Low δ18O silicic volcanic rocks at the Calabozos caldera complex, southern Andes

  title={Low $\delta$18O silicic volcanic rocks at the Calabozos caldera complex, southern Andes},
  author={Anita L. Grunder},
  journal={Contributions to Mineralogy and Petrology},
  • A. Grunder
  • Published 1 March 1987
  • Geology
  • Contributions to Mineralogy and Petrology
Sr- and Pb-isotope data from the Calabozos center (87Sr/86Sr=∼ 0.7043, 206Pb/204Pb=18.64–18.66, 207Pb/204Pb=15.59–15.60, 208Pb/204Pb=38.52–38.55) fall within the range of values reported for the southern volcanic zone (33–42° S) of the Andean arc. The range of δ18O (5.0–6.3), however, includes unusually low values compared to volcanic rocks of similar bulk composition in the region. The Calabozos caldera complex lies at 35 °30′ S, where the continental crust under the Andes thins southward from… 

Petrogenesis of the Swaziland and Northern Natal Rhyolites of the Lebombo Rifted Volcanic Margin, South East Africa

TheJozini and Mbuluzi rhyolites and Oribi Beds of the southern Lebombo Monocline, southeastern Africa, have geochemical characteristics that indicate they were derived by partial melting of a mixture

Pleistocene to Holocene Growth of a Large Upper Crustal Rhyolitic Magma Reservoir beneath the Active Laguna del Maule Volcanic Field, Central Chile

The rear-arc Laguna del Maule volcanic field (LdM) in the Andean Southern Volcanic Zone, 36 (cid:2) S, is among the most active latest Pleistocene–Holocene rhyolitic centers globally and has been

Oxygen isotope heterogeneity of the mantle deduced from global 18O systematics of basalts from different geotectonic settings

Based upon a compilation and analysis of O-isotope data for Neogene volcanic rocks worldwide, the δ18O variation for 743 basalts (historic lavas, submarine glasses, and lavas with <0.75 wt% H2O) is

Oxygen isotope geochemistry of the lassen volcanic center, California: Resolving crustal and mantle contributions to continental Arc magmatism

This study reports oxygen isotope ratios determined by laser fluorination of mineral separates (mainly plagioclase) from basaltic andesitic to rhyolitic composition volcanic rocks erupted from the

Volcán Quizapu, Chilean Andes

Quizapu is a flank vent of the basalt-to-rhyodacite Holocene stratocone, Cerro Azul, and lies at the focus of a complex Quaternary volcanic field on the Andean volcanic front. The Quizapu vent



Combined Sr–O isotope relationships and petrogenesis of Andean volcanics of South America

Active andesitic-type volcanism in the southern Andes (lat. 42–36° S) is characterized by low Sr- and O-isotopic compositions which fall in the range 87Sr/86Sr = 0.7036–0.7043, δ18O = 5.2–6.8‰. In

The Loma Seca Tuff and the Calabozos caldera: A major ash-flow and caldera complex in the southern Andes of central Chile

A 26 × 14-km composite ring-structure caldera of late Pleistocene age has been discovered and mapped near the Andean crest in central Chile (35°30′S). Rhyodacitic to dacitic zoned ash-flow sheets,

Catastrophic isotopic modification of rhyolitic magma at times of caldera subsidence, Yellowstone Plateau Volcanic Field

The Yellowstone Plateau volcanic field has undergone repeated eruption of rhyolitic magma strongly depleted in 18O. Large calderas subsided 2.0, 1.3, and 0.6 Ma ago, on eruption of ash flow sheets

Petrogenesis of the Superstition-Superior Volcanic Area as Inferred from Strontium- and Oxygen-Isotope Studies

Apparent initial Sr 87 /Sr 86 ratios of five ash-flow tuffs (0.7063 to 0.7139) and several mafic to silicic lavas (0.7055 to 0.7131) indicate that the magmas were derived below the base of the

18O/16O ratios in ash-flow tuffs and lavas erupted from the central Nevada caldera complex and the central San Juan caldera complex, Colorado

Oxygen isotope compositions were measured on 129 quartz, feldspar, and biotite phenocrysts from ash-flow tuffs and lava domes erupted from the Oligocene central Nevada and central San Juan caldera

The oxygen isotope geochemistry of igneous rocks

Oxygen isotope analyses have been obtained for 443 igneous rock and mineral samples from various localities throughout the world. Detailed studies were made on the Medicine Lake, Newberry, Lassen,

Sr, Nd, Pb and O Isotope Composition of Late Cenozoic Volcanics, northernmost SVZ (33–34°S)

The three northernmost (33–34°S) volcanic centres in the SVZ share more petrochemical similarities with the volcanoes of the CVZ than the volcanoes further south in the southern Andes, including the