLean, Noah ^{[2
]}

Noble, Stephen R. ^{[1
]}

机构：

[1] British Geol Survey, NERC Isotope Geosci Lab, Keyworth NG12 5GG, Notts, England

[2] MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA

来源：

SCIENCE | 2012年 / 335卷 / 6076期

基金：

英国自然环境研究理事会;

关键词：

DECAY CONSTANTS; ISOTOPIC COMPOSITION; HALF-LIVES; FRACTIONATION; CM-247; GEOCHRONOLOGY; ABUNDANCE; ANOXIA;

D O I：

10.1126/science.1215507

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

The present-day U-238/U-235 ratio has fundamental implications for uranium-lead geochronology and cosmochronology. A value of 137.88 has previously been considered invariant and has been used without uncertainty to calculate terrestrial mineral ages. We report high-precision U-238/U-235 measurements for a suite of uranium-bearing minerals from 58 samples representing a diverse range of lithologies. This data set exhibits a range in U-238/U-235 values of >5 per mil, with no clear relation to any petrogenetic, secular, or regional trends. Variation between comagmatic minerals suggests that U-238/U-235 fractionation processes operate at magmatic temperatures. A mean U-238/U-235 value of 137.818 +/- 0.045 (2 sigma) in zircon samples reflects the average uranium isotopic composition and variability of terrestrial zircon. This distribution is broadly representative of the average crustal and "bulk Earth" U-238/U-235 composition.

引用

页码：1610 / 1614

页数：5

共 41 条

[1] Meteorite phosphates show constant 176Lu decay rate since 4557 million years ago [J].

Amelin, Y .

SCIENCE, 2005, 310 (5749) :839-841

[2] U-Pb chronology of the Solar System's oldest solids with variable 238U/235U [J].

Amelin, Yuri ;

Kaltenbach, Angela ;

Iizuka, Tsuyoshi ;

Stirling, Claudine H. ;

Ireland, Trevor R. ;

Petaev, Michail ;

Jacobsen, Stein B. .

EARTH AND PLANETARY SCIENCE LETTERS, 2010, 300 (3-4) :343-350

[3]

[Anonymous], EOS AGU SPRING M S

[4] Temperature dependence of the isotope chemistry of the heavy elements [J].

Bigeleisen, J .

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1996, 93 (18) :9393-9396

[5] CM-247 AS A SHORT-LIVED R-PROCESS CHRONOMETER [J].

BLAKE, JB ;

SCHRAMM, DN .

NATURE-PHYSICAL SCIENCE, 1973, 243 (130) :138-140

[6] CHRONOMETER FOR S-PROCESS NUCLEOSYNTHESIS [J].

BLAKE, JB ;

LEE, T ;

SCHRAMM, DN .

NATURE-PHYSICAL SCIENCE, 1973, 242 (120) :98-100

[7] Variations in 238U/235U in uranium ore deposits: Isotopic signatures of the U reduction process? [J].

Bopp, Charles John, IV ;

Lundstrom, Craig C. ;

Johnson, Thomas M. ;

Glessner, Justin J. G. .

GEOLOGY, 2009, 37 (07) :611-614

[8] New constraints on early Solar System chronology from Al-Mg and U-Pb isotope systematics in the unique basaltic achondrite Northwest Africa 2976 [J].

Bouvier, Audrey ;

Spivak-Birndorf, Lev J. ;

Brennecka, Gregory A. ;

Wadhwa, Meenakshi .

GEOCHIMICA ET COSMOCHIMICA ACTA, 2011, 75 (18) :5310-5323

[9] 238U/235U Variations in Meteorites: Extant 247Cm and Implications for Pb-Pb Dating [J].

Brennecka, G. A. ;

Weyer, S. ;

Wadhwa, M. ;

Janney, P. E. ;

Zipfel, J. ;

Anbar, A. D. .

SCIENCE, 2010, 327 (5964) :449-451

[10] Rapid expansion of oceanic anoxia immediately before the end-Permian mass extinction [J].

Brennecka, Gregory A. ;

Herrmann, Achim D. ;

Algeo, Thomas J. ;

Anbar, Ariel D. .

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2011, 108 (43) :17631-17634

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