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Articles 1 - 6 of 6
Full-Text Articles in Volcanology
Insights Into The Petrogenesis Of Alkalic, Shonkinitic Magmas From The Adel Hill Volcanic Field, Montana, Kenneth L. Brown, C. L. Mcleod, M. L. Lytle, T. J. Cracas, B. J. Shaulis, M. Loocke
Insights Into The Petrogenesis Of Alkalic, Shonkinitic Magmas From The Adel Hill Volcanic Field, Montana, Kenneth L. Brown, C. L. Mcleod, M. L. Lytle, T. J. Cracas, B. J. Shaulis, M. Loocke
Geology and Environmental Geoscience Faculty Publications
Shonkinites are rare alkali-rich igneous rocks found in the geological record from the Precambrian to the Eocene. This study investigates the Upper Cretaceous shonkinites from the Adel Hills Volcanic Field (AHVF), central Montana. The AHVF shonkinites are porphyritic with large, euhedral to subhedral phenocrysts of diopside that exhibit sector zoning. Other major mineral phases include plagioclase, sanidine, and secondary zeolites. Minor and accessory phases identified with SEM-EDS include magnetite, apatite, rare ilmenite and pyrite, and secondary calcite. Bulk rock SiO2 ranges from 47 to 49 wt% with Na2O + K2O varying from 5.50 to 7.34 wt% within that silica range. …
The Role Of Cumulate Plagioclase Entrainment In The Steens Basalt, Se Oregon: Insights From The Magma Chamber Simulator, Valerie Strasser
The Role Of Cumulate Plagioclase Entrainment In The Steens Basalt, Se Oregon: Insights From The Magma Chamber Simulator, Valerie Strasser
All Master's Theses
The Steens Basalt, located in SE Oregon, is the oldest and most mafic member of the Columbia River Basalt Group (CRBG). Because the Steens Basalt contains large (up to 6 cm) and abundant (up to 40%) plagioclase crystals, it is classified as a Giant Plagioclase basalt (GPB). Understanding the origin of these giant plagioclase yields insight into magmatic processes like recharge, crustal assimilation, cumulate entrainment, and fractional crystallization. Because large and abundant plagioclase are found in other flood basalt provinces worldwide, these results could also enhance understanding of magma evolution and storage conditions for GPB worldwide. The Steens basalt is …
Trace Element And Isotopic Fingerprinting Of Olivine Phenocrysts As Recorders Of Magmatic Processes In The Golden Trout Volcanic Field, Kern Plateau, Ca, Mark E. Szymanski
Trace Element And Isotopic Fingerprinting Of Olivine Phenocrysts As Recorders Of Magmatic Processes In The Golden Trout Volcanic Field, Kern Plateau, Ca, Mark E. Szymanski
Cal Poly Humboldt theses and projects
Quaternary mafic volcanism in the western Basin and Range and in the southeastern Sierra Nevada is largely controlled by extensional stresses that promote magma generation through decompression melting of the lithospheric and asthenospheric mantle. Where volcanism occurs in the Sierra Nevada, like at the Golden Trout Volcanic Field GTVF), the eruption rate, number of vents, and eruption volume is an order of magnitude less than at neighboring Basin and Range volcanic fields such as the Big Pine Volcanic Field (BPVF). To determine the factors that cause these differences in adjacent and contemporaneous volcanic fields, I sampled rocks from both fields …
Timing And Source Of Alkali Enrichment At Mt. Etna, Sicily: Constraints From Clinopyroxene Geobarometry And In Situ Sr Isotope Data, Kaitlyn Nelson
Timing And Source Of Alkali Enrichment At Mt. Etna, Sicily: Constraints From Clinopyroxene Geobarometry And In Situ Sr Isotope Data, Kaitlyn Nelson
All Master's Theses
Since 1971, Mt. Etna, Europe’s largest and most active volcano, has exhibited increased eruption frequency and explosivity. Associated with this increased activity, researchers have documented higher abundances of alkali elements (K, Rb, Cs) as well as elevated 87Sr/86Sr in Etnean lavas. The source of this alkali-enrichment has been hotly debated, with end-member hypotheses involving mantle vs. crustal contributions. To further characterize the evolution of the subvolcanic magma storage and transport system, as well as the timing and source of alkali-enrichment, clinopyroxene from ten samples erupted between 1329 and 2004 was targeted for in situ textural, major element …
Volcanic Evolution Of The Southern Quinn Canyon Range: Implications For Regional Correlation Of Volcanic Units, Christina Emery
Volcanic Evolution Of The Southern Quinn Canyon Range: Implications For Regional Correlation Of Volcanic Units, Christina Emery
UNLV Theses, Dissertations, Professional Papers, and Capstones
The southern Quinn Canyon Range lies in an area of the Great Basin subjected to large-volume Oligocene-Miocene silicic volcanism and smaller volume basaltic volcanism during the Pliocene. Three major ash-flow tuff units were correlated in the southern Quinn Canyon Range (the Pahranagat Tuff, Clifford Spring Tuff, and the Cow Canyon Tuff) with regional units by utilizing U/Pb and 40 Ar/ 39Ar geochronology, geochemical correlation, and field mapping. Isotopic analysis suggests that basalt in the southern Quinn Canyon Range is part of the Death Valley-Pancake Range Basalt Zone and is similar to Reveille Range Episode 1 and 2 basalts. Further comparison …
Petrogenesis Of The Linked River Mountains Volcanic Section And Wilson Ridge Pluton, Denise Kelly Honn
Petrogenesis Of The Linked River Mountains Volcanic Section And Wilson Ridge Pluton, Denise Kelly Honn
UNLV Theses, Dissertations, Professional Papers, and Capstones
The River Mountains (RM) volcanic suite and Wilson Ridge pluton (WRP), in the northern Colorado River extensional corridor of southern Nevada and northwestern Arizona, provide an ideal opportunity to investigate one of the most fundamental questions in igneous petrology: Do volcanic rocks erupt from subjacent plutons and do plutons vent to form volcanic fields? The RM volcanic suite (14.47± 0.26 to 12.66 ± 0.54 Ma; uncertainties are 2sigma) consists of a stack of andesite and rhyolite sills beneath a stratovolcano that primarily erupted dacite with lesser volumes of basalt and rhyolite. This volcanic suite is cored by a multiphase quartz …