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Full-Text Articles in Geology

The Role Of Introductory Geoscience Courses In Preparing Teachers—And All Students—For The Future: Are We Making The Grade?, Anne E. Egger Oct 2019

The Role Of Introductory Geoscience Courses In Preparing Teachers—And All Students—For The Future: Are We Making The Grade?, Anne E. Egger

Geological Sciences Faculty Scholarship

Introductory geoscience courses enroll hundreds of thousands of students a year, most of whom do not major in the geosciences. For many, including future K–12 teachers, an introductory course is the only place they will encounter Earth science at the college level. New standards for K–12 science education have profound implications for teacher preparation, particularly in Earth science. The new standards call for taking a systems approach, highlighting how humans interact with Earth, making use of science and engineering practices, and engaging students in discourse. Analysis of responses to the National Geoscience Faculty Survey (n = 813 in 2004; …


The Spatial And Temporal Evolution Of The Portland And Tualatin Basins, Oregon, Usa, Darby Patrick Scanlon Aug 2019

The Spatial And Temporal Evolution Of The Portland And Tualatin Basins, Oregon, Usa, Darby Patrick Scanlon

Dissertations and Theses

The Portland and Tualatin basins are part of the Puget-Willamette Lowland in the Cascadia forearc of Oregon and Washington. The Coast Range to the west has undergone Paleogene transtension and Neogene transpression, which is reflected in basin stratigraphy. To better understand the tectonic evolution of the region, I modeled three key stratigraphic horizons and their associated depocenters (areas of maximum sediment accumulation) through space and time using well log, seismic, outcrop, aeromagnetic, and gravity data. Three isochore maps were created to constrain the location of Portland and Tualatin basin depocenters during 1) Pleistocene to mid-Miocene (0-15 Ma), 2) eruption of …


Effects Of Heat Treatment Of Spinels As Determined By Vis/Nir And Raman Spectroscopy And Xrd, Jill Reale, Dr. Michael B. Wolf Jun 2019

Effects Of Heat Treatment Of Spinels As Determined By Vis/Nir And Raman Spectroscopy And Xrd, Jill Reale, Dr. Michael B. Wolf

Celebration of Learning

Heat treatment is done to improve the color and clarity and, therefore, the value of gemstones. The objectives of this study include observing color and inclusion changes in pink spinels after heat treatment, and analyzing structural changes within differently colored spinels using Raman Spectroscopy and X-ray diffraction with a Paris Edinburgh Press. We expected the heat treatment to yield color changes and fading of small inclusions. Cut and polished spinels were heated to 1400C for 2 days or 850C for 3 days. Future experiments involve 800C, 750C, and 700C all for 1 week, 1500C for 4 days, and 1600C for …


Investigation Of Pervasive Clay Layers And Their Effect On Groundwater Flow Using Electrical Resistivity Tomography In The San Antonio Groundwater Basin, James M. Carlson Jun 2019

Investigation Of Pervasive Clay Layers And Their Effect On Groundwater Flow Using Electrical Resistivity Tomography In The San Antonio Groundwater Basin, James M. Carlson

Natural Resources Management and Environmental Sciences

The United States Geological Survey is developing an integrated hydrologic model of the San Antonio Creek Groundwater Basin to better understand and simulate the integrated surface water and groundwater system. An abrupt 60 meter offset in groundwater depth over a distance of less than one kilometer is observed in well readings within the Cañada De Las Flores region of the groundwater basin. Abrupt changes in groundwater levels are often explained by the presence of a fault in the subsurface vertically offsetting sedimentary units. However, observations of the structural geology of this region indicates that faulting is unlikely and suggests an …


Genetic Sequencing For Measuring Biodiversity In Recent And Ancient Marine Sediments, Lauren Judge May 2019

Genetic Sequencing For Measuring Biodiversity In Recent And Ancient Marine Sediments, Lauren Judge

Celebration of Learning

Taxonomic biodiversity, measured by counting the number of species present in a given area, is the most common method of capturing ecosystem biodiversity in recent and ancient environments. While this method is widely accepted, it is limited by poor preservation and identification of many individuals, making it impossible to include every species within an ecosystem and resulting in the loss of some diversity information. To address this issue, we measured the genetic biodiversity (in which species are determined based on sequencing of their DNA) of shallow marine ecosystems by extracting and sequencing the 18S ribosomal gene from bulk carbonate sediment …


Geochemical Analysis Of The Chinchín Formation In Southern Ecuador, Katherine Ludwig May 2019

Geochemical Analysis Of The Chinchín Formation In Southern Ecuador, Katherine Ludwig

Celebration of Learning

The subduction of the Nazca Plate under the South American Plate has led to the uplift of the majority of the Andes Mountains, but in Ecuador, the Nazca Plate subducts underneath the North Andes Plate, which then collides with the South American Plate. This tectonic setting has formed two parallel mountain chains as well as a complex series of basins between them. However, the formations that make up these basins are poorly understood. This study focuses on the Chinchín Formation, an ~3.5 km thick, volcanic formation that serves as the bedrock of the Quingeo Basin in southern Ecuador. This study …


Multi-Proxy Characterization Of Acex Subunit 1/5 (The “Zebra” Interval) To Better Understand Sediment Deposition At This Critical Age Boundary And Paleoceanographic Transition, Victoria Hojnacki May 2019

Multi-Proxy Characterization Of Acex Subunit 1/5 (The “Zebra” Interval) To Better Understand Sediment Deposition At This Critical Age Boundary And Paleoceanographic Transition, Victoria Hojnacki

Senior Honors Projects, 2010-2019

Sediment cores recovered from the Lomonosov Ridge on IODP Expedition 302, the Arctic Coring Expedition (ACEX), provided the first major insights into long-term Cenozoic history of climate and ocean conditions in the central Arctic. However, the ACEX record is hampered by a major hiatus or severely condensed interval (depending on age-model interpretations) at 198.7 mcd separating the middle Eocene and Miocene records. Lithologic subunit 1/5 lies above this depth horizon, and is informally called the “zebra interval” because of distinctive stripes - black and gray tilted and cross-banded silty-clay layers, up to 3 cm thick that characterize the lower ~2.5 …


Fun In A Kansas Salt Mine, Robert F. Diffendal Jr. Apr 2019

Fun In A Kansas Salt Mine, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Most people probably do not know that salt deposits hundreds of feet thick lie buried beneath large parts of western Kansas, western Oklahoma and a small part of the northeastern Texas Panhandle. Native Americans and early European explorers found that where the salt deposits came near the land surface (for, example north of Hutchinson, Kansas) salt is dissolved by ground water and increases the salinity of rivers, streams, springs and ponds. This salty water was used as a salt source by these peoples. The Hutchinson Salt, a 275 million-year-old Middle Permian deposit, was discovered in an exploratory drill hole in …


Utilizing Geophysical Attributes To Investigate The Architecture Of A Pinnacle Reef Complex, Michigan Basin, Usa, Austin M. Johnson Apr 2019

Utilizing Geophysical Attributes To Investigate The Architecture Of A Pinnacle Reef Complex, Michigan Basin, Usa, Austin M. Johnson

Masters Theses

The Silurian Niagaran Pinnacle Reefs of the Michigan Basin retain their relevance after primary recovery of hydrocarbons and are excellent candidates for carbon dioxide sequestration, natural gas storage, and enhanced oil recovery. Due to the nature of carbonate rocks, these reef complexes are heterogeneous and lateral interpolation between observations in wells, is ambiguous. Ambiguity has led to large uncertainty and disagreement regarding reef architectures and their internal facies distributions. Previous models of these reef complexes have relied almost entirely on well logs and conventional core. This study focused on integrating 3D seismic reflection data to reduce uncertainty when delineating the …


The Modern Mississippi: Provenance Indicators And Human Impact, Brittney Anne Gregory Mar 2019

The Modern Mississippi: Provenance Indicators And Human Impact, Brittney Anne Gregory

LSU Doctoral Dissertations

Given the significant degree to which the modern Mississippi River and its tributaries have been altered through dams, levees, and diversions, it is important to understand how sediment is transported from source to sink. The objective of this dissertation is to explore how the modern Mississippi River transports sediment from its tributaries to its delta using three independent proxies. Provenance indicators have traditionally been an effective way with which to characterize sediment transport in large river systems. First, detrital U-Pb zircon dating is used to investigate modern flux and possible anthropogenic influences on coarse-grained sediment within the modern Mississippi River. …


Investigations Of The Potential For Irrigated Agriculture On The Bonaparte Plains: Bore Completion Report, 2nd Edition, D L. Bennett Feb 2019

Investigations Of The Potential For Irrigated Agriculture On The Bonaparte Plains: Bore Completion Report, 2nd Edition, D L. Bennett

Resource management technical reports

Drilling programs were undertaken in 2013 and 2016 by the former Department of Agriculture and Food, Western Australia and in 2017 by DPIRD, at 10 sites in the Bonaparte Plains area, north of Kununurra in the East Kimberley region of Western Australia (WA).

These drilling programs were a component of resource availability and risk investigations conducted to determine the potential for developing irrigated agriculture on 30 000 hectares of Cockatoo Sands — free-draining loamy soils that have the potential to support crops in the wet and dry seasons. There was limited hydrogeological information available at a suitable scale for the …


Biodiversity And Distribution Of Benthic Foraminifera In Harrington Sound, Bermuda: The Effects Of Physical And Geochemical Factors On Dominant Taxa, Nam Le Jan 2019

Biodiversity And Distribution Of Benthic Foraminifera In Harrington Sound, Bermuda: The Effects Of Physical And Geochemical Factors On Dominant Taxa, Nam Le

Honors Theses

Harrington Sound, Bermuda, is a nearly enclosed lagoon acting as a subtropical/tropical, carbonate-rich basin in which carbonate sediments, reef patches, and carbonate-producing organisms accumulate. Here, one of the most important calcareous groups is the Foraminifera. Analyses of common benthic orders, including miliolids (Quinqueloculina and Triloculina spp.) and rotaliids (Homotrema rubrum, Elphidium spp., and Ammonia beccarii), are essential in understanding past and present environmental conditions affecting the island's coastal environment. These taxa have been studied previously; however, factors explaining their individual patterns of abundance in the Sound are not well detailed. The goal of this study is …


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

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

Dissertations, Master's Theses and Master's Reports

The Southern Complex is part of the Archean Superior Province in the Upper Peninsula of Michigan and includes a batholithic sized body of Archean high-K megacrystic granitoid rocks informally called the Bell Creek granite. U-Pb zircon ages of the granitoid from previous studies suggest an emplacement age of ~2.6 Ga (Tinkham, 1997). Based on those ages the Bell Creek granite formed around the Archean-Proterozoic transition. This transition is a crucial time period in Earth’s history for crustal growth because of the onset of subduction and increased sedimentary environments at the end of the Archean (Taylor and McLennan, 1995). In this …


Interpreting Vegetation And Soil Anomalies In The Guarumen Area Of Northwestern Venezuela Using Remote Sensing Applications, Tyler Edward Ricketts Jan 2019

Interpreting Vegetation And Soil Anomalies In The Guarumen Area Of Northwestern Venezuela Using Remote Sensing Applications, Tyler Edward Ricketts

Electronic Theses and Dissertations

The Guarumen area of Venezuela is a tectonically active region that is approximately 1,640 mi2 across the northern portions of the Barinas Basin and the foothills of the Mérida Andes. It is structurally influenced by the Caribbean plate to the north, the Nazca plate to the west, and the Maracaibo block against the Guyana Shield of the South American Plate. These result in an oblique boundary that gives rise to the fold-and-thrust belt of the Mérida Andes to the west, and the Caribbean Mountain system to the north, in concordance to the right-lateral shearing that is evidenced by the Boconó …


Geology Of Southeastern Nebraska, Robert Matthew Joeckel, Dana Divine, Leslie M. Howard, Kathleen Cameron, Michele M. Waszgis Jan 2019

Geology Of Southeastern Nebraska, Robert Matthew Joeckel, Dana Divine, Leslie M. Howard, Kathleen Cameron, Michele M. Waszgis

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


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

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

Honors Theses

Foreland basin sediment deposition in North-Central Pennsylvania during Late Devonian time records erosion of hinterland source terranes exhumed during regional plate convergence, including the collisional Acadian orogeny. The Catskill clastic wedge preserves a coarsening-upwards stratigraphic succession from marine to fluvial environments associated with sediment progradation and sea-level regression, yet depositional timescales and quantitative provenance data are largely unconstrained.

Detailed facies analysis of eight outcrops spanning >2 km of stratigraphy in Lycoming Co., Pennsylvania documents distinct upsection changes, interpreted to reflect changes in depositional environments consistent with previous sedimentology of the Catskill clastic wedge. Stratigraphy displays a transition from nearshore marine …


Exploration For Alteration Halos Around The Ag-W Deposits In Southeastern Missouri, Usa, Daniel Joseph Warbritton Jan 2019

Exploration For Alteration Halos Around The Ag-W Deposits In Southeastern Missouri, Usa, Daniel Joseph Warbritton

Masters Theses

"The St. Francois Mountains in SE Missouri are an extensive terrane of granitic ring complexes and associated rhyolites. They were an important source of Ag, W, and Sn and mined intermittently from the 1800s until the 1950s. The Ag-W ores occur in the Silvermine Granite and rhyolite roof rocks. The deposits are classified as a xenothermal ore system with mineralization occurring in quartz veins and surrounding greisen (up to 2.5 m). Exploration for hydrothermal ore deposits often focuses on the identification of alteration halos in the surrounding host rocks. In the vast majority of xenothermal ore deposits, such as in …


The Medicine Hat Block And The Assembly Of Laurentia: New Interpretations From Single-Grain Zircon Analyses, Blake Oswell Ladouceur Jan 2019

The Medicine Hat Block And The Assembly Of Laurentia: New Interpretations From Single-Grain Zircon Analyses, Blake Oswell Ladouceur

Electronic Theses and Dissertations

The Medicine Hat Block (MHB) is one of the core cratonic elements that amalgamated in the Paleoproterozoic to form Laurentia. However the role of the MHB in the formation of Laurentia is poorly constrained due to virtually all of the MHB being concealed by Proterozoic and younger supracrustal sequences limiting availability of data. The primary sources of samples from the MHB are 1) xenoliths of variable metamorphic grade including gneisses amphibolites and meta-plutonic rocks collected from Eocene volcanic rock; and 2) similar lithologies recovered from boreholes that penetrate to the MHB basement. Previous work on samples from the MHB yielded …


Interactions Of Bacterial Communities With Hydrous Sulfate Minerals In Water-Restricted Gypsic Environments: A Case Study Based In The White Sands National Monument, Brandon Nicholas Lajoie Jan 2019

Interactions Of Bacterial Communities With Hydrous Sulfate Minerals In Water-Restricted Gypsic Environments: A Case Study Based In The White Sands National Monument, Brandon Nicholas Lajoie

Open Access Theses & Dissertations

Microbial communities have been commonly found to survive and thrive in arid to hyper-arid gypsic environments that are considered hostile to most other forms of life. The mechanisms through which microbes have conquered these harsh environments remain poorly understood. Here I hypothesize that the microbial communities in water-restricted gypsic settings could benefit in terms of energy and water sources via their interactions with the abundant hydrous sulfate minerals [i.e., gypsum (CaSO4·2H2O)] that build up these niches. Gypsum is of high bio-relevance because its sulfate component may be used as electron acceptor by sulfate-reducing bacteria and the crystallization water may be …


Beneath The Gypsum Dunes: Cenozoic History Of Wind And Water From A Core Drilled At White Sands, New Mexico, Jackson Bentley Jakeway Jan 2019

Beneath The Gypsum Dunes: Cenozoic History Of Wind And Water From A Core Drilled At White Sands, New Mexico, Jackson Bentley Jakeway

Graduate Theses, Dissertations, and Problem Reports (ETD)

White Sands, New Mexico is the largest gypsum dune field on planet Earth, the result of reworking of gypsum deposits. The dunes have been well studied, but the Cenozoic history preceding the formation of the dune field has been poorly studied. A core drilled to a depth of 192 ft (58.5 m) beneath the modern dune field contains deposits from saline lakes, sandflats, perennial freshwater lakes, perennial brackish to saline lakes, and saline mudflats.

The core is composed of bottom-growth bedded gypsum, gypsum sandstone and siltstone, mixed siliciclastic-gypsum sandstones and siltstones, laminated siliciclastic mudstones, gypsum mudstones, and carbonate mudstones. Bottom-growth …


A Soil Genesis Investigation Into Possible Long-Range Transport Of Foreign Sediments In The Stann Creek District Of Belize, Heath Sawyer Jan 2019

A Soil Genesis Investigation Into Possible Long-Range Transport Of Foreign Sediments In The Stann Creek District Of Belize, Heath Sawyer

Cal Poly Humboldt theses and projects

Throughout the world, long range transport (LRT) of aeolian dust plays a major role in the total global dust budget. Research suggests that LRT dust from the deserts of North Africa play a role in soil genesis in the Americas. The focus of this study is a preliminary investigation for evidence of North African dust or volcanic ash influence on the soils in the Cockscomb Basin Wildlife Sanctuary in Stann Creek District, Belize. A series of 7 soil profiles were analyzed from a catena transect to determine if there is evidence of foreign materials by using X-ray diffraction and Scanning …


An Analysis Of Fractures Around The Sevier Fault Zone Near Orderville, Utah, Charley H. Hankla Jan 2019

An Analysis Of Fractures Around The Sevier Fault Zone Near Orderville, Utah, Charley H. Hankla

Senior Independent Study Theses

Structural discontinuities—such as opening mode joints, shear fractures, and faults— tend to occur in close geographic proximity to one another; however, the timing relationships between these structures is not always easy to discern in the field. In southwestern Utah, the Jurassic Navajo Sandstone is cut by large-scale normal faults associated with the Sevier Fault Zone, making it perfect for observing several fracture types. The aim of this study is to complete a dynamic and kinematic analyses of the fractures near a major fault and to determine the chronologic relationships between the fractures. Specifically, we observed a previously unnamed segment of …


X-Ray Fluorescence Applications In Mudrock Characterization: Investigations Into Middle Devonian Stratigraphy, Appalachian Basin, Usa, Keithan Garrett Martin Jan 2019

X-Ray Fluorescence Applications In Mudrock Characterization: Investigations Into Middle Devonian Stratigraphy, Appalachian Basin, Usa, Keithan Garrett Martin

Graduate Theses, Dissertations, and Problem Reports (ETD)

Mudrocks are characterized by nanometer-scale pore sizes and nano-darcy permeability, which plays a significant role in hydrocarbon flow during production. Resulting from these characteristics, mudrocks were exclusively considered a source rock, which charged overlying, more porous mediums. Hydraulic fracturing, a technology used to create artificial fractures to liberate hydrocarbons from the reservoir, enabled natural gas to be produced from mudrock reservoirs economically. Over the last fifteen years, this technology motivated research efforts to understand reservoir characteristics of mudrock. These investigations significantly improved our knowledge of mudrock systems, but have also highlighted key areas that are undeveloped and/or where conflicting hypotheses …


Margaret White Springs Recharge Study, Buffalo National River, North-Central Arkansas, Usa, Ashlon Elizabeth Leonard Dec 2018

Margaret White Springs Recharge Study, Buffalo National River, North-Central Arkansas, Usa, Ashlon Elizabeth Leonard

Graduate Theses and Dissertations

Margaret White Springs (MWS) is one of the largest springs in the middle section of the Buffalo National River (BNR) and contributes several tens of cubic feet per second of flow to river discharge on average, yet the source of the water has not been fully studied or documented. The spring is located approximately 4 miles downstream from Robertson Hole, a losing reach of the river. At Robertson Hole the river loses a significant amount of flow to groundwater, which during the dry season (summer) can be as much as 100%. Flow in the main channel is re-established at MWS; …


Subsurface Analysis Of Mississippian Tripolitic Chert In Northwest Arkansas, Thomas Jason Liner Dec 2018

Subsurface Analysis Of Mississippian Tripolitic Chert In Northwest Arkansas, Thomas Jason Liner

Graduate Theses and Dissertations

Over the past 70 years the Mississippian strata of Northwest Arkansas have been studied in great detail. The study area is located on the escarpment between the Boston Mountains Plateau and the Springfield Plateau where a surface occurrence of Mississippian age rock allows for access to outcrops in close proximity to gas wells that encounter subsurface Mississippian strata. Many outcrops found in Northwest Arkansas expose Lower Mississippian (Kinderhookian-Osagean) strata that represent a full third order transgressive/regressive sequence that is unconformity bounded. These Mississippian outcrops are commonly treated as surface analogs to the Mississippi Lime Play in North Central Oklahoma. This …


Crustal Seismic Anisotropy Of The Ruby Mountains Core Complex And Surrounding Northern Basin And Range, Justin T. Wilgus Oct 2018

Crustal Seismic Anisotropy Of The Ruby Mountains Core Complex And Surrounding Northern Basin And Range, Justin T. Wilgus

Earth and Planetary Sciences ETDs

Metamorphic core complexes (MCC) are distinctive uplifts that expose deeply exhumed and deformed crustal rocks due to localized extensional deformation. Consequently, their detailed structure provide a window into deep crustal mechanics. The North American Cordillera contains numerous MCC, one of which is the Ruby Mountains core complex (RMCC) located in the highly extended northern Basin and Range. To constrain the extent to which anisotropy below the RMCC deviates from the regional Basin and Range average and test the depth dependence of crustal anisotropy we conduct a radial anisotropy investigation below the RMCC and surrounding northern Basin and Range. Data from …


A Regional Survey Of River-Plume Sedimentation On The Mississippi River Delta Front, Andrew J. Courtois Oct 2018

A Regional Survey Of River-Plume Sedimentation On The Mississippi River Delta Front, Andrew J. Courtois

LSU Master's Theses

Many studies of the Mississippi River Delta (MRD) have shown historic declines in sediment load over the last few decades. Recent studies also reported that ~50% of the suspended load during floods is sequestered within the delta. While the impact of declining sediment load on wetland loss is relatively well documented, submarine sedimentary processes on the delta front during this recent period of are understudied. To better understand modern sediment dispersal and deposition across the Mississippi River Delta Front, 31 multicores were collected in June 2017 from locations extending offshore from the main river outlets in water depths of 25-280 …


Mass-Transport Deposits In The Northern Gulf Of Mexico And Their Implications For Hydrocarbon Exploration, Michael Raymond Arthur Oct 2018

Mass-Transport Deposits In The Northern Gulf Of Mexico And Their Implications For Hydrocarbon Exploration, Michael Raymond Arthur

Masters Theses & Specialist Projects

This study investigates Mio-Pliocene mass-transport deposits (MTDs) in an understudied, hydrocarbon-rich region of the northeastern Gulf of Mexico. The research utilizes a high-quality 3D seismic dataset with an area of 635 km2, along with wireline logs and biostratigraphic data. With the help of quantitative seismic geomorphology techniques, detailed mapping of MTDs suggests a complex erosional and depositional history. Deposition of a MTD unit resulted in a 180 m topographic high that substantially influenced the distribution and morphology of subsequent MTDs, specifically the bifurcation of later mass-transport flows. This bifurcation contributed to the generation of a non-shielded erosional remnant with an …


Unroofing History Of The Northwestern Ethiopian Plateau: Insights From Low-Temperature Apatite Thermochronology, Shelby Bowden Oct 2018

Unroofing History Of The Northwestern Ethiopian Plateau: Insights From Low-Temperature Apatite Thermochronology, Shelby Bowden

Masters Theses & Specialist Projects

The geology of Ethiopia is dominated by the Ethiopian Plateau that is similar in elevation to, but aerially larger than, the Colorado Plateau. Several rivers have incised through the plateau, creating gorges that reach up to 1.5 km in depth. The plateau uplifted to its current elevation and was subsequently incised sometime after the Oligocene flood basalt event that signaled the arrival of the African Superplume below Kenya and Ethiopia. Due to its size and extent, published climate modeling has indicated that Late Cenozoic plateau formation could have been a driving force in the East African Cenozoic climate changes. Although …


New Insights Into Carboniferous Cyclothems. The Fourth Biennial Field Conference Of The American Association Of Petroleum Geologists (Aapg) Midcontinent Section Fourth Biennial Field Conference Abstracts And Guidebook, Robert Matthew Joeckel, Christopher R. Fielding Oct 2018

New Insights Into Carboniferous Cyclothems. The Fourth Biennial Field Conference Of The American Association Of Petroleum Geologists (Aapg) Midcontinent Section Fourth Biennial Field Conference Abstracts And Guidebook, Robert Matthew Joeckel, Christopher R. Fielding

Conservation and Survey Division: Faculty and Staff Publications

The term “cyclothem” was coined by Wanless & Weller (1932) to describe repetitive stratigraphic successions of Carboniferous age in Illinois. Nonetheless, comparable rhythmicity had been identified in Carboniferous rocks both in the central and eastern USA, and in Europe during the preceding century. Cyclothems were found to comprise repetitive vertical successions of sandstones, heterolithic (thinly interbedded) sandstones and mudrocks, mudrocks, limestones, and coals, in many cases with pedogenic overprinting of these lithologies. As usage of the term “cyclothem” increased, so did the diversity of successions to which the term was applied, to the point where many geologists advocated abandonment of …