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Physical Sciences and Mathematics Commons

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Geology

Brigham Young University

Theses/Dissertations

Ignimbrite

Publication Year

Articles 1 - 3 of 3

Full-Text Articles in Physical Sciences and Mathematics

Cooling Before Super-Eruption: No Role For Rejuvenation In The Cottonwood Wash Tuff Magma Body, Southern Great Basin Ignimbrite Province, Utah And Nevada, Keryn Tobler Ross Dec 2015

Cooling Before Super-Eruption: No Role For Rejuvenation In The Cottonwood Wash Tuff Magma Body, Southern Great Basin Ignimbrite Province, Utah And Nevada, Keryn Tobler Ross

Theses and Dissertations

The model of rejuvenation of a near-solidus crystal mush to produce large volumes of crystal-rich magma is tested here by analyzing the mineralogical, chemical, modal, and physical characteristics of the 31.1 Ma super-eruptive (2000 km3) Cottonwood Wash Tuff. It is the oldest in a series of three so-called "monotonous intermediate" ignimbrites from the Indian Peak-Caliente volcanic field in southern Utah and Nevada. A crystal-rich (~50% Pl > Qz ≈ Hbl ≈ Bt > Mag ≈ Ilm > Cpx + Zrn + Ap+ Po) dacite (62 - 69 wt% SiO2), the Cottonwood Wash Tuff is similar in age, volume, mineralogy, crystallinity, and elemental composition …


Cooling Before Super-Eruption: No Role For Rejuvenation In The Cottonwood Wash Tuff Magma Body, Southern Great Basin Ignimbrite Province, Utah And Nevada, Keryn Tobler Ross Dec 2015

Cooling Before Super-Eruption: No Role For Rejuvenation In The Cottonwood Wash Tuff Magma Body, Southern Great Basin Ignimbrite Province, Utah And Nevada, Keryn Tobler Ross

Theses and Dissertations

The model of rejuvenation of a near-solidus crystal mush to produce large volumes of crystal-rich magma is tested here by analyzing the mineralogical, chemical, modal, and physical characteristics of the 31.1 Ma super-eruptive (2000 km3) Cottonwood Wash Tuff. It is the oldest in a series of three so-called “monotonous intermediate” ignimbrites from the Indian Peak-Caliente volcanic field in southern Utah and Nevada. A crystal-rich (~50% Pl > Qz ≈ Hbl ≈ Bt > Mag ≈ Ilm > Cpx + Zrn + Ap+ Po) dacite (62 – 69 wt% SiO2), the Cottonwood Wash Tuff is similar in age, volume, mineralogy, crystallinity, and elemental composition …


Exploring Connections Between A Very Large Volume Ignimbrite And An Intracaldera Pluton: Intrusions Related To The Oligocene Wah Wah Springs Tuff, Western Us, Chloe Noelle Skidmore May 2013

Exploring Connections Between A Very Large Volume Ignimbrite And An Intracaldera Pluton: Intrusions Related To The Oligocene Wah Wah Springs Tuff, Western Us, Chloe Noelle Skidmore

Theses and Dissertations

The Wah Wah Springs Tuff and the Wah Wah Springs Intrusive Granodiorite Porphyry(Wah Wah Springs Intrusion) both originated from the Indian Peak caldera complex, which wasa major focus of explosive silicic activity in the middle Cenozoic Great Basin ignimbrite flareup. This caldera formed 30.0 Ma when an estimated 5,900 km3 of crystal-rich dacitic magma erupted to create the Wah Wah Springs Tuff. The Wah Wah Springs Intrusion later intruded the tuff, causing resurgence of the caldera. Field, modal, and geochemical evidence suggest the tuff and intrusion are cogenetic. The mineral assemblages of the two rocks are similar: both include similar …