Physical Sciences and Mathematics Commons^™

Size, Timing, And Landscape Impacts Of Glacial Lake Outburst Floods In The Channeled Scabland Of Eastern Washington, Usa, Karin E. Lehnigk

Doctoral Dissertations

Extreme floods have dramatically altered landscapes on Earth and Mars through bedrock erosion, sediment deposition, and canyon formation. The Channeled Scabland of the Columbia Plateau in eastern Washington, USA, is perhaps the most striking example of such a landscape, where outburst floods from an ice-dammed glacial Lake Missoula eroded immense canyons and transported large volumes of sediment during the late Pleistocene. Despite advances in numerical modeling and geochemical exposure dating methods, it has remained a challenge to untangle the complex interactions between floodwater, bedrock, and glacial ice to link the size of a flood with its impact on the landscape. …

Meteorite Investigation And Classification, Olivia N. Benest

Undergraduate Student Research Internships Conference

Several meteorites arrive on Earth every day, but only a small percentage of them are found. They are easiest to spot on deserts or frozen ice. Western has a large number of unclassified meteorites found in the Northwest Africa (NWA) and Oman deserts. These meteorites include chondrites, achondrites, irons, and even Lunar and Martian meteorites. Classifying a meteorite requires detailed examination by optical microscopy, as well as micro X-ray diffraction (µXRD), and Electron Probe Microanalysis (EPMA), to observe their mineralogy (metal, oxide, sulfide, and silicate mineral phases), textures (e.g. chondrules, CAIs) and composition, in order to classify their petrologic type …

Halogen And Non-Traditional Isotope Geochemistry Of Planetary And Terrestrial Materials, Anthony Gargano, Zachary Sharp, Justin Simon, Charles Shearer, Adrian Brearley, James Day

Earth and Planetary Sciences ETDs

This dissertation presents the advances in non-traditional isotope geochemistry of planetary and terrestrial materials encompassing chlorine, sulfur, and zinc isotopes, as well as halogen geochemistry. A wide breadth of materials was studied throughout the completion of this work including iron meteorites, achondrites, chondrites, Apollo lunar samples, as well ancient marine chert, and carbonate sediments. Much of the focus involved the development of a method capable of simultaneously measuring the halogen contents and chlorine isotope compositions of geological materials. Here, I present these data sets to broadly characterize the process of devolatilization of planetary materials, and specifically the problem of ‘halogen-poisoning’ …

Early Solar System Chronology And Isotopic Linkage Of Non-Carbonaceous Chondrules, Clasts And Achondrites, Philip M. Reger

Electronic Thesis and Dissertation Repository

Chondrules are ubiquitous igneous spherules, the main constituents of ordinary chondrites, and are considered to be critical building blocks of planetesimals, yet their age and formation mechanism(s) remain debated. Differences between ages determined from the long-lived Pb-Pb and the short-lived ²⁶Al-²⁶Mg chronometers have been attributed to the heterogeneous distribution of ²⁶Al in the solar nebula, a radionuclide that was responsible for early differentiation of planetesimals.

To evaluate this hypothesis, the ²⁶Al-²⁶Mg and the ²⁰⁷Pb-²⁰⁶Pb isotopic compositions were both measured by multi-collector ICP-MS in individual chondrules and igneous clasts in unequilibrated …