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

Earth Sciences Commons™

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

Geology

Discipline
Institution
Publication Year
Publication
Publication Type
File Type

Articles 1 - 30 of 902

Full-Text Articles in Earth Sciences

Minerals Rock!: Improving Audience Engagement And Interest In Stem Through Enhancement Of The In-Person And Online Mineral Collection At Ursinus College, Juliette Lyons Jul 2026

Minerals Rock!: Improving Audience Engagement And Interest In Stem Through Enhancement Of The In-Person And Online Mineral Collection At Ursinus College, Juliette Lyons

Environment and Sustainability Summer Fellows

Museums are a vital source of educational resources for the general public. They provide information on a variety of topics and disciplines and encourage visitors to be excited about and engaged in learning something new. As we work to comprehend key topics such as climate change, it is especially important for the broader public to better understand science, including geology. While the geological collection at Ursinus, Pieces of Earth’s History, is not in a museum, implementing methods that museums use can improve the reception of the collection. Through the application of research gathered through articles, journals, books, and talking with …


Ecological Footprint Assessment, Santina Benincasa Jul 2026

Ecological Footprint Assessment, Santina Benincasa

Open Educational Resources

This handout guides students through a structured ecological footprint assessment using the online Footprint Calculator. By following a series of steps—selecting their location, entering detailed lifestyle information, and reviewing personalized results—students evaluate how many planets would be required if everyone lived with their same resource consumption patterns. The activity prompts learners to identify the largest contributors to their footprint, quantify their impact in global hectares, and explore scenario-based changes that could reduce their environmental demand. Through reflection, students consider how everyday human behaviors influence Earth’s productive capacity and resource availability. Overall, the exercise encourages critical thinking about sustainability and personal …


Shallow-Marine Crinoid Genera May Have Been More Resilient Across Permian Extinction Events In Terms Of Richness Than Deep-Marine Crinoid Genera, Amelia C. Kolstad Jun 2026

Shallow-Marine Crinoid Genera May Have Been More Resilient Across Permian Extinction Events In Terms Of Richness Than Deep-Marine Crinoid Genera, Amelia C. Kolstad

University Honors Theses

Throughout the Phanerozoic, one of the most successful phyla of marine invertebrates has been Echinodermata. Echinodermata was particularly successful throughout the Paleozoic, with class Crinoidea making up a majority of occurrences. The proportion of echinoderm occurrences that are crinoids declined massively at the end of the Permian and continued to decrease into modern day, never fully recovering. One of the factors thought to have been so important for crinoid success in the Paleozoic and their decreasing success throughout geologic time has been their propensity for success in shallow-marine environments, though crinoids also exist within deep-marine environments. This study seeks to …


Analyzing Surface Water And Groundwater Interactions From Pfas Contamination In The West Plains Region Of Spokane County, Jerusha R. Hampson May 2026

Analyzing Surface Water And Groundwater Interactions From Pfas Contamination In The West Plains Region Of Spokane County, Jerusha R. Hampson

2026 Symposium

The West Plains region of Spokane County has been significantly impacted by PFAS contamination due to the decades-long use of aqueous film-forming foam (AFFF) for firefighting training at both Fairchild Air Force Base (FAFB) and the Spokane International Airport (SIA). Groundwater contamination is significant, but surface waters are impacted by the contamination as well. Groundwater flows to the north and east, meaning surface water bodies that make up the northern and eastern boundaries (Deep Creek, Hangman Creek, and the Spokane River) can be impacted by PFAS contamination. The West Plains aquifer system is complex but combining data about aquifer flow …


Mineralogy, Geology, And Geochemistry Of The Mcafee Quarries And Greater Mcafee Area, Sussex County, New Jersey, Cristian J. Van Rossen May 2026

Mineralogy, Geology, And Geochemistry Of The Mcafee Quarries And Greater Mcafee Area, Sussex County, New Jersey, Cristian J. Van Rossen

Theses, Dissertations and Culminating Projects

The Franklin Marble is one of North America’s most famous geologic units, a result of its complex geology, diverse mineralogy, and significant ore deposits. While it has been widely studied, a location that has received little attention is that of the quarries at McAfee, Vernon Township, NJ. This study addresses this oversight by investigating the mineralogy, geology, and geochemistry of the marble and associated geologic units found in the area. Sample analysis consisted of physical and optical analysis as well as chemical analysis using SEM-EDS. Geochemical analysis using ICP-MS allowed for major, trace, and rare earth element concentrations of select …


Active And Passive Seismic Studies Across Glacial And Geothermal Environments, Lucia Fernanda Gonzalez May 2026

Active And Passive Seismic Studies Across Glacial And Geothermal Environments, Lucia Fernanda Gonzalez

Open Access Theses & Dissertations

The collection of passive and active-source seismic data remains central to the detailed investigation and understanding of complex Earth processes across diverse and often inaccessible environments. Of equal importance is the selection of methodologies that must be tailored to the geological setting and dataset resolution to accurately depict the subsurface. In this dissertation, we apply a range of classic and/or "newly" developed algorithms, unique to each chapter, on seismic datasets from distinct glaciological and geothermal settings to evaluate their performance and enhance subsurface interpretation. In Chapter 1, we analyze active-source seismic data from Lemon Creek Glacier in Juneau, Alaska, using …


Geology Lab Activities An Open Educational Resource For Community College Students And Instructors, Rondi Davies, Ari Nakamura Mar 2026

Geology Lab Activities An Open Educational Resource For Community College Students And Instructors, Rondi Davies, Ari Nakamura

Open Educational Resources

I'm delighted to present the updated version of Geology Lab Activities, initially developed during the COVID-19 pandemic for online learning. As we have returned to the classroom, this revised edition remains a versatile educational tool for community college students, adaptable for both online and in-person classes.

This manual combines my preferred open-access materials with my own contributions, forming a cohesive resource for non-major geology students. Thanks to a CUNY OER grant, I partnered with graphic designer Ari Nakamura, whose innovative and elegant design has truly elevated the book.

Our labs are crafted to be engaging and relevant for non-major …


Geochemical And Petrological Observations Of The June Lake Basalt, Eastern California, Daniel Jacob Abel Jan 2026

Geochemical And Petrological Observations Of The June Lake Basalt, Eastern California, Daniel Jacob Abel

Cal Poly Humboldt theses and projects

The June Lake basalt is a monogenetic cinder cone and 11-km-long lava flow in eastern California located ~10 km NW of the Long Valley caldera. The stratigraphic position of the June Lake basalt between Tahoe and Tioga glacial deposits suggests an eruption age of only ~20-45ka. This age places the June Lake Basalt among the youngest volcanic eruptions in the Long Valley-Mono Basin region, where volcanic activity spans from the late Pliocene to the Holocene. The goal of this study is to use field observations coupled with whole-rock and crystal geochemical analyses to investigate the magma source and pre-eruption magma …


Preliminary Analysis Of The Spatial Distribution Of Microplastics Along The Cuyahoga River, Northeast, Ohio, Ella Pitz Jan 2026

Preliminary Analysis Of The Spatial Distribution Of Microplastics Along The Cuyahoga River, Northeast, Ohio, Ella Pitz

Williams Honors College, Honors Research Projects

Plastics are nearly ubiquitous throughout modern society, and when left in the natural environment, they degrade into microplastics. Microplastics are particles that range in diameter from 5 millimeters down to nanometers, and microplastics pose many potential environmental and health risks due to their small size and ease of ingestion. While the study of microplastics in the environment has become more common over the past ten years, microplastic concentrations remain unexplored in many regions throughout the country. Here I present a method for separating microplastics from organic matter and clastic sediment as well as preliminary measurements of microplastic concentrations in sediment …


An Analysis Of Volcanic Lightning And Its Controlling Factors, Nathan Stamford Jan 2026

An Analysis Of Volcanic Lightning And Its Controlling Factors, Nathan Stamford

Honors Theses

Volcanic lightning, first documented during the 79 AD eruption of Mount Vesuvius, includes any electrical discharge that is generated during a volcanic eruption rather than a thunderstorm. By analyzing individual eruptions and performing laboratory experiments, previous research has identified multiple controlling factors that influence the charging mechanisms and generation of volcanic lightning. While the previous research has made significant discoveries about the phenomenon, the exact relationship between many of these controlling factors and volcanic lightning generation has been poorly quantified. In this study, we investigate these controlling factors and show that they have a wide range of influence over volcanic …


Paleo-Environmental Change In Deer Lagoon, Whidbey Island Interpreted From Diatoms And Lithology, Lourdes Garcia Jan 2026

Paleo-Environmental Change In Deer Lagoon, Whidbey Island Interpreted From Diatoms And Lithology, Lourdes Garcia

All Master's Theses

Puget Sound is a densely populated, tectonically active area that can be affected by earthquakes from local crustal faults and the Cascadia subduction zone capable of producing abrupt coseismic subsidence. Tidal wetlands are particularly sensitive to abrupt changes because they are depositional environments that reside at sea-level and their lithology and ecological communities are strongly controlled by elevation within the tidal frame. As a result, coseismic subsidence can disrupt established environmental gradients and leave distinguishable signatures preserved within the stratigraphy, like tidal mud directly over peat deposits. These preserved records provide an opportunity to reconstruct past earthquakes and associated relative …


Paleoflood Chronology For The West Branch Of The Susquehanna River Using Abandoned Chute Channel Sediments, Pennsylvania, Usa, Juliette A. Vanluven Jan 2026

Paleoflood Chronology For The West Branch Of The Susquehanna River Using Abandoned Chute Channel Sediments, Pennsylvania, Usa, Juliette A. Vanluven

Honors Theses

Anthropogenic climate change is altering the hydrologic cycle, increasing flood frequency and severity, with associated increased risks in population exposure. This is associated with increasing risks to the population of the Susquehanna River Valley, which supports over 600,000 people today. However, our understanding of the frequencies of large floods is limited by relatively short instrumental records. By studying sediments from an abandoned chute channel in the Robert Allen Natural Area near Williamsport, PA, we can extend the existing flood records using paleoflood slackwater sediments along the West Branch of the Susquehanna River.  Sylvan Dell is an abandoned chute channel that …


The Effects Of A Microplate On Plume-Ridge Interactions: Constraints From Comparing Easter And Juan Fernandez Microplates In The Eastern Pacific Ocean, Katherine Ames, Jennifer Georgen Jan 2026

The Effects Of A Microplate On Plume-Ridge Interactions: Constraints From Comparing Easter And Juan Fernandez Microplates In The Eastern Pacific Ocean, Katherine Ames, Jennifer Georgen

OES Faculty Publications

This study investigates the nature of plume-ridge interactions near a tectonic microplate using mantle Bouguer anomaly (MBA) gravity calculations. The focus of this investigation is a comparison of the Easter and Juan Fernandez microplates, which are located in the eastern Pacific Ocean along the Pacific, Nazca, and Antarctic plate boundaries. The microplates have several similar characteristics, including general size, time of formation, and clockwise rotation within the larger bounding mid-ocean ridge systems. Unlike the Juan Fernandez microplate, however, the Easter microplate is located near a mantle plume (Easter/Salas y Gomez). Previously published geochemical data suggest that material from this plume …


Road Log For The Natural History Of The Owens Valley And Eastern Sierra Nevada, D. D. Trent Jan 2026

Road Log For The Natural History Of The Owens Valley And Eastern Sierra Nevada, D. D. Trent

Eastern Sierra History Journal

D.D. Trent, who taught Geology at Citrus College in Southern California for many years, developed this 1982 Road Log for his students for use on field trips. It contains many scientific findings and historical insights about the region and he also contributed hand-drawn maps and illustrations to capture their attention. The Road Log is introduced by Char Miller's essay, "Driving into the Past" and then annotated and updated by Prof. Nicole Moore in an article that follows.


D.D. Trent 1982 Natural History Of Owens Valley/Eastern Sierra: Annotations And Updates, Nicole E. Moore Jan 2026

D.D. Trent 1982 Natural History Of Owens Valley/Eastern Sierra: Annotations And Updates, Nicole E. Moore

Eastern Sierra History Journal

Prof. Moore offers some annotations to and updates of D.D. Trent's 1982 Road Log. These revisions are part of the evolution of scientific knowledge and the adaptation of new technologies that enable a deeper understanding of the geology of the Owens Valley and Eastern Sierra. Like Trent, Moore has routinely taken her students up US 395 to explore and assess the region's geological formations.


Integrated Seismic And Sequence Stratigraphic Analysis Of The Abu Madi Formation, Baltim Field, Nile Delta, Egypt, Nouran Mostafa Eissa, Mostafa Toni, Alhussein Adham Basheer, Amr Talaat, Amir Ismail Jan 2026

Integrated Seismic And Sequence Stratigraphic Analysis Of The Abu Madi Formation, Baltim Field, Nile Delta, Egypt, Nouran Mostafa Eissa, Mostafa Toni, Alhussein Adham Basheer, Amr Talaat, Amir Ismail

Trends in advanced sciences and technology

Despite the economic significance of the Messinian Abu Madi Formation as a primary gas reservoir target in the Nile Delta Basin, a high-resolution, field-scale integration of seismic sequence stratigraphy with quantitative petrophysical characterization remains lacking for the Baltim area. This study addresses this gap by presenting an integrated seismic sequence stratigraphic and petrophysical analysis of the Upper Miocene Abu Madi Formation within the prolific Baltim gas fields, offshore Nile Delta, Egypt. The objectives are to characterize its depositional architecture, delineate reservoir distribution, and assess hydrocarbon potential. The workflow synthesizes well log data from five key wells with a grid of …


Structural Geology Of The Brady Mountain Area, Ouachita Mountains, Arkansas: Integrating Field Mapping, Geospatial Techniques, Photogrammetry And 3d Modeling For Structural Analysis, Emmanuel Darko, Zachariah Fleming Dec 2025

Structural Geology Of The Brady Mountain Area, Ouachita Mountains, Arkansas: Integrating Field Mapping, Geospatial Techniques, Photogrammetry And 3d Modeling For Structural Analysis, Emmanuel Darko, Zachariah Fleming

Electronic Theses and Dissertations

Much of the Ouachita orogenic belt, representing the deformed Paleozoic rocks flanking the southern margin of the North American craton, is buried beneath post-orogenic Mesozoic and Tertiary sediments composing the Gulf Coastal Plain. The Ouachita Mountains of Arkansas and Oklahoma are the largest areas of outcrop for the Pennsylvanian-age Ouachita orogenic belt, making it an ideal place to study the orogeny. This study focuses on the Brady Mountain area within the Benton Uplift, the orogenic core of the Ouachita Mountains in western Arkansas. The region is comprised of numerous ridges trending nearly east-west and are for the most part densely …


East Antarctic Ice Sheet History At The Outback Nunataks Using Geographic Information Systems And Cosmogenic Dating, Jacob P. Baker Dec 2025

East Antarctic Ice Sheet History At The Outback Nunataks Using Geographic Information Systems And Cosmogenic Dating, Jacob P. Baker

Electronic Theses, Projects, and Dissertations

This study investigates the history of ice sheet surface elevation at the Outback Nunataks in East Antarctica using exposure age dating and geomorphic mapping. We identified glacial landforms at Roberts Butte, Miller Butte, and Frontier Mountain, in the Outback Nunatak range, using 2023 Landsat Image Mosaic of Antarctica (LIMA) and 2022 Reference Elevation Model of Antarctica (REMA). We collected bedrock and glacial erratic samples for cosmogenic nuclide analysis from Roberts Butte and Miller Butte during the 2023-24 United States Antarctic Program field season. Analysis of glacial erratics reflect inherited cosmogenic nuclide concentrations, resulting in apparent exposure ages between 359 and …


One Year Of Analysis Of Pfas Contamination In Surface Waters Of The West Plains Region Of Spokane County, Jerusha R. Hampson Jul 2025

One Year Of Analysis Of Pfas Contamination In Surface Waters Of The West Plains Region Of Spokane County, Jerusha R. Hampson

2025 Symposium

The West Plains has been significantly impacted by PFAS contamination due to the decades-long use of aqueous film-forming foam (AFFF) for firefighting training at both Fairchild Air Force Base (FAFB) and the Spokane International Airport (SIA). Groundwater contamination is significant, but less work had been done to understand contamination in surface waters. We now have over a year of data with most locations were sampled seasonally. Though FAFB and SIA are likely sources for some of the contamination, other, smaller sources exist. Surface waters are important to study as they form the boundaries of the West Plains and often function …


The Discovery, Communication, And Implementation Of New Geologic Findings: Examining The Cascadia Earthquake, Saylor Brainard Jun 2025

The Discovery, Communication, And Implementation Of New Geologic Findings: Examining The Cascadia Earthquake, Saylor Brainard

University Honors Theses

The Cascadia Subduction Zone, located off the Coast of the Pacific Northwest, is at risk of generating a 9.0 magnitude earthquake in the near future. Despite its significance, the discovery of the seismic potential of Cascadia didn't occur until 1987, when geologist Brian Atwater searched for non-traditional forms of earthquake evidence. As decades of continued research fleshed out Atwater's initial discovery, the implications associated with the discovery became apparent, presenting Washington and Oregon with the high probability that a massive earthquake will take place within the next century. Communicating the severity of this geologic discovery to both the public and …


Investigation Of Retention And Dehydration Of Preformed Particle Gel For Conformance Control In Fractured Carbonates, Abdulaziz A. Almakimi, Abdullah O. Almansour, Junchen Liu, Baojun Bai, Ibnelwaleed A. Hussein Jun 2025

Investigation Of Retention And Dehydration Of Preformed Particle Gel For Conformance Control In Fractured Carbonates, Abdulaziz A. Almakimi, Abdullah O. Almansour, Junchen Liu, Baojun Bai, Ibnelwaleed A. Hussein

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Preformed particle gel (PPG) treatment has proved to be among the most effective methods to reduce excessive water production in fractured reservoirs. The blocking ability of PPGs to fractures or fracture-like features is highly dependent on injected gel properties and volume. Gel dehydration during extrusion through fracture is common and has a considerable effect on gel properties, transport, and plugging efficiency. As the gel particles propagate through the fracture, continuous dehydration is often associated and causes the gel to concentrate and require high-pressure gradients to move. Dehydration might be desirable to a certain limit because it can help to form …


Latah Formation: History And Case Studies, Kylee M. Woodworth May 2025

Latah Formation: History And Case Studies, Kylee M. Woodworth

2025 Symposium

The Latah Formation is a series of discontinuous sedimentary interbeds between the flows of the Columbia River Flood Basalts outcropping across northern Idaho and eastern Washington. Ages ranging between the Middle to Upper Miocene, the sediments represent varied fluvio-lacustrine environments. The deposits are predominantly composed of claystones and shales as alternating, laminated couplets, many containing a variety of fossils. Though the sediments may appear similar across localities, they come from different source rocks, ranging from ashes from Yellowstone hotspot to metamorphic rock from nearby hills. These ancient lacustrine and fluvial environments allowed for great preservation of fossils, often in great …


Structural Analysis Of Catawissa Quadrangle, Columbia County, Pennsylvania, Kylee M. Woodworth May 2025

Structural Analysis Of Catawissa Quadrangle, Columbia County, Pennsylvania, Kylee M. Woodworth

2025 Symposium

Catawissa Mountain within Columbia County, Pennsylvania is a part of a much large system of mountains called the Appalachian Mountains. Though little more than hills today, the Appalachian Mountains are some of the oldest mountains in the Americas, dating back to after the separation of the supercontinent, Pangea. This presentation is about the structure interpretations of the Catawissa 7.5 Minute Quadrangle, located in Columbia County, Pennsylvania, including fold analysis of the SW trending Catawissa Syncline, formed from Appalachian fold-thrust belt. These analyses are to decipher how the mountain formed from the surrounding regional tectonics and the timeframe of when the …


Geochemistry Of The Inyo Volcanic Chain, And Evaluation Of The Portable Niton Xrf Instrument, Dylan Terry May 2025

Geochemistry Of The Inyo Volcanic Chain, And Evaluation Of The Portable Niton Xrf Instrument, Dylan Terry

Electronic Theses, Projects, and Dissertations

The Inyo Volcanic Chain (IVC) is a series of rhyolitic lava domes straddling the northwest rim of the Long Valley Caldera (LVC), most recently erupting ~650 years ago, producing the South Deadman, Obsidian, and Glass Creek Domes. For this study, samples were analyzed for geochemistry and petrography at six of the IVC domes. To measure geochemistry, a portable x-ray fluorescence machine (PXRF) was used, in part to test how well it performed on felsic rocks. The PXRF performed poorly with the factory calibration in detecting most elements, though detection of some elements improved with a calibration curve applied. The three …


A Mineralogical And Geochemical Investigation Of The Influence Of Tectonic Setting On Accessory Mineral Assemblages In Serpentinites Along The Western North American Margins, Bryan H.T. Seymour May 2025

A Mineralogical And Geochemical Investigation Of The Influence Of Tectonic Setting On Accessory Mineral Assemblages In Serpentinites Along The Western North American Margins, Bryan H.T. Seymour

Electronic Theses, Projects, and Dissertations

Serpentinites are metamorphic rocks typically produced by hydrating mantle peridotites to form assemblages containing one or more serpentine minerals. They occur in various tectonic and geologic settings, such as submarine hydrothermal systems, ophiolite sequences, and the forearc mantle. Serpentinites are associated with highly reduced conditions, as indicated by low oxygen fugacity (ƒO₂) values. Previous investigations suggest that oxygen fugacity varies with tectonic setting due to differences in environmental conditions. To test this hypothesis, we analyzed serpentinites from a wide variety of tectonic settings in western North America: The New Idria forearc diapir (CA), Canyon Mountain Island arc complex (OR), Josephine …


Lidar-Based Delineation Of Karst Features In The Gypsum Plain, Eddy County, New Mexico And Culberson County, Texas, Kaitlyn Rae Levassar May 2025

Lidar-Based Delineation Of Karst Features In The Gypsum Plain, Eddy County, New Mexico And Culberson County, Texas, Kaitlyn Rae Levassar

Electronic Theses and Dissertations

The Gypsum Plain of the Delaware Basin encompasses approximately 1,800 km2 of massive to laminated gypsum (anhydrite in the subsurface) outcrop of early Ochoan Castile and Salado strata. These extensive Permian-age evaporites host significant karst phenomena as a result of the region's complex hydrogeologic system which has continuously evolved since the early Paleogene. Karst features that manifest surficially as sinkholes when breached range from extensive hypogene cave systems to epigene features and suffosion caves. In contrast, paleo-collapse structures forming breccia pipes attesting to more ancient karst within these strata often manifest as topographic highs across the Gypsum Plain.

Until …


A New Method Using Lidar And Well Logs To Identify And Correlate The Pennsylvanian Atoka Formation Subdivisions In The Surface Outcrops Of The Boston Mountains, Arkansas, Robert Brent Boyd May 2025

A New Method Using Lidar And Well Logs To Identify And Correlate The Pennsylvanian Atoka Formation Subdivisions In The Surface Outcrops Of The Boston Mountains, Arkansas, Robert Brent Boyd

Graduate Theses and Dissertations

The surface outcrops of the Boston Mountains in northwest Arkansas primarily consist of the Pennsylvanian Atoka formation. Where fully preserved in the Arkoma Basin to the south, the Atoka formation exceeds 18,000 ft of sand and shale. However, it remains undifferentiated on the surface geological map of Arkansas. This study investigates the possibility of identifying and correlating the subsurface subdivisions of the Atoka Formation to the surface outcrops of the Boston Mountains using a new method. Recognizing the Atoka subdivisions in surface outcrops using standard lithology and biostratigraphy correlation techniques has been challenging. The subdivision of the Atoka has instead …


Leveraging Machine Learning Models For Enhanced Landslide Prediction In Western North Carolina, Andrew Edmonds May 2025

Leveraging Machine Learning Models For Enhanced Landslide Prediction In Western North Carolina, Andrew Edmonds

Graduate Theses and Dissertations

Landslides pose significant hazards to human safety, infrastructure, and the environment, particularly in regions of high elevation that experience extended periods of heavy rainfall. This research focuses on preparing and evaluating landslide susceptibility maps (LSMs) for the Blue Ridge Mountains, a portion of the Appalachian Mountains in western North Carolina, utilizing three machine learning algorithms: Logistic Regression, Random Forest, and Gradient Boosting Regression. Sixteen landslide conditioning factors, reflecting topographic, geological, environmental, and anthropogenic influences, were identified for model input. The landslide inventory database, comprising 7,350 locations, was randomly divided into training (80%) and testing (20%) sets. The performance of each …


Insights From Automated Mineralogic Analysis Of Modern Sand, Quinten Jones May 2025

Insights From Automated Mineralogic Analysis Of Modern Sand, Quinten Jones

Graduate Theses and Dissertations

Methods for determining and categorizing the modal compositions of sand and sandstone have long been a subject of debate in the field of sedimentary geology. Point counting is the most commonly used technique for determining modal compositions from petrographic slides, which are then categorized based on relative proportions of quartz, feldspar, and rock (or lithic) fragments. However, this approach fails to adequately preserve relevant textural data, such as grain size and sorting, which play an important role in diagenesis and in influencing reservoir quality. Additionally, the categorical nature of point counting results in a lack of specificity and loss of …


Geology Of Nacogdoches, Texas : Geogulf 2025, R. Larell Nielson Apr 2025

Geology Of Nacogdoches, Texas : Geogulf 2025, R. Larell Nielson

Faculty Publications

Nacogdoches and East Texas are geologically interesting places to live and work. This field trip will visit the locations indicated on the maps below (Figures 1 and 2). Our location is on the Sabine Uplift and is east of the East Texas Salt Dome Basin (Figure 3 and 4). The first producing oil well in Texas was drilled near Woden by Taliaferro Barret in 1866 at a depth of 106 feet, producing about 10 barrels a day from the Sparta Sand (Figures 5 and 6). Stratigraphic units that we will see are: Sparta Sand, Weches Formation, Queen City Sand, Reklaw …