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Full-Text Articles in Physical Sciences and Mathematics
Basal Travertine Of The Bouse Formation: Geochemistry, Diagenesis And Implications For The Integration Of The Colorado River, Christina Ferguson
Basal Travertine Of The Bouse Formation: Geochemistry, Diagenesis And Implications For The Integration Of The Colorado River, Christina Ferguson
Earth and Planetary Sciences ETDs
The Pliocene Bouse Formation is discontinuously exposed in the lower Colorado River region and is a record of the first arrival of the Colorado River to the Gulf of California 5 million years ago. It consists broadly of a lower carbonate member (travertine, marl, and bioclastic units) and an upper siliciclastic member (claystone, mudstone, and Colorado River sands). This paper focuses on the basal travertine (synonymous with “tufa”) unit of the lower carbonate member. Because of its basal position and its chemical encrustation of pre-Bouse topography, the travertine can offer insight into the earliest depositional settings and may be a …
Constraining The Oxygen Values Of The Late Cretaceous Western Interior Seaway Using Marine Bivalves, Camille H. Dwyer
Constraining The Oxygen Values Of The Late Cretaceous Western Interior Seaway Using Marine Bivalves, Camille H. Dwyer
Earth and Planetary Sciences ETDs
The Western Interior Seaway (WIS) remains an oceanographic enigma, including its circulation, similarity to the open ocean, and the fidelity of geochemical proxies to reconstruct paleoenvironments. Across the late Campanian and early Maastrichtian I test whether: 1) the WIS had unique δ18OVPDB compared to other marine settings, 2) increasing oceanographic restriction changed the stable isotope composition, and 3) biases, e.g., taxonomy or diagenesis, influenced stable isotope compositions. Results indicate distinct δ18OVPDB in the WIS compared to other marine settings. δ18OVPDB values were stable through time, suggesting insignificant oceanographic restriction and a …
The Effect Of Depositional Environment And Early Marine Diagenesis On Carbonate-Associated Sulfate, Jocelyn Ann Richardson
The Effect Of Depositional Environment And Early Marine Diagenesis On Carbonate-Associated Sulfate, Jocelyn Ann Richardson
Arts & Sciences Electronic Theses and Dissertations
The long-term redox state of Earth’s surface environments is governed by the relative burial proportions of redox-sensitive carbon and sulfur species throughout geologic time. The sulfur isotopic signature of seawater sulfate (δ34SSO4) traces the relative proportions of sulfur buried as sulfide (commonly pyrite) and sulfate (as evaporites, barite or carbonate-associated sulfate) and weathering source to the ocean. Thus, δ34SSO4 is a powerful tool to understand the evolution of redox conditions and the marine biogeochemical sulfur cycle. Due to the spatial and temporal extent of carbonates in the rock record, carbonate-associated sulfate (δ34SCAS) is a common proxy for the isotopic composition …
Facies And Diagenesis Analyses Of The Fort Terrett Formation Of The Lower Cretaceous Edwards Group, Near Junction, Texas, Richard Alden Urwin Jr.
Facies And Diagenesis Analyses Of The Fort Terrett Formation Of The Lower Cretaceous Edwards Group, Near Junction, Texas, Richard Alden Urwin Jr.
Electronic Theses and Dissertations
The Fort Terrett Formation was deposited on the western edge of the Comanche Shelf in central Texas. The predominate lithology of the Fort Terrett Formation is limestone which caps the hills that surround Junction, Texas. Deposition of the Fort Terrett Formation occurred within shallow, quiet waters during the Lower Cretaceous. Rose (1974) developed a general stratigraphic correlation and lithostratigraphic framework for the Cretaceous Shelf and established a regional correlation. Four stratigraphic divisions have been recognized in the Fort Terrett Formation. These are: a basal nodular unit, a burrowed unit, a dolomitic unit, and the Kirschberg evaporites. Wilkerson (2018) provided the …
Ediacaran Depositional Age And Subsequent Fluid-Rock Interactions In The Mutual And Browns Hole Formations Of Northern Utah, Ashley W. Provow
Ediacaran Depositional Age And Subsequent Fluid-Rock Interactions In The Mutual And Browns Hole Formations Of Northern Utah, Ashley W. Provow
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Constraining the depositional age of Neoproterozoic stratigraphy in western North America has implications for correlating global glaciation and tectonic events. The depositional ages of the Neoproterozoic Mutual and Browns Hole formations of northern Utah are controlled by two conflicting datapoints. However, new U-Pb geochronological data from 95 detrital apatite grains refines the maximum depositional age of the volcanic member of the Browns Hole Formation to 613 ± 12 Ma (2σ). This places new restrictions on the time available for the deposition of underlying units. Due to debate regarding the age models for underlying stratigraphy, two scenarios for sediment accumulation rates …
Provenance, Redox Conditions, And Diagenesis Of Shales In Chang 7 Member Of Upper Triassic Yanchang Formation, Ordos Basin, China, Bin Sun
Doctoral Dissertations
“This study aims to decipher provenance, redox conditions, and burial history of shales in Chang 7 Member of Upper Triassic Yanchang Formation, Ordos Basin, China. The first paper discusses the origins of single-channeled, vertical, sinuous, and calcite-bitumen-filled cracks in the shales. Results show that in early diagenesis, unconsolidated mud was expanded open by escaping gases produced during organic matter maturation under hydrothermal influences. Calcite initially filled the cracks; bitumen and pyrite came in later and occupied the cracks in various ways. Compaction occurred next and folded the calcite- and bitumen-filled cracks into sinuous shapes. The second paper uses geochemical and …
Sequence Stratigraphy, Diagenesis, And Depositional Facies Of An Exposed Megaflap: Pennsylvanian Hermosa Group, Gypsum Valley Salt Wall, Paradox Basin, Colorado, Kyle Thomas Deatrick
Sequence Stratigraphy, Diagenesis, And Depositional Facies Of An Exposed Megaflap: Pennsylvanian Hermosa Group, Gypsum Valley Salt Wall, Paradox Basin, Colorado, Kyle Thomas Deatrick
Open Access Theses & Dissertations
Outcrop exposures mostly of the Pennsylvanian Honaker Trail Formation provide a 2 km strike-oriented view of a megaflap on the southwestern flank of the Gypsum Valley salt wall, Paradox Basin, Colorado that serves as an outcrop analog for megaflaps recently drilled unexpectedly in the Gulf of Mexico and other salt basins worldwide. The near vertical (80-90°) stratal panel comprises a 60 m thick succession of non-evaporite facies of the Pennsylvanian upper Paradox Formation, overlain by a 117 m section of cyclic shallow marine carbonates and siliciclastics of the Honaker Trail Formation. Near vertical upper Paradox and Honaker Trail strata are …
Diagenesis And Diagenetic Facies Distribution Prediction Of Chang 8 Tight Oil Reservoir In Maling Area, Ordos Basin, Nw China, Meng Wang, Shu Liu, Ming Zeng, Gang Lin, Yulin Cheng, Long Fang, Jiaming Zeng
Diagenesis And Diagenetic Facies Distribution Prediction Of Chang 8 Tight Oil Reservoir In Maling Area, Ordos Basin, Nw China, Meng Wang, Shu Liu, Ming Zeng, Gang Lin, Yulin Cheng, Long Fang, Jiaming Zeng
Turkish Journal of Earth Sciences
In this study, characteristics of Chang 8 tight sandstone pore structure and diagenesis are analyzed. A classification standard for sandstone diagenetic facies is established. Combined with the probabilistic neural network method, logging curves are used to predict the distribution of diagenetic facies. The following results are found: the Chang 8 reservoir has low porosity-low permeability characteristics, and the pore-throat structures have strong microscopic heterogeneity; both compaction and siliceous and carbonate cementation promote reservoir densification; chlorite cement lining, hydrocarbon emplacement, and the dissolution of feldspar and rock fragments have constructive effects on reservoir development; and two favorable diagenetic facies, a weakly …