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Articles 1 - 30 of 76
Full-Text Articles in Physical Sciences and Mathematics
Untangling The Nature And Timescales Of Magmatic Processes Driving Eruptions At Quiescent Volcanoes: Examples From Momotombo, Nicaragua, And Cumbre Vieja, Canary Islands, Samantha Tramontano
Untangling The Nature And Timescales Of Magmatic Processes Driving Eruptions At Quiescent Volcanoes: Examples From Momotombo, Nicaragua, And Cumbre Vieja, Canary Islands, Samantha Tramontano
Dissertations, Theses, and Capstone Projects
Across all scales of human relationships (i.e. person-to-person, country-to-country, etc.), qualms can take the form of long-standing wars, quick and intense bouts, or petty exchanges. While our understanding of human behavior is ever increasing, reactions and behaviors of self and others may still come as a surprise. Expressions of disagreement can occur suddenly or following years to centuries of accumulated grievances. The solid earth is also a system that behaves (like human emotion) predictably at times and unpredictably at other times. Some volcanoes, a tangible surface expression of solid earth processes, exhibit precursory signals prior to eruption (e.g. the bulging …
Connections Between Eruption Style And Magmatic Reservoir Evolution: Insights From Augustine Volcano, Alaska, Usa, Mahinaokalani G. Robbins
Connections Between Eruption Style And Magmatic Reservoir Evolution: Insights From Augustine Volcano, Alaska, Usa, Mahinaokalani G. Robbins
WWU Graduate School Collection
At a single volcano, eruptive behavior can change through time as the plumbing system evolves. Augustine Volcano, a frequently active intermediate stratovolcano in the Alaska-Aleutian arc (USA), is an ideal setting to investigate magma reservoir processes due to its frequent modern and Holocene eruption history. Its most recent 2006 CE eruption included mixed effusive and moderately explosive (VEI 3) events and has been studied in detail. Proximal fall deposits from this eruption were generally mixed fine ash to lapilli with variable thickness, but typically ~5 cm on the island (Wallace et al., 2010). The Pre-contact “Tephra M” was deposited by …
Using Chemical Zoning In Minerals To Understand Magmatic Processes At Augustine Volcano, Alaska, Sloane Kennedy
Using Chemical Zoning In Minerals To Understand Magmatic Processes At Augustine Volcano, Alaska, Sloane Kennedy
WWU Graduate School Collection
The eruption behavior of a volcano is intrinsically linked to magmatic evolution. Augustine Volcano is an active stratovolcano in the Aleutian Arc (AK, USA), showing stratigraphic evidence that eruptions before 1,800 C.E. were more explosive, producing thick pumice deposits, compared to the six eruptions observed in the last 200 years. Tephra B, an understudied ~400-year-old pumice fall unit, represents the last more explosive style eruption at Augustine - making it ideal for studying how changes in magmatic evolution can result in changes in eruption style. For this thesis, I used textural zoning patterns and chemical variations (major and trace elements) …
Magmatic Evolution Of The Chasca Orkho Lava Series And Its Magmatic Enclaves, Volcán Ollagüe, Central Andes, Nathaniel W. Lenhard
Magmatic Evolution Of The Chasca Orkho Lava Series And Its Magmatic Enclaves, Volcán Ollagüe, Central Andes, Nathaniel W. Lenhard
MSU Graduate Theses
Magma mixing is a common factor in the creation of intermediate composition magmas and a potential instigator of a volcanic eruption. Magmatic enclaves, physical evidence of magma mixing within a volcanic system, are a phenomenon whose mechanisms remain unclear and debated. Common hypotheses explaining the occurrence of magmatic enclaves within a host lava range from the repeated injection of a new magma into a shallow reservoir to the disruption of equilibrium within a stratified magma chamber. Within the Andean Central Volcanic Zone (CVZ), the occurrence of magmatic enclaves yields similar geochemical compositions to their respective host rocks, bringing more difficulty …
Petrological And Geochemical Evaluation Of Rare-Earth Element Potential In The Sparta Granite Complex, Max J. Eshbaugh
Petrological And Geochemical Evaluation Of Rare-Earth Element Potential In The Sparta Granite Complex, Max J. Eshbaugh
Honors College Theses
Rare earth elements (REEs) are important resources with applications in the electronics, renewable energy, and automotive industries. REEs may be concentrated in the residual weathered portion of igneous parent rocks, typically granites. These residual deposits are mined in southeast Asia, but analogous climatic and geologic conditions suggest the existence of economically viable REE residual deposits in the southeastern United States (U.S.). The Sparta Granite Complex in east-central Georgia is a granitoid complex emplaced at the end of the Alleghanian orogeny, forming a suture between the Savannah River and Milledgeville terranes. Petrologic and geochemical assessments of the Sparta Granite and overlying …
Petrology And Geochemistry Of Evolved Achondrites: Planetesimal Mantles And Crusts, Zoltan Vaci
Petrology And Geochemistry Of Evolved Achondrites: Planetesimal Mantles And Crusts, Zoltan Vaci
Earth and Planetary Sciences ETDs
Melting and differentiation are fundamental to early solar system evolution on planetary bodies that accreted enough material to heat up radioactively or through impacts and breach their solidi. Partially and fully melted material is present in the meteorite record in the form of primitive achondrites and achondrites, which are fragments of planetesimals that underwent heating events in the first few million years of solar system history. Although the vast majority of this material is mafic or ultramafic, new evolved samples, recovered in the last few decades, are pushing the petrologic and geochemical boundaries of planetesimal melting, differentiation, and crust formation. …
Petrogenesis And Tectonic Implications Of Cordierite-Orthoamphibole Gneisses (Cog) In The Nw Wyoming Province, Brianna K. Crenshaw Ms
Petrogenesis And Tectonic Implications Of Cordierite-Orthoamphibole Gneisses (Cog) In The Nw Wyoming Province, Brianna K. Crenshaw Ms
Graduate Student Theses, Dissertations, & Professional Papers
Studying cordierite orthoamphibole gneisses (COG) from five different mountain ranges across the Montana Metasedimentary Terrane (MMT) of the Wyoming Province offers a unique opportunity to elucidate the enigmatic origins and petrogenesis of the lithology in addition to gaining a further understanding of Precambrian crustal assembly processes. Geochemical analyses suggest that COG originates from a basalt that underwent metasomatic alteration, likely via seawater, prior to metamorphism. Moreover, COG is considered to represent oceanic crust that was part of the epicontinental sea adjacent to the Wyoming Province before collision with the Medicine Hat Block. Field observations of associated lithologies such as marbles, …
Multiple Generations Of Phlogopite In An Alnöite Diatreme: Insights Into The Petrogenesis Of The Avon Alkaline Igneous Province, Missouri, Nathan Gregory Limbaugh
Multiple Generations Of Phlogopite In An Alnöite Diatreme: Insights Into The Petrogenesis Of The Avon Alkaline Igneous Province, Missouri, Nathan Gregory Limbaugh
Masters Theses
“Alkaline Ultramafic Carbonatite (AUC) complexes, although rare, are valued for diamonds and REEs, and as windows into subcontinental and mantle processes as recorded by rock fabrics, mineral spatial relationships, and mineral compositions. We report specifically on olivine and phlogopite petrographic relationships and compositions from the Devonian alnoite diatreme-facies of the Avon Alkaline Igneous Province, Missouri. The diatreme alnoite is a mixture of domains of olivine magmaclasts (OM) set in a crystal-rich melilite matrix. OM are highly fractured, serpentinized olivine pseudomorphs with variable amounts of pristine olivine fragments. Larger olivine domains typically exhibit clear crystal faces and irregular “channels” indicative of …
Stratigraphy, Petrology, Diagenesis, Paleontology, And Depositional Environments Of The Harrisburg Member Of The Kaibab Formation In Northern Arizona And Southern Utah, Zachery T. Case
Electronic Theses and Dissertations
The Kaibab Formation has two members, the Fossil Mountain Member below and the Harrisburg Member above. They were deposited in shallow-marine shelf to restricted coastal settings. Stratigraphically above are the Rock Canyon Conglomerate and the Moenkopi Formation; consisting of the Timpoweap and Lower Red members; which are the only members present in the study area. The Rock Canyon Conglomerate was deposited in depressions and as a regolith. The Timpoweap and Lower Red members were deposited in shallow marine to tidal environments.
Nine stratigraphic units were identified in the Harrisburg Member. Units one, two, three, five, six, seven, and nine are …
Provenance And Maximum Depositional Age Analysis Of The Moenave Formation Using Detrital Zircon U-Pb Geochronology And Sandstone Petrography, Asher Rea Boudreaux
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
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, Provenance, And Depositional Setting Of The Lower Tallahatta Formation (Meridian Sand) In Grenada County, Mississippi, Husamaldeen Zubi
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 …
In Situ Dating Of Multiple Events In Granulite-Facies Rocks Of The Larsemann Hills, Prydz Bay, East Antarctica Using Electron Microprobe Analysis Of Monazite, Steven K. Spreitzer
In Situ Dating Of Multiple Events In Granulite-Facies Rocks Of The Larsemann Hills, Prydz Bay, East Antarctica Using Electron Microprobe Analysis Of Monazite, Steven K. Spreitzer
Electronic Theses and Dissertations
The metamorphic rocks exposed along the southeast coast of Prydz Bay were affected by several metamorphic and plutonic events associated with collision in the Neoproterozoic and Cambrian. Critical units exposed in the Larsemann Hills and nearby ice-free areas include (1) basement Søstrene Orthogneiss, (2) cover sequence Brattstrand Paragneiss and (3) anatectic pegmatites intrusive into the Brattstrand Paragneiss. Zircon U-Pb data from previous studies yielded a maximum depositional age of 1023 ± 19 Ma for the Brattstrand Paragneiss, but only approximate ca. 900 Ma to ca. 1000 Ma and ca. 530 Ma ages for two metamorphic events. In order to constrain …
The Littlefield Rhyolite, Eastern Oregon: Distinct Flow Units And Their Constraints On Age And Storage Sites Of Grande Ronde Basalt Magmas, Brian Mcculloch Webb
The Littlefield Rhyolite, Eastern Oregon: Distinct Flow Units And Their Constraints On Age And Storage Sites Of Grande Ronde Basalt Magmas, Brian Mcculloch Webb
Dissertations and Theses
The Littlefield Rhyolite consists of widespread, high-temperature, hotspot-related rhyolitic lavas that erupted in eastern Oregon contemporaneous to late-stage Grande Ronde Basalt lavas. The estimated total volume of erupted rhyolites is ~100 km3 covering ~850 km2.
The focus of this study has been to investigate the stratigraphy and petrology of the Littlefield Rhyolite and whether field and geochemical relationships exist to help constrain the timing and storage sites of Grande Ronde Basalt magmas. Although often indistinguishable in the field, our data reveal that the Littlefield Rhyolite consists of two geochemically distinct rhyolite flow packages that are designated here …
Magmatic Hydrothermal Alteration And Secondary Post-Shock Features In Martian Olivine-Phyric Basalt Northwest Africa 10416; Petrology And Geochemistry Of Primitive Achondrite Northwest Africa 11042, Zoltan Vaci
Earth and Planetary Sciences ETDs
The Martian olivine-phyric basalt Northwest Africa (NWA) 10416 contains large olivine xenocrysts whose cores have been stained brown by hydrothermal alteration and whose rims are composed of pristine olivine overgrowths. Microanalysis of these olivine cores reveals various degrees of amorphization, some of which have been overprinted by terrestrial weathering, evident as part of a weathering rind along the exposed surface of the meteorite. Studies of a completely unweathered terrestrial analogue basalt from southern Colorado reveal similar features and indicate that both basalts were altered in a supersolidus magma chamber setting. The alteration features in NWA 10416 thus imply the presence …
Re-Evaluating The Tectonic Model For The Arbuckle Mountains, Oklahoma By Spatial And Geometric Analysis Of Stratigraphic And Structural Trends, Dakota James Kolb
Re-Evaluating The Tectonic Model For The Arbuckle Mountains, Oklahoma By Spatial And Geometric Analysis Of Stratigraphic And Structural Trends, Dakota James Kolb
Electronic Theses and Dissertations
Understanding the spatial distribution and geometric relations between stratigraphy and structural features can allow for a more accurate tectonic timeline to be considered for not only the Arbuckle Mountains but for the assembly of modern North America. The Arbuckle Mountains in south central Oklahoma exhibit structurally complex stratigraphy associated with regional features like the Southern Oklahoma Aulacogen, the Arbuckle Anticline and the Washita Valley fault. Camp Classen YMCA and Turner Falls city park in Davis, OK, hosts observed, but largely unmapped, small scale structural features that best represent the magnitude of deformation. The goal of this study was to determine …
New Insights Into The Martian Crust And Angrite Parent Body Through Meteorites, Alison R. Santos
New Insights Into The Martian Crust And Angrite Parent Body Through Meteorites, Alison R. Santos
Earth and Planetary Sciences ETDs
Petrologic studies of two new, unique meteorites were conducted in order to characterize the samples and provide insights into their parent bodies. The first sample, Northwest Africa 7034, is the first martian meteorite breccia to be discovered. In an effort to understand the martian crustal materials sampled by the breccia, we developed a classification scheme for the breccia clasts based on their texture, mineralogy, and chemistry. We then further investigated two clast groups which contained trends in mineralogy and chemistry that suggested a possible genetic relationship between the two. Our findings suggest they are not related by a simple igneous …
Petrology Of The Paired Dominion Range 2010 Howardites: Indications Of Magmatic Complexity On Asteroid Vesta, Timothy Michael Hahn Jr.
Petrology Of The Paired Dominion Range 2010 Howardites: Indications Of Magmatic Complexity On Asteroid Vesta, Timothy Michael Hahn Jr.
Masters Theses
A comprehensive petrologic and geochemical characterization of six paired howardites collected from the Dominion Range, Antarctica was conducted. These howardites are megaregolith samples from the asteroid 4 Vesta. Collectively, they contain an assortment of igneous rock fragments that indicate magmatic processes were capable of producing a variety of rock types; 22 chemically and texturally discrete basaltic eucrite, cumulate eucrite, and diogenite lithologies are recognized. The implications for remote-sensing observations of Vesta are discussed. The petrogenesis of two previously unrecognized lithologies are described in further detail: an evolved dacite that we propose is a residual melt from extensive crystallization, and a …
Geological Bodies, Savannah Fulmer
Geological Bodies, Savannah Fulmer
Honors Projects
‘Geological Bodies’ is a series of character designs that were developed to personify the traits of nine different rocks. The artwork is accompanied with written documentation of the research and execution.
Geochemical And Petrological Characterizations Of Peridotite And Related Rocks In Marquette County, Michigan, Andrew Lloyd Sasso
Geochemical And Petrological Characterizations Of Peridotite And Related Rocks In Marquette County, Michigan, Andrew Lloyd Sasso
Masters Theses
This study characterizes the following rock units in Marquette County, Michigan in terms of geochemistry and petrology: (1) Presque Isle Peridotite, (2) Deer Lake Peridotite, (3) Yellowdog Peridotite, and (4) Black Rock Point Gabbro. Analyses were conducted to determine if any petrological or geochemical relationships exist between these units, and to assess the potential of these units to host magmatic sulfide deposits.
The generated data and chosen geotectonic proxies indicate that Black Rock Point Gabbro and Deer Lake Peridotite crystallized from unrelated magmas, probably during the formation of the Great Lakes Tectonic Zone (2.7-1.85 Ga). No evidence was found which …
Avon Alkaline Igneous Province, Missouri: Characterization Of Subcontinental Mantle Source And Evolution Via Chemical Analysis Of Olivine, Zachary William Freeman
Avon Alkaline Igneous Province, Missouri: Characterization Of Subcontinental Mantle Source And Evolution Via Chemical Analysis Of Olivine, Zachary William Freeman
Masters Theses
"This article presents the crystallization age of, and composition of olivine phenocrysts within an alnoite of, the Avon Alkaline Igneous Province (AAIP) of Ste. Genevieve County, Missouri. The AAIP is an ultramafic igneous province consisting of approx. 80 known intrusives of diverse lithology and texture. 40Ar/39 Ar geochronology indicates an emplacement age of 386 +/- 1 Ma, which establishes the AAIP as the only known Devonian-age ultramafic igneous body in the Midwestern U.S. Study of the AAIP provides a unique opportunity to characterize the Devonian-age subcontinental mantle and the processes that generated the suite of ultramafic rocks present …
Exploring Martian Magmas: From The Mantle To The Regolith, Arya Sigrid Waltraud Udry
Exploring Martian Magmas: From The Mantle To The Regolith, Arya Sigrid Waltraud Udry
Doctoral Dissertations
The planet Mars is geologically more similar to Earth than to other planets of the solar system. For the past 50 years, new rovers, orbital spacecraft, and new martian meteorites have helped us to understand the geological processes that occurred on Mars. In this dissertation, I investigate a wide range of martian igneous compositions, such as shergottite and nakhlite meteorites, Gusev and Gale surface basalts, and the Northwest Africa (NWA) 7034 breccia. I attempt to better understand magmatic processes that occurred in the martian mantle and crust as well as surficial processes using various petrologic and geochemical tools.
As shown …
Eclogites And Eclogites: Oxygen Isotope Evidence Of A Shared Subduction Origin For Franciscan Eclogites And Moses Rock Eclogite Xenoliths, William F. Hoover
Eclogites And Eclogites: Oxygen Isotope Evidence Of A Shared Subduction Origin For Franciscan Eclogites And Moses Rock Eclogite Xenoliths, William F. Hoover
Honors Papers
Eclogites can be found in two distinct tectonic settings in the western USA: in the Franciscan Complex as tectonic blocks in a fossil accretionary wedge, and in the Navajo Volcanic Field as xenoliths in diatremes. Intra-crystal oxygen isotope analyses of garnets from these two settings provide important information on the source, composition and timing of fluid interactions in both eclogite settings. Because of the well-documented relationship between Franciscan subduction and the volcanism in the Navajo Volcanic Field, the samples in this study can be directly compared to determine if they share a common origin. The Navajo eclogites in this study …
Earthquake Petrology: Linking Fault-Related Deformation To The Earthquake Cycle, Mitchell R. Prante
Earthquake Petrology: Linking Fault-Related Deformation To The Earthquake Cycle, Mitchell R. Prante
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Faults have a controlling influence on a variety of geologic processes including fluid flow, the mechanical behavior of the crust, and seismicity. The geologic sciences have long recognized that faults generate earthquakes; however, few indicators of ancient earthquakes exist in fault-zones. This dissertation documents several indicators for the preservation of ancient earthquakes in fault-zones including frictional melt (pseudotachylyte), highly-polished fault slip surfaces, and hydrothermal alteration.
These deformation products result from rapid generation of frictional heat during earthquakes. This dissertation also focuses on the seismic potential of continental low-angle normal faults (LANF). We document the preservation of voluminous pseudotachylyte along a …
Petrogenesis Of The Linked River Mountains Volcanic Section And Wilson Ridge Pluton, Denise Kelly Honn
Petrogenesis Of The Linked River Mountains Volcanic Section And Wilson Ridge Pluton, Denise Kelly Honn
UNLV Theses, Dissertations, Professional Papers, and Capstones
The River Mountains (RM) volcanic suite and Wilson Ridge pluton (WRP), in the northern Colorado River extensional corridor of southern Nevada and northwestern Arizona, provide an ideal opportunity to investigate one of the most fundamental questions in igneous petrology: Do volcanic rocks erupt from subjacent plutons and do plutons vent to form volcanic fields? The RM volcanic suite (14.47± 0.26 to 12.66 ± 0.54 Ma; uncertainties are 2sigma) consists of a stack of andesite and rhyolite sills beneath a stratovolcano that primarily erupted dacite with lesser volumes of basalt and rhyolite. This volcanic suite is cored by a multiphase quartz …
Petrologic Evidence For Mafic Recharge At Volcán Barú, Western Panama: Implications For A Late Pleistocene Sector Collapse, Shannon M. Brady
Petrologic Evidence For Mafic Recharge At Volcán Barú, Western Panama: Implications For A Late Pleistocene Sector Collapse, Shannon M. Brady
Honors Theses
The purpose of this study is to gain a better understanding of the petrologic conditions of the magma chamber beneath Volcán Barú in western Panama. Volcán Barú is an andesite stratovolcano that experienced a large sector collapse during the Late Pleistocene, which destabilized the southwestern flank of its edifice. Samples were taken from the cores of hummocks and megaclasts deposited as a result of this sector collapse, which are inferred to have been intact wall rock from the pre-collapse edifice. These samples range in composition from 51.8 to 61.7 wt. % SiO2 and have a geochemical signature that is consistent …
Petrogenesis Of The Greenwater Range: Comparison To The Crater Flat Volcanic Field And Implications For Hazard Assessment, Ashley Kaye Tibbetts
Petrogenesis Of The Greenwater Range: Comparison To The Crater Flat Volcanic Field And Implications For Hazard Assessment, Ashley Kaye Tibbetts
UNLV Theses, Dissertations, Professional Papers, and Capstones
Pliocene basalts of the Greenwater Range, California erupted from 24 volcanic vents now represented by volcanic plugs, craters and scoria mounds. Basaltic magmas originated in the asthenospheric mantle, but show evidence of a lithospheric component. Depths and temperatures of melting calculated using a silica activity geobarometer are 54.3–89.6 km and 1367-1435oC, placing melting in the asthenosphere. The preferred petrogenetic model involves melting of lithospheric mantle thermally and mechanically, but not chemically, converted to asthenospheric mantle. Melting depths correspond to low velocity zones in the mantle as revealed in seismic profiles. Chemical and lithologic similarities between basalt in the Greenwater Range …
The No. 5 Block In Eastern Kentucky: A Critical Re-Examination Of The Petrology With Special Attention To The Origin Of Inertinite Macerals In The Splint Lithotypes, Allison Ranae Richardson
The No. 5 Block In Eastern Kentucky: A Critical Re-Examination Of The Petrology With Special Attention To The Origin Of Inertinite Macerals In The Splint Lithotypes, Allison Ranae Richardson
University of Kentucky Master's Theses
Microbes, including fungi and bacteria, and insects are responsible for the consumption and subsequent degradation of plant materials into humus. These microbes directly and indirectly affect the physical and chemical characteristics of coal macerals. Efforts to understand and determine the origins of inertinite macerals are largely misrepresented in the literature, conforming to a single origin of fire. This study focuses on the variability of physical and inferred chemical differences observed petrographically between the different inertinite macerals and discusses the multiple pathways plant material may take to form and or degrade these macerals.
Petrographic results show that fungal activity plays a …
Banda Forearc Metamorphic Rocks Accreted To The Australian Continental Margin: Detailed Analysis Of The Lolotoi Complex Of East Timor, Carl Eldon Standley
Banda Forearc Metamorphic Rocks Accreted To The Australian Continental Margin: Detailed Analysis Of The Lolotoi Complex Of East Timor, Carl Eldon Standley
Theses and Dissertations
Petrologic, structural and age investigations of the Lolotoi Complex of East Timor indicate that it is part of a group of thin metamorphic klippen found throughout the region that were detached from the Banda forearc and accreted to the NW Australian continental margin during Late Miocene to Present arc-continent collision. Metamorphic rock types are dominated by (in order of greatest to least abundance), greenschist, graphitic phyllite, quartz-mica schist, amphibolite and pelitic schist. Mineral, whole rock, and trace element geochemical analyses of metabasites indicate that protolith compositions are consistent with tholeiitic basalt and basaltic andesite with mixed MORB and oceanic arc …
Major- And Minor-Element Analysis Of Apollo 14 Volcanic Green Glasses B, And Petrogenic Modeling Of Apollo 14 Green Glasses A And B, Vera Assis Fernandes
Major- And Minor-Element Analysis Of Apollo 14 Volcanic Green Glasses B, And Petrogenic Modeling Of Apollo 14 Green Glasses A And B, Vera Assis Fernandes
Geology Theses and Dissertations
The lunar picritic volcanic glasses have been identified as being quenched samples of primary magmas extruded onto the lunar surface via fire-fountains. The study of the composition of these glasses is of extreme importance for the understanding of the Moon's mantle composition and petrogenetic processes.
Based on their chemical signature (low-Ti and high Mg#) and physical characteristics, the lunar picritic glasses are believed to represent primary magmas. Experimental data suggest that these melts formed at 360-500 km depth (18-25 kbar) in the lunar mantle, and were transported onto the lunar surface through a "channel" network (McKenzie, 1985b) that isolated these …