Results 251 to 260 of about 47,311 (284)

Sm-Nd Isotopic Data and Earth's Evolution

Science, 1996
Samuel A. Bowring and Todd Housh (1) report Sm/Nd isotopic data giving a wide range of initial ENd values, from +3.5 to -4 at 4.0 billion years ago (Ga) and from +4 to -7 at 3.6 Ga. Their samples were from the Acasta gneisses of northern Canada, which represent the oldest known outcrops of continental crust (2).
S, Moorbath, M J, Whitehouse
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Sm-Nd isotopic evolution of chondrites

Earth and Planetary Science Letters, 1980
The ^(143)Nd/^(144)Nd and ^(147)Sm/^(144)Nd ratios have been measured in five chondrites and the Juvinas achondrite. The range in ^(143)Nd/^(144)Nd for the analyzed meteorite samples is 5.3 e-units (0.511673–0.511944) normalized to ^(150)Nd/^(142)Nd= 0.2096. This is correlated with the variation of 4.2% in ^(147)Sm/^(144)Nd (0.1920–0.2000).
Jacobsen, Stein B., Wasserburg, G. J.
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New Nd magnetic phase in Sm/Nd superlattices

Journal of Magnetism and Magnetic Materials, 2004
Magnetic phases and coherence have been investigated in a (001) Sm/Nd superlattice using Resonant X-ray magnetic scattering. The magnetic phases in Sm layers are similar to the ones evidenced in double hexagonal compact thick films. On the contrary, the magnetism in Nd layers exhibits strong differences with the bulk case, especially the occurrence of ...
S. Soriano, C. Dufour, K. Dumesnil, Ph. Mangin, A. Stunault   +4 more
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Sm-Nd chronology and petrogenesis of mesosiderites

Geochimica et Cosmochimica Acta, 1994
We have obtained Sm-Nd data from four mesosiderite silicate clasts, including three clasts with a variety of textures from the Vaca Muerta type 1A mesosiderite and one gabbroic clast from the Mt. Padbury mesosiderite. The gabbroic Vaca Muerta Pebble 12 and basaltic Pebble 16 yield identical ^(147)Sm- ^(143)Nd ages of 4.48 ± 0.19 AE and 4.48 ± 0.09 AE ...
Stewart, Brian W., Papanastassiou, D. A., Wasserburg, G. J.   +2 more
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Sm-Nd isotopic provinces of the Aldan Shield

Doklady Earth Sciences, 2006
The formation of the Early Precambrian continental crust is among the most topical problems of modern geology and petrology and has remained a subject of debate for several decades. The Sm‐Nd isotopic mapping, which occupies an important place among modern methods developed for the solution of this issue, makes it possible to estimate the relative ...
A. B. Kotov, E. B. Sal’nikova, V. A. Glebovitsky, V. P. Kovach, A. M. Larin, S. D. Velikoslavinsky, N. Yu. Zagornaya   +6 more
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Evidence for extreme Sm Nd fractionation during chemical weathering

Chemical Geology, 2021
Abstract During subaerial chemical weathering, submarine weathering and other intracrustal processes, Sm Nd chemical fractionation remains uncertain, while a little is known about the conditions, scale and magnitude, specific processes and actual mechanism for possible Sm Nd fractionation.
Jin-Liang Feng, Ji-Feng Zhang, Shao-Peng Gao, Chao-Feng Li, Jian-Ting Ju, Xiao-Ming Liu, Le-Le Pei, Kun-Ying Wang   +7 more
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Sm-Nd crustal provinces in Antarctica

Doklady Earth Sciences, 2008
Since the 1960s, the structure and age of the Antarctic crust has been the object of systematic study [1, 2, and others]. East Antarctica is an ancient platform, while the West Antarctica and Transantarctic Mountains are composed of different-age Phanerozoic fold systems.
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Sm-Nd Dating

1988
The Sm-Nd system is useful for determining crystallization ages of igneous and metamorphic rocks. It has proven especially valuable for dating mafic and ultramafic rocks that are, in general, difficult to date using other methods. The principles of Sm-Nd dating are identical to those of Rb-Sr dating, which have been discussed in detail elsewhere (e.g ...
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SmNd ages for norwegian garnet peridotite

Lithos, 1986
Abstract SmNd results for ga-WR-cpx from garnet Iherzolite in Almklovdalen, western Norway, define an isochron with age of 1703 ± 29 Ma and /get = + 4.7 ± 0.7 (2/gs) which falls on a depleted mantle curve. Garnet websterite from the same peridotite body falls close to the Iherzolite isochron.
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Do supercontinents introvert or extrovert?: Sm-Nd isotope evidence

Geology, 2003
In recent years, two end-member models for the formation of supercontinents have emerged. In the classical Wilson cycle, oceanic crust generated during supercontinent breakup (the interior ocean) is consumed during subsequent amalgamation so that the supercontinent turns “inside in” (introversion).
J. Brendan Murphy, R. Damian Nance
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