Geology Commons^™

Insights On Magmatic Addition Beneath The Mid-Atlantic Coastal Plain From Crustal Seismic Refraction Data, Thomas W. Luckie

Earth and Planetary Sciences ETDs

Magmatic addition can lead to intraplate crustal growth through plume-generated voluminous underplating of mafic material, particularly during early syn-rift processes. In addition, magmatism facilitates crustal growth and rift development by assisting extensional tectonic forces. Therefore, understanding the relationship between magmatism and rifting may help explain both these processes. In the summer of 2015 the GeoPRISMS Eastern North American Margin (ENAM) Community Seismic Experiment collected two margin-dip active source seismic refraction profiles in eastern North Carolina and southeastern Virginia using five onshore explosive shots on a northern profile and six on a southern profile (see figure). Analysis of these data resulted …

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 …

Classifying Microseismicty At Mount St. Helens Using A Large-N Array, Margaret E. Glasgow

Earth and Planetary Sciences ETDs

A dense array of ~1,000 continuously recording, short-period geophones was deployed in the summer of 2014 within ~15 km of Mount St. Helens. Two earthquake catalogs created using reverse time imaging and template detection techniques, increase the detection rate and completeness of the earthquake catalog when compared to the permanent network, Pacific Northwest Seismic Network, catalog. An investigation into event type for ~200 of the earthquake detections leads to the discrimination of two major classification groups, volcano-tectonic and long period. Previous to this study, long period earthquakes had not been identified in the upper crust during a volcanically inactive period …

A Multi-Proxy Stalagmite Reconstruction Of The Climate Of Southwestern North America From The Middle To Late Holocene, Christine Allen

Earth and Planetary Sciences ETDs

The seasonal balance of moisture has a significant effect on natural ecosystems and culture in southwestern North America (SWNA), and it thus is necessary to understand the cause of this moisture variability in order to better predict the scope of potential future changes. Studies of modern SWNA climate indicate that most of the annual moisture at this site comes from monsoonal summer precipitation and a lesser amount of Pacific winter moisture. The climate of the Holocene is of particular interest for constraining natural variability of interglacial climates prior to any anthropogenic influence. An overall transition to a wetter Late Holocene …

The Dynamic Geomorphic Setting Of The Late Pleistocene Hartley Mammoth Site: Burial And Skeletal Preservation In A Slump-Block Depression Near Abiquiu, New Mexico, Jennifer K. Muus

Earth and Planetary Sciences ETDs

Near Abiquiu in northern New Mexico, the skeletal remains of two mammoths were discovered in the summer of 2014 in the near-surface deposits of a very small alluvial channel. The channel occupies a depression on the backtilted top of a Toreva slump block, a highly unusual setting for a mammoth burial. Geomorphological investigation of the site has provided insight into processes leading to burial and preservation of the remains, as well as local environmental change. Field mapping of sediment sources and LiDAR scans of the contributing slope basin and slump bench provided a map of geomorphic features and surficial geologic …

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 …

Abrupt Ocean Anoxia During The Late Ordovician Mass Extinction Detected Using Uranium Isotopes Of Marine Carbonates, Rickey Bartlett, Maya Elrick, Yemane Asmerom, Viorel Atudorei

Earth and Planetary Sciences ETDs

The Ordovician witnessed an explosion in marine biodiversity punctuated by the first of the ‘big-5’ Phanerozoic mass extinctions, the Late Ordovician mass extinction (LOME). The LOME consists of two discrete pulses occurring at the beginning and end of the Hirnantian. Lithologic and geochemical evidence suggests widespread marine anoxia triggered the second LOME pulse; however, most of these redox proxies record local bottom water or porewater conditions rather than global seawater conditions. To evaluate global redox trends, we utilize uranium (U) isotopes and trace element geochemistry of marine carbonates as a global marine redox proxy.

Bulk carbonate samples were collected from …

Birth And Evolution Of The Rio Grande Fluvial System In The Last 8 Ma:Progressive Downward Integration And Interplay Between Tectonics, Volcanism, Climate, And River Evolution, Marisa N. Repasch

Earth and Planetary Sciences ETDs

The Rio Grande-Rio Chama (RG-RC) fluvial system has evolved dramatically over the last 8 Ma, undergoing channel migrations, drainage capture and integration events, volcanic damming, and carving and refilling of paleocanyons. Volcanism concurrent with the development of the river system provides a unique opportunity to apply multiple geochronometers to the study of its incision and drainage evolution. This paper reports 19 new ⁴⁰Ar/³⁹Ar basalt ages and 19 detrital mineral samples (zircon and sanidine) collected from RG-RC alluvium overlain by dated basalt flows in the context of a compilation of published ⁴⁰Ar/³⁹Ar basalt ages. The …

Cl In The Early Solar System, Jeffrey Williams

Earth and Planetary Sciences ETDs

The early solar nebula is thought to have been a turbulent disk of dust and gas. An unknown mechanism caused the disk to collapse, such as a nearby super nova. This collapse led to high temperatures and high particle densities at the mid-plane of the disk. An unknown mechanism caused the temperature in local area to become hot enough to cause some material to melt –creating the first igneous material of the solar system. These melt spherules, called chondrules, cooled and accreted together with dust and ice to form larger bodies called chondrites. Once the chondritic bodies were of sufficient …

Modeling The Influence Of The Heterogeneous Substrate On The Transport Of The Jet Fuel Solute Plume, Kirtland Air Force Base, Albuquerque, New Mexico, Hannah Sarah Gatz-Miller

Earth and Planetary Sciences ETDs

A subsurface model was developed to characterize the influence of heterogeneity on solute phase plume migration of the Jet Fuel spill of Kirtland Air Force Base. Core –logs from KAFB boreholes were compiled, and lithology was interpolated across the study area using transition probability geostatistics (T-PROGS). High conductivity materials in the travel path resulted in a faster than average breakthrough time while, if low conductivity materials were placed in the travel path, particles were either forced to divert around the low K material, which added time and changed the direction of travel, or were forced by the hydraulic gradient to …

Neotectonic Evolution Of Grand Canyon : Interaction Between Volcanism, River Incision, Epeirogenic Uplift, And Faulting, Ryan Crow

Earth and Planetary Sciences ETDs

This thesis focuses on the effects of volcanism, river incision, epeirogenic uplift, and faulting on the landscape evolution of the Grand Canyon region. In the first chapter the migration of increasingly asthenospheric basaltic volcanism is used to constrain lithospheric modification of the Colorado Plateau margins. Buoyancy modification of the upper mantle, driven by the upwelling, is a likely driver for recent uplift of the area. In the second chapter, correlation between oversteepened rivers and areas of high-velocity upper mantle is used to show that recent and ongoing mantle-driven uplift is modulating the surface along the western margin of the Colorado …

Soil Geomorphology Of The Eastern Sevilleta Long Term Ecological Research Site, Debra Bryan-Ricketts

Earth and Planetary Sciences ETDs

Soils in the arid to semi-arid piedmont landscapes of central New Mexico were examined in order to evaluate surficial processes and landscape evolution in the central Rio Grande Rift. These soils were found to contain key information regarding pedologic and geomorphic responses to climate change, rifting and base level drop. A rare association of sepiolite and palygorskite occurs in old soils formed in eolian fines. Pedologic and mineralogical data indicate that palygorskite formed by transformation of dust-borne, aluminum-rich minerals, and that sepiolite subsequently formed by transformation of palygorskite. The association of these two minerals, and geomorphic observations, confirm the existence …

Refining Models Of Crustal Growth And Evolution In Southwestern Laurentia With Paired U-Pb And Lu-Hf Analyses Of Igneous And Detrital Zircon, Mark E. Holland

Earth and Planetary Sciences ETDs

The origin and evolution of continental crust is a fundamental and debated topic in geoscience. For over thirty years, Proterozoic crust of the southwestern United States has been a field laboratory for studying orogenic processes in the middle crust, and the growth of continental lithosphere via accretionary orogenesis. Three distinct crustal provinces are delineated based on differences in isotopic, structural, and geochronologic characteristics. To address questions about the origin of each province, this dissertation is composed of three chapters that present new U-Pb and Lu-Hf isotope analysis of plutonic, volcanic, and detrital zircon from the oldest known rocks in each …

Volatile Light Hydrocarbons In Geothermal Gas Emissions From Yellowstone National Park, Usa, And Comparisons To El Salvador And Honduras, Bethany Burnett

Earth and Planetary Sciences ETDs

Twenty-six samples from hot springs and fumaroles in Yellowstone National Park (YNP) and 11 in Central America were analyzed for inorganic gases (CO₂, SO₂, H₂S, HCl, Ar, N₂, CO, H₂, He, 0₂), methane, and trace volatile light hydrocarbons. Stable isotope analyses of carbon and nitrogen were used in conjunction with the gas geochemistry to determine potential sources of hydrocarbons.

δ¹³C-CH₄ values ranged between -37.6 and-18.2‰ for YNP, from -31.9 to -30.2‰ for El Salvador, and from -38.8 to -23.9‰ for Honduras. δ¹³C-CO_{2 …}

Seasonal Biogeochemistry And Mineral Cycling Of The Middle Rio Grande Alluvial Aquifer, New Mexico, David Stewart Vinson

Earth and Planetary Sciences ETDs

The Rio Grande in central New Mexico flows through a semi-arid, historically aggrading Quaternary rift basin. Flow regulation measures include dams, irrigation diversions, levees, and bank stabilization. These have caused severe impairment including incision, lowered water tables, and less overbank flooding; disrupted groundwater - surface water interactions; altered seasonal organic carbon dynamics; and declining native biota. Previously dynamic flowpaths in the shallow alluvial aquifer (hyporheic corridor) have become are less reversible due to parallel drain ditches with lower beds than the river. These ditches impose relatively static hydraulic gradients on the alluvial aquifer that force water to flow from the …

Biogeochemistry Of The Middle Rio Grande Bosque: Links Among Surface Water, Groundwater, And Sediments, Susan E. Block

Earth and Planetary Sciences ETDs

The potential for water contamination is great in areas where land use is both urban and agricultural. Such land uses can load the surface water and groundwater with nutrients and toxic trace metals. Water pollution can be further increased when natural watersheds have been altered by human activities. The surface and groundwaters of the Middle Rio Grande, NM, USA are part of one such ecosystem.

Because redox processes are important controls on nutrient cycling and contaminant transport, it is vital to understand the redox zonation of an aquifer. This research has been conducted to address such biogeochemical zonation in the …

A Late Pleistocene And Holocene High-Resolution Glacial And Paleoclimate Record From The Southern Sangre De Cristo Mountains, Northern New Mexico, Jake Armour

Earth and Planetary Sciences ETDs

Bog deposits in the Winsor Creek drainage basin, southern Sangre de Cristo Mountains, New Mexico contain a high-resolution record of Pleistocene to Holocene glacial activity. Sediment cores were recovered from an alpine bog (elevation 3,100 m) behind a Pinedale age moraine, 2 km from a high-elevation (-3600 m) cirque. Three cores reached glacial talus and consist of -6 meters of finely laminated to coarsely laminated lake clays, grading into gyttja. Superimposed on this long-term, lake-bog transition record are many distinct coarse-grained detrital packages punctuating times of rapid environmental change.

Accelerator mass spectrometry (AMS) carbon dating, sedimentology, variations in rock magnetic …

Genesis And Evolution Of Proterozoic Crustal Boundaries In The Southern Rocky Mountains., Colin Arthur Shaw

Earth and Planetary Sciences ETDs

The lithosphere of the southwestern United States is a mosaic of Proterozoic arc terranes assembled to the southern margin of the Archean Wyoming craton between 1.8 and 1.6 Ga. This mosaic was profoundly transformed by ca. 1.4 Ga intracontinental plutonism, metamorphism, and tectonism. These processes of assembly and tectonic reactivation during the early stages of continental evolution laid the foundation for the development of the continental architecture of the southwestern United States.

This dissertation comprises three independent studies focused on different aspects of the Proterozoic evolution of tectonic boundaries exposed in the Southern Rocky Mountains. The first study is a …

Hydrologic Budget Analysis And Numerical Simulations Of Groundwater Flow In Los Alamos Canyon Near Los Alamos, New Mexico, Robert Norman Gray

Earth and Planetary Sciences ETDs

A hydrologic budget analysis for the Los Alamos Canyon watershed was prepared including annual budgets for the 1993, 1994, and 1995 water years and detailed budget calculations for the upper basin and middle/upper canyon areas covering nine separate stress periods from 7/10/94 to 11/2/95 corresponding to varying alluvial aquifer behaviors. Data sources included daily measurements of precipitation and snowpack depths, streamflow discharge, and latent heat energy flux from which evapotranspiration rates were determined. Average annual precipitation rates over the watershed varied from ~23 to ~31 inches during the analyzed periods. The annual evapotranspiration component was determined to represent between ~ …

The Terraces Of Cochiti Canyon: Soil Development And Relation To Tectonism In The Pajarito Fault Zone, Scott Benjamin Aby

Earth and Planetary Sciences ETDs

The history of motion on splays of the Pajarito Fault Zone in the area of Cochiti Canyon in the Jemez Mountains is examined using morphometric techniques and investigations of river terrace soils and deformation. Hypsometry, sinuosity and long-profile analysis all suggest that the main splay of the Pajarito Fault has been active in the late Pleistocene and possibly Holocene, but no calibration is available that numerically constrains this activity. Terraces were mapped and correlated based on soil development and landscape position, Correlation revealed the presence of three strath terraces between 87 and 18 .5 meters above present grade and one …

Stratigraphy, Chemistry And Petrogenesis Of Volcanic Rocks Of The Mid-Tertiary Boot Heel Volcanic Field, Southwestern New Mexico And Southeastern Arizona, Charles R. Bryan

Earth and Planetary Sciences ETDs

The mid-Tertiary Boot Heel volcanic field is located in the Basin and Range Province of southwestern New Mexico and southeastern Arizona. The field is defined on the basis of nine regional ash-flow tuffs, which have been correlated throughout the area, and for which probable source cauldrons have been identified. These tuffs are: tuff of Woodhaul Canyon (35.3 Ma); Bluff Creek Tuff (35.1 Ma); tuff of Steins (34.4 Ma); Oak Creek Tuff (33.5 Ma), tuff of Black Bill Canyon (stratigraphically constrained to 32.7-33.5 Ma); Gillespie Tuff (32.7 Ma); tuff of Horseshoe Canyon (27.6 Ma); Park Tuff (27.4 Ma); and Rhyolite Canyon …

The Magmatic History Of An Aubrite Parent Asteroid: Evidence From Igneous Clasts And Trace Elements, Maya Monica Wheelock

Earth and Planetary Sciences ETDs

Norton County aubrite contains numerous igneous-textured clasts that survived severe brecciation. These clasts were studied in order to obtain information about the suite of original igneous lithologies that crystallized on an aubrite parent body. The majority of igneous clasts are pyroxenites (enstatite, with minor diopside, +/- forsterite) and orthopyroxenites (enstatite, +/- forsterite). Phase relations and textural evidence are consistent with formation from a nearly pure enstatite magma body or magma ocean, at (or near) the surface of the parent body.

A new sulfide-dominated lithology was identified in Norton County. The sulfide portion is dominated by coarse-grained oldhamite (CaS) containing rounded …

Geochemistry Of Metal Segregation In Aubrites, And The Origin Of Their Metallic Phases, Ignacio Casanova

Earth and Planetary Sciences ETDs

In this work, I have carried out a petrographic and geochemical study of the metallic particles present in aubrites with the aim of constraining ideas about their origin and evolution. The extremely low oxygen fugacities under which enstatite meteorites formed (e.g. Larimer and Buseck, 1974; Fogel et al., 1989) and their consequent unique composition make interpretations difficult due to the lack of experimental data on highly reducing systems. I have tried to overcome the paucity of experimental data by using a theoretical thermodynamic approach to study the significance of such unique compositions based on three main themes: (1) the …

Hydrology Of A Large, Closed Arid Watershed As A Basis For Paleohydrological And Paleoclimatological Studies In The Mojave River Drainage System, Southern California, Yehouda Enzel

Earth and Planetary Sciences ETDs

A physical link between anomalous, present-day atmospheric circulation patterns over the North Pa1cific Ocean, extreme storms in southern California, the largest floods of record and lake stands in the Mojave River watershed in the Mojave Desert is demonstrated by analyzing hydrologic and climatic data. This link is then used as a modem analog to interpret hydroclimatic conditions during the latest Quaternary recorded in lake deposits in the Silver Lake playa, the terminal basin of the of the Mojave River.

The Mojave River filters out small to medium floods by discharge loss through infiltration into the alluvial aquifer and allows only …

Hillslope Processes On Late Quaternary Cinder Cones Of The Cima Volcanic Field, Eastern Mojave Desert, California, Claire Estelle Renault

Earth and Planetary Sciences ETDs

Four basaltic cinder cones of the cima volcanic field were studied in an attempt to understand the geomorphic and volcanic processes involved in the constructional and degradational evolution of late Quaternary cinder cones in an arid climate. Modern hillslope processes were mapped on cone slope and soil and subsurface stratigraphy were documented in the surrounding debris-apron deposits. In addition, morphometric parameters shown to be sensitive to cinder cone age (Dohrenwend et al., 1986) were measured on the four cinder cones to evaluate previous studies which estimated the relative or absolute age of cinder cones based only on morphologic changes in …

Quaternary Alluvial Sequence Of The Upper Pecos River And A Tributary, Glorieta Creek, North-Central New Mexico, Paul Arthur Karas

Earth and Planetary Sciences ETDs

Quaternary alluvial deposits preserved on terraces along the Pecos River and a tributary, Glorieta Creek, provide a record of the evolution of these two drainages. Alluvium deposited by the Pecos River can be subdivided into six units on the basis of relative topographic position and degree of soil development on original surfaces. Deposits consist of thin (1 to 10m) veneers on scattered strath terrace remnants. Only four Quaternary alluvial units have been identified along Glorieta Creek. Alluvium deposited by this stream forms nearly continuous fill terraces of thickness equal to or greater than the Pecos River alluvium. Alluvial deposits of …

Geology And Petrogenesis Of Ash-Flow Tuffs And Rhyolitic Lavas Associated With The Gila Cliff Dwellings Basin-Bursum Calder Complex, Southwestern New Mexico, Sheila June Seaman

Earth and Planetary Sciences ETDs

The Mogollon-Datil volcanic field of southwestern New Mexico was the site of extensive mid-Tertiary felsic volcanism. The Bursum caldera-Gila Cliff Dwellings basin is a volcanic complex in which stratigraphic and compositional relationships between eruptive units are controversial. Uncertainties associated with the complex include the relative ages of the two overlapping structures, the caldera of origin of ash-flow tuff which fills the Gila Cliff Dwellings basin, and the reconciliation of stratigraphic and chemical relations between volcanic units. A stratigraphic, structural, paleomagnetic, and petrologic study of six ash-flow tuff and lava units has contributed data to several problems concerning the geologic history …

Long-Term Tributary Adjustments To Base-Level Lowering, Northern Rio Grande Rift, New Mexico, Keith Irvin Kelson

Earth and Planetary Sciences ETDs

ABSTRACT

Late Cenozoic (post-3.6 Ma) entrenchment of the Rio Grande in northern New Mexico formed a gorge over 200 m deep and induced different types of fluvial adjustments on two adjacent tributaries. Rio Hondo (drainage area 181 km2 ) has a concave-up long-profile and flows in a narrow valley containing six Quaternary strath terraces with parallel long-profiles grading to the Rio Grande. In contrast, Rio Pueblo de Taos (drainage area 1080 km2 ) has a convex-up long-profile and flows in a wide valley containing four strath terraces which do not grade to the Rio Grande. Although smaller in drainage area, …

The Virginius Vein Ore Deposit, Northwestern San Juan Mountains, Colorado: A Study Of The Mineralogy, Structure, And Fluid Inclusions Of An Epithermal Base-Metal And Silver Vein In A Volcanic Environment, Berton Woodward Coxe

Earth and Planetary Sciences ETDs

The Virginius ore deposit, Ouray and San Miguel Counties, Colorado, yielded 14.5 million oz of silver between 1880 and 1912. The deposit consists of several quartz, base-metal, and silver mineralized fissures which is hosted by Tertiary volcanic rocks of the San Juan volcanic field and was deposited in fractures radial to the northwest margin of the Silverton caldera.

Four stages of mineralization have been recognized: (I) quartz, galena, sphalerite, chalcopyrite, and argentiferous tetrahedrite; this stage comprises a bulk of the total vein material and all of the silver; (II) rhodonite, rhodochrosite, quartz, magnetit, galena, chalcopyrite, and pyrite; this stage is …

Dynamics Of Clastic Sedimentation And Watershed Evolution Within A Low-Relief Karst Drainage Basin, Mammoth Cave Region, Kentucky, John D. Pickle

Earth and Planetary Sciences ETDs

The hydrology and sedimentology of the Mill Hole drainage basin, a low-relief karst system in the Mammoth Cave Region, Kentucky, depend upon the interactions of surface and groundwater drainages and the distribution of lithologies within the basin. This basin is characterized by sinking streams in the headwaters (Glasgow Uplands) draining into cave rivers beneath the sinkhole-pocked plain (sinkhole plain), which, in turn, flow beneath a sandstone-capped upland (Chester Cuesta) and emerge at base-level springs. Karst windows expose the subterranean drainage within the Chester Cuesta.