Results 201 to 210 of about 278,731 (238)

The Geophysical significance of calc‐alkaline andesites in New Zealand

New Zealand Journal of Geology and Geophysics, 1969
Abstract Andesite volcanoes of the North Island of New Zealand are divided on the basis of their potash contents into two groups; a low potash group which includes the Northland, Coromandel, and Taupo Volcanic Zone andesites, and a high potash group which contains the volcanoes of western Taranaki. There are no significant differences
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The multistage crystallization of zircon in calc‑alkaline

2016
CL imaging and U–Th–Pb data for a population of zircons from two of the Évora Massif granitoids (Ossa-Morena Zone, SW Iberia) show that both calcalkaline granitoids have zircon populations dominated by grains with cores and rims either showing or not showing differences in Th/U ratio, and having ages in the range ca.
Pereira, M. Francisco, Chichorro, Martim, Moita, Patricia, Santos, J. Francisco, Sola, A.M. Rita, Williams, Ian S., Silva, Jose B., Armstrong, Richard A.   +7 more
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Crystal clots, amphibole fractionation and the evolution of calc-alkaline magmas

Contributions to Mineralogy and Petrology, 1979
Petrographic and microprobe investigations of calc-alkaline (CA) rocks from the High Cascade Range (i.e., Mt. St. Helens, Mt. Jefferson, Crater Lake and Mt. Shasta) of western North America show that crystal clots represent primary igneous phase assemblages and are not products of amphibole reactions with melt.
Garcia, Michael O., Jacobson, Sara S.
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A non-basaltic experimental cotectic array for calc-alkaline batholiths

Lithos, 2021
This work was supported through the Spanish Research Agency (AEI) Grant N° PGC2018-096534-B-I00 (Proyecto IBERCRUST). I acknowledge with thanks Taras Gerya and Gabi Gutiérrez Alonso for constructive reviews that improved the manuscript.
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Amphibole stability in H2O-undersaturated calc-alkaline melts

Earth and Planetary Science Letters, 1972
Abstract The upper stability limit of amphibole in silicate melts has previously been shown to increase in temperature when the mole fraction of H 2 O in the fluid phase in equilibrium with the melt was decreased from 1.0 to 0.5. New experiments on amphibole stability in melts of andesite composition show that the amphibole stability limit also ...
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Archaean calc-alkaline volcanism in the Pilbara Block, Western Australia

Precambrian Research, 1984
Abstract Archaean calc-alkaline volcanics occur in two distinct settings in the Pilbara Block. Within the ca. 3500 Ma old Warrawoona Group, sequences of intermediate to acid volcanics are interlayered with an extensive sequence of komatiites and tholeiitic basalts.
M.E. Barley, G.C. Sylvester, D.I. Groves, G.D. Borley, N. Rogers   +4 more
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Uranium and potassium in calc-alkaline volcanic rocks from Sardinia

Lithos, 1976
Abstract The U content of major rock-forming minerals in a suite of calc-alkaline volcanic rocks from Sardinia is very low and their partition coefficient of U (D U = C S /C L ) is smaller than 0.1. The values of D U of the mineral phases decrease from basalt to dacite and, in all rocks, the bulk of U and K is present in the groundmass.
J Dostal, S Capedri, C Dupuy
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Evolution of calc-alkaline magmas of the Okhotsk-Chukotka volcanic belt

Petrology, 2011
Petrological, geochemical, and isotope geochronological aspects of the evolution of calc-alkaline magmatism were investigated in the Western Okhotsk flank zone, the Okhotsk segment, and the Eastern Chukchi flank zone of the Okhotsk-Chukotka volcanic belt (OCVB).
V. V. Akinin, E. L. Miller
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Calc-alkaline plutonism in the intra-oceanic Aleutian arc, Alaska

1990
Some of the best developed calc-alkaline plutons in an oceanic island arc are found in the Aleutian arc, Alaska. These Tertiary plutons are similar in many ways to continental granodioritic I-type plutons, but are smaller and have isotopic ratios and Rb contents that reflect their oceanic setting.
S. Mahlburg Kay, R. W. Kay, G. P. Citron, M. R. Perfit   +3 more
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Distribution of elements in igneous rocks of the normal calc-alkaline sequence

Scottish Journal of Geology, 1969
Synopsis Compilations of published data on the abundance of elements in normal plutonic igneous rocks are given in 14 graphs, each of which depicts the data for a particular group of elements.
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