Physical Sciences and Mathematics Commons^™

Late Neoarchean To Middle Paleoproterozoic Geology Of Devon And Ellesmere Islands, Canadian Arctic, Joshua P. Laughton

Electronic Thesis and Dissertation Repository

The northernmost exposure of the Laurentian shield in Canada outcrops on Devon and Ellesmere islands within the Canadian Arctic Archipelago. Due to the remote location, the basement rocks of these islands have received little attention. From this study, zircon crystallization ages demonstrate that Devon Island is underlain by a late Neoarchean terrane comprising orthogneisses emplaced at ca. 2.55–2.51 Ga and an interleaved metasedimentary sequence deposited at ca. ≥2.47 Ga. On northern Devon Island, younger metasedimentary sequence(s) were deposited at ca. 2.2–1.9 Ga and intruded by ca. 2.01–1.95 Ga granitoids. Devon and Ellesmere islands experienced widespread metamorphic activity associated with the …

U-Pb Zircon Geochronology And Structure Of Regional Blueschist Units In The Easton Metamorphic Suite, Northwest Cascades, Wa, Katherine Lang

WWU Graduate School Collection

The Easton metamorphic suite of the Northwest Cascades Thrust System (NWCS) is a well-preserved subduction accretion complex in Washington State. The regional blueschist units of the Easton metamorphic suite include the Mt. Josephine semi-schist, Darrington Phyllite, and Shuksan greenschist/blueschist and all are interpreted to have accreted after the onset of Jurassic subduction beneath North America. This study uses zircon U-Pb geochronology, structure, and field observations to test the regional correlations between units in the Easton metamorphic suite and address models for the timing of subduction accretion along the North American margin in the Late Jurassic – Early Cretaceous. The results …

Pleistocene Deposits Of Lower Wahweap Creek And Its Tributaries, Southern Utah, Noah Slade

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The famous landscapes of the Colorado Plateau have been created over millions of years, primarily by erosive forces of wind and water. Interruptions in the long-term erosion of the landscape occur when streams gain more sediment than they can transport, which causes deposition along channels and floodplains. The resulting sequences of terrace deposits are used by geologists to study when and how river systems have evolved.

Mammoth bones were recently discovered in stream deposits along Wahweap Creek, a tributary of the Colorado River in southern Utah. Previous work indicates that the deposits pre-date the last ice age, making it one …

Petrochronology And Statistical Analysis To Integrate Different Types Of Data To Solve Complex Earth Systems Problems, Claire Ostwald Harrigan

Boise State University Theses and Dissertations

Complex Earth systems problems, like reconstructing orogens and calibrating the geologic time scale, require investigations that link time to geologic processes. To use time as a means of organizing geologic evidence, geochronometric dates must be contextualized by integrating with different data types. This is the work of petrochronology—linking mineral ages to geochemical, textural, or other geologic information. The U-Pb isotopic system as preserved in the minerals zircon (ZrSiO₄) and titanite (CaTiSiO₅) can be used in a petrochronological context to date geologic events including the age of granitoid pluton emplacement, the age of rock fabric formation in …

Geology Of The Jacksonville 7.5 Minute Quadrangle And U–Pb And (U–Th)/He Reveal Sediment Routing And Uplift In The Southern Appalachian Valley And Ridge Province, Derek L. Spurgeon

MSU Graduate Theses

The southern Appalachian Mountains have experienced multiple deformation events having undergone two full Wilson cycles. The foreland Valley and Ridge province is composed of sedimentary Paleozoic rock that range in age from earliest Cambrian to Middle Pennsylvanian. This sedimentary basin was intensely folded and faulted during the collision of Gondwana during the Middle to Late Carboniferous Period. From previous geologic structural mapping that has taken place, some large-scale structures in the Valley and Ridge Province seem to be out of sequence. To better understand the relationships in these structures, geologic mapping in high detail at the 1:24,000 scale coupled with …

U-Pb Apatite Chronometry Of Intrusions In An Accretionary Metamorphic Belt In Western Idaho, Usa, Colleen Grace Rankin

MSU Graduate Theses

The Salmon River suture zone in west-central Idaho, USA records the tectonic processes where island arcs, similar to modern-day Japan, were accreted to the North American continent in the Jurassic and Cretaceous periods (160-90 million years ago). This suture zone contains metamorphic rocks that were buried deep within the crust at depths of 20 kilometers or more and have subsequently been brought to the surface. The exhuming processes responsible for the metamorphic rocks in the Salmon River suture zone remains unclear. Two competing hypotheses have been proposed to explain the transport of the rocks from the Salmon River suture zone …

Disequilibrium Melting Of The Continental Crust During Emplacement Of The Mt. Princeton Batholith, Central Colorado Volcanic Field, Loren A. Bohannon

MSU Graduate Theses

Assimilation and crystallization are difficult to constrain at magmatic boundaries, including the interactions of magma with the surrounding country rock. The assumption of the relationship between a magma and what it is intruding upon is relegated to homogenous bodies or epizonal plutons. Realistically, wall rock influences chemical heterogeneity and isotopic variance at the outcrop scale and changes depending on distance from the magma-wall rock interface. Here, we present a case study of the 35 Ma Mt. Princeton Batholith and the host Precambrian rocks of the Central Colorado Volcanic Field. We assess chemical heterogeneity by whole rock and mineral trace element …

Chemical And Thermal Influence On Intermediate Magma Storage Conditions: Volcán Ollagüe, Chile-Bolivia, Central Andes, Drew Allen Laviada-Garmon

MSU Graduate Theses

Continental arc volcanoes are the single best portrayal of the evolution of recycled earth material stemming from subduction, one of the most important and foundational phenomena in global tectonics. Understanding the genesis of intermediate-composition magmas produced at arc volcanoes is a difficult process making them a focal point for investigation. Geochemical investigation of zircon and plagioclase mineral phases erupted from continental arcs can provide insight into magma process, generation, storage conditions, timescales and differentiation of sub-volcanic plumbing systems prior to eruption events. The Central Volcanic Zone is a prime example of continental arc volcanism through subduction, and is host to …

Reconstructing The Transition From Laramide Contraction To Rio Grande Rift Extension, Aaron Conley

Open Access Theses & Dissertations

Exposure of tilted Eocene-Oligocene volcanic and sedimentary units unconformably overlying folded and thrusted Mesozoic rocks in the southern Indio Mountains provide an important geologic record of the transition from Laramide contraction to Rio Grande rift extension. Detailed geologic mapping and cross-section reconstruction combined with sedimentary analysis and geo/thermochronologic methods are used to test the hypothesis that Laramide contractional structures and post-Laramide topography focused ignimbrite and sedimentary deposition within two paleovalleys located in the northwest and northeast portions of the study area. Laramide deformation in the study area is confined to Mesozoic units and includes a series of low-angle thrust faults …

The Birth And Incision History Of The San Juan River In The Past 5 Ma, Micael T. Albonico

Earth and Planetary Sciences ETDs

This study addresses the evolution of the San Juan River system and its confluence with the Colorado River, ~ 100 km above the regionally important Lees Ferry knickzone. The San Juan River is a 600-km-long continental-scale tributary of the Colorado River. From its headwaters in the San Juan Mountains in Colorado, the San Juan River flows across the Colorado Plateau, and into the Colorado River upstream of Grand Canyon. Published apatite fission track and apatite (U-Th)/He thermochronologic data show that rocks in Marble Canyon, as well as in middle and upper reaches of the San Juan River, were >75 °C …

Geology And Lithogeochemistry Of The Pickett Mountain Volcanogenic Massive Sulfide Deposit, Northern Maine, Michael J. Mccormick

Electronic Theses and Dissertations

The Pickett Mountain deposit is a volcanogenic massive sulfide (VMS) base-metal deposit located 15 miles north of Patten, ME. The deposit, discovered in 1979, was abandoned in 1989. The deposit remained abandoned until 2017, when Wolfden Mt. Chase LLC purchased the land for further development after Maine mining regulations changed. This project is a collaboration between the University of Maine, the University of Maine – Presque Isle, Wolfden Resources Corp., and the University of New Brunswick to better understand the regional and deposit-scale geology related to the deposit to fill in gaps of the geologic story of northern Maine as …

Evidence For Middle Miocene Elevated Topography Isolating The Southern Klamath Mountains Province: A U-Pb & Lu-Hf Detrital Zircon Study Of The Weaverville Formation, Dana J. Christensen

Cal Poly Humboldt theses and projects

The Klamath Mountains Province (KMP) records a robust history of active North American margin tectonics and crustal growth through the subduction-accretion of oceanic and island-arc terranes spanning Devonian through Cretaceous time. However, preservation of Cenozoic rocks is minimal, rendering the geologic record, topography, and tectonics during this timeframe difficult to reconstruct. The only Miocene terrestrial sedimentary unit that exists in the KMP is the fluvially deposited Tertiary Weaverville Formation (Tw) that is preserved in five fault-bounded basins in the southern part of the province. This study presents new uranium-lead (U-Pb) age data and epsilon hafnium (εHf) isotopic ratios from detrital …

Crustal Evolution Of The New England Appalachians: The Rise And Fall Of A Long-Lived Orogenic Plateau, Ian Hillenbrand

Masters Theses

The rise and demise of mountain belts, caused by growth, modification, or removal of the continental lithosphere are fundamental processes that influence almost all Earth systems. Understanding the nature, timing, and significance of active processes in the creation and evolution of modern mountain belts is challenged by a lack of middle crustal and lower crustal exposures. Analogues can be found in ancient orogens, whose deeply eroded roots offer a window into deeper processes, yet this record is complicated by overprinting events and complex deformational histories. Research presented herein constrains the tectonic history of multistage Appalachian Orogen, type locality of the …

Sedimentology, Sequence Stratigraphy, And High-Precision U-Pb Age Constraints On The Late Paleozoic Ansilta Formation, Calingasta-Uspallata Basin, Nw Argentina, John Ethan Malone

Theses and Dissertations

The Ansilta Formation, located several kilometers east of the Astronomical Observatory El Leoncito near Barreal, San Juan Province, Argentina was deposited during the late Mississippian to early Pennsylvanian. This succession includes glacimarine, nearshore, and fluvial systems deposited at the mid-Carboniferous portion of the late Paleozoic ice age within the Calingasta—Uspallata Basin on the western margin of the Protoprecordillera. The lower member of the Ansilta Formation is equivalent to the nearby Leoncito, Majaditas, and Hoyada Verde formations, and is composed of diamictite, conglomerates, sandstones, pebbly mudstones, and laminated mudstone. Glacial environments are unique in that facies changes occur as a result …

Early Meteoritic Records Of Asteroidal Melt And Impact Environments, Brendt Hyde

Electronic Thesis and Dissertation Repository

The characterization of meteorites formed in early melt and impact environments helps deepen our understanding of the processes involved in the formation and modification of terrestrial bodies in the solar system. The main objective of this thesis is to interpret and describe a range of igneous and metamorphic environments on asteroidal bodies, through the chemical, microstructural and isotopic analysis of meteorites, and to place these in the context of evolving rocky bodies in the early protoplanetary disk. Study of the meteorite Northwest Africa (NWA) 869 has led to the novel discovery of a eucrite impactor clast in chondritic regolith material. …

Evidence For Polyphase Deformation In The Shear Zones Bounding The Chester And Athens Domes, Southeastern Vermont, From 40ar/39ar Geochronology, Kristin Schnalzer

Graduate College Dissertations and Theses

The Chester and Athens Domes are a composite mantled gneiss dome in southeast Vermont. While debate persists regarding the mechanisms of dome formation, most workers consider the domes to have formed during the Acadian Orogeny. This study integrates the results of 40Ar/39Ar step-heating of single mineral grains, or small multigrain aliquots, with data from microstructural analyses from samples collected in multiple transects across the dome-bounding shear zone(s) in order to understand the relationship between metamorphism and deformation. Results from the sheared units along the north and south transects are presented from west to east. In the north, hornblende from the …

Timing And Conditions Of Metamorphism In The Cascades Crystalline Core From Garnet Lu-Hf And Sm-Nd Geochronology, Peter Baker

WWU Graduate School Collection

The Chiwaukum Schist and Tonga Formation of Cascades Crystalline Core experienced three distinct metamorphic events: (M1) an early metamorphism that predates regional pluton emplacement, (M2) low-pressure contact metamorphism in the aureoles of the Mount Stuart batholith and Beckler Peak pluton, and (M3) regional Barrovian metamorphism. The timing of these distinct metamorphic events is critical to testing models for the tectonic evolution of the region and mechanisms that lead to burial of rocks within the orogen. I present new garnet Lu-Hf and Sm-Nd isochrons, average pressure and temperature calculations, and pseudosection modeling from the Chiwaukum Schist and Tonga Formation in order …

Reinterpreting The Tectonic Model Of The Southern Part Of The Taconic Orogeny Through A Provenance Study Of Late Ordovician Sandstones, Juan Carlos Guerrero

LSU Master's Theses

A provenance study of quartz arenites that stratigraphically are closely associated with major Ordovician K-bentonites has been conducted in order to further our understanding of the tectonic setting of eastern Laurentia during the Late Ordovician. Using laser ablation ICP-MS, detrital zircons separated from Ordovician sandstone samples in the southeastern Appalachian Mountains (Virginia to Alabama) were dated using U-Pb geochronology. Analytical results show three dominate age ranges for the zircons from these sandstones: ~440-490 Ma, ~900-1300 Ma, and ~1300-1500 Ma. In addition, some zircon ages grouped into older ranges of ~1600-1800 Ma, ~1800-1900 Ma, and ~2600-2800 Ma. Zircon ages from ~900-2800 …

In-Situ Zircon And Monazite Geochronology From Compositionally Distinct Layers In A Single Migmatitic Paragneiss Sample Located In The Eastern Adirondack Mountains, Ny, Kaitlyn Suarez

Masters Theses

Migmatites are a common rock type in the Adirondack Mountains, NY. We analyzed a single sample of biotite-garnet-sillimanite paragneiss with foliation parallel leucosome along Route 22 south of Whitehall, NY in order to determine the timing of melting using both in-situ monazite and zircon U/Pb geochronology from the restite and leucosome layers of the same rock. Monazite was analyzed via in-situ EMPA on the Ultrachron microprobe at the University of Massachusetts. Zircon was analyzed via LA-ICP-MS (in-situ and mounted mineral separates) at the LaserChron Center. Monazite analyses from the restite yielded six compositionally distinct populations with dates of 1178 ± …

Petrogenesis Of The El Rechuelos Rhyolite, Jemez Mountains Volcanic Field, New Mexico, Usa, Kelsy Jo Konkright

UNLV Theses, Dissertations, Professional Papers, and Capstones

The El Rechuelos Rhyolite represents volcanic activity preceding the multiple caldera collapse events of the Jemez Mountains volcanic field (JMVF) in northern New Mexico. This study focuses on seven rhyolitic units clustered north of the Valles caldera. These units have been studied in order to interpret their relationships to one another and the eruptive history of the JMVF. Additionally, this study adds to the research on the relationships between effusive and explosive rhyolitic volcanism, and understanding how caldera-forming eruptions develop from silicic systems.

Limited previous research includes K/Ar dates and a few inconsistent 40Ar/39Ar dates, in addition to whole rock …

High-Resolution Investigation Of Event Driven Sedimentation: Response And Evolution Of The Deepwater Horizon Blowout In The Sedimentary System, Rebekka A. Larson

USF Tampa Graduate Theses and Dissertations

This Dissertation combines the investigation of the sedimentological impacts of the Deepwater Horizon (DwH) blowout event in the deep-sea benthos, with the refinement and advancement of methods and approaches for high-resolution investigations of events preserved in sedimentary records. An approach that combined, rapid collection of cores, a continued annual time series collection of cores, and high-resolution sampling and analyses, in particular short-lived Radioisotopes (SLRad), enabled the temporal resolution required to detect the sedimentary response to the short-duration DwH event, and evaluate post-event sedimentation patterns at a comparable time scale (months).

The collection of 179 sediment cores from 80 sites between …

Late Devonian Sedimentary Record Of Appalachian Tectonics And Erosion: Geochronology And Geochemistry Of Detrital Muscovite And Zircon From Central Pennsylvania Strata, Cole T. Gardner

Honors Theses

Foreland basin sediment deposition in North-Central Pennsylvania during Late Devonian time records erosion of hinterland source terranes exhumed during regional plate convergence, including the collisional Acadian orogeny. The Catskill clastic wedge preserves a coarsening-upwards stratigraphic succession from marine to fluvial environments associated with sediment progradation and sea-level regression, yet depositional timescales and quantitative provenance data are largely unconstrained.

Detailed facies analysis of eight outcrops spanning >2 km of stratigraphy in Lycoming Co., Pennsylvania documents distinct upsection changes, interpreted to reflect changes in depositional environments consistent with previous sedimentology of the Catskill clastic wedge. Stratigraphy displays a transition from nearshore marine …

Evaluating Stable Isotope And Geochronologic Techniques For Paleoclimate Reconstruction: Case Study Of The Santa Cruz Formation, Argentina, Robin B. Trayler

Boise State University Theses and Dissertations

Stable isotope analysis has become the method of choice for many studies investigating the paleoecology and paleoclimate of fossil mammal faunas. While organic tissues (collagen, keratins, proteins) persist for < 10⁵ years highly mineralized tooth enamel is resistant to alteration and degradation and faithfully preserves its isotopic composition for millions (> 10⁶) years. Reconstructing past climates from these records relies on both understanding both micro-scale mechanisms of isotope incorporation into individual teeth, and macro-scale changes in isotope compositions over hundreds of thousands or millions of years. In this dissertation I address three questions.

First, how does the geometry and …

Geochronologic Constraints On The Timing Of Metamorphism And Exhumation Of The Tillotson Peak Complex In Northern Vermont, Cheyne Aiken

Graduate College Dissertations and Theses

The Tillotson Peak Complex (TPC) in northern Vermont records high-pressure (HP) subduction zone metamorphism that occurred during the Ordovician Taconic Orogeny, and subsequent retrograde metamorphism and deformation that occurred during the Silurian Salinic Orogeny. Previous studies have documented a polymetamorphic history, with peak metamorphic pressures possibly up to 2.5 GPa and temperatures of 550°C. Prior to this research, constraints on the timing of metamorphism in the TPC were limited to a single Middle Ordovician 40Ar/39Ar total fusion age for glaucophane. This study integrates 40Ar/39Ar step heating analyses of multiple mineral phases and U-Pb dating of titanite with field and microstructural …

In Situ Dating Of Multiple Events In Granulite-Facies Rocks Of The Larsemann Hills, Prydz Bay, East Antarctica Using Electron Microprobe Analysis Of Monazite, Steven K. Spreitzer

Electronic Theses and Dissertations

The metamorphic rocks exposed along the southeast coast of Prydz Bay were affected by several metamorphic and plutonic events associated with collision in the Neoproterozoic and Cambrian. Critical units exposed in the Larsemann Hills and nearby ice-free areas include (1) basement Søstrene Orthogneiss, (2) cover sequence Brattstrand Paragneiss and (3) anatectic pegmatites intrusive into the Brattstrand Paragneiss. Zircon U-Pb data from previous studies yielded a maximum depositional age of 1023 ± 19 Ma for the Brattstrand Paragneiss, but only approximate ca. 900 Ma to ca. 1000 Ma and ca. 530 Ma ages for two metamorphic events. In order to constrain …

Investigations On The Mesozoic Geologic And Tectonic History Of The Jackson Mountains, Northwest Nevada, Thomas Anthony Colby

Boise State University Theses and Dissertations

New geologic mapping, high-precision U-Pb zircon geochronology, and isotope geochemistry provide insight into the early Mesozoic paleogeography and magmatic, stratigraphic, and structural evolution of the Jackson Mountains in the Black Rock Desert region of northwest Nevada. The magmatic history of the Jackson Mountains records Late Triassic to Early Jurassic (~215-195 Ma) marine deposition of the Boulder Creek Beds adjacent to the arc followed by the Early Jurassic (~193-189 Ma) eruption and emplacement of the Happy Creek Igneous Complex and associated plutons of the Early Mesozoic Intrusive Suite. Pb, Sr, and Nd isotopic data from Early Jurassic intrusive rocks of the …

Geochronology Of The Tectonic, Stratigraphic, And Magmatic Evolution Of Neoproterozoic To Early Paleozoic, North American Cordillera And Cryogenian Glaciation, Vincent H. Isakson

Boise State University Theses and Dissertations

Neoproterozoic sedimentary successions contain evidence for some of the most extreme climate fluctuations, breakup of the paleo-supercontinent Rodina, multiple low-latitude global glaciations, and the resultant evolution and radiation of complex life. The stratigraphic record of these events are found on all major continents and have been associated with, in part, global ‘Snowball Earth’ events. However, the understanding and integration of these, and related phenomenon, are limited by disparate and imprecise age constraints that prohibit clear correlation between locations.

This research focused on high-precision geochronology within an integrated framework of sedimentology, stratigraphy, and geochemistry to resolve the timing and duration of …

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

MSU Graduate Theses

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 …

Provenance Analysis Of Granite Cobbles In The Tiskilwa Till Using U -Pb Geochronology, Paul Antone Meister

Theses and Dissertations

U-Pb isotopic ages were determined for zircons extracted from granitic and related rocks in the Tiskilwa till to determine their origin. Crystalline cobbles (n = 750) were collected at localities from each of the four of the sub-lobes of the terminal Wisconsin moraines. Two sites were chosen from the Decatur, Peoria, and Princeton sub-lobes with one sample taken from the Harvard sub-lobe. Each sample was then individually processed, the zircons handpicked (n = 301), and geochronology conducted using LA-MC-ICPMS at the University of Arizona Laserchron Center. A Kolmogorov-Smirnov (K-S) statistical analysis show that all samples have identical zircon age spectra …

Birth And Evolution Of The Rio Grande Fluvial System In The Last 8 Ma:Progressive Downward Integration And Interplay Between Tectonics, Volcanism, Climate, And River Evolution, Marisa N. Repasch

Earth and Planetary Sciences ETDs

The Rio Grande-Rio Chama (RG-RC) fluvial system has evolved dramatically over the last 8 Ma, undergoing channel migrations, drainage capture and integration events, volcanic damming, and carving and refilling of paleocanyons. Volcanism concurrent with the development of the river system provides a unique opportunity to apply multiple geochronometers to the study of its incision and drainage evolution. This paper reports 19 new ⁴⁰Ar/³⁹Ar basalt ages and 19 detrital mineral samples (zircon and sanidine) collected from RG-RC alluvium overlain by dated basalt flows in the context of a compilation of published ⁴⁰Ar/³⁹Ar basalt ages. The …