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Full-Text Articles in Geology

Evaluation Of Possible Source Rocks In Northern Nye County, Nevada: Implications For Hydrocarbon Exploration, Inessa Yurchenko Aug 2012

Evaluation Of Possible Source Rocks In Northern Nye County, Nevada: Implications For Hydrocarbon Exploration, Inessa Yurchenko

UNLV Theses, Dissertations, Professional Papers, and Capstones

The presence of oil outside of Railroad Valley, northern Nye County has sparked the interest of exploration companies in Nevada. The geology in this region is very complex and the level of petroleum exploration is low. In order to understand the distribution of oil, a complete petroleum systems analysis is required. Previous studies confirmed that the Mississippian Chainman Shale and Cretaceous to Paleocene Sheep Pass Formation, Member B are source rocks. However, a number of other possible source rocks exist in northern Nye County, but they are not confirmed because of incomplete datasets. The goal of this thesis project is …


A Subsurface Stratigraphic Study Of The Middle Atoka, Sebastian County, Arkansas, Sara Beth Sutton Aug 2012

A Subsurface Stratigraphic Study Of The Middle Atoka, Sebastian County, Arkansas, Sara Beth Sutton

Graduate Theses and Dissertations

Raster log images were analyzed to study the subsurface stratigraphy of the Middle Atoka in the Arkoma Basin of the western portion (Sebastian County) of Arkansas. The most significant sandstone units of the Middle Atoka in this area were determined to be two generally coarsening-upward sequences in the lower portion of the formation. Based on lithologic correlations, these two units were determined to be the informally named Casey and Freiburg members of the Middle Atoka. Thickness information based on picked tops was used to create isopach maps of the units of interest. The log signatures and geometry of the sand …


Sequence Stratigraphy And Depositional Systems Of The Mansfield Sand, Upper Atoka Formation, Arkoma Basin, Arkansas, Scott Cherry Aug 2012

Sequence Stratigraphy And Depositional Systems Of The Mansfield Sand, Upper Atoka Formation, Arkoma Basin, Arkansas, Scott Cherry

Graduate Theses and Dissertations

The Mansfield sand is an informally named member of the Pennsylvanian Atoka Formation in Arkansas. Once a productive gas reservoir, the Mansfield is situated in a double plunging anticline in the southern portion of the Arkoma Basin. The formation is internally composed of sandstone units ranging in thickness from tens of feet to over a hundred feet interbedded with shale units ranging in thickness from several tens of feet to hundreds of feet. Previous studies have focused on the stratigraphy of the lower and middle Atoka. A detailed subsurface study of the stratigraphic framework of the Mansfield sand was conducted …


Chronostratigraphic Framework For The Iodp Expedition 318 Cores From The Wilkes Land Margin: Constraints For Paleoceanographic Reconstruction, Lisa Tauxe, Catherine E. Stickley, Saiko Sugisaki, Peter K. Bijl, Steven M. Bohaty, Henk Brinkhuis, Carlota Escutia, J. A. Flores, A. J. P. Houben, M. Iwai, Francisco J. Jiménez‐Espejo, Robert Mckay, Sandra Passchier, Jörg Pross, Christina Riesselman, Ursula Röhl, Francesca Sangiorgi, Kevin Welsh, Adam Klaus, Annick Fehr, James Bendle, Robert B. Dunbar, J. Gonzàlez, T. Hayden, K. Katsuki, M. P. Olney, Stephen Pekar, P. K. Shrivastava, Tina Van De Flierdt, Trevor Williams, M. Yamane Jun 2012

Chronostratigraphic Framework For The Iodp Expedition 318 Cores From The Wilkes Land Margin: Constraints For Paleoceanographic Reconstruction, Lisa Tauxe, Catherine E. Stickley, Saiko Sugisaki, Peter K. Bijl, Steven M. Bohaty, Henk Brinkhuis, Carlota Escutia, J. A. Flores, A. J. P. Houben, M. Iwai, Francisco J. Jiménez‐Espejo, Robert Mckay, Sandra Passchier, Jörg Pross, Christina Riesselman, Ursula Röhl, Francesca Sangiorgi, Kevin Welsh, Adam Klaus, Annick Fehr, James Bendle, Robert B. Dunbar, J. Gonzàlez, T. Hayden, K. Katsuki, M. P. Olney, Stephen Pekar, P. K. Shrivastava, Tina Van De Flierdt, Trevor Williams, M. Yamane

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

[1] The Integrated Ocean Drilling Program Expedition 318 to the Wilkes Land margin of Antarctica recovered a sedimentary succession ranging in age from lower Eocene to the Holocene. Excellent stratigraphic control is key to understanding the timing of paleoceanographic events through critical climate intervals. Drill sites recovered the lower and middle Eocene, nearly the entire Oligocene, the Miocene from about 17 Ma, the entire Pliocene and much of the Pleistocene. The paleomagnetic properties are generally suitable for magnetostratigraphic interpretation, with well‐behaved demagnetization diagrams, uniform distribution of declinations, and a clear separation into two inclination modes. Although the sequences were discontinuously …


4th International Union Of Soil Sciences Soil Classification Conference Field Tour Guidebook Jun 2012

4th International Union Of Soil Sciences Soil Classification Conference Field Tour Guidebook

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


North Central Region Soil Survey Conference Field Tour Jun 2012

North Central Region Soil Survey Conference Field Tour

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Transitional Facies And Sequence Stratigraphic Complexity Of Shallow-Marine Star Point Formation To Coastal-Plain Blackhawk Formation Along Depositional-Strike, Wasatch Plateau, Utah, Andrew M. Ranson May 2012

Transitional Facies And Sequence Stratigraphic Complexity Of Shallow-Marine Star Point Formation To Coastal-Plain Blackhawk Formation Along Depositional-Strike, Wasatch Plateau, Utah, Andrew M. Ranson

LSU New Orleans Theses and Dissertations

Facies and stratigraphic architecture right at the transition from marine to non-marine environments is poorly documented. In the Cretaceous outcrops of Utah, Star Point and Blackhawk Formations are well studied. The nature of spatio-temporal transition of these two Formations, in the deposition-strike orientation, remains undocumented. This study characterizes facies and stratigraphic complexity at the transition of the two Formations that crop out in depositional-strike orientation in the Wasatch Plateau. Data from outcrop including photomosiacs and measured sections demonstrate this complexity at a range of scales. The Star Point constitutes a shoreface environment. The Blackhawk constitutes a coastal-fluvial environment.

In the …


High-Resolution Correlation Of The Upper Cretaceous Stratigraphy Between The Book Cliffs And The Western Henry Mountains Syncline, Utah, U.S.A., Drew L. Seymour May 2012

High-Resolution Correlation Of The Upper Cretaceous Stratigraphy Between The Book Cliffs And The Western Henry Mountains Syncline, Utah, U.S.A., Drew L. Seymour

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

This study presents high-resolution correlations of the Upper Cretaceous stratigraphy between the Book Cliffs and the western Henry Mountains Syncline in Utah. The objective of this study is to understand changes in patterns of regional sediment dispersal during the Late Cretaceous on the western margin of the Cretaceous Western Interior Seaway. The intensely studied Book Cliffs consist of formations deposited in terrestrial, marginal-marine, and open-marine environments. A composite section was logged at Coal Canyon near Green River, UT. The western Henry Mountains Syncline is located in south-central Utah ~135 km S-SW of Coal Canyon. A composite section was logged at …


Data Integration And Reservoir Characterization Of The Pennsylvanian Bartlesville Sandstone, Caroline Vance O'Keefe May 2012

Data Integration And Reservoir Characterization Of The Pennsylvanian Bartlesville Sandstone, Caroline Vance O'Keefe

Graduate Theses and Dissertations

The Glenn Pool Oil Field of Northeastern Oklahoma was established as the first major oil discovery of the fledgling state of Oklahoma. Fully developed by 1912, the field is now nearing depletion even under secondary and tertiary recovery efforts after production for approximately 100 years. Large amounts of residual oil estimated to still be in place have motivated exploration into other recovery methods, including polymer flooding and horizontal drilling. Success of these programs is dependent upon accurate characterization of the reservoir. Because most of the drilling occurred many decades ago, much of the data associated with this field predates electric …


Stratigraphy And Provenance Of Shallow Sandstones Endountered In Wells In Townships 9 And 10 North, Ranges 6 And 7 West, White County, Arkansas, Lacie Knight May 2012

Stratigraphy And Provenance Of Shallow Sandstones Endountered In Wells In Townships 9 And 10 North, Ranges 6 And 7 West, White County, Arkansas, Lacie Knight

Graduate Theses and Dissertations

Paleozoic formations in western Arkansas have been well-studied; however, they are not well-understood in the eastern part of the state. The study area encompasses Townships 9. N. and 10. N., Ranges 6. W. and 7. W. in north-central White County, Arkansas. This area is at the intersection of four physiographic provinces as defined by the Arkansas Geologic Survey- the Ozark Plateaus, the Arkansas River Valley, the Ouachita Mountains, and the Mississippi Alluvial Plain. Interpretations of the surface unit in the area disagree. The Arkansas Geologic Map shows that the Morrowan Hale Formation crops out in the area; however, various petroleum …


Burial And Exhumation History Of Mississippian Strata In East-Central Nevada, Yuki Yunika Agulia May 2012

Burial And Exhumation History Of Mississippian Strata In East-Central Nevada, Yuki Yunika Agulia

UNLV Theses, Dissertations, Professional Papers, and Capstones

Zircon (U-Th)/He analyses and vitrinite reflectance (Ro) analyses were performed on a suite of Mississippian sedimentary rocks collected in east-central Nevada in order to test Permian exhumation described in a previous study.

The zircon analyses produced three clusters of ages: 1) older than, 2) similar to, and 3) younger than depositional age. The majority of zircons shows ages that are older than the sandstone deposition age. Young ages were recorded in three localities that may indicate reset ages/residence within the (U-Th)/He partial retention zone (HePRZ). Moderate-high ratios of Th/U may indicate a magmatic source. Vitrinite reflectance (Ro) analyses show values …


The Effects Of Salt Diapirs On The Thermal Maturity Of Surrounding Sediments In The Western Pyrenees, Spain, Nicholas Martin Downs May 2012

The Effects Of Salt Diapirs On The Thermal Maturity Of Surrounding Sediments In The Western Pyrenees, Spain, Nicholas Martin Downs

UNLV Theses, Dissertations, Professional Papers, and Capstones

Salt diapirs have been modeled as having a large effect on the thermal maturity of surrounding sediments as a result of the high thermal conductivity contrast between halite and other lithologies. The goal of this study was to confirm these and other theoretical predictions through sampling of three salt structures in the western Pyrenees, Spain. Stratigraphic units around these three diapirs were targeted based on their lithologies and positions relative to the diapirs. Samples were analyzed for vitrinite reflectance and quartz cementation to determine their levels of thermal maturity. Remote sensing instruments were used to attempt to measure present day …


U/Pb Detrital Zircon Study Of The Upper Cretaceous To Miocene Strata Of Kodiak Island, Alaska, Sarah J. Olivas^, Cameron Davidson, John I. Garver, Diane I. Doser*, Hannah Hilbert-Wolf Apr 2012

U/Pb Detrital Zircon Study Of The Upper Cretaceous To Miocene Strata Of Kodiak Island, Alaska, Sarah J. Olivas^, Cameron Davidson, John I. Garver, Diane I. Doser*, Hannah Hilbert-Wolf

COURI Symposium Abstracts, Spring 2012

No abstract provided.


Sensitivity Analysis Of The Gems Soil Organic Carbon Model To Land Cover Land Use Classification Uncertainties Under Different Climate Scenarios In Senegal, Amadou M. Dieye, David P. Roy, N. P. Hanan, S. Lui, M. Hansen, A. Toure Feb 2012

Sensitivity Analysis Of The Gems Soil Organic Carbon Model To Land Cover Land Use Classification Uncertainties Under Different Climate Scenarios In Senegal, Amadou M. Dieye, David P. Roy, N. P. Hanan, S. Lui, M. Hansen, A. Toure

GSCE Faculty Publications

Spatially explicit land cover land use (LCLU) change information is needed to drive biogeochemical models that simulate soil organic carbon (SOC) dynamics. Such information is increasingly being mapped using remotely sensed satellite data with classification schemes and uncertainties constrained by the sensing system, classification algorithms and land cover schemes. In this study, automated LCLU classification of multi-temporal Landsat satellite data were used to assess the sensitivity of SOC modeled by the Global Ensemble Biogeochemical Modeling System (GEMS). The GEMS was run for an area of 1560km2 in Senegal under three climate change scenarios with LCLU maps generated using different Landsat …


Depositional Environments And Sequence Stratigraphy Of A Breathitt Group Exposure, U.S. 25e, Flat Lick, Kentucky, Kathryn E. Hoffmeister, Eric G. Hogan, Steven M. Holland Jan 2012

Depositional Environments And Sequence Stratigraphy Of A Breathitt Group Exposure, U.S. 25e, Flat Lick, Kentucky, Kathryn E. Hoffmeister, Eric G. Hogan, Steven M. Holland

Information Circular--KGS

The Pennsylvanian fluvial deltaic Breathitt Group is exposed along U.S. 25E near Flat Lick, Ky. This exposure is ideal for field trips because of the quality of the exposure, its accessibility, the range of facies present, and its potential for demonstrating principles of outcrop-based sequence-stratigraphic interpretation. Eight facies are present and represent deposition in fluvial, delta-plain, and delta-front environments. Several facies contain an abundance of trace fossils, and a wide range of sedimentary structures are also present. Flooding surfaces are well developed in the delta front and delta plain and are characterized by abrupt contacts with distal, deeper-water deltaic environments …


Three-Dimensional Hydrostratigraphy Of The Platte River Valley Near Ashland, Nebraska: Results From Helicopter Electromagnetic (Hem) Mapping In The Eastern Nebraska Water Resources Assessment (Enwra), P. R. Hanson, Jesse T. Korus, Dana Divine Jan 2012

Three-Dimensional Hydrostratigraphy Of The Platte River Valley Near Ashland, Nebraska: Results From Helicopter Electromagnetic (Hem) Mapping In The Eastern Nebraska Water Resources Assessment (Enwra), P. R. Hanson, Jesse T. Korus, Dana Divine

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Exploring The Role Of Organic Matter Accumulation On Delta Evolution, Jorge Lorenzo Trueba, Vaughan Voller, Chris Paola, Robert Twilley, Azure Bevington Jan 2012

Exploring The Role Of Organic Matter Accumulation On Delta Evolution, Jorge Lorenzo Trueba, Vaughan Voller, Chris Paola, Robert Twilley, Azure Bevington

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

We explore the role of plant matter accumulation in the sediment column in determining the response of fluvial-deltas to base-level rise and simple subsidence profiles. Making the assumption that delta building processes operate to preserve the geometry of the delta plain, we model organic sedimentation in terms of the plant matter accumulation and accommodation (space made for sediment deposition) rates. A spatial integration of the organic sedimentation, added to the known river sediment input, leads to a model of delta evolution that estimates the fraction of organic sediments preserved in the delta. The model predicts that the maximum organic fraction …


Three-Dimensional Hydrostratigraphy Of The Sprague, Nebraska Area: Results From Helicopter Electromagnetic (Hem) Mapping For The Eastern Nebraska Water Resources Assessment (Enwra), Dana Divine, Jesse T. Korus Jan 2012

Three-Dimensional Hydrostratigraphy Of The Sprague, Nebraska Area: Results From Helicopter Electromagnetic (Hem) Mapping For The Eastern Nebraska Water Resources Assessment (Enwra), Dana Divine, Jesse T. Korus

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Effectiveness Of Four Water-Bearing Zones Of The Glacierized Basin In Meltwater Runoff Modeling, Umesh K. Haritashya Jan 2012

Effectiveness Of Four Water-Bearing Zones Of The Glacierized Basin In Meltwater Runoff Modeling, Umesh K. Haritashya

Department of Earth, Environment and Sustainability Faculty Publications

Meltwater runoff modeling from glacierized basins needs several input data, including total meltwater contributing area. This study utilizes optical remote sensing data to assess glacierized basins in the central Himalayas where snow and glaciers contribute substantially to the water resources. Result shows that there are four main water-bearing zones in the basin: (a) dry snow, (b) wet snow, (c) exposed glacial ice, and (d) debris-covered glacial ice, and it is possible to differentiate and map these zones and their spatio-temporal variations from satellite sensor data. These zones can then be incorporated in meltwater runoff modeling as separate entities because they …


Holocene Arroyo Cut And Fills Cycles, South-Central Washington, Matthew Ian Durkee Jan 2012

Holocene Arroyo Cut And Fills Cycles, South-Central Washington, Matthew Ian Durkee

All Master's Theses

Ephemeral streams have cut deeply incised arroyos into alluvial and eolian sediments in many of the watersheds within the Yakima Training Center (YTC) military reservation, south-central Washington. The most recent channel incision episode along Selah Creek is primarily attributed to multiple failures of an irrigation reservoir dam during the winters of 1909 and 1910. The modern arroyo exposed evidence of at least one previous episode of arroyo incision to a depth of ~4 m that occurred just prior to 1530- 1340 cal yr BP. Filling of this paleo-arroyo with fine to coarse grained sand ceased between 650-103 cal yr BP. …


Guidebook To The Geology Of The Platte River Valley Between Duncan And Schuyler, Nebraska, P.R. Hanson, Robert Matthew Joeckel, Aaron R. Young, Dana Divine, Jesse T. Korus Dr. Jan 2012

Guidebook To The Geology Of The Platte River Valley Between Duncan And Schuyler, Nebraska, P.R. Hanson, Robert Matthew Joeckel, Aaron R. Young, Dana Divine, Jesse T. Korus Dr.

Conservation and Survey Division: Faculty and Staff Publications

The Platte River is considered to be a classic example of a braided stream, that is, a comparatively shallow stream with a high width:depth ratio.


Three Geologic Cross Sections Across Portions Of Eastern Nebraska Showing Quaternary Lithologic Units And Stratigraphy Of Uppermost Bedrock, Jesse T. Korus, Dana Divine, P. R. Hanson, J. S. Dillon Jan 2012

Three Geologic Cross Sections Across Portions Of Eastern Nebraska Showing Quaternary Lithologic Units And Stratigraphy Of Uppermost Bedrock, Jesse T. Korus, Dana Divine, P. R. Hanson, J. S. Dillon

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Nebraska Statewide Groundwater-Level Monitoring Report 2011, Jesse T. Korus Dr., Mark E. Burbach, Leslie M. Howard Jan 2012

Nebraska Statewide Groundwater-Level Monitoring Report 2011, Jesse T. Korus Dr., Mark E. Burbach, Leslie M. Howard

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Nebraska Statewide Groundwater-Level Monitoring Report 2012, A. R. Young, M. E. Burbach, J. T. Korus, L. M. Howard Jan 2012

Nebraska Statewide Groundwater-Level Monitoring Report 2012, A. R. Young, M. E. Burbach, J. T. Korus, L. M. Howard

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Provenance And Geological Significance Of Red Mud And Other Clastic Sediments Of The Mugnano Cave (Montagnola Senese, Italy), Francesco Iacoviello, Ivan Martini Jan 2012

Provenance And Geological Significance Of Red Mud And Other Clastic Sediments Of The Mugnano Cave (Montagnola Senese, Italy), Francesco Iacoviello, Ivan Martini

International Journal of Speleology

The Mugnano cave is characterized by a thick clastic sedimentary fill showing a great variability of sedimentary facies, ranging from clay to coarse-grained sand deposits. This paper deals with combined sedimentological and mineralogical (XRD and SEM) studies of these sediments and bedrock insoluble residues in order to understand the origin and geological significance of cave deposits, with particular attention to red mud sediments, often considered as the residue of host rock dissolution. Three different sedimentary facies were recognized: i) YS, yellow sand with occasionally shell fragments, testifying the arrival of sediments from the surrounding landscape; ii) RS, red laminated mud; …


Paired Positive Carbonate Carbon Isotope, Organic Carbon Isotope, And Oxygen Isotope Composition Study Across The Lower Mississippian Positive Carbon Isotope Excursion, Southeastern Nevada, Usa, Robert Alan Henry Dec 2011

Paired Positive Carbonate Carbon Isotope, Organic Carbon Isotope, And Oxygen Isotope Composition Study Across The Lower Mississippian Positive Carbon Isotope Excursion, Southeastern Nevada, Usa, Robert Alan Henry

UNLV Theses, Dissertations, Professional Papers, and Capstones

A prominent positive carbonate carbon isotope (delta13Ccarb) excursion of Early Mississippian age (ca 351 Ma) has been documented by previous studies from numerous sites globally. This delta13Ccarb excursion has been interpreted as resulting from enhanced organic carbon burial that removed 13C-depleted carbon from the ocean and atmosphere. Anticipated outcomes from enhanced organic carbon burial would include a similar positive excursion in organic carbon isotopes (delta13Corg) and a global cooling event resulting from reduced CO2 in the atmosphere and ocean. These predictions, however, were not tested sufficiently in previous studies. This research has tested these predictions through an integrated study of …


Stratigraphic Record Of Holocene Coseismic Subsidence, Padang, West Sumatra, Tina Dura, Charles M. Rubin, Harvey M. Kelsey, Benjamin P. Horton, Andrea Hawkes, Christopher H. Vane, Mudrik Daryono, Candace Grand Pre, Tyler Landinsky, Sarah Bradley Nov 2011

Stratigraphic Record Of Holocene Coseismic Subsidence, Padang, West Sumatra, Tina Dura, Charles M. Rubin, Harvey M. Kelsey, Benjamin P. Horton, Andrea Hawkes, Christopher H. Vane, Mudrik Daryono, Candace Grand Pre, Tyler Landinsky, Sarah Bradley

All Faculty Scholarship for the College of the Sciences

Stratigraphic evidence is found for two coseismic subsidence events that underlie a floodplain 20 km south of Padang, West Sumatra along the Mentawai segment (0.5°S–0.3°S) of the Sunda subduction zone. Each earthquake is marked by a sharp soil‐mud contact that represents a sudden change from mangrove to tidal flat. The earthquakes occurred about 4000 and 3000 cal years B.P. based on radiocarbon ages of detrital plant fragments and seeds. The absence of younger paleoseismic evidence suggests that late Holocene relative sea level fall left the floodplain too high for an earthquake to lower it into the intertidal zone. Our results …


Stratigraphic Analysis And Regional Correlation Of Isolated, Top-Truncated Shallow Marine Sandstone Bodies Within The Upper Cretaceous Frontier Formation, Bighorn And Washakie Counties, Wyoming, Andrew J. Hutsky Jul 2011

Stratigraphic Analysis And Regional Correlation Of Isolated, Top-Truncated Shallow Marine Sandstone Bodies Within The Upper Cretaceous Frontier Formation, Bighorn And Washakie Counties, Wyoming, Andrew J. Hutsky

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

A detailed sedimentologic and stratigraphic analysis facilitated interpretations of depositional environment, sequence stratigraphy, and sandstone body geometry for isolated, top-truncated, shallow marine sandstone bodies of the Upper Cretaceous (Cenomanian-Turonian) Frontier Formation, northeast Bighorn Basin, Wyoming. The Frontier Formation interval is ~160 meters thick and was deposited as a complex clastic wedge that prograded into Cretaceous Western Interior Seaway (KWIS). The vertical interval comprises several incomplete coarsening-upward cycles, composed of basal offshore marine and prodeltaic shales progressively overlain by proximal shallow marine/fluvial facies that are capped by pebble lags. Sedimentary structures, vertical stacking patterns, and lateral variability within these cycles record …


Taxonomic Composition, Paleoecology And Biostratigraphy Of Late Cretaceous Diatoms From Devon Island, Nunavut, Canadian High Arctic, Jakub Witkowski, David M. Harwood, Karen Chin Jun 2011

Taxonomic Composition, Paleoecology And Biostratigraphy Of Late Cretaceous Diatoms From Devon Island, Nunavut, Canadian High Arctic, Jakub Witkowski, David M. Harwood, Karen Chin

Department of Earth and Atmospheric Sciences: Faculty Publications

Upper Cretaceous sediments of the Kanguk Formation exposed in Eidsbotn and Viks Fiord grabens on Devon Island, Nunavut, Canadian High Arctic, yielded 91 fossil marine diatom species and varieties (including indeterminate taxa), representing 41 genera. Excellent preservation of the assemblages was aided by shallow burial, protection in down­faulted linear grabens, and the presence of abundant volcanic material. Planktonic species and resting spores com­prise nearly 70% of the diatom assemblage, and provided abundant food resources for the Late Cretaceous Arctic eco­system. Deposition of the approximately 225 m-thick stratigraphic sequence was predominantly in a shallow marine neritic setting, with an upward progression …


Lateral Variability Of Facies And Cycles In The Furongian (Late Cambrian) Carbonate Platform: An Example From The Big Horse Member Of The Orr Formation In Western Utah, U.S.A., Ratna Widiarti May 2011

Lateral Variability Of Facies And Cycles In The Furongian (Late Cambrian) Carbonate Platform: An Example From The Big Horse Member Of The Orr Formation In Western Utah, U.S.A., Ratna Widiarti

UNLV Theses, Dissertations, Professional Papers, and Capstones

Carbonate depositional cycles and sequences have been proposed to be formed by glacioeustatic sea-level changes. This mechanism would be questionable during times of high atmospheric CO2 and negligible continental ice sheets such as the supergreenhouse time in the Furongian (late Cambrian), during which limited glacioeustatic sea-level changes would be expected. A detailed sedimentological study of the Furongian Orr Formation in western Utah is aimed at testing the hypothesis that, under supergreenhouse climate conditions, most meter-scale carbonate cycles may have been formed through autocyclic processes and thus they should be laterally variable. The research was conducted in a small area ( …