Origin of Late Paleogene to Neogene basalts and associated coeval felsic volcanic rocks in Southwest Hokkaido, northern NE Japan arc: Constraints from Sr and Nd isotopes and major- and trace-element chemistry

Lithos ◽  
2011 ◽  
Vol 125 (1-2) ◽  
pp. 368-392 ◽  
Author(s):  
Koshiro Takanashi ◽  
Kenji Shuto ◽  
Makoto Sato
Keyword(s):  
Trace Element ◽  
Volcanic Rocks ◽  
Nd Isotopes ◽  
Sr And Nd Isotopes ◽  
Trace Element Chemistry ◽  
Element Chemistry ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks ◽  
Ne Japan

TRACE ELEMENT CHEMISTRY OF EMERALDS

2018 ◽  
Author(s):  
Casey Beaudoin ◽  
◽  
G. Nelson Eby
Keyword(s):  
Trace Element ◽  
Trace Element Chemistry ◽  
Element Chemistry

Chemical variation of clinopyroxene phenocrysts from the trachybasaltic lavas of Mount Etna, Sicily

1980 ◽  
Vol 43 (330) ◽  
pp. 765-770 ◽  
Author(s):  
A. M. Duncan ◽  
R. M. F. Preston
Keyword(s):  
Trace Element ◽  
Mount Etna ◽  
Chemical Variation ◽  
Etna Volcano ◽  
Trace Element Chemistry ◽  
Sector Zoning ◽  
Steady Decrease ◽  
Element Chemistry

SummaryThe chemical variation of clinopyroxene phenocrysts from the trachybasaltic lavas of Etna volcano is described. The phenocrysts show a limited, but distinct trend in chemical variation from calcic-augite in the hawaiites to augite in the benmoreites. The trend of this variation is unusual, being one of Mg-enrichment with differentiation of the magma. Ca shows a steady decrease in the clinopyroxenes from the hawaiites to the benmoreites. Na, however, shows little chemical variation in the pyroxenes. The trace element chemistry is briefly examined. The clinopyroxenes show well-developed oscillatory and sector zoning. The basal {11} sectors are enriched in Si and Mg and depleted in Ti, Al, and Fe relative to the {100}, {110}, and {010} prism sectors.

Geochemistry and Isotope Composition of Paleoproterozoic Granites and Felsic Volcanics of the Elash Graben: Evidence of the Heterogeneity of the Early Precambrian Crust

2021 ◽  
Vol 62 (10) ◽  
pp. 1175-1187
Author(s):  
A.D. Nozhkin ◽  
O.M. Turkina ◽  
K.A. Savko
Keyword(s):  
Isotope Composition ◽  
Volcanic Rocks ◽  
Rare Metal ◽  
Temporal Association ◽  
Metal Deposit ◽  
Wide Range ◽  
Rare Metal Deposit ◽  
Geochronological Study ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks

Abstract —The paper presents results of a petrogeochemical and isotope–geochronological study of the granite–leucogranite association of the Pavlov massif and felsic volcanics from the Elash graben (Biryusa block, southwest of the Siberian craton). A characteristic feature of the granite–leucogranites is their spatial and temporal association with vein aplites and pegmatites of the East Sayan rare-metal province. The U–Pb age of zircon from granites of the Pavlov massif (1852 ± 5 Ma) is close to the age of the pegmatites of the Vishnyakovskoe rare-metal deposit (1838 ± 3 Ma). The predominant biotite porphyritic granites and leucogranites of the Pavlov massif show variable alkali ratios (K2O/Na2O = 1.1–2.3) and ferroan (Fe*) index and a peraluminous composition; they are comparable with S-granites. The studied rhyolites of the Tagul River (SiO2 = 71–76%) show a low ferroan index, a high K2O/Na2O ratio (1.6–4.0), low (La/Yb)n values (4.3–10.5), and a clear Eu minimum (Eu/Eu* = 0.3–0.5); they are similar to highly fractionated I-granites. All coeval late Paleoproterozoic (1.88–1.85 Ga) granites and felsic volcanics of the Elash graben have distinct differences in composition, especially in the ferroan index and HREE contents, owing to variations in the source composition and melting conditions during their formation at postcollisions extension. The wide range of the isotope parameters of granites and felsic volcanic rocks (εNd from +2.0 to –3.7) and zircons (εHf from +3.0 to +0.8, granites of the Toporok massif) indicates the heterogeneity of the crustal basement of the Elash graben, which formed both in the Archean and in the Paleoproterozoic.

Geochemistry of the 1989–1990 eruption of redoubt volcano: Part I. Whole-rock major- and trace-element chemistry

1994 ◽  
Vol 62 (1-4) ◽  
pp. 429-452 ◽  
Author(s):  
Christopher J. Nye ◽  
Samuel E. Swanson ◽  
Victoria F. Avery ◽  
Thomas P. Miller
Keyword(s):  
Trace Element ◽  
Trace Element Chemistry ◽  
Element Chemistry
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