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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 …

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 ± …

A Survey Of Sierra Nevada Magmatism Using Great Valley Detrital Zircon Trace-Element Geochemistry: View From The Forearc, Kathleen D. Surpless, D. Clemens-Knott, A. P. Barth, M. Gevedon

Kathleen D. Surpless

The well-characterized Sierra Nevada magmatic arc offers an unparalleled opportunity to improve our understanding of continental arc magmatism, but present bedrock exposure provides an incomplete record that is dominated by Cretaceous plutons, making it challenging to decipher details of older magmatism and the dynamic interplay between plutonism and volcanism. Moreover, the forearc detrital record includes abundant zircon formed during apparent magmatic lulls, suggesting that understanding the long-term history of arc magmatism requires integrating plutonic, volcanic, and detrital records. We present trace-element geochemistry of detrital zircon grains from the Great Valley forearc basin to survey Sierra Nevadan arc magmatism through Mesozoic …

Evaluating Zircon Strain Chronometry Of A Grenville Front Deformation Fabric Through Microstructural Analysis And Quartz Piezometry, Kaitlyn Petkau

Electronic Thesis and Dissertation Repository

Zircon strain chronometry can allow correlation of isotopic ages with microstructural fabrics to place an absolute age on the timing of deformation. However, the general applicability of zircon strain chronometry to problems in regional continental tectonics is still being tested and this study is the first effort to apply the approach to the ~1 Ga (billion year old) Grenville Province of the Precambrian Canadian Shield. Samples were analyzed from the 1747 +6/-5 Ma Wanapitei Complex, a poly-deformed mafic metaplutonic body that preserves fabric evidence for several stages in the tectonic history of the Grenville Front. This study is the first …

The Modern Mississippi: Provenance Indicators And Human Impact, Brittney Anne Gregory

LSU Doctoral Dissertations

Given the significant degree to which the modern Mississippi River and its tributaries have been altered through dams, levees, and diversions, it is important to understand how sediment is transported from source to sink. The objective of this dissertation is to explore how the modern Mississippi River transports sediment from its tributaries to its delta using three independent proxies. Provenance indicators have traditionally been an effective way with which to characterize sediment transport in large river systems. First, detrital U-Pb zircon dating is used to investigate modern flux and possible anthropogenic influences on coarse-grained sediment within the modern Mississippi River. …

A Survey Of Sierra Nevada Magmatism Using Great Valley Detrital Zircon Trace-Element Geochemistry: View From The Forearc, Kathleen D. Surpless, D. Clemens-Knott, A. P. Barth, M. Gevedon

Geosciences Faculty Research

The well-characterized Sierra Nevada magmatic arc offers an unparalleled opportunity to improve our understanding of continental arc magmatism, but present bedrock exposure provides an incomplete record that is dominated by Cretaceous plutons, making it challenging to decipher details of older magmatism and the dynamic interplay between plutonism and volcanism. Moreover, the forearc detrital record includes abundant zircon formed during apparent magmatic lulls, suggesting that understanding the long-term history of arc magmatism requires integrating plutonic, volcanic, and detrital records. We present trace-element geochemistry of detrital zircon grains from the Great Valley forearc basin to survey Sierra Nevadan arc magmatism through Mesozoic …

Zircon (U-Th)/He Thermochronologic Investigation Of The Long-Term Thermal History Of Proterozoic Rocks In West Texas And Southern New Mexico, Nathan Zachary Reade

Open Access Theses & Dissertations

The tectonic history of west Texas and southern New Mexico is well documented, however existing geologic data only provide limited snapshots of the region’s prolonged and complex tectonic evolution. Zircon (U-Th)/He (ZHe) thermochronology is used to examine the long-term thermal history of Proterozoic rocks exposed in the southern Rio Grande rift. ZHe data were collected from the Carrizo Mountains (10 dates), Cookes Range (16 dates), and Franklin Mountains (30 dates) in order to constrain the long-term (>1 Ga) thermal history of rocks in this region and relate this history to known tectonic or climatic events. Individual ZHe dates range …

Testing For Sedimentary Recycling Using Detrital Monazite Geochronology, Zircon “Double Dating”, And Textures In Pennsylvanian Arenites Of The Central Appalachian Basin, Eastern Kentucky: Implications For Single Mineral Sedimentary Provenance Analysis, Steve C. Zotto

Theses and Dissertations--Earth and Environmental Sciences

Detrital monazite Th-Pb and detrital zircon U-Pb and U-Th/He double-dating coupled with sandstone petrography and exhumation rates can be used to test for sediment recycling in Pennsylvanian sandstones within the Alleghenian clastic wedge. The Alleghenian clastic wedge is a logical system in which to test for sediment recycling as four major collisional events (Grenville, Taconic, Acadian and Alleghenian orogenies) likely reworked the continental margin and recycled siliciclastic sediment. The combination of these geochronologic and thermochronologic methods provide a more accurate assessment of the proportion of recycled sediment in the Grundy Formation (sublitharenite) and the Corbin Sandstone (quartz arenite), which past …

Application Of Zircon Typology Method To Felsic Rocks (Cappadocia, Central Anatolia, Turkey): A Zircon Crystallization Temperature Perspective, Lütfi̇ye Akin, Erkan Aydar, Axel Karl Schmitt, Hüseyi̇n Evren Çubukçu

Turkish Journal of Earth Sciences

Zircon typology was developed nearly half a century ago as a tool for constraining the thermochemical conditions in granitic magmas from the morphology of zircon prismatic and pyramidal crystal surfaces. Although the method precedes experimentally constrained zircon-based thermometers (zircon saturation, Ti-in-zircon), the morphology of zircon remains an important criterion for zircon studies commonly relying on visual recognition of crystals during sample purification via hand-picking. This may introduce selection bias if morphologically distinct zircon crystals are present in a population. We conducted a comparison between zircon typology and thermochemical constraints from zircon thermometry and whole rock compositions. Therefore, we focused on …

Detrital Zircon Provenance And Correlation Of Two Newly Discovered Ripley Formation Bentonites: Pontotoc County, Mississippi, Elizabeth Jayne Vitale

Electronic Theses and Dissertations

Two newly discovered bentonite deposits in northern and southern Pontotoc County, Mississippi occur in the Upper Cretaceous outcrop in a banded pattern on the northeastern margin of the Mississippi Embayment (MSE). The entire Ripley Formation (Fm) consists of ~73 m of fossiliferous clay, sand, and calcareous sand beds. The bentonites are located stratigraphically within the Chiwapa Sandstone Member (CSM) at the top of the Ripley Fm and stratigraphically lie above previously mined bentonites in central Pontotoc County. Since the northern and southern bentonites differ stratigraphically from the previously mined bentonites, it is possible that there are other unknown bentonite deposits …

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 …

The Origin Of An Archean Batholith In Michigan’S Upper Peninsula, Brandi Petryk

Dissertations, Master's Theses and Master's Reports

The Southern Complex is part of the Archean Superior Province in the Upper Peninsula of Michigan and includes a batholithic sized body of Archean high-K megacrystic granitoid rocks informally called the Bell Creek granite. U-Pb zircon ages of the granitoid from previous studies suggest an emplacement age of ~2.6 Ga (Tinkham, 1997). Based on those ages the Bell Creek granite formed around the Archean-Proterozoic transition. This transition is a crucial time period in Earth’s history for crustal growth because of the onset of subduction and increased sedimentary environments at the end of the Archean (Taylor and McLennan, 1995). In this …