Physical Sciences and Mathematics Commons^™

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 …

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 …

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 …

Age, Provenance, And Structure Of The Weatherby Formation, Eastern Izee Sub-Basin, Blue Mountains Province, Oregon And Idaho, Bryant Douglas Ware

Boise State University Theses and Dissertations

The terranes of the Blue Mountains province of eastern Oregon and west-central Idaho provide an important link between the geology of the North American Cordillera exposed in Canada and Alaska in the north and Nevada and California in the south. The Izee basin is a volcanic-rich sedimentary sequence onlapping the volcanic arc and accretionary mélange terranes of the Blue Mountains, and comprises the marine flysch Weatherby Formation at its eastern extent. This study sought to establish the stratigraphic and structural relationships between the Weatherby Formation and the proximal Baker and Olds Ferry terranes. Small-scale mapping, structural measurements, and geochronological data …

Geochemical, Isotopic, And U-Pb Geochronologic Investigations Of Intrusive Basement Rocks From The Wallowa And Olds Ferry Arc Terranes, Blue Mountains Province, Oregon-Idaho, Gene Alan Kurz

Boise State University Theses and Dissertations

Late Paleozoic to Mesozoic arc terranes comprising the Blue Mountains Province of northeastern Oregon and western Idaho are poorly understood in terms of the timing and duration of recorded magmatism and deformation. Intrusive basement rocks of the Wallowa and Olds Ferry arc terranes are investigated using a combination of highprecision U-Pb geochronology, radiogenic isotope and trace element geochemistry, and structural geology to help constrain their tectonomagmatic evolution and to provide a better understanding for the accretionary history of the Blue Mountains Province.

The Cougar Creek Complex is a compositionally diverse intrusive complex interpreted as the mid-crustal portion of the Wallowa …

Internal Structure And Geochronology Of The Gerrei Unit In The Flumendosa Area, Variscan External Nappe Zone, Sardinia, Italy, Ashley V. Dack

Boise State University Theses and Dissertations

To investigate the stratigraphy and structural evolution of the Variscan Orogen of the External Nappe Zone, Sardinia, Italy, field work and geochronologic analyses were combined to assess both regional and orogen scale issues. Geologic mapping, structural analysis, and sampling in the Flumendosa area coupled with high-precision U-Pb zircon geochronology were used to determine the duration of Ordovician magmatic activity and the structural evolution of the Variscan Orogen.

To constrain the duration of magmatism for the Flumendosa area, U-Pb ID/TIMS zircon analyses were performed on samples from a lower volcanic flow of the Ordovician Volcanic Unit and an upper, syn to …