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The Depositional Environment Of The Triassic Cow Branch Formation, Dan River Basin Of Virginia And North Carolina Through Petrographic Study And Geochemical Analysis, And In Relation To Taphonomic Processes And Vertebrate Morphology, Gina M. Workman

All Graduate Reports and Creative Projects, Fall 2023 to Present

The Upper Triassic Cow Branch Formation of the Dan River Basin, located in southern Virginia and northern North Carolina, has long captivated generations of geoscientists. Since the 1970s, researchers have sought to unravel the mystery surrounding the depositional environment of this ancient lake system. This world-class lagerstätte hosts a diverse assemblage of fossil fauna and flora, with a notable preservation bias toward fossil vertebrates, most prominently the archosauromorph, Tanytrachelos ahynis. The geology of the Cow Branch strata continues to evoke a persistent question: Are these sediments representative of a shallow or deep lake?

I undertook a petrographic and geochemical study …

Age Dating Young Groundwater: How To Determine Groundwater Age From Environmental Tracer Data, D. K. Solomon, T. E. Gilmore

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

The Appalachian System Of Basins And Platforms As A Tectonostratigraphic Analogue To The Barents Sea Shelf: Where Arctic Meets The Appalachians, Gustavo De Aguiar Martins

Theses and Dissertations--Earth and Environmental Sciences

Divided between Norway and Russia, the Barents Sea shelf (BSS) is an ~1.4 million km² Arctic province, containing significant hydrocarbon accumulations. However, much of the area is frontier, and geologic data are often restricted or unavailable. One strategy to mitigate lack of geologic data is the use of analogues from well-known, mature basins. Even though there have been attempts to use analogues to study the geology of the BSS, such use is limited. Moreover, no analogue, to my knowledge, has been capable of addressing the regional tectonostratigraphic development of the shelf as a whole.

In this research, the Appalachian …

3d Hydrostratigraphic And Hydraulic Conductivity Modeling Using Supervised Machine Learning, T. A. Tilahun, Jesse T. Korus Dr.

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Late Holocene Paleoflood Hydrology Of The Snake River In The Lower Hells Canyon, Idaho, Kent C. Allen

All Master's Theses

The Snake River watershed spans a large geographic region from the Rocky Mountains to the inland Pacific Northwest, and a comprehensive paleoflood chronology on the mainstem of the river is key to identifying the frequency and magnitude of large prehistoric floods within the region. We examined and compared four sites of slackwater deposits along a 20-km reach of the Lower Hells Canyon on the Snake River, Idaho. The sites contain evidence of up to 34 paleofloods within the last 1700 years. Stratigraphic breaks, soils, and in-situ plant or archaeological materials demarcate distinct layers that represent discrete paleoflood events. Radiocarbon dates …

Interpretive Geologic Maps And Cross Sections For Phelps, Kearney, And Adams Counties In Nebraska, Dana Divine, Leslie M. Howard

Conservation and Survey Division: Faculty and Staff Publications

Data from thousands of test-hole and well logs were interpreted to improve understanding and management of the High Plains aquifer in a three-county study area adjacent to the Big Bend reach of the Platte River. Five principal conclusions resulted from these interpretations: (1) the extent of Neogene Ogallala deposits beneath the study area is different than previously mapped; (2) a large paleovalley incised into Cretaceous bedrock probably cuts across Kearney and Adams counties and may be the course of the ancestral Platte River prior to formation of the Big Bend; (3) a groundwater mound created by irrigation canals artificially raises …

Major Lower Paleozoic Horizons Of The Southern Illinois Basin, John B. Hickman

Report of Investigations--KGS

The geology exposed at the surface in the southern Illinois Basin has been mapped in great detail by countless workers over the past century. With the exception of limited and scattered exposures in incised river valleys, the oldest rocks exposed outside of the Jessamine, Nashville, and Ozark Domes surrounding the Illinois Basin are Mississippian in age. Extensive deposits of Cambrian–Devonian sediments occur in the subsurface above crystalline basement in this region, however. All available data for the region were analyzed to produce a single, comprehensive set of interpretations. The data used in this study include 1:24,000-scale geologic quadrangle maps, oil …

Orientation Of Paleostress Of Raplee Ridge Anticline, Loren Randall Holyoak, John S. Maclean

The Compass: Earth Science Journal of Sigma Gamma Epsilon

During the Laramide Orogeny several major folds were formed in Southern Utah, one of those being the Raplee Ridge anticline. Raplee Ridge is approximately eight miles from Mexican Hat, Utah. The San Juan River cuts through the anticline, exposing the Honaker Trail Formation’s beds of shale and limestone with chert nodules. Accompanying the mountain-scale ductile deformation of the Raplee Ridge anticline are decimeter-scale brittle conjugate fractures in the limestone’s chert nodules. The objective of this study is to compare the orientation of paleostress that formed the Raplee Ridge anticline with the conjugate fractures within the chert nodules to see if …

Mapping And Reconstructing The Paleotsunami Record In Queule, South-Central Chile, Pedro I. Matos Llavona

All Master's Theses

Records of past tsunamis help constrain the long-term characteristics of megathrust earthquakes and elucidate the role of sea-level in the preservation of tsunami deposits. Near Queule, south-central Chile (39.3˚S, 73.2˚W), three sand layers interpreted as tsunami deposits are interbedded with dark, organic-rich, silt deposits along a tidal channel landward of a sand spit capped by eolian sand dunes. The uppermost sand layer is attributed to the tsunami from the Mw 9.5 1960 earthquake. The sand layer is widespread, tabular, oxidized, thins landward, and generally occurs at a depth of <20 cm. The spatial distribution of the deposit corresponds closely with the extent of the 1960 tsunami sand on 1961 aerial photographs. We computed numerical simulations of the 1960 tsunami in Queule using the GeoClaw finite-slip hydrodynamic model based on three published earthquake sources. The simulations showed inundation up to 4km inland that overtopped the coastal dunes; agreeing with historical documentation and testimonies of 1960 tsunami survivors. Stratigraphically below the 1960 tsunami deposit are two tabular, landward-thinning sand layers with sharp lower contacts above silty organic-rich layers. Combined radiocarbon ages of seeds, charcoal and wood fragments found at the contacts with the underlying organic layers yielded ages of 5460-5320 and 5990-5910 cal. years BP. These sand layers have similar distribution patterns to the 1960 sand layer, but are finer grained, thinner and less oxidized. Below this sequence of interbedded tsunami sands and silty organic layers there is an abrupt contact underlain by a distinct sequence of four inorganic silt layers alternating with dark brown organic-rich silts, which are older than 6280-6110 cal. years BP. The deepest studied layer is a thick, fine, gray sand. We interpret the gray sand as a submarine environment during the mid-Holocene sea-level high stand, and the alternating inorganic and organic silts as tidal to shallow sub-tidal environments, possibly indicating co-seismic land-level changes. Gradual sea level fall after the deposition of the two paleotsunami sand deposits that changed the geomorphology of the coast and limited the accommodation space necessary to preserve additional overwash sediments could explain the 5000-year hiatus with no evidence of earthquakes or tsunamis. Further research will offer possible explanations for the exception of the 1960 tsunami in breaking this long-term pattern.

Exploring The Northwest Margin Of The High Plains Aquifer: Structure, Depositional History And Hydrogeology, Nebraska Geological Society Field Trip, Doug Hallum, Dennis O. Terry, Jr., Michael Leite, Jennifer Balmat

Conservation and Survey Division: Faculty and Staff Publications

The northwest portion of the High Plains Aquifer in Nebraska corresponds with the western Sandhills, Box Butte, Sioux and Dawes County tablelands, and the Nebraska Pine Ridge in northwest Nebraska. This field excursion will travel beyond the margins of the High Plains aquifer into the White River valley and onto the Oglala National Grasslands. These areas are not only rich in natural resources, but rich in history as well. While this excursion will explore earth history, depositional environments and a portion of the High Plains Aquifer, the authors encourage all attendees to take additional time to explore the cultural, military …

Sequence Stratigraphy Of Campanian-Maastrichtian Strata In Eastern Alabama, David Simmons

Master's Theses

Eastern Alabama is an area of interest due to the transition from the Gulf Coastal Plain to the Atlantic Coastal Plain. Coastal Plain investigations have been sparse compared to research conducted in the oil rich areas down dip in the Gulf of Mexico. A sequence stratigraphic framework using the T-R cycle methodology of Embry (2002) has been established by integrating surface and subsurface lithologic data with biostratigraphic zonations into Petra ®. High sedimentation from the ancestral Chattahoochee River and lower relative sea-level formed an additional depositional sequence within the Santonian-Campanian aged Blufftown Formation in eastern Alabama. The sequence is approximately …

Influences Of Hurricanes, Floods, And Organic Production On River-Delta Evolution Over Decadal To Centennial Time-Scales, Crawford M. White

LSU Doctoral Dissertations

Episodic overbank flooding and sediment resuspension events (such as cold front passages or tropical cyclones) are recognized as important natural components for wetlands maintaining vertical equilibrium with sea-level. However, the relative importance of these components to an anthropogenically unmodified delta complex remains unclear. This study uses sediment cores to describe the relative importance of these vertical accretion components the Lafourche and Balize Deltas of the Mississippi River. Existing wetlands of the abandoned lower Lafourche receive no direct fluvial sediment, but instead are supported by sediment resuspended by tropical cyclones and cold fronts that pass over them. Wetlands of the modern …

Sandstones And Utah’S Canyon Country: Deposition, Diagenesis, Exhumation, And Landscape Evolution, David Loope, Richard Kettler, Kendra Murray, Joel Pederson, Peter Reiners

Department of Earth and Atmospheric Sciences: Faculty Publications

South-central Utah’s prominent sandstones and deeply dissected landscapes are the focus of this four-day trip, which begins and ends in Grand Junction, Colorado. Studies of the apatite grains in sandstones adjacent to igneous intrusions are revealing new information on the timing and rate of Cenozoic erosion. Iron-oxide-cemented concretions in other rocks record how reduced-iron carbonates and subsurface microbes interacted when near-surface, oxygenated waters started to flush the reducing, CO₂-rich waters from Colorado Plateau aquifers. New geochronologic techniques that are being applied to the plateau rocks have the potential to expand our knowledge of how diagenetic episodes relate to …

Sedimentological And Stratigraphic Study Of A Falling-Stage Delta Complex In The Upper Cretaceous (Turonian) Ferron Sandstone Member Of The Mancos Shale, South-Central Utah, Usa, Fares Alaboud

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The character and distribution of lithofacies in falling-stage deltas are incompletely documented. This paper presents a sedimentological and stratigraphic evaluation of a superbly-exposed interval of Cretaceous deltaic strata that are believed to be of falling stage origin. The studied interval forms part of the Upper Cretaceous (Turonian) Ferron Sandstone Member of the Mancos Shale in the southernmost Henry Mountains Basin of south-central Utah, USA. The interval of interest is exposed in three dimensions over a 20 km² area in a series of canyon walls. Observed facies include fine-grained mudrocks (offshore basin), mudrocks with thinly interlaminated sandstone (prodelta), thinly interbedded …

Geology Of The Southern Reveille Range, Nye County, Nevada, Matthew Alan Mckelvey

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Reveille Range in central Nevada provides a unique window into the mid-Miocene geology and volcanology of the central Great Basin during the "ignimbrite flare up." Although faulted along its margins, the interior of the range is relatively undeformed thus preserving volcanic centers. The Reveille Range contains three mid-Miocene caldera complexes. Previous studies have identified the Goblin Knobs caldera (25.6 Ma) in the central Reveille Range and the caldera of northern Reveille Range (25.3 Ma) to the north. These calderas are completely filled with intracaldera tuffs. This study has identified a younger third caldera located in the southern part of …

An Ordovician Global Reference Section Recently Selected In Oklahoma, Daniel Goldman, Stephen A. Leslie, Stig M. Bergström, Jaak Nõlvak, Seth A. Young, Stanley C. Finney

Department of Earth, Environment and Sustainability Faculty Publications

Ordovician fossil faunas are characterized by a marked biogeographic differentiation that results in a minimal similarity between most North American faunas and those of major Ordovician areas elsewhere in the world. This provincial distribution of most fossils has led to establishment of different schemes of fossil-based regional stages in, for instance, North America, Baltoscandia, China, and the British Isles.

Because these chrono-stratigraphic units have been largely based on shelly fossils with distributions restricted to a particular region, it has been impossible in most cases to establish a precise international correlation of these regional stages. Furthermore, some general terms, such as …

Pamphlet To Accompany Geologic Map Gmc-34: Geologic Map Of The O’Neill 1º X 2º Quadrangle, Nebraska, With Configuration Maps Of Surfaces Of Formations, Robert F. Diffendal Jr., Michael R. Voorhies, E. Jane Voorhies, H. E. Lagarry, C. L. Timperley, M. E. Perkins

Robert F. Diffendal, Jr., Publications

This map is necessarily generalized. It is based primarily on data from 7.5’ surficial geologic quadrangle maps of the map area prepared by the authors principally from 1991 to 2000, from Voorhies (unpublished data, 1974), as well as data from test-hole drilling done across the quadrangle by the Conservation and Survey Division, University of Nebraska, and its cooperators over many years since the 1930s. For more detailed information, consult the geologic data files of the Conservation and Survey Division, School of Natural Resources, University of Nebraska-Lincoln. The quadrangle is mostly covered by vegetation and Holocene sediments. Limited good exposures of …

The Global Stratotype Section And Point (Gssp) For The Base Of The Katian Stage Of The Upper Ordovician Series At Black Knob Ridge, Southeastern Oklahoma, Usa, Daniel Goldman, Stephen A. Leslie, Jaak Nõlvak, Seth Young, Stig M. Bergström, Warren D. Huff

Department of Earth, Environment and Sustainability Faculty Publications

The International Subcomission on Ordovician Stratigraphy (ISOS) of the International Commission on Stratigraphy (ICS) recently defined the base of the global Upper Ordovician Series to be at the first appearance datum (FAD) of the graptolite species Nemagraptus gracilis in the Fågelsång GSSP in southern Sweden. This designation recognized the tremendous utility for global correlation of the first appearance of a cosmopolitan taxon that occurs within a consistent succession of other first appearance datums (e.g., Finney and Bergström, 1986; Bergström et al., 2000). Current efforts by the ISOS have focused on subdividing the Upper Ordovician into three stages and choosing appropriate …

Mapping Of A Detachment Fault In Kythera Island And Study Of The Related Structural Shear Sense Indicators, Antonios Marsellos

Geology Theses and Dissertations

Kythera Island is located on the prominent submarine horst between Crete and the Peloponnese in the southwestern part of the Aegean. The structure of Kythera is characterized by a pile of tectonic slices derived from different paleogeographic zones. The upper unmetamorphosed units comprise pelagic limestones and cherts of Pindos zone emplaced by thrusting in the Eocene on top of Tripolis zone neritic limestones. These units are separated from the lower metamorphosed unit of Phyllite-Quartzite (PQU) exposed in the northern part of Kythera by an extensional detachment fault of Late Miocene age. The lower tectonic unit of PQU was affected by …

Magmatic Processes Operating During The Middle To Late Pliocene And Pleistocene Along The Transition Zone Near 43º North, Christy L. Lee

Dissertations and Theses

A geochemical and structural transition zone exists between the Cascades and Basin and Range provinces in Oregon. Geologic mapping in this area has allowed the definition of six volcanic rock sequences: 1) interfingered alkali-rich basaltic trachyandesite to trachydacite lava flows and low-alkali basaltic andesite lava flows, 2) HAOT lava flows, 3) basaltic andesite lava flows, 4) andesite lava flows and vent deposits with minor basaltic andesite lava flows, 5) HAB lava flows, and 6) interfingered basaltic andesite, andesite, and trachyandesite lava flows.

Geochemical models of sequence 1 alkali-rich rocks suggest the fractionation of the parent assemblage plag (An₅₅)+magn+ol±aug …

Grand Tour-Part 2: Petrogenesis And Thermal Evolution Of Deep Continental-Crust: The Record From The East Humboldt Range, Nevada, Allen J. Mcgrew, Mark T. Peters

Department of Earth, Environment and Sustainability Faculty Publications

The northern part of the East Humboldt Range, Nevada, provides a rare opportunity to explore the petrogenetic environment of deep levels in the middle crust during both large-scale Mesozoic contraction and Cenozoic regional extension. On this segment of the field trip, we will explore evidence bearing on the character of the metamorphic and magmatic history of this terrane, and attempt to link these constraints to the rheology and tectonic evolution of the middle crust during the Mesozoic and Cenozoic.

The Grand Tour Of The Ruby-East Humboldt Metamorphic Core Complex, Northeastern Nevada: Part 1-Introduction & Road Log, Arthur W. Snoke, Keith A. Howard, Allen J. Mcgrew, Bradford R. Burton, Calvin G. Barnes, Mark T. Peters, James E. Wright

Department of Earth, Environment and Sustainability Faculty Publications

The purpose of this geological excursion is to provide an overview of the multiphase developmental history of the Ruby Mountains and East Humboldt Range, northeastern Nevada. Although these mountain ranges are commonly cited as a classic example of a Cordilleran metamorphic core complex developed through large-magnitude, mid-Tertiary crustal extension, a preceding polyphase Mesozoic contractional history is also well preserved in the ranges. An early phase of this history involved Late Jurassic two-mica granitic magmatism, high-temperature but relatively low-pressure metamorphism, and polyphase deformation in the central Ruby Mountains. In the northern Ruby Mountains and East Humboldt Range, a Late Cretaceous history …

Geology Beneath The Primary Management Systems Evaluation Area (Msea) Site Southwest Of Shelton, Buffalo County, Nebraska, Robert F. Diffendal Jr., Frank A. Smith

Robert F. Diffendal, Jr., Publications

In 1990, as part of a national presidential initiative on water quality, researchers from the University of Nebraska–Lincoln (UNL) Institute of Agriculture and Natural Resources (IANR) received a multiyear grant from the U.S. Department of Agriculture, Cooperative State Research Service, to study management of irrigated corn and soybeans to minimize groundwater contamination. D. G. Watts, R. F. Spalding, and J.S. Schepers, of the IANR led a study at one of the Management Systems Evaluation Areas (MSEA). This area was made up of two sites, a primary site on a terrace of the Platte River near Shelton and a secondary site …

Application Of Sealevel Stratigraphy To Neogene Great Plains Stratigraphy, Robert F. Diffendal Jr., A. Lowrie

Robert F. Diffendal, Jr., Publications

Absolute-dated high frequency (Milankovitch cycles) marine climate/sealevel oscillatory stratigraphy can be correlated generally with continental stratigraphies. Improvements in absolute dating of Neogene formations across the North American Great Plains make this a candidate area in which to correlate marine and continental stratigraphies. Mid-latitude continental areas respond directly to climate variations. During glaciated/ cold climates, sealevel lowering results in steepened river gradients, increased erosion all along the river channel, and larger stress-bed loads. This, combined with glacial catastrophic flooding, produces greater cut-and-fill sequences along river systems than crevasse splays along the emergent coastal plain, deltas along the shelf, and submarine fans …

Stable Isotope Composition Of Calcareous Paleosols And Ground-Water Cements From The Ogallala Group (Neogene), Western Nebraska, Leonard Robert Gardner, Robert F. Diffendal Jr., Douglas F. Williams

Robert F. Diffendal, Jr., Publications

A preliminary survey has been made of the stable isotope composition of secondary carbonates in the Ogallala Group of western Nebraska. The purpose of the study was to ascertain whether the isotopic signatures of calcareous paleosols in the fine grained facies of the Ogallala and groundwater cements in gravel facies might provide a basis for stratigraphic correlation and/or paleoclimatic interpretation.

The groundwater cemented channel gravels are modestly depicted in IRO (δ¹⁸O = –10‰) as compared to calcareous paleo'sols (δ¹⁸O = –8.0 to –9.0‰). Gravels of different age, however, have essentially identical isotopic signatures. The isotopic variability …

Development And Application Of Some Quantitative Stratigraphic Techniques To The Coos Bay Coalfield, A Tertiary Fluvio-Deltaic Complex In Southwestern Oregon, Willard Sidney Titus Iii

Dissertations and Theses

A computer technique for interpreting geophysical logs of drill-holes in quantitative lithologic terms has been developed and tested on the deposits of the late Eocene Coaledo Formation, a well-studied fluvio-deltaic complex in southwestern Oregon. The technique involves the use of induced and natural gamma logs for separation of coal and claystone from coarse-grained detrital rocks and the use of the ratio of resistivity and natural gamma responses (defined here as the "grain size index") to divide the coarse elastic rocks into a series of textural classes corresponding to the Wentworth-Odden particle size scale.

Biomarker Geochemistry Of The Miocene Monterey Formation, West San Joaquin Basin, California: Implications For Petroleum Generation, Michael A. Kruge

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Much of the Miocene Monterey Formation of California is rich in biogenic sediment, especially organic matter and silica. Because of the geologic structure, the Monterey in the subsurface near Lost Hills in the San Joaquin Basin forms a natural laboratory for the study of the diagenetic responses of these materials. Rocks of similar age and lithology are buried to depths ranging between 500 and 3500 m, and are thus exposed to a temperature range of 45–130°C. The diagenetic progression of silica from opal-A to opal-CT to microquartz is well-documented in Monterey burial history studies. However, diagenetic indicators need to be …

The Stratigraphic Relationships Of The Columbia River Basalt Group In The Lower Columbia River Gorge Of Oregon And Washington, Terry Leo Tolan

Dissertations and Theses

The purpose of this study was to produce a detailed geologic map of the CRBG in the western portion of the Columbia River Gorge (fig. 1). The objectives were (1) to identify and delineate the extent of the Priest Rapids Member and Pomona Member intracanyon flows, and (2) to define the relationship of post-CRBG units to the CRBG intracanyon flows.

Regional Implications Of The Geology Of The Ogallala Group (Upper Tertiary) Of Southwestern Morrill County, Nebraska, And Adjacent Areas, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

A part of a filled Ogallala Group (upper Tertiary) paleovalley system exhumed by recent stream erosion in southwestern Morrill County, Nebraska, and adjacent areas contains steep gradient gullies filled with locally derived sediments. Younger channels filled with granitic gravels derived by stream erosion of the Rocky Mountains to the west and southwest cut across and through these older filled gullies, indicating that there were at least two periods of downcutting followed by periods of filling during the development of this system.

Individual clasts from younger Ogallala gravels are often as large as or larger than clasts from Quaternary gravels transported …

Tourmaline - A Prospecting Guide For Massive Base-Metal Sulfide Deposits In The Penobscot Bay Area, Maine, John F. Slack

Maine Collection

Tourmaline - A Prospecting Guide for Massive Base-Metal Sulfide Deposits in the Penobscot Bay Area, Maine

by John F. Slack, U.S. Geological Survey

Special Economic Studies Series No.8

Maine Geological Survey, Department of Conservation, Augusta, Maine (June, 1980).

Contents: Abstract / Introduction / Geologic Setting / Massive Sulfide Deposits / Tourmaline Occurrences / Tourmaline: A Guide to Ore / Acknowledgements / References Cited