Magma genesis and chamber processes at Los Humeros caldera, Mexico—Nd and Sr isotope data

Nature ◽  
1983 ◽  
Vol 302 (5903) ◽  
pp. 52-55 ◽  
Author(s):  
Surendra P. Verma
Keyword(s):  
Sr Isotope ◽  
Magma Genesis ◽  
Isotope Data

Origin of the Ordovician Mansehra granite in the NW Himalaya, Pakistan: constraints from Sr–Nd isotopic data, zircon U–Pb age and Hf isotopes

2018 ◽  
Vol 481 (1) ◽  
pp. 277-298 ◽  
Author(s):  
Masatsugu Ogasawara ◽  
Mayuko Fukuyama ◽  
Rehanul Haq Siddiqui ◽  
Ye Zhao
Keyword(s):  
Granitic Magma ◽  
Geochemical Data ◽  
Large Contribution ◽  
Crustal Material ◽  
Sr Isotope ◽  
Nw Himalaya ◽  
Nd Isotope ◽  
Isotope Data ◽  
Late Neoproterozoic ◽  
T Values

AbstractThe Mansehra granite in the NW Himalaya is a typical Lesser Himalayan granite. We present here new whole-rock geochemistry, Rb–Sr and Sm–Nd isotope data, together with zircon U–Pb ages and Hf isotope data, for the Mansehra granite. Geochemical data for the granite show typical S-type characteristics. Zircon U–Pb dating yields 206Pb/238U crystallization ages of 483–476 Ma. The zircon grains contain abundant inherited cores and some of these show a clear detrital origin. The 206Pb/238U ages of the inherited cores in the granite cluster in the ranges 889–664, 1862–1595 and 2029 Ma. An age of 664 Ma is considered to be the maximum age of the sedimentary protoliths. Thus the Late Neoproterozoic to Cambrian sedimentary rocks must be the protolith of the Mansehra granitic magma. The initial Sr isotope ratios are high, ranging from 0.7324 to 0.7444, whereas the εNd(t) values range from −9.2 to −8.6, which strongly suggests a large contribution of old crustal material to the protoliths. The two-stage Nd model ages and zircon Hf model ages are Paleoproterozoic, indicating that the protolith sediments were derived from Paleoproterozoic crustal components.

scholarly journals Geochemical and Nd, Pb, and Sr Isotope Data from Deccan Alkaline Complexes--Inferences for Mantle Sources and Plume-Lithosphere Interaction

1998 ◽  
Vol 39 (11-12) ◽  
pp. 1847-1864 ◽  
Author(s):  
A. Simonetti ◽  
S. L. Goldstein ◽  
S. S. Schmidberger ◽  
S. G. Viladkar
Keyword(s):  
Sr Isotope ◽  
Isotope Data ◽  
Mantle Sources ◽  
Alkaline Complexes

The origin of basic rocks of the Korosten AMCG complex, Ukrainian shield: Implication of Nd and Sr isotope data

Lithos ◽  
2006 ◽  
Vol 90 (3-4) ◽  
pp. 214-222 ◽  
Author(s):  
Leonid Shumlyanskyy ◽  
Rob M. Ellam ◽  
Olexander Mitrokhin
Keyword(s):  
Ukrainian Shield ◽  
Sr Isotope ◽  
Isotope Data ◽  
Basic Rocks

Sm–Nd, Pb–Pb, and Rb–Sr systematics of the basement in the Cigar Lake area, Saskatchewan, Canada

1993 ◽  
Vol 30 (4) ◽  
pp. 731-742 ◽  
Author(s):  
Maurice Pagel ◽  
Annie Michard ◽  
Martine Juteau ◽  
Laurent Turpin
Keyword(s):  
Isotope Geochemistry ◽  
Sedimentary Cover ◽  
Lake Area ◽  
Sr Isotope ◽  
Pb Isotope ◽  
Mineralizing Fluid ◽  
Isotope Data ◽  
Basement Rocks ◽  
Strong Contrast

The Sm–Nd, Pb–Pb, and Rb–Sr isotope geochemistry of graphitic metapelitic gneisses and their altered equivalents from the Cigar Lake area (Saskatchewan, Canada) has been investigated. Some granitic gneisses were also analyzed for Pb–Pb and Rb–Sr. Sm–Nd data show that the metapelitic gneisses are composed of detritus from heterogeneous, mainly mantle-derived Archean rocks (2.5–2.6 Ga) and that the Sm–Nd system has not been significantly perturbed during subsequent alteration and metamorphic events. The Pb–Pb age for samples of the less altered graphitic metapelitic gneisses is 1.77 ± 0.03 Ga. The crustal common Pb is located on the Pb–Pb isochron, but there are different zones with high and variable U/Pb ratios (μ = 15–280). The Pb–Pb age for the granitic gneisses is 1.79 ± 0.11 Ma. The Pb isotope data show that there has been no major uranium redistribution in the basement after the Hudsonian orogeny. However, there has been a strong perturbation of the U–Pb system in the regolithic zone beneath the Athabasca cover. In some samples, uranium was added during the mineralizing event. The Rb–Sr system in the graphitic metapelitic gneisses was also affected.The 87Sr/86Sr ratio in pitchblende is 0.709. At 1.3 Ga, there is a strong contrast between the 87Sr/86Sr ratio in the Athabasca sandstones (0.706–0.710) and the 87Sr/86Sr ratio in the metapelitic gneisses from the basement (0.725–0.775). The upper zone of the regolith is characterized by a low 87Sr/86Sr ratio (0.705–0.707). The Pb–Pb and Rb–Sr data are consistent with the circulation of a fluid with a low 87Sr/86Sr ratio, derived from the sedimentary cover; this fluid passed through the most permeable zones of the basement rocks, especially the regolith. The mineralizing fluid had a 87Sr/86Sr value typical of a fluid in equilibrium with the Athabasca sandstones.

Geochemical and Sr-isotope data on historic lavas of Mount Etna

1993 ◽  
Vol 56 (1-2) ◽  
pp. 57-69 ◽  
Author(s):  
M. Barbieri ◽  
R. Cristofolini ◽  
M.C. Delitala ◽  
M. Fornaseri ◽  
R. Romano ◽  
...  
Keyword(s):  
Mount Etna ◽  
Sr Isotope ◽  
Isotope Data
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