Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 31

Full-Text Articles in Physical Sciences and Mathematics

Thermochronology And Exhumation Dynamics Of Metamorphic Units In The Salmon River Suture Zone, Jonathan J. Cone Jan 2024

Thermochronology And Exhumation Dynamics Of Metamorphic Units In The Salmon River Suture Zone, Jonathan J. Cone

MSU Graduate Theses

The Salmon River suture zone in western Idaho records the Jurassic-Cretaceous (160-90 Ma) accretion of amalgamated volcanic arc terranes onto the North American continent. Rocks exposed at the surface record burial to depths of more than 20 kilometers, with unclear drivers for uplift and exhumation. Two competing hypotheses have been proposed to explain the transport of deep crustal rocks to the surface: (1) delamination of a dense lithospheric root resulted in rapid isostatic uplift of the crust and (2) exhumation of crustal blocks along thrust faults. To test these models, I present temperature-time (T-t) paths for mid-crustal metamorphic rocks constructed …


Geology Of The Jacksonville 7.5 Minute Quadrangle And U–Pb And (U–Th)/He Reveal Sediment Routing And Uplift In The Southern Appalachian Valley And Ridge Province, Derek L. Spurgeon Jan 2022

Geology Of The Jacksonville 7.5 Minute Quadrangle And U–Pb And (U–Th)/He Reveal Sediment Routing And Uplift In The Southern Appalachian Valley And Ridge Province, Derek L. Spurgeon

MSU Graduate Theses

The southern Appalachian Mountains have experienced multiple deformation events having undergone two full Wilson cycles. The foreland Valley and Ridge province is composed of sedimentary Paleozoic rock that range in age from earliest Cambrian to Middle Pennsylvanian. This sedimentary basin was intensely folded and faulted during the collision of Gondwana during the Middle to Late Carboniferous Period. From previous geologic structural mapping that has taken place, some large-scale structures in the Valley and Ridge Province seem to be out of sequence. To better understand the relationships in these structures, geologic mapping in high detail at the 1:24,000 scale coupled with …


U-Pb Apatite Chronometry Of Intrusions In An Accretionary Metamorphic Belt In Western Idaho, Usa, Colleen Grace Rankin Jan 2022

U-Pb Apatite Chronometry Of Intrusions In An Accretionary Metamorphic Belt In Western Idaho, Usa, Colleen Grace Rankin

MSU Graduate Theses

The Salmon River suture zone in west-central Idaho, USA records the tectonic processes where island arcs, similar to modern-day Japan, were accreted to the North American continent in the Jurassic and Cretaceous periods (160-90 million years ago). This suture zone contains metamorphic rocks that were buried deep within the crust at depths of 20 kilometers or more and have subsequently been brought to the surface. The exhuming processes responsible for the metamorphic rocks in the Salmon River suture zone remains unclear. Two competing hypotheses have been proposed to explain the transport of the rocks from the Salmon River suture zone …


The Physical Properties Of Volcanic And Impact Melt, Gavin Douglas Tolometti Aug 2021

The Physical Properties Of Volcanic And Impact Melt, Gavin Douglas Tolometti

Electronic Thesis and Dissertation Repository

The emplacement mechanisms of lunar impact melt flows, that form from hypervelocity impact events, have been a subject of debate in the lunar science community, because of their unique physical properties that separate them from other geologic features. Understanding how lunar impact melt flows were emplaced on the surface of the Moon will not only grant us new information about the flow dynamics of impact melt but provide insight into the production and distribution of impact melt and how it built and modified the surfaces of planetary surfaces.

Lunar impact melt flows exhibit surface roughness textures and morphologies that are …


Late Miocene Unroofing Of The Inner Lesser Himalaya Recorded In The Nw Himalaya Foreland Basin, Elise Marie Exnicios Jul 2021

Late Miocene Unroofing Of The Inner Lesser Himalaya Recorded In The Nw Himalaya Foreland Basin, Elise Marie Exnicios

LSU Master's Theses

Testing models that link climate and solid Earth tectonics requires independent erosional, structural and climatic histories. Two well preserved stratigraphic sections of the Himalayan foreland basin are exposed in NW India. The Jawalamukhi (13–5 Ma) and Joginder Nagar sections (21–13 Ma) are dated by magnetostratigraphy and span a period of significant climate change and tectonic evolution. We use detrital zircon U-Pb dating and apatite fission track analyses to reconstruct changes in the patterns of erosion and exhumation in this area from the Early Miocene to Pliocene. The provenance of the foreland sediments shows that since at least ~21 Ma the …


Mesoproterozoic Basement From The Central And Southern Appalachians Reveal High-Temperature Magmatic Conditions And Non-Laurentian Origin Of Earth's Most Zircon Fertile Magmas, Kyle Makovsky May 2021

Mesoproterozoic Basement From The Central And Southern Appalachians Reveal High-Temperature Magmatic Conditions And Non-Laurentian Origin Of Earth's Most Zircon Fertile Magmas, Kyle Makovsky

Dissertations - ALL

The Mesoproterozoic (1.4-0.9 Ga) Grenville Orogeny led to the formation of the supercontinent Rodinia. One unique characteristic of the Grenville Orogeny is that it produced a volumetrically significant amount of zirconium- (Zr) enriched granitoids, evidently more than any period both prior to and after the Grenville. To investigate this further, Mesoproterozoic basement rocks were sampled along the axis of the current Appalachian Mountains from western North Carolina north to southern New York, as well as from the northern Andes in southern Colombia. Zircon was extracted from these rocks to exploit its propensity to incorporate several isotopic tracers useful in determining …


Mesoproterozoic Basement From The Central And Southern Appalachians Reveal High-Temperature Magmatic Conditions And Non-Laurentian Origin Of Earth’S Most Zircon Fertile Magmas, Kyle Makovsky May 2021

Mesoproterozoic Basement From The Central And Southern Appalachians Reveal High-Temperature Magmatic Conditions And Non-Laurentian Origin Of Earth’S Most Zircon Fertile Magmas, Kyle Makovsky

Dissertations - ALL

The Mesoproterozoic (1.4-0.9 Ga) Grenville Orogeny led to the formation of the supercontinent Rodinia. One unique characteristic of the Grenville Orogeny is that it produced a volumetrically significant amount of zirconium- (Zr) enriched granitoids, evidently more than any period both prior to and after the Grenville. To investigate this further, Mesoproterozoic basement rocks were sampled along the axis of the current Appalachian Mountains from western North Carolina north to southern New York, as well as from the northern Andes in southern Colombia. Zircon was extracted from these rocks to exploit its propensity to incorporate several isotopic tracers useful in determining …


Detrital Zircon Petrochronology For Sedimentary Provenance Analysis: Source To Sink Of The Mississippi/Missouri River Drainage Basin, Sage Denali Muttel Aug 2020

Detrital Zircon Petrochronology For Sedimentary Provenance Analysis: Source To Sink Of The Mississippi/Missouri River Drainage Basin, Sage Denali Muttel

MSU Graduate Theses

Detrital petrochronology can provide a detailed look into sedimentary provenance through integrated mineral radioisotopic ages with corresponding mineral chemistry. By combining U-Pb ages and Th/U values of detrital zircon from 13 samples collected from Quaternary sand deposits in the Upper Missouri, Yellowstone, Bighorn, Platte, Kansas, Arkansas, Mississippi, Red and Brazos Rivers, an interpretation of detailed signatures that record evidence of the evolution of the Mississippi/Missouri River drainage and the tectonic events that shaped it were observed. Low Th/U values in zircon correlate temporally to convergent magmatism, whereas, higher and more variable Th/U zircon are coeval with known extensional tectonism. Using …


“The Tale Of 3,000 Zircons”: An Investigation Of Grenville Sedimentation In Amazonia Using U/Pb Detrital Zircon Geochronology, Felicia R. Harris Jan 2020

“The Tale Of 3,000 Zircons”: An Investigation Of Grenville Sedimentation In Amazonia Using U/Pb Detrital Zircon Geochronology, Felicia R. Harris

Theses and Dissertations--Earth and Environmental Sciences

The continental collision between Laurentia and Amazonia that generated Rodinia and the Grenville Orogen is proposed to be one of the largest, hottest and longest-lived orogens in Earth history. Subsequent erosion and weathering led to a mountain range’s worth of sediment recycled into clastic systems across North America, otherwise known as the “Great Grenville Sedimentation Event”. The Sunsas orogeny in Amazonia is correlative to the Grenville in North America and is proposed to be the result of final Rodinian collision at 1200-1000 Ma. Despite the connection between the two ranges and the robust sedimentary record in North America, little work …


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 Sep 2019

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 Aug 2019

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 ± …


Evaluating Zircon Strain Chronometry Of A Grenville Front Deformation Fabric Through Microstructural Analysis And Quartz Piezometry, Kaitlyn Petkau Jun 2019

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 Mar 2019

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. …


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 Jan 2019

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 Jan 2019

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 …


Late Devonian Sedimentary Record Of Appalachian Tectonics And Erosion: Geochronology And Geochemistry Of Detrital Muscovite And Zircon From Central Pennsylvania Strata, Cole T. Gardner Jan 2019

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 …


Detrital Zircon Provenance And Correlation Of Two Newly Discovered Ripley Formation Bentonites: Pontotoc County, Mississippi, Elizabeth Jayne Vitale Jan 2019

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 …


The Origin Of An Archean Batholith In Michigan’S Upper Peninsula, Brandi Petryk Jan 2019

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 …


New Ca-Id-Tims Detrital Zircon Constraints On Middle Neoproterozoic Sedimentary Successions, Southwestern United States, Abigail R. Bullard Dec 2018

New Ca-Id-Tims Detrital Zircon Constraints On Middle Neoproterozoic Sedimentary Successions, Southwestern United States, Abigail R. Bullard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Three related sedimentary successions located in Arizona, Utah, and California were deposited in basins on proto-North America during the early rifting of Rodinia (~780 Mya). Previous detrital zircon U-Pb maximum ages for the units are inexact, making it difficult to piece together what happened at this point in Earth history.

We report better maximum age constraints on these units obtained by subjecting detrital zircons to high-precision CA-ID-TIMS analysis, which provide more exact 206Pb/238U ages. These new data significantly improve the precision for the base of the ChUMP units, with an average age of 775.63 ± 0.27 Ma …


Assessing A Potential Paleothermal Anomaly Near A Salt Wall Using (U-Th)/He Thermochronology And Silica Cementation Analysis, Onion Creek, Utah, Richard Gregory Ness Dec 2016

Assessing A Potential Paleothermal Anomaly Near A Salt Wall Using (U-Th)/He Thermochronology And Silica Cementation Analysis, Onion Creek, Utah, Richard Gregory Ness

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Onion Creek salt wall in Fisher Valley, Utah is an exposed salt structure that lies adjacent to sandstones of the Permian age Cutler Group. The thermal conductivity of salt is two to four times greater than other sedimentary rocks and has been shown to act as a regional conduit for heat flow which has implications for petroleum systems in hydrocarbon exploration. Numerical models predict that thermal anomalies should extend 1.5 times the radius of a salt structure into adjacent strata. I hypothesized that an elevated paleothermal anomaly exists in sandstones of the Cutler Group where they are located near …


Microstructural Geochronology Of Zircon Across The Central Uplift Of The Vredefort Impact Structure, South Africa, Connor Lawrence Davis Sep 2016

Microstructural Geochronology Of Zircon Across The Central Uplift Of The Vredefort Impact Structure, South Africa, Connor Lawrence Davis

Electronic Thesis and Dissertation Repository

The Vredefort central uplift, or ‘dome,’ represents the erosional remnant of one of the largest (~300 km diameter) and oldest (~2.020 Ga) terrestrial impact structures. This investigation was performed to help elucidate the complexity of the shock process on zircon, incorporating various electron beam methods, including BSE and SE imaging, EBSD, CL, and EDS (mapping and semi-quantitative compositional analysis). A new shock microstructural progression in terrestrial zircon is suggested, as well as a complete structure-wide analysis of impact melt inclusions in zircon. Regional trends in the effects of shock on zircon are included. Impact melt glass inclusion compositions vary widely, …


Strength Study Of Zircon Under High Pressure, Ievgeniia Morozova Jun 2015

Strength Study Of Zircon Under High Pressure, Ievgeniia Morozova

Electronic Thesis and Dissertation Repository

Zircon (ZrSiO4) is a strong accessory mineral that can retain U, Th and Hf within its structure. This makes zircon an important material in geochemical and geochronological studies. In addition, the strong thermal shock resistance of zircon allows for dating the formations of melt and impact events and to separate shocked and potentially shocked country rocks. However, the deformation mechanism and microstructure behavior of zircon at high pressure is poorly understood. Therefore, this work aims to study the deformation and texture of zircon in situ at high pressure and room temperature, and also to examine the microstructure of …


The Lithotectonic Setting And Paragenetic History Of Deposit No.1, Mary River District, North Baffin Island, Sean A. Fulcher May 2015

The Lithotectonic Setting And Paragenetic History Of Deposit No.1, Mary River District, North Baffin Island, Sean A. Fulcher

Electronic Thesis and Dissertation Repository

Baffinland Iron Mines Corporation is currently extracting the highest grade BIF-hosted direct shipping iron ore in the world from their flagship Deposit No.1 on north Baffin Island. This deposit and several other prospects are hosted within the isoclinally folded Mary River Group, a Neoarchean greenstone belt terrane hosting Algoma-type BIF, ultramafics volcaniclastics and sediment. Mary River Group supracrustals are juxtaposed against Mesoarchean basement gneisses due to a regional Transhudson Orogen overprint, forming a regional dome-keel tectonic framework.

Detail mapping and core logging of Deposit No.1 combined with geochemistry and geochronology reveal the footwall rocks, previously interpreted as gneisses, volcanics and …


Radon Loss From Zircon: Effects Of Microstructure On Radon Emanation And Diffusion, Marty Eakin Jan 2014

Radon Loss From Zircon: Effects Of Microstructure On Radon Emanation And Diffusion, Marty Eakin

Wayne State University Theses

Radon emanation from rocks and minerals is ubiquitous, but the mechanisms of radon loss are not well understood. Quantification of radon emanation rates from zircon has potential bearing on the reliability of U-Pb ages of zircon bearing rocks. The 238U decay chain includes 222Rn, a noble gas, which has a half-life of 3.82 days and can escape from the crystal structure of zircon if sufficient pathways exist, or by recoil if the parent 238U was very near the outer edge of the crystal. Loss of 222Rn ultimately leads to a deficiency of 206Pb, resulting in discordance between 238U-206Pb, 235U-207Pb, and …


Application Of Detrital Zircon Geochronology To Determine The Sedimentary Provenance Of The Middle Bloyd Sandstone, Arkoma Shelf, Northern Arkansas, Greg Michael Buratowski Jan 2014

Application Of Detrital Zircon Geochronology To Determine The Sedimentary Provenance Of The Middle Bloyd Sandstone, Arkoma Shelf, Northern Arkansas, Greg Michael Buratowski

Graduate Theses and Dissertations

The sedimentary provenance of the middle Bloyd sandstone and subsequent sediment transport and dispersal patterns of the Early Pennsylvanian were interpreted by utilizing U-Pb detrital zircon geochronology. Eight middle Bloyd sandstone samples were analyzed. A total of 855 concordant analyses resulted. Peaks occurred at 350-500 Ma, 950-1200 Ma, 1300-1500 Ma, 1800-2300 Ma, and >2500 Ma. These peaks were determined to represent crystalline source rocks on the Laurentian craton from Acadian-Taconic, Grenville, Midcontinent Granite-Rhyolite, Yavapai-Mazatzal, Paleoproterozoic, and Archean Superior Provinces respectively. Grenville age zircons were the most common zircons identified in the middle Bloyd sandstone samples. The Appalachian Mountain region is …


Mapping And Zircon Geochronology Of The Lyon Inlet Boundary Zone, Nunavut; A Crustal Scale Break In The Churchill Province, Nikolas B. Ganderton Apr 2013

Mapping And Zircon Geochronology Of The Lyon Inlet Boundary Zone, Nunavut; A Crustal Scale Break In The Churchill Province, Nikolas B. Ganderton

Electronic Thesis and Dissertation Repository

An important aspect of geology is the understanding of processes that created and modified continents and their resources. Knowledge of the age of formation and metamorphism of crystalline crust is thus important, and has been pursued in a recently discovered crustal-scale boundary on the southern Melville Peninsula (Nunavut, Canada) through field mapping, U-Pb zircon geochronology and electron beam analysis. This >250km-long crustal feature is termed here the Lyon Inlet Boundary Zone (LIBZ). Three samples from a 15 by 20 km map area reveal a complex Archean history with the dominant granitoid unit crystallizing at 2770±38 Ma and metamorphosed at 2670±36 …


In-Situ, Integrated U-Pb, Hf And O Isotopic Study Of Igneous, Metamorphic And Detrital Zircons. Implications To Crustal Evolution And Geodynamics, Munazzam Ali Mahar Jan 2013

In-Situ, Integrated U-Pb, Hf And O Isotopic Study Of Igneous, Metamorphic And Detrital Zircons. Implications To Crustal Evolution And Geodynamics, Munazzam Ali Mahar

Open Access Theses & Dissertations

Zircon data from South Karakoram gneiss dome provide evidence for Proterozoic inherited cores (1.8-1.9 Ga and 2.3-.2.5 Ga) surrounded by migmatitic overgrowth with ages ranging from ~6 to ~20Ma. Oxygen isotopic data of Neogene migmatite and inherited core is similar and indistinguishable ranging from 7.5 to 9.5 /. However, Neogene overgrowth is significantly less evolved than the inherited core in terms of Hf composition. This implies that the Hf composition of the migmatitic zircons is not controlled exclusively by the dissolution of the inherited cores and that contamination by external melts is likely. Isotopic data from the Baltoro plutonic unit …


Investigating The Utility Of Detrital Mineral Microchemistry And Radiogenic Isotope Compositions As Provenance Discriminators, Jack Hietpas Aug 2012

Investigating The Utility Of Detrital Mineral Microchemistry And Radiogenic Isotope Compositions As Provenance Discriminators, Jack Hietpas

Earth & Environmental Sciences - Dissertations

The provenance of clastic sediments remains one of the key tools for understanding the complex dynamic history of the Earth. Detritus shed from ancient orogens may be the only evidence available for determining the timing, evolution, paleogeography, and existence of tectonic events active over the 4.56 Ga of Earth history. The focus of this dissertation research is to assess the strengths and limitations of existing, as well as novel, tools for determining the provenance of siliciclastic sediments.

The utility of detrital monazite crystallization ages was investigated as a provenance indicator in both modern and ancient sedimentary systems. The results from …


Deep Crustal Evolution Of The Western Churchill Province, Nunavut, Canada: Isotopic (U-Pb, O), Trace Element And Micro-Structural Analysis Of Zircon From Lower Crustal Xenoliths, Duane C. Petts Jun 2012

Deep Crustal Evolution Of The Western Churchill Province, Nunavut, Canada: Isotopic (U-Pb, O), Trace Element And Micro-Structural Analysis Of Zircon From Lower Crustal Xenoliths, Duane C. Petts

Electronic Thesis and Dissertation Repository

Zircon from lower crustal xenoliths can preserve unique crustal formation records of unexplored levels of the lithosphere. The first such records for the western Churchill province (Nunavut, Canada) are presented here. Zircon SIMS U-Pb geochronology and oxygen isotope analysis were conducted on kimberlite-hosted granulite-facies xenoliths: four metabasites (#9864; #9865; #9866; #9870) from the Rankin Inlet region, and five metabasites (#10162; #10163; #10167; #10169; #10179) and three metatonalite/anorthosites (#10158; #10164; #10168) from the Repulse Bay region. For the Rankin Inlet suite, oscillatory planar zoned, igneous cores from metabolite xenolith #9865 record dates between ca. 2.9–2.6 Ga, whereas complex to radial-sector zoned …


The Behavior Of Zircon During Partial Melting In Anatectic Migmatites: Insights To Metamorphism, Deformation And Tectonism In The Central Santa Fe Range, Northern New Mexico, Michelle Renee Stropky May 2012

The Behavior Of Zircon During Partial Melting In Anatectic Migmatites: Insights To Metamorphism, Deformation And Tectonism In The Central Santa Fe Range, Northern New Mexico, Michelle Renee Stropky

UNLV Theses, Dissertations, Professional Papers, and Capstones

Three lithologic assemblages exposed in the central Santa Fe Range, northern New Mexico include (1) a septum of Proterozoic low temperature (~700oC, 5.5 kbars), semi-pelitic anatectic migmatites surrounded by (2) deformed megacrystic biotite granite that is intruded by (3) discrete plutons of largely undeformed hornblende biotite tonalite. Metamorphic fabrics in the migmatite record three deformation events (D1 - D3); a composite S1/S2 fabric (D1 and D2) that formed contemporaneous with anatexis and is folded about a southwest plunging map-scale (D3) antiform. The megacrystic granite exhibits a pervasive S1 subsolidus foliation that parallels the S1/S2 fabric in the migmatite and is …