The High Lava Plains province (HLP) of southeastern Oregon is a Miocene to Recent volcanic upland characterized by widespread basaltic volcanism and west-migrating rhyolitic volcanism. New ⁴⁰Ar/³⁹Ar ages for HLP rhyolites demonstrate that the trend of migrating rhyolitic volcanism is robust, reflecting westward migration at a rate of -35 km/m.y....
Volcán Miño (21°11'S) is located on the westernmost periphery of a longlived complex of stratovolcarioes and domes called the Aucanquilcha Complex. The Aucanquilcha Complex ranges in age from 11 Ma to 1-lolocene and lies along the main N-S trending axis of Quaternary volcanoes in the Andean Central Volcanic Zone (CVZ)....
Columbia River Basalt Group dikes cut the tonalite-granodiorite Wallowa Batholith in northeastern Oregon, providing a natural setting in which to examine partial melting. Many dikes have up to 5 m-wide zones of quenched partially melted wallrock at their margins. This paper examines the progressive partial melting reactions in biotite-and hornblende-bearing...
The Aucanquilcha Volcanic Cluster (AVC) is the erupted part of a magmatic system with a complex and long-lived history. The AVC lies at 21°S in the high Andes and is built on thick continental crust. The thick crust in the area combined with the prolonged magmatic activity make it an...
The pressure history of a continental magmatic system can be deciphered by analyzing the composition of amphiboles in the eruptive products where the pressure of equilibration correlates with the depth of the magmatic system. This can reveal vertical evolution of the magma as amphibole composition varies significantly with temperature and...
Oregon’s High Lava Plains Province (HLP) has strongly bimodal basalt and rhyolitic volcanism. The Province caps the northern margin of the Basin and Range Province and serves as a transitional region between westward extension of the Basin and Range Province and unextended crust to the north . The High Lava...
The Central Oregon High Cascade Range is an anomalously mafic segment of the Cascade Arc due to ongoing intra-arc extension, which allows most magmas to traverse the crust without stalling and evolving to more evolved compositions. North Sister, a composite volcano in this arc segment, has produced a seemingly monotonous...
Volcan Aucanquilcha, a Pleistocene to Recent composite volcano in northern Chile, is the youngest and center-most member of the 11 m.y.-old Aucanquilcha Volcanic Cluster (AVC). The AVC has produced [approximately]350 km³ of lava over its history. Magmatism started slowly and was punctuated by high rates of eruption between 4.5 and...
The Yanacocha Mining District in northern Perú is considered the largest group of
high-sulfidation style epithermal gold deposits in the world. District-scale geologic mapping coupled with detailed 40Ar/39Ar geochronology, geochemistry and petrography establish the volcanic history of the area and analyze the temporal and spatial evolution of volcanism, hypogene advanced...