The Eruptive Rocks

Soil Science (Impact Factor: 0.79). 06/1948; 66(1):78.
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    • "In their modified alkali-lime index or MALI diagram (Na 2 O + K 2 O–CaO versus SiO 2 ), CB samples with b60 wt.% SiO 2 are mainly calcic, whereas high-silica samples straddle boundaries, ranging from strongly calcic to alkalic, with most samples falling on or near the calcalkalic alkali-calcic boundary (Fig. 6b). Based on aluminium saturation index (Al/(Ca + Na + K) (Shand, 1943), most CB samples are "
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    ABSTRACT: Large volume, plutonic belts, such as the ∼ 221,000 km2, ca. 1.865–1.845 Ga Cumberland batholith (CB) of the Trans-Hudson Orogen in Canada, are major components of Paleoproterozoic orogenic belts. In many cases, they have been interpreted as continental arc batholiths. The petrogenesis and tectonic context of the CB and implications for crustal growth and recycling are interpreted herein based on a 900 km geochemical-isotopic (Nd–O) transect across it and into granitoid plutons within bounding Archean cratons in central and southern Baffin Island.
    Full-text · Article · Jun 2010 · Lithos
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    • "The Asarcik (Saplica, Catakhan), Eskine, and Saydere samples display linear trends in Harker FIG. 3. A. Classification of the Asarcik (Saplica, Catakhan), Eskine, and Saydere intrusives: total alkali versus SiO 2 diagram (Middlemost, 1994). B. Shand's index values (Shand, 1951). diagrams (Figs. 4 and 5). "
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    ABSTRACT: A series of Cretaceous to Eocene granitoids are present in the Eastern Pontides of northeastern Turkey. The Asarcik (Saplica, Catakhan), Eskine, and Saydere (Sebinkarahisar-Giresun) are the least-studied, thus least-understood plutons in the orogen. Rock assemblages range from monzonite to granite. They contain mainly K-feldspar, plagioclase, quartz, hornblende, biotite, and Fe-Ti oxides. They are high-K, calc-alkaline, and I-type granites. Chondrite-normalized REE patterns are fractionated and have small negative Eu anomalies. They show enrichment in LILE and LREE relative to HFSE, displaying features of arc-related granitoids. Low molar Al2O3/(FeO+MgO+TiO2) in combination with variable molar (Na2O+K2O)/(FeO+MgO+TiO2) ratios indicate that the magmas were derived from mafic lower-crustal source rocks. The Eu and Sr anomalies and unfractionated HREE suggest the presence of plagioclase and absence of garnet in the source.
    Full-text · Article · Jun 2008 · International Geology Review
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    • "). B. K 2 O versus SiO 2 diagram (classification boundaries after Le Maitre et al., 1989). C. Shand's index values of the rock types (after Shand, 1951). "
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    ABSTRACT: The western Anatolian magmatic province is typified by a large number of Late Cenozoic postcollisional granitoids. Of these magmatics, the Egrigöz pluton is one of the largest and leastunderstood plutons in the Menderes Massif. The Egrigöz intrusives are subalkaline, high-K, and calc-alkaline, and have characteristics of I-type granites. They consist mainly of granodiorite and granite. The intrusive rocks show enrichment in LILE and LREE relative to HFSE. Their chondrite-normalized REE patterns are fractionated and have small negative Eu anomalies. Geochemical characteristics of the Egrigöz pluton indicate an origin through partial melting of mafic lower-crustal source rocks. In western Anatolia, the melt generation mechanism for the intrusive rocks could be crustal extension and uplift following collision.
    Full-text · Article · Apr 2008 · International Geology Review
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