Physical Sciences and Mathematics Commons^™

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 …

Petrology Of The Earliest Cascade Volcanic Units In Washington: The Northcraft, Tukwila, And Rattlesnake Mountain Formations And Implications For The Evolution Of The Cascade Arc, Louisa Cryan, Jeffrey H. Tepper

Summer Research

Cascade arc magmatism began ~45 million years ago, following the reconfiguration of the Farallon-North American subduction zone. This project seeks to classify the path of magmatism throughout the history of the Cascade arc, as well as categorize the earliest expressions of the Cascade arc. Three volcanic units, the Northcraft Formation (NF), Tukwila Formation (TF), and Rattlesnake Mountain Formation (RM) will serve as examples of the earliest Cascades-related lavas. Their categorization by field setting, geochemical characteristics, isotopic data, and age will create a better understanding of how Cascades magmatism began and developed over time.

Analysis has shown these units to contain …

Petrology Of The Eocene Goble Volcanics, Southwest Washington: An Early Phase Of The Cascade Arc, Clara Phipps, Jeffrey H. Tepper

Summer Research

The Eocene Goble Volcanics (GV), comprised of >1000 km² of subaerial lavas and tuffs, are one of the most voluminous igneous formations in SW WA. Whole rock K-Ar ages of 45 to 32 Ma (Beck and Burr, 1979) suggest these rocks are an early expression of the Cascade arc, but their location is anomalous, lying between oceanic Crescent Fm basalts of the Siltezia terrane to the west and younger arc rocks to the east. The goals of this research are to determine the chemical and Sr-Nd isotopic traits of the GV and better establish the tectonic setting in which …

Petrology, Provenance, And Depositional Setting Of The Lower Tallahatta Formation (Meridian Sand) In Grenada County, Mississippi, Husamaldeen Zubi

Electronic Theses and Dissertations

The Meridian Sand represents the lowermost member of the Middle Eocene Tallahatta Formation, which is found in the Gulf Coast region of the United States. Five stratigraphic sections in Grenada County were measured and described. Twenty-one sand and sandstone samples, and 2 mud samples were collected from all sections. Textural analyses were performed on all 23 samples to determine their lithologic properties. Petrographic descriptions and modal analyses were performed on thin sections made from the 21 sand and sandstone samples, and 400 grains were point counted in each sample. Geochemical analyses were carried out on all sand, sandstone, and mud …