Geology Commons^™

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 …

Shock Effects Recorded By The U-Pb Radiometric System In Zircons Of Apollo 17 Impact Breccias And By Raman Spectroscopy In Enstatite Meteorites, Bidong Zhang

Electronic Thesis and Dissertation Repository

Impact cratering processes and formations are ubiquitous on the rocky planets within the Solar System. The Earth-Moon system was formed by a massive planetary impact, and numerous impacts afterwards significantly reshaped the topography and lithology of the Moon surface. This dissertation focuses on studying some specific geochemical, geochronological, and geophysical signatures of impact processes preserved in lunar rocks and asteroidal meteorites.

The zircon U-Pb radiometric system is one of the most reliable geochronometers in measuring geological time. Recently, unsupported radiogenic Pb enrichment has been reported to compromise the accuracy and precision of zircon U-Pb geochronometer in terrestrial rocks. In Chapter …

Ni And Fe Isotope Fractionation During Weathering And The Formation Of Ni Laterite Ore Deposits In The Philippines, Congxi Zhu

Electronic Thesis and Dissertation Repository

Weathering processes on Ni-rich ultramafic rocks in tropical areas produce laterites that become exploitable for Ni mining. To better understand these processes, samples were collected stratigraphically with water samples from several Ni mines in the Philippines and studied for Ni and Fe isotope compositions. This study found that Ni isotope fractionation takes place during the formation of Ni-enriched minerals (goethite), when light Ni isotopes are preferentially incorporated into new minerals formed, leaving heavy Ni isotopes in groundwater. The Δ⁶⁰Ni_{Limonite-Bedrock} is up to -0.19 ± 0.32‰. Even though Fe is partitioned with redox state change during these reactions, …

Impact Cratering Processes On The Earth And Moon: Meteorites, Complex Craters, And The Origin Of The Moon, Patrick Hill

Electronic Thesis and Dissertation Repository

This thesis seeks to understand the mechanism of hypervelocity impacts, lunar origin and geology, and stable isotope techniques and its application to lunar material. Three lunar regolith breccias, Dhofar 1673, Dhofar 1983, and Dhofar 1984, were examined. The petrography, mineralogy, isotope chemistry, and bulk chemistry of these meteorites were quantified to investigate their origin. The chemistry of the impact melt rock and bulk chemical analysis suggests sourcing from either the Feldspathic or Outer Feldspathic Highland Terranes. Given the similarities in the meteorites, and the proximal location of each find (within 500 m), this thesis proposes strong evidence for their pairing. …

Enstatite Achondrites As Indicators Of Processes And Environments In The Early Solar System, Diego David Uribe

Electronic Thesis and Dissertation Repository

This thesis investigates the processes and environments of formation of the anomalous enstatite achondrites NWA 4301, Zakłodzie, and NWA 8173 to determine how they relate to other enstatite meteorites (chondrites, impact melt rocks, aubrites, and so-called “primitive enstatite achondrites”). Observations of Zakłodzie and NWA 4301 showed both meteorites may share a common parent body, but experienced different metamorphic conditions. Different zonation patterns in plagioclase, silica polymorphs and associations, and sulfide assemblages indicate Zakłodzie experienced higher metamorphic temperatures and cooled faster than NWA 4301, therefore NWA 4301 was buried deeper in the parent body relative to Zakłodzie. In NWA 8173, mineral …

Crystal Structure And Al/Si Cation Ordering In "Fassaite": A Combined Single Crystal, 27al And 29si Nmr Study, Monika M. Haring

Electronic Thesis and Dissertation Repository

Al-,Ti-rich diopside, referred to herein as fassaite, occurs in both terrestrial and extraterrestrial environments. The composition of fassaite, Ca(Mg,Al)(Si,Al)₂O₆, makes it ideal for Al/Si cation ordering studies. In this study, crystal XRD, ²⁷Al and 29Si MAS NMR as well as ²⁷Al 3QMAS NMR is used to study cation ordering in extraterrestrial fassaite from Allende CAIs and a terrestrial analogue from Fassa Valley Italy. From ²⁷Al and ²⁹Si spectroscopy, fassaite from Allende CAIs is found to have more local Al/Si cation ordering than terrestrial Fassaite. Both terrestrial and extraterrestrial have C2/c …