Geochemistry Commons^™

Using A Novel Chain Of Chemical, Crystallographic, And Isotopic Analytical Techniques To Examine The Formation Histories Of Features In Chondritic Meteorites And Orbicular Granites, Samuel P. Alpert

Dissertations, Theses, and Capstone Projects

Understanding the chemistry, crystallography, and isotopic variability of minerals allows us to place significant constraints on the formation history of their host rocks. These constraints provide insight into everything from the distribution of water in the solar system to the onset of plate tectonics. Electron beam instruments and ion probes are important tools used by modern geologists to obtain crystallographic, chemical, and isotopic data. Here I present a new workflow, using these instruments, combining wavelength dispersive spectrometry (WDS), backscattered electron (BSE) imaging, machine learning algorithms, electron backscatter diffraction (EBSD), and secondary ion mass spectroscopy (SIMS), to place quantitative constraints on …

Petrologic And Geochemical Constraints On The Pre-Eruptive Storage Conditions Of Magmas Erupted During The ~12.5 Ka Flare Up Of Medicine Lake Volcano, Ca, Regina M. Khoury

Cal Poly Humboldt theses and projects

The Medicine Lake Volcano (MLV) system in the California Cascades is composed of a large shield volcano with numerous basaltic to rhyolitic vents on and around the flanks, many of which are aligned with N-S trending normal faults. A significant portion of the post-glacial volcanic activity at MLV is comprised of the ~12.5 ka “flare up” eruptions of basalt and basaltic andesite magmas from seven discrete flank vents. Prior work documented surface areas (0.02-198 km²), volumes (0.0001-4.35 km³), and eruption styles (Hawaiian to Strombolian; Donnelly-Nolan, 2010) of the ~12.5 ka deposits. This study uses new geologic …

Untangling The Nature And Timescales Of Magmatic Processes Driving Eruptions At Quiescent Volcanoes: Examples From Momotombo, Nicaragua, And Cumbre Vieja, Canary Islands, Samantha Tramontano

Dissertations, Theses, and Capstone Projects

Across all scales of human relationships (i.e. person-to-person, country-to-country, etc.), qualms can take the form of long-standing wars, quick and intense bouts, or petty exchanges. While our understanding of human behavior is ever increasing, reactions and behaviors of self and others may still come as a surprise. Expressions of disagreement can occur suddenly or following years to centuries of accumulated grievances. The solid earth is also a system that behaves (like human emotion) predictably at times and unpredictably at other times. Some volcanoes, a tangible surface expression of solid earth processes, exhibit precursory signals prior to eruption (e.g. the bulging …

Magmatic Evolution Of The Chasca Orkho Lava Series And Its Magmatic Enclaves, Volcán Ollagüe, Central Andes, Nathaniel W. Lenhard

Graduate Theses/Dissertations

Magma mixing is a common factor in the creation of intermediate composition magmas and a potential instigator of a volcanic eruption. Magmatic enclaves, physical evidence of magma mixing within a volcanic system, are a phenomenon whose mechanisms remain unclear and debated. Common hypotheses explaining the occurrence of magmatic enclaves within a host lava range from the repeated injection of a new magma into a shallow reservoir to the disruption of equilibrium within a stratified magma chamber. Within the Andean Central Volcanic Zone (CVZ), the occurrence of magmatic enclaves yields similar geochemical compositions to their respective host rocks, bringing more difficulty …

Petrological And Geochemical Evaluation Of Rare-Earth Element Potential In The Sparta Granite Complex, Max J. Eshbaugh

Honors College Theses

Rare earth elements (REEs) are important resources with applications in the electronics, renewable energy, and automotive industries. REEs may be concentrated in the residual weathered portion of igneous parent rocks, typically granites. These residual deposits are mined in southeast Asia, but analogous climatic and geologic conditions suggest the existence of economically viable REE residual deposits in the southeastern United States (U.S.). The Sparta Granite Complex in east-central Georgia is a granitoid complex emplaced at the end of the Alleghanian orogeny, forming a suture between the Savannah River and Milledgeville terranes. Petrologic and geochemical assessments of the Sparta Granite and overlying …

Petrology And Geochemistry Of Evolved Achondrites: Planetesimal Mantles And Crusts, Zoltan Vaci

Earth and Planetary Sciences ETDs

Melting and differentiation are fundamental to early solar system evolution on planetary bodies that accreted enough material to heat up radioactively or through impacts and breach their solidi. Partially and fully melted material is present in the meteorite record in the form of primitive achondrites and achondrites, which are fragments of planetesimals that underwent heating events in the first few million years of solar system history. Although the vast majority of this material is mafic or ultramafic, new evolved samples, recovered in the last few decades, are pushing the petrologic and geochemical boundaries of planetesimal melting, differentiation, and crust formation. …

Frozen In Time: A Numerical Modeling Approach To The Study Of Ice Bearing Planetesimals Through Carbonaceous Chondrites, Jasmine M. Bayron

Dissertations, Theses, and Capstone Projects

Icy planetesimals are significant objects of study for meteoritics, planetary science, and astrobiology due to their connections to the origins of life and liquid water on Earth. An existing closed system aqueous alteration model was adapted to simulate several scenarios involving early Solar System geologic processes occurring in an icy planetesimal interior. The model described in this work has been developed not only to test the validity of constraints currently thought to apply to CM1 parent bodies, but to directly compare the implications of these constraints for the isotopic composition and the modal mineralogy of carbonaceous chondrites. Isotopic ratios of …

Multiple Generations Of Phlogopite In An Alnöite Diatreme: Insights Into The Petrogenesis Of The Avon Alkaline Igneous Province, Missouri, Nathan Gregory Limbaugh

Masters Theses

“Alkaline Ultramafic Carbonatite (AUC) complexes, although rare, are valued for diamonds and REEs, and as windows into subcontinental and mantle processes as recorded by rock fabrics, mineral spatial relationships, and mineral compositions. We report specifically on olivine and phlogopite petrographic relationships and compositions from the Devonian alnoite diatreme-facies of the Avon Alkaline Igneous Province, Missouri. The diatreme alnoite is a mixture of domains of olivine magmaclasts (OM) set in a crystal-rich melilite matrix. OM are highly fractured, serpentinized olivine pseudomorphs with variable amounts of pristine olivine fragments. Larger olivine domains typically exhibit clear crystal faces and irregular “channels” indicative of …

Petrogenesis And Tectonic Implications Of Cordierite-Orthoamphibole Gneisses (Cog) In The Nw Wyoming Province, Brianna K. Crenshaw Ms

Graduate Student Theses, Dissertations, & Professional Papers

Studying cordierite orthoamphibole gneisses (COG) from five different mountain ranges across the Montana Metasedimentary Terrane (MMT) of the Wyoming Province offers a unique opportunity to elucidate the enigmatic origins and petrogenesis of the lithology in addition to gaining a further understanding of Precambrian crustal assembly processes. Geochemical analyses suggest that COG originates from a basalt that underwent metasomatic alteration, likely via seawater, prior to metamorphism. Moreover, COG is considered to represent oceanic crust that was part of the epicontinental sea adjacent to the Wyoming Province before collision with the Medicine Hat Block. Field observations of associated lithologies such as marbles, …

Provenance And Maximum Depositional Age Analysis Of The Moenave Formation Using Detrital Zircon U-Pb Geochronology And Sandstone Petrography, Asher Rea Boudreaux

Graduate Theses and Dissertations

In southwestern Utah and northeastern Arizona, Moenave Formation (latest Triassic(?)-Jurassic) is bracketed by well-studied Mesozoic units extensively sampled for detrital zircon geochronology and is poorly documented in regard to provenance, representing an important gap in knowledge. The Moenave Formation provides a unique opportunity to employ detrital zircon U-Pb geochronology and sandstone petrography relevant to completing the paleogeographic, evolutionary, and climatic story of the region. This study aims to characterize the sedimentary provenance of the Moenave Formation and to identify, or at least improve constraints on, the stratigraphic position of the Triassic-Jurassic boundary (TJB) and placement of the end-Triassic extinction (ETE), …

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 …

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 …

Archived Rock Samples From Jane Selverstone's Research Collection, Jane Selverstone

Earth and Planetary Sciences Faculty and Staff Publications

This Excel spreadsheet lists all of the rock samples from Jane Selverstone's research collection that have been archived into the Earth and Planetary Sciences Collections at the University of New Mexico. All samples are listed by original (published) sample number and by an affiliated International GeoSample Number. Samples are grouped by research project, and doi information is given for all publications resulting from work on each project. Rock samples include various combinations of hand specimens, powders, thin sections, and billets from which thin sections were prepared. Information is included to identify the drawers within which each sample can be found …

Record Of Massive Upwellings From The Pacific Large Low Shear Velocity Province, Pilar Madrigal, Esteban Gazel, Kennet E. Flores, Michael Bizimis, Brian Jicha

Faculty Publications

Large igneous provinces, as the surface expression of deep mantle processes, play a key role in the evolution of the planet. Here we analyse the geochemical record and timing of the Pacific Ocean Large Igneous Provinces and preserved accreted terranes to reconstruct the history of pulses of mantle plume upwellings and their relation with a deep-rooted source like the Pacific large low-shear velocity Province during the Mid-Jurassic to Upper Cretaceous. Petrological modelling and geochemical data suggest the need of interaction between these deep-rooted upwellings and mid-ocean ridges in pulses separated by ∼10–20 Ma, to generate the massive volumes of melt …

Geochemical And Petrological Characterizations Of Peridotite And Related Rocks In Marquette County, Michigan, Andrew Lloyd Sasso

Masters Theses

This study characterizes the following rock units in Marquette County, Michigan in terms of geochemistry and petrology: (1) Presque Isle Peridotite, (2) Deer Lake Peridotite, (3) Yellowdog Peridotite, and (4) Black Rock Point Gabbro. Analyses were conducted to determine if any petrological or geochemical relationships exist between these units, and to assess the potential of these units to host magmatic sulfide deposits.

The generated data and chosen geotectonic proxies indicate that Black Rock Point Gabbro and Deer Lake Peridotite crystallized from unrelated magmas, probably during the formation of the Great Lakes Tectonic Zone (2.7-1.85 Ga). No evidence was found which …

Avon Alkaline Igneous Province, Missouri: Characterization Of Subcontinental Mantle Source And Evolution Via Chemical Analysis Of Olivine, Zachary William Freeman

Masters Theses

"This article presents the crystallization age of, and composition of olivine phenocrysts within an alnoite of, the Avon Alkaline Igneous Province (AAIP) of Ste. Genevieve County, Missouri. The AAIP is an ultramafic igneous province consisting of approx. 80 known intrusives of diverse lithology and texture. ⁴⁰Ar/³⁹ Ar geochronology indicates an emplacement age of 386 +/- 1 Ma, which establishes the AAIP as the only known Devonian-age ultramafic igneous body in the Midwestern U.S. Study of the AAIP provides a unique opportunity to characterize the Devonian-age subcontinental mantle and the processes that generated the suite of ultramafic rocks present …

Enriched Continental Flood Basalts From Depleted Mantle Melts: Modeling The Lithospheric Contamination Of Karoo Lavas From Antarctica, Jussi S. Heinonen, Arto V. Luttinen, Wendy A. Bohrson

All Faculty Scholarship for the College of the Sciences

Continental flood basalts (CFBs) represent large-scale melting events in the Earth’s upper mantle and show considerable geochemical heterogeneity that is typically linked to substantial contribution from underlying continental lithosphere. Large-scale partial melting of the cold subcontinental lithospheric mantle and the large amounts of crustal contamination suggested by traditional binary mixing or assimilation-fractional crystallization models are difficult to reconcile with the thermal and compositional characteristics of continental lithosphere, however. The well-exposed CFBs of Vestfjella, western Dronning Maud Land, Antarctica, belong to the Jurassic Karoo large igneous province and provide a prime locality to quantify mass contributions of lithospheric and sublithospheric sources …

Petrogenesis Of The Greenwater Range: Comparison To The Crater Flat Volcanic Field And Implications For Hazard Assessment, Ashley Kaye Tibbetts

UNLV Theses, Dissertations, Professional Papers, and Capstones

Pliocene basalts of the Greenwater Range, California erupted from 24 volcanic vents now represented by volcanic plugs, craters and scoria mounds. Basaltic magmas originated in the asthenospheric mantle, but show evidence of a lithospheric component. Depths and temperatures of melting calculated using a silica activity geobarometer are 54.3–89.6 km and 1367-1435oC, placing melting in the asthenosphere. The preferred petrogenetic model involves melting of lithospheric mantle thermally and mechanically, but not chemically, converted to asthenospheric mantle. Melting depths correspond to low velocity zones in the mantle as revealed in seismic profiles. Chemical and lithologic similarities between basalt in the Greenwater Range …

The Petrogenesis Of Andesites Produced During Regional Extension: Examples From The Northern Mccullough Range, Nv And Xitle Volcano, Mexico, Kelly Ann Boland

UNLV Theses, Dissertations, Professional Papers, and Capstones

Andesite dominated volcanic systems produced during regional crustal extension remain a relatively unexplored aspect of andesite petrogenesis. In the southern Basin and Range province, thick sections of andesite and basaltic andesite have been documented in areas including the Piute Range, California, the Eldorado Range, Nevada, and the McCullough Range, Nevada. The northern McCullough Range, located 20 miles south-southeast of Las Vegas, is an ideal place to study the petrogenesis of an andesite dominated system. This area contains a mid-Miocene stratocone composed mainly of a 1200 m thick section of andesite flows that formed synchronous with regional extension.

The northern McCullough …

Mining In Maine : Past, Present, And Future, Carolyn A. Lepage

Maine Collection

Mining in Maine : Past, Present, and Future

by Carolyn A. Lepage, Michael E. Foley, and Woodrow B. Thompson

Maine Geological Survey, Department of Conservation, Augusta, Me., 1990.

Contents: Introduction / The Early Years: Pre-Civil War / The Civil War to World War II / The War Years of the 1940's / The Postwar Years: 1940's to 1960 / The 1960's / The 1970's / Maine Mineral Resources Association / The 1980's / Current Mining and Exploration / Future Potential / Acknowledgments / References

Petrology And Major Element Geochemistry Of Basaltic Glasses From The Blanco Trough, Northeast Pacific, Glenn A. Gaetani

Geology Theses and Dissertations

The original electron microprobe analyses of suite of basaltic glasses recovered in 1968 by W.G. Melson and co-workers from the Blanco Trough have extremely unusual characteristics. Their compositions plot in a region of the normative Ol-Di-Pl-SiO2 tetrahedron which suggests that they represent liquids in equilibrium with an upper mantle assemblage of olivine + orthopyroxene at 10-15 kb. Given the present state of controversy surrounding the composition and depth of origin of primary MORB, natural examples of such liquids would be very important. The major element variations observed in the suite imply that the dominant phases are olivine and an iron-aluminum …

Petrology And Mineral Chemistry Of Some Jan Mayen Volcanics, Carla A. White

Geology Theses and Dissertations

The island of Jan Mayen is the northernmost active volcano on the Mid-Atlantic Ridge. The rocks of Jan Mayen belong to the potassic series of the alkaline rocks and appear to belong to the straddle type association. The ankaramites and alkali olivine basalts are characterized by the presence of large xenocrysts of rimmed chromium diopside, titaniferous salite, olivine (Fo83 to Fo88), magnetite and sometimes plagioclase (bytownite rimmed by labradorite). Phenocrysts of olivine (Fo74) and plagioclase (andesine) are present in several rocks. These and phenocrysts lie in a matrix composed of` titaniferous salite, olivine (Fo58), plagioclase (andesine), magnetite, biotite and sometimes …

Petrology Of The Oceanographer Fracture Zone (35ºn35ºw), Tsugio Shibata

Geology Theses and Dissertations

During a geological and geophysical survey of the Oceanographer Fracture Zone (35°N, 35°W), seventeen dredge hauls containing a variety of rocks were obtained. Petrographic study shows that these rock samples can be classified into six main rock types: fresh basalt, weathered basalt, metabasalt, gabbro, metagabbro, and serpentinite. Most of the dredge hauls were positioned on the steep, southern wall of the fracture zone, and an inference from the dredging results suggests that basalt is the most abundant rock type which outcrops at the junction between the rift valley and the fracture zone; however, as we move away from the junction, …

Petrology Of The Nemeiben Lake Ultramafic And Associated Nickel-Sulphide Deposits, Anantaramam Peddada

Geology Theses and Dissertations

The Nemeiben Lake ultramafic body is located in the center of Saskatchewan, Canada, within the Churchill Province of the Canadian Shield. The ultramafic rocks consist of serpentinites, partly serpentinized and uralitized pyroxenite, and unaltered pyroxenite. Associated sulphide mineralization is of disseminated, net texture, and fracture filling types. The ore minerals present are pyrrhotite, pentlandite, chalcopyrite, pyrite, marcasite, violarite, bravoite and native copper. The sulphides are considered to be initially of magmatic origin formed from a sulphide melt separated at a late stage during crystallization of the ultramafic rocks. Subsequent serpentinization has locally redistributed the ores.
Serpentinization in the Nemeiben Lake …

A Detailed Economic Investigation Of Geochemical And Aeromagnetic Anomalies North Central Maine, W. F. Stickney, R. S. Young, L. A. Wing

Maine Collection

A Detailed Economic Investigation of Geochemical and Aeromagnetic Anomalies North Central Maine

W.F.Stickney, R.S.Young and L.A.Wing

Special Economic Series No.4, Maine Geological Survey, Department of Economic Development, Augusta, Maine (March 1965).

Contents: Foreword / Part I - Geology (W.F. Stickney) / Part II - Geophysics (R.S. Young) / Part III - Geochemistry (L.A. Wing) / References

Genetic Study Of Some Pyrrhotite Deposits Of Maine And New Brunswick, Dept. Of Development Of Industry And Commerce

Maine Collection

Genetic Study of Some Pyrrhotite Deposits of Maine and New Brunswick

by Robert S. Houston

Maine Geological Survey - Bulletin 7

Department of Development of Industry and Commerce, Augusta, Maine (January, 1956).

Contents: Abstract / Introduction / Field and Laboratory Studies / Regional Geography / Regional Geology / Pyrrhotite Deposits / Description of Individual Deposits / Literature Cited

Report Of The State Geologist 1953-1954, Maine Geological Survey

Maine Collection

Report of the State Geologist 1953-1954.

Maine Geological Survey - Maine Development Commission, Augusta, Maine - July 1955.

Contents: Joseph M. Trefethen -- Review of Maine Mineral Outlook / Henry W. Allen -- Limestone Investigations, 1953-54 / Wm.T. Forsyth -- Airbourne Magnetometer Survey in Eastern Maine / Gary M. Boone -- Petrology of the Farmington, Maine Area / Joseph M. Trefethen, Henry Allen, and Wm. T. Forsyth -- Scheelite Occurrences in Maine / Wm.T. Forsyth -- Beneficiation Tests on the Warren Sillimanite Gneiss / Wm. T. Forsyth -- Pyrrhotite Mineralization at Iron Hill, Gardiner, Maine / Joseph M. Trefethen -- …

Maine Geological Survey - Bulletin 6 : Pegmatites And Associated Rocks In The Newry Hill Area, Oxford County, Maine., Vincent E. Shainin, Louis F. Dellwig

Maine Collection

Maine Geological Survey - Bulletin 6 : Pegmatites and Associated Rocks in the Newry Hill Area, Oxford County, Maine.

Joseph M. Trefethen, State Geologist.

by Vincent E. Shainin, University of Maine and Louis F. Dellwig, U.S. Geological Survey.

Maine Development Commission, Augusta, Maine, 1955

Report Of The State Geologist 1951-1952, Maine Geological Survey

Maine Collection

Report of the State Geologist 1951-1952.

Maine Geological Survey - Maine Development Commission, Augusta, Maine - December, 1953.

Contents: Joseph M. Trefethen -- New England Mineral Resources / Henry Allen -- Progress Report of Limestone Survey, Knox County / Wm. Forsyth -- Mineralogical Variations of the Ellsworth Schist in Blue Hill, Maine / Lawrence A. Wing -- Preliminary Report on Eastern Maine Granites / Kern Jackson -- A Preliminary Report on the Geology of a Portion of the Rumford Quadrangle, Maine / Robert M. Zink -- Certain Aspects of the Ecology of Venus and Mya at Bunganuc and at Morgan …

Report Of The State Geologist 1947-1948, Maine Geological Survey

Maine Collection

Report of the State Geologist 1947-1948.

Maine Geological Survey - Maine Development Commission, Augusta, Maine - March 1949.

Contents: Activity of the Maine Geological Survey, 1947-48 / Joseph M. Trefethen -- Review of the Aroostook County Manganese Deposits / Joseph M. Trefethen -- Notes on Ground Water Conditions in Maine / Joseph M. Trefethen -- The Desert of Maine / Henry Allen and Elbert Pratt -- Reconnaissance Surveys of Limestones in Franklin County, Maine / Lawrence Wing and Arthur Dawson -- Preliminary Report on Asbestos and Associated Rocks of Northwestern Maine / Lawrence Goldthwait -- Clay Survey 1948 / Earl …