Browsing by Subject "Wilcox"
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Item Letter to A.C. Wright from H.B. Stenzel on 1948-12-17(1948-12-17) Stenzel, Henryk B.Item Letter to F.Stearns MacNeil from H.B. Stenzel on 1943-09-23(1943-09-23) Stenzel, H.B.Item Letter to Frederick F. Mellen from H.B. Stenzel on 1941-05-15(1941-05-15) Stenzel, H.B.Item Letter to H.B. Stenzel from F.Stearns MacNeil on 1943-09-17(1943-09-17) MacNeil, F.StearnsItem Letter to H.B. Stenzel from Felix A. Vogel, Jr. on 1938-06-27(1938-06-27) Vogel, Felix A., Jr.Item Letter to H.B. Stenzel from J.E. Adams on Undated(0000-00-00) Adams, John EmeryItem Letter to H.B. Stenzel from L.W. Storm on 1941-10-10(1941-10-10) Storm, L.W.Item Letter to H.B. Stenzel from Michael W. Beckman on 1941-09-07(1941-09-07) Beckman, Michael W.Item Letter to Henryk B. Stenzel from James A. Lewis on 1941-03-17(1941-03-17) Lewis, James A.Item Letter to M.C. Israelsky from H.B. Stenzel on 1940-07-30(1940-07-30) Stenzel, Henryk B.Item Linking Gulf of Mexico margin submarine canyons to regional tectonics and interaction of Paleogene Lower Wilcox high frequency sequences with the Yoakum Canyon(2017-05) Clayton, Clarke Austin; Steel, R. J.; Olariu, CornelIn northern Gulf of Mexico, a clustering in a 100-150 km wide area of six Late Cretaceous-Paleogene age incisions up to 1000 m deep and 100 km long suggest a structural rather than eustatic control. The incisions counterintuitively align with the basinward trend of the San Marcos Uplift instead of forming in front of large sediment fairways (rivers) that formed depocenters of the Rio Grande and Houston embayments. The Sabine Arch and LaSalle Arch also uplift regions around the Gulf of Mexico Basin, which align with large slope incisions that indicate a possible main control of tectonism on canyon formation. This study proposes three new possible mechanisms, shelf edge bulge model, low uplift rate model (LUR), and high uplift rate model (HUR), for canyons formation in addition to the two ‘conventional’ models of cutting during lowstand (Posamentier et al., 1991) and cutting during transgression (Galloway, 1991). In addition to the tectonic control of canyon formation, canyon evolution can be longer lived than previously described for some of the Wilcox Group large-scale incisions. By mapping 12 high frequency regressive-transgressive sequences within the Lower Wilcox in the San Marcos Arch region: (1) Sand thickening patterns towards the Yoakum Canyon margin (2) Mis-match of log signature correlation across the Yoakum Canyon (indicating the canyon acted as a “sediment barrier” in the study region) suggest that canyon was active for a longer period than previously described.With the Yoakum Canyon being active during Lower Wilcox time, the canyon(s) evolution would be in the scale of 4 to 5 million years rather than 1 million to 100,000 years. Over this time scale, the deep-water sediment was delivered into the submarine canyon (s) when lateral switching of the shelf-delta depocenters reached close to the head of the canyon during delta transits across the inner to outer shelf. The relationship of Wilcox Group incisions with tectonics and long-lived evolution of canyons provides insight into the large volume of clastic sediment and possible new mechanisms for sediment delivery to the deep water Gulf of Mexico.Item Low pH waters in the vicinity of Oak Hill Mine : a statistical evaluation of water quality(2014-08) Mercier, Lilith Joy; Sharp, John Malcolm, Jr.Lignite (brown coal) mine-mouth power plants supply a significance portion of electricity generated annually in Texas. Most lignite is produced from the Wilcox Group at surface mines located near a power plant. At the Oak Hill Mine, a lignite mine in the Sabine Uplift area of northeast Texas, the presence of low pH seeps has delayed the release of some portions of the reclaimed land from bond of some until all surface water bodies achieves a stable pH between 6 and 9. But this federal requirement may require an artificial elevation of surface water pH above the natural range for low volume, groundwater-fed surface water bodies in that region. The primary objective of this thesis is to determine whether the distribution of groundwater pH at Oak Hill Mine has become more acidic as a result of mining activity. This study shows that low pH (<6.0) groundwater was common within the mine permit area prior to mining activities; the 95% confidence interval for the median pH of overburden pre-disturbance (OP) wells is 4.7 to 4.8. This naturally occurring, low pH groundwater is produced by the weathering (oxidative dissolution) of pyrite in the Carrizo Sand and overburden Wilcox Group. Although low pH groundwater occurs naturally within the Oak Hill Mine permit area, groundwater pH has also decreased (groundwater has become more acidic) as a result of mining activities. The 95% confidence interval for the median pH of overburden reclamation (OR) wells is 4.1 to 4.2, indicating that mining activities has changed the median groundwater pH by approximately -0.5 standard units. Underburden groundwater is less acidic than overburden groundwater, but also becomes more acidic after mining activities. Underburden pre-disturbance (UP) groundwater has a median pH of 6.2 to 6.3 at the 95% confidence interval, whereas underburden reclamation (UR) groundwater has a median pH of 5.6 to 5.8 at the 95% confidence interval.Item Southern Gulf of Mexico Wilcox source-to-sink : investigating siliciclastic sedimentation in Mexico deep-water(2016-09-20) de la Rocha Bascon, Luciana; Snedden, John W. (John William); Tinker, Scott W. (Scott Wheeler); Fisher, William LA source-to-sink system comprises all areas that contribute to erosion, transportation, and deposition of sediments. Therefore, a source-to-sink analysis in a continental-marine siliciclastic system requires data that extend from headwaters to the deep-marine basin-floor fans. The vast amount of data available from the U.S. Gulf of Mexico (GoM) Basin has allowed researchers to develop detailed source-to-sink reconstructions of numerous deep-water fan complexes and their corresponding onshore siliciclastic sources. Paleogeographic maps indicate that Wilcox siliciclastic deep-water systems resulted from erosion and extensive fluvial transport of sediments from the Laramide tectonic front belt into the GoM Basin. In contrast, less is known about sedimentation in the southern region of the GoM offshore Mexico. Indeed, there is no consensus regarding the influence of the southern Laramide upland sediment sources upon Mexican deep-water strata. To explain sedimentation in Mexico’s deep water, a three-phased approach was employed: 1) characterization of the deep-water depocenters; 2) determination and analysis of potential basinal entry points; and 3) semi-quantitative analysis of source to sink scaling relationships. Isochore and structural mapping of the Paleocene and Eocene Wilcox depocenters were constructed using well logs, biostratigraphic information, and marine seismic data. Potential entry points were identified by analysis of onshore data, including evaluation of Wilcox fluvial-deltaic systems rimming the GoM. Empirical scaling relationships between and within fluvial and deep-water source to sink segments highlights potential avenues of sediment flux into the basin. This project provides a new understanding of the Wilcox source-to-sink history of the Gulf of Mexico Basin. The paleogeography of the GoM Basin changed greatly from north to south. The U.S. sector and northern Mexico were a passive margin: continental-scale fluvial systems fed a broad, gently dipping shelf. Conversely, the southern Gulf of Mexico Basin was an active margin: small-scale fluvial systems sourced from the Hidalgoan uplands migrated directly into foreland Basins located in the Basin slope. Results presented here indicate that several systems rimming the southern GoM transported sediment from the mountain belt into the deep-water gulf. During the Paleocene, sediment was mostly routed through canyons in eastern Mexico and through long fan complexes extending from the U.S. into Mexican waters. During the early Eocene, accommodation in certain areas of the foreland were filled, and sediment transport was dominantly from eastern Mexico into deep-water areas. Deepwater depocenters documented in this study not only provide information about the history of siliciclastic sedimentation in the deep-basin, but also highlight the tectonic evolution of the North American craton. The development and extent of deep-water fans in the GoM basin appear to be significantly affected by the timing and location of tectonic uplift. Thus, we hypothesize that the stratigraphic record of deep-water fans in many other geologic systems could be used to illuminate information about the terrestrial record of the source area.Item Weighing controls on shoreline and shelf-margin growth : insights from Wilcox Group, Gulf of Mexico and from numerical models(2018-05) Zhang, Jinyu, Ph. D.; Steel, R. J.; Ambrose, William A.; Fisher, William; Covault, Jacob; Stockli, Daniel; Zeng, HongliuThis research investigates the relative importance of sediment supply, accommodation, and a series of morphological parameters in controlling shoreline migration, the fundamental process and building block during the accretion of entire shelf-margin sedimentary prism. A better understanding of these controls provides insights on different source-to-sink systems and on the evaluating hydrocarbon potential of frontier basins. These studies were carried out in Wilcox Group, Gulf of Mexico (Chapters 2 and 3) and include two numerical modeling studies (Chapters 4 and 5). The greenhouse Wilcox shoreline shows repeated long-distance shoreline regression and retreat, in fact about 37 times during building of Wilcox Group, a stratigraphic scenario a bit different from previous hypotheses that the shoreline movement in low-amplitude, low-frequency greenhouse conditions should be limited. We therefore, suggest that the Wilcox shoreline was controlled by both greenhouse eustasy and variable sediment supply, the latter likely caused by Paleogene hyperthermals. Furthermore, integrated analysis on the paleohydrology of feeder channels, shelf-edge trajectory, and published eustatic curve indicates that a decreasing sediment supply and increasing accommodation controlled the transition of Lower Wilcox shelf margin from being progradation-dominated to aggradation-dominated. BQART model, a widely accepted method of reconstructing sediment load, and Monte Carlo simulation are used for reconstructing the Paleogene Wilcox sediment supply. By comparing with the downstream sediment record, this method shows reliable accuracy and precision. The downstream sediment records are mostly within P10-P90 reconstructed sediment load. This study also shows various tectonic, climatic, and geologic factors controlling the sediment supply. A geometric model of shoreline regression is integrated with sensitivity analysis to understand the relative importance of controls on the formation of highstand shelf-edge deltas. The result indicates the formation of highstand shelf-edge deltas is controlled by multiple accommodation and morphological parameters. Among them, the shelf width is the most important control, whereas subsidence and eustasy are much less important than previous literature implied. This dissertation emphasizes that there are multiple factors that control the shoreline and shelf-margin growth. It is important for future researches to develop and assess multiple hypotheses for evaluating combinations of controls including sediment supply, relative sea level, and morphological parameters.