Geochemistry Commons^™

Interpretations Of Lava Flow Properties From Radar Remote Sensing Data, Gavin Douglas Tolometti, Catherine Neish, Gordon R. Osinski, Scott S. Hughes, Shannon E. Kobs-Nawotniak

Earth Sciences Publications

The surface morphology and roughness of a lava flow provides insight on its lava properties and emplacement processes. This is essential information for understanding the eruption history of lava fields, and magmatic processes beneath the surface of Earth and other planetary bodies such as the Moon. The surface morphology is influenced by lava properties such as viscosity, temperature, composition, and rate of shear. In this work, we seek to understand how we can interpret the emplacement processes and lava properties of lava flows using remote sensing data. Craters of the Moon (COTM) National Monument and Preserve in Idaho hosts a …

Experimental And Thermodynamic Constraints On Mineral Equilibrium In Pantelleritic Magmas., Pierangelo Romano, Bruno Scaillet, John C. White, Joan Andujar, Ida Di Carlo, Silvio G. Rotolo

EKU Faculty and Staff Scholarship

Crystallization experiments on two pantellerites from Pantelleria, Italy, provide new evidence for the relation-ships between mineral phases in pantelleritic rocks as well as the influence of temperature and redox conditionson mineral assemblages. Experiments were performed at 1 kbar with temperature ranging between 750–900°C,andfluid saturation conditions with XH2O (=H2O/H2O+CO2) between 0 and 1. Redox conditions were fixed at, or slightly below, the FMQ buffer. Results show that at temperature of 900 °C pantelleritic magmas are well above the liquidus regardless their water content; we also observed a decrease in liquidus temperature (800°C) with increasingly reducing conditions. Mineral assemblages of the natural …

Geochemistry Of The Lazufre Volcanic Complex: Determining The Geometries And Processes Of The Magmatic Sources In The Central Andean Volcanic Zone, Brooke Erin Benz

Graduate Theses/Dissertations

The Central Andes in South America contain many active volcanoes and volcano complexes due to constant subduction producing extrusive rocks varying in composition. The Lazufre Complex, Chile-Argentina border, consists of two Pleistocene volcanic centers, Lastarria and Cordon del Azufre andesite and dacite lava flows and domes. Whole-rock K-Ar dates of lavas from Cordon del Azufre place the most recent eruptions at 0.6-0.3 Ma ±0.3 Ma. Major-element data of plagioclase and pyroxene show homogeneous compositions between the centers, which is consistent with whole rock major- and trace-element compositions. The primary composition of the pyroxenes are augite and diopsides for cpx and …

Pumice Compositions And Mineral Chemistry From Lascar Volcano, Chile, Madelaine M. Stearn

Graduate Theses/Dissertations

Lascar volcano is one the most active volcano in the Central Volcanic Zone of the Andean Cordillera, with 36 Holocene eruptions including a VEI 4 eruption in April 1993. Activity has not been consistent throughout time, and therefore, the processes behind it are poorly understood. Lascar volcano has cyclic behavior and has had four stages of activity, each of which had a unique eruptive style and product composition. Stage I (<43 >ka) had primarily mafic andesite lavas erupted effusively from a stratocone. Stage II initiated with dome building events ESE of the original vent and culminated in the 26.45 ka …

Analysis Of Cryptotephra At Whitney Mesa Nature Preserve, Henderson, Nevada, Alex Newsom

Calvert Undergraduate Research Awards

Advanced Undergraduate Winner

Cryptotephra (small volcanic shards ranging 20-80 microns in size) were discovered within Unit X of the Las Vegas Formation at Whitney Mesa Nature Preserve, Henderson, Nevada. Cryptotephra are deposited soon after a volcanic eruption and can be used as a dating tool to create narrow time constraints for surrounding sediments. Cryptotephra have many applications but are mainly useful as a dating tool. Their study has important implications for the understanding of the timing of palaeoclimatological and paleoenvironmental events as well as for archaeological studies to date important events in human history.

The Whitney Mesa cryptotephra were correlated …

Characterization Of Magma Storage And Dynamics At Akutan, Semisopochnoi, And Okmok Volcanoes From Analytical And Numerical Models Of Geodetic, Seismic, And Petrologic Data, Kimberly Degrandpre

Earth Sciences Theses and Dissertations

Volcanic eruptions can cause significant socioeconomic loss, but a better understanding of the processes and dynamics influencing the evolution of volcanic plumbing systems will advance the development of eruption forecasting models that will ultimately mitigate hazards and risks associated with eruptive events. Geologic and geophysical data must be integrated in 3D, finite- element, multiphysical, numerical models to define the coupled evolution of magmatic and crustal stress regimes in volcanic environments, but in data limited regions this is not always an option. The remote nature of the Aleutian Island Arc restricts ground-based monitoring and sampling efforts, and due to sparse temporal …

Geochemical Constraints On Mantle Sources And Basalt Petrogenesis In The Strait Of Sicily Rift Zone (Italy): Insights Into The Importance Of Short Lengthscale Mantle Heterogeneity., John C. White, David A. Neave, Silvio G. Rotolo, Don F. Parker

EKU Faculty and Staff Scholarship

Igneous activity from the late Miocene to historic time (most recently 1891 ce) in the Strait of Sicily has created two islands (Pantelleria and Linosa) and several seamounts. These volcanoes are dominated by transitional (ol+hy-normative) to alkaline (ne-normative) basaltic lavas and scoriae; peralkaline felsic rocks (trachyte-rhyolite) crop out only on Pantelleria. Although most likely erupted through continental crust, basalts demonstrate no evidence of crustal contamination and are geochemically similar to oceanic island basalts (OIB). Despite their isotopic similarities, there are considerable compositional differences with respect to major and trace element geochemistry both between and within the two islands that are …

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 …

Anatomy Of The Magmatic Plumbing System Of Los Humeros Caldera (Mexico): Implications For Geothermal Systems., Federico Lucci, Gerardo Carrasco-Nuñez, Federico Rossetti, Thomas Theye, John C. White, Stefano Urbani, Hossein Azzizi, Yosihiro Asahara, Guido Giordano

EKU Faculty and Staff Scholarship

Understanding the anatomy of magma plumbing systems of active volcanoes is essential not only for unraveling magma dynamics and eruptive behaviors but also to define the geometry, depth, and temperature of the heat sources for geothermal exploration. The Pleistocene–Holocene Los Humeros volcanic complex is part of the eastern Trans- Mexican Volcanic Belt (central Mexico), and it constitutes one of the most important exploited geothermal fields in Mexico with ca. 90MWof produced electricity. With the aim to decipher the anatomy (geometry and structure) of the magmatic plumbing system feeding the geothermal field at Los Humeros, we carried out a field-based petrological …

Geochemical Analysis Of The Chinchín Formation In Southern Ecuador, Katherine Ludwig

Celebration of Learning

The subduction of the Nazca Plate under the South American Plate has led to the uplift of the majority of the Andes Mountains, but in Ecuador, the Nazca Plate subducts underneath the North Andes Plate, which then collides with the South American Plate. This tectonic setting has formed two parallel mountain chains as well as a complex series of basins between them. However, the formations that make up these basins are poorly understood. This study focuses on the Chinchín Formation, an ~3.5 km thick, volcanic formation that serves as the bedrock of the Quingeo Basin in southern Ecuador. This study …

Petrology And Geochemistry Of The Bearwallow Mountain Andesite, Mogollon-Datil Volcanic Field, New Mexico, Conor Lee O'Dowd

Graduate Theses/Dissertations

The Mogollon-Datil volcanic field (MDVF), located in southern New Mexico, is the result of episodic volcanism and the transition between arc and rift magmatism. The MDVF has been the focus of several mapping, stratigraphic, petrologic, geochronological, and geochemical studies to understand the complete volcanic and tectonic history. However, the majority of previous studies lack geochemical analyses on intermediate composition volcanic rocks, giving more attention to the large-volume ignimbrites and rhyolite flows as well as the minor basalt flows that occurred between 36 and 20 Ma. I present new whole-rock major- and trace-element analyses and petrographic textures on one of the …

Petrogenesis Of Off-Axis Lavas Erupted Along The 8˚20’ N Seamount Chain, East Pacific Rise, Molly Kassandra Anderson

Boise State University Theses and Dissertations

Lavas erupted at off-axis seamounts provide a window into mantle heterogeneity and melting systematics that are not easily observed on-axis at fast spreading mid-ocean ridges (MORs). This is because axial melts are efficiently mixed and homogenized within shallow axial magma chambers prior to eruption. To understand the deeper magmatic processes contributing to oceanic crustal formation, we examine the compositions of lavas erupted along a chain of off-axis seamounts, adjacent to the East Pacific Rise (EPR). Essential questions include: (1) What is the range of compositional variability erupted off-axis and how does that compare to lavas erupted on-axis? (2) Is there …

Carbonatites As A Record Of The Carbon Isotope Composition Of Large Igneous Province Outgassing, Ellen Gales

Dissertations and Theses

Large igneous province (LIP) eruptions have been linked in some cases to major perturbations of Earth’s carbon cycle. However, few observations directly constrain the isotopic composition of carbon released by LIP magmas because carbon isotopes fractionate during degassing, which hampers understanding of the relative roles of mantle versus crustal carbon reservoirs. Carbonatite magmatism associated with LIPs provides a unique window into the isotopic systematics of LIP carbon because the majority of carbon in carbonatites crystalizes rather than degassing. Here, we present new δ¹³C data for the Guli carbonatites in the Siberian Traps. In addition, we compile ~260 published …

Quantifying Magma Recharge At Parinacota Volcano, Northern Chile (52 Ka - Recent): Insight From The Magma Chamber Simulator, Jennifer Mcleod

All Master's Theses

The Magma Chamber Simulator (MCS; Bohrson et al., 2014) was used to produce new thermodynamic models that constrain and quantify recharge and fractional crystallization (RFC) processes for the Old Cone (OC; 52-20 ka; 56-66 wt.% SiO₂) and Healing Flows (HF; >8 ka-recent; 58-64 wt.% SiO₂) eruptive stages of Parinacota volcano, northern Chile. Using the MCS, over 200 RFC models were produced that constrain host magma initial conditions, including pressure, fO₂ and H₂O, and host and recharge magma masses, temperatures and compositions. A Rhyolite Domes (RD; 47-40 ka; 74 wt.% SiO₂) …

Volatiles And Trace Element Contents In Melt Inclusions From The Zoned Green Tuff Ignimbrite (Pantelleria, Sicily): Petrological Inferences., Pierangelo Romano, John C. White, Alessandro Ciulla, Ida Di Carlo, Claudia D'Oriano, Patrizia Landi, Silvio G. Rotolo

EKU Faculty and Staff Scholarship

The island of Pantelleria is one of the best known localities of bimodal mafic-felsic magmatism (alkali basalt and trachyte-pantellerite). Among the felsic rocks, the coexistence in a single eruption of products of both trachyte and pantellerite compositions is limited to few occurrences, the Green Tuff (GT) ignimbrite being one of these. The GT is compositionally zoned from pantellerite (70.1 wt% SiO2, mol Na+K/Al = 1.86, 1871 ppm Zr) at the base to crystal-rich (>30 vol%) comenditic trachyte (63.4 wt% SiO2, mol Na+K/Al = 1.10, 265 ppm Zr) at the top, although the pantellertic compositions dominate the erupted volume. We …

Compositional And Thermodynamic Variability In A Stratified Magma Chamber: Evidence From The Green Tuff Ignimbrite (Pantelleria, Italy)., Katarzyna M. Liszewska, John C. White, Ray Macdonald, Bogusław Bagiński

EKU Faculty and Staff Scholarship

The Green Tuff Ignimbrite, Pantelleria, is compositionally zoned from pantellerite at the base to comenditic trachyte at the top, the variation apparently representing an inverted vertical zonation in the pre-eruptive reservoir. The main phenocryst assemblages are alkali feldspar + olivine + clinopyroxene + ilmenite + apatite in the trachytes and alkali feldspar + aenigmatite + clinopyroxene + quartz in the rhyolites. Thermodynamic modelling indicates that the temperature range was ~900–700°C, fO2 FMQ –1.5 to FMQ –0.5 (where FMQ is fayalite–magnetite–quartz buffer) and aSiO2 (relative to quartz saturation) 0.74–1.00. Melt water contents ranged from ~1wt % in the trachytes to ~4wt …

Interpreting The Origin And Evolution Of ‘Karst’ Features From A Siliceous Hydrothermal Terrane: A Case Study From The Upper Geyser Basin In Yellowstone National Park, Usa, Kevin W. Blackwood, Lainee A. Sanders, Stacy I. Gantt-Blackwood

International Journal of Speleology

The Upper Geyser Basin in Yellowstone National Park occurs over a siliceous hydrothermal terrane containing numerous hot springs and geysers. The pool and vent-conduit geometries of these hydrothermal features share a resemblance to conventional karst features known from other rock types, suggesting karst processes could be responsible for their origin and/or evolution. Hypogene speleogenesis is a cave-forming process in which the formation of caves is decoupled from and occurs independently of surface recharge. The geologic setting for hypogene speleogenesis typically occurs at the distal end of regional groundwater systems wherein the hydrogeology is manifested by ascending fluids and/or by geochemical …

Volcanic Glass As A Paleoenvironmental Proxy: Comparing Preparation Methods On Ashes From The Lee Of The Cascade Range In Oregon, Usa, Tessa Boe Carlson

Dissertations and Theses

Deuterium ratios (δD) of hydrated volcanic glass have been used to reconstruct paleoenvironments, although the reliability and proper sample preparation protocol have been debated. In this study, hydrated volcanic ash samples from the lee of the Cascades were prepared using two separate methods. Method 1 involves sonicating and rinsing samples with hydrochloric acid (HCl) followed by hand-selection of glass shards (125-212µm). Method 2 requires hydrochloric acid (HCl) and hydrofluoric acid (HF) abrasion as well as heavy liquid separation of shards (70-150µm). Method 2 produced more consistent results with decreased intra-replicate variability in both water content (-0.92 wt. %) and deuterium …

Extremely High Diversity Of Sulfate Minerals In Caves Of The Irazú Volcano (Costa Rica) Related To Crater Lake And Fumarolic Activity, Andrés Ulloa, Fernando Gázquez, Aurelio Sanz-Arranz, Jesús Medina, Fernando Rull, José María Calaforra, Guillermo E. Alvarado, María Martínez, Geoffroy Avard, J. Maarten De Moor, Jo De Waele

International Journal of Speleology

The caves of the Irazú volcano (Costa Rica), became accessible after the partial collapse of the NW sector of the Irazú volcano in 1994, offering the opportunity to investigate active minerogenetic processes in volcanic cave environments. We performed a detailed mineralogical and geochemical study of speleothems in the caves Cueva los Minerales and Cueva Los Mucolitos, both located in the northwest foothills of the main crater. Mineralogical analyses included X-ray diffraction (XRD) and Raman spectroscopy, while geochemical characterization used Energy Dispersive X-ray spectroscopy (EDX) coupled to Scanning Electron Microscopy (SEM). In addition, measurements of environmental parameters in the caves, …

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 …

Giant Plagioclase In The Steens Basalt, Se Oregon: Cumulate Entrainment Revealed By Textural And In Situ Chemical Analysis, Conner H. Toth

All Master's Theses

Many of the lava flows comprising the Steens Basalt in SE Oregon, the oldest and most mafic formation of the Columbia River Basalt Group (CRBG), contain exceptionally large (up to 5 cm) and abundant (up to 40 modal %) plagioclase crystals. This thesis presents a model for giant plagioclase formation in a complex system that integrates petrographic and in situ plagioclase compositional analyses with whole-rock data and computational modeling to explain systematic textural and chemical differences between plagioclase of the lower and upper Steens Basalt sub-sections. Lower Steens plagioclase are typically more chemically homogenous than upper Steens plagioclase and exhibit …

Quantifying Crustal Assimilation In Historical To Recent (1329-2005) Lavas At Mt. Etna, Italy: Insights From Thermodynamic Modeling, Marie Takach

All Master's Theses

The nearly continuous volcanic eruption record at Mt. Etna dating back approximately 700 years provides an excellent opportunity to investigate the geochemical evolution of a highly active volcano. Of particular interest is elucidating the cause of a selective enrichment in alkali elements (K, Rb, Cs) and ⁸⁷Sr/⁸⁶Sr. This alkali enrichment trend, which began in the 17^th century and accelerated after 1971, was accompanied by an increase in the volume, frequency, and explosivity of eruptions. To explain this enrichment, two major arguments are invoked: (1) crustal contributions (e.g., assimilation of the sedimentary basement), and (2) changes in …

Tuhualite In A Peralkaline Rhyolitic Ignimbrite From Pantelleria, Italy, Boguslaw Baginski, Ray Macdonald, John C. White, Lidia Jezak

EKU Faculty and Staff Scholarship

An occurrence of the rare mineral tuhualite (NaFe3+Fe2+Si6O15) is reported in a peralkaline rhyolitic ignimbrite from the 11 island of Pantelleria, Italy. The mineral formed during devitrification of glassy fiamme and varies in form from anhedral plates to 12 perfect euhedral in open vesicles. There is significant replacement of Fe2+ by Mn (FMQ in the presence of a 14 hydrous fluid.

40ar/39ar Ages And Zircon Petrochronology For The Rear Arc Of The Izu-Bonin-Marianas Intra-Oceanic Subduction Zone, Graham Dm Andrews

Faculty & Staff Scholarship

Long-lived intra-oceanic arcs of Izu-Bonin-Marianas (IBM)-type are built on thick, granodioritic crust formed in the absence of pre-existing continental crust. International Ocean Discovery Program Expedition 350, Site U1437, explored the IBM rear arc to better understand continental crust formation in arcs. Detailed petrochronological (U–Pb geochronology combined with trace elements, oxygen and hafnium isotopes) characterizations of zircon from Site U1437 were carried out, taking care to exclude potential contaminants by (1) comparison of zircon ages with ship-board palaeomagnetic and biostratigraphic ages and 40Ar/39Ar geochronology, (2) analysing zircon from drill muds for comparison, (3) selectively carrying out in situ analysis in petrographic …

Conduction Plus Convection Heat Flow Modeling For The Linga Complex, Peruvian Coastal Batholith, Luciano Uriel González Olivares

Loma Linda University Electronic Theses, Dissertations & Projects

Factors affecting the thermal evolution of the Linga magmatic intrusion in the Ica-Pisco area of the Peruvian Coastal Batholith were studied using field work, petrography, geochemistry data, and computer modeling. Field work and petrography involved collecting samples for geochemical analysis and documenting widespread propylitic and potassic hydrothermal alteration. Major element geochemistry was used to estimate rock density, viscosity, liquidus temperature, and water content. The δ18O values of seven fresh samples showed a slightly increasing west-east and old-young trend of approximately 7-8‰, indicating an increasing crustal component. The δ18O and δD values for eleven altered samples indicated that alteration came mostly …

The Dynamic Relationship Between The Bear River, Quaternary Basaltic Center, Normal Faults, And The Resulting Rearrangement Of Rivers In The Northeast Edge Of The Great Basin, Southeast Idaho, Brady Utley

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

The objective of this research project in Gem Valley graben, southeast Idaho is to identify the location, age and history of the Quaternary diversion of the Bear River into paleo-Lake Thatcher, and then into the Lake Bonneville basin from the Columbia River basin. Mapping, geochemical analysis, cross-cutting relationships, and five new age determinations, together with prior published research, shed new light on the complex history of interaction between the volcanic rocks, rivers, lakes, and faults in Gem Valley. Research goals were to test the hypothesis that local faulting and volcanism drove the diversion of the Bear River and controlled the …

Magmatic Hydrothermal Alteration And Secondary Post-Shock Features In Martian Olivine-Phyric Basalt Northwest Africa 10416; Petrology And Geochemistry Of Primitive Achondrite Northwest Africa 11042, Zoltan Vaci

Earth and Planetary Sciences ETDs

The Martian olivine-phyric basalt Northwest Africa (NWA) 10416 contains large olivine xenocrysts whose cores have been stained brown by hydrothermal alteration and whose rims are composed of pristine olivine overgrowths. Microanalysis of these olivine cores reveals various degrees of amorphization, some of which have been overprinted by terrestrial weathering, evident as part of a weathering rind along the exposed surface of the meteorite. Studies of a completely unweathered terrestrial analogue basalt from southern Colorado reveal similar features and indicate that both basalts were altered in a supersolidus magma chamber setting. The alteration features in NWA 10416 thus imply the presence …

Petrography And Geochemistry Of Oligocene Rhyolitic Volcanic Rocks, Western Mogollon-Datil Volcanic Field, New Mexico, Emily Elizabeth Salings

Graduate Theses/Dissertations

The Mogollon-Datil volcanic field (MDVF), located in southern New Mexico, is the remnant of extreme and punctuated volcanism over ~12 m.y. of activity. The Bursum caldera is the youngest of three nested calderas in the Mogollon Mountains in the western MDVF. Here I present data from a high-silica, large volume tuff associated with the Bursum caldera, the Bloodgood Canyon Tuff (BCT). Extensive mapping by previous workers have provided a limited whole rock geochemical dataset and descriptions of the unit, but a detailed study had not been conducted. I present new whole-rock major- and trace-element analyses, Sr, Nd, and Pb isotope …

Geochronology Of Calc-Alkaline Ash Flow Tuff Units In The Ogollon Datil Volcanic Field, Southern New Mexico: U-Pb In Zircon, Shannon Porter Rentz

Graduate Theses/Dissertations

Caldera systems are capable of outputting voluminous quantities of volcaniclastic material with wide ranging negative environmental impacts. Determining the behaviors of previously erupted caldera systems may help inform predictive models used to evaluate hazards and assess risks for analogous currently active volcanic systems. The Mogollon-Datil volcanic field (MDVF) is a 40-24 Ma cluster of caldera activity in southern New Mexico tied to the subduction, and possible delamination, of the Farallon plate beneath the North American plate. A regional ignimbrite flare up from 36-24 Ma produced at least 28 caldera-forming eruptions. The calc-alkaline magmatism of three calderas in this field (the …

Timing Of Speleogenesis Of Las Karmidas Cave (Mexico): First Description Of Pseudokarst Developed In Ignimbrite, María Del Pilar Aliaga-Campuzano, Rafael López-Martínez, Pablo Dávila-Harris, Ramón Espinasa-Pereña, Adriana Espino Del Castillo, J.P. Bernal

International Journal of Speleology

Las Karmidas Cave (Puebla State, Mexico) is an unusual type of pseudokarstic cavity generated by piping and erosive processes within the contact of a diamicton and an overlying Quaternary ignimbrite. Morphological evidence suggests that the cave was developed in two stages: a phreatic stage and a vadose stage. The latter was characterized by the formation of carbonate speleothems. The absolute upper-age limit for the cave (168 +7.1/-7.5 ka) was established by U-Th dating of zircons grains extracted from the overlying ignimbrite, whilst a minimum age for the transition from a phreatic to vadose regime (95.6 ± 2.1 ka) was constrained …