Generation of voluminous silicic magmas and formation of mid-Cenozoic crust beneath north-central Mexico: evidence from ignimbrites, associated lavas, deep crustal granulites, and mantle pyroxenites
Article Abstract:
The upper ignimbrite that represents the voluminous mid-Cenozoic rhyolites in La Olivina region, north central Mexico, has been formed by assimilation-fractional crystallization of mantle-derived basaltic magmas. The isotopic content of the magmas is similar to that of pyroxenites obtained from the mantle. The lower ignimbrite was formed from basaltic magma before the formation of the upper ignimbrite. Analysis of granulite xenoliths shows that large volumes of cumulates form at crustal depths greater than those exposed by the orogenic uplift.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1996
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Magmatic processes that generated the rhyolite of Glass Mountain, Medicine Lake volcano, N. Carolina
Article Abstract:
Basaltic andesite and andesite magmatic inclusions were analyzed during melting experiments to characterize the geochemical processes that led to the formation of rhyolites from Glass Mountain, Medicine Lake, NC. Melting experiments indicated the role of erupted rhyolite in generating the present petrological characteristics of Glass Mountain. The presence of amphibole in the magmatic inclusions also provided mineralogical evidence of crystallization which occurred near H2O-saturated conditions.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1997
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Compositional gradients in large reservoirs of silicic magma as evidenced by ignimbrites versus Taylor Creek Rhyolite lava domes
Article Abstract:
Twenty lava domes and flows in the Taylor Creek Rhyolite in New Mexico exhibit chemical variations indicative of a vertical zonation in the magma reservoir of the formation. The zonation in the reservoir was probably the result of country rock-contamination of the dome-feeding portion of the reservoir. Such contamination is recorded in the trace element-composition of the different domes and lava flows.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1992
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