This research focuses on how sediment supply, sea level and delta processes control the partitioning of the sediment budget across and into the topset, slope and basinfloor compartments of deepwater basins. Addressing this problem provides significant insight to characterize source-to-sink systems, improve tectono-stratigraphic models and predict sand bypass to deepwater areas. The research was carried out in the Lance-Fox Hills-Lewis shelf margin formed during the Maastrichtian in the Washakie-Great Divide basin of southern Wyoming. I use a database with approximately 520 wells integrated with outcrops to develop a high resolution, dynamic stratigraphy approach for shelfmargin characterization. The results emphasize the driving role of sediment supply in rapid shelf-margin building and deepwater sand emplacement. On the study margin, high sediment supply was able to outpace shelf accommodation even at times of relatively high and rising sea level. At these times, shelf margin clinoforms developed a more aggradational architecture with relatively thick and more marine influenced topsets formed in response to basin deepening due to rapid subsidence. The high supply and subsidence are interpreted to have resulted from crustal loading and significant erosion during prominent Laramide thrust-driven source uplift. The high supply caused the formation of highstand shelf-edge deltas with strong wave and river influences. These deltas resulted in extensive coastal sand belts at the shelf margin, and bypass of significant volumes of sand to deepwater areas. In contrast, during times of stable to very low rates of sea level rise, the basin developed more progradational clinoforms with more terrestrial and generally thinner topsets. More of the sediment was funneled to the basin floor and shelfedge deltas were under strong river and tidal influence. Stable or even falling sea level resulted from decreased subsidence or slight basin uplift, interpreted to have resulted from decreasing uplift, tectonic quiescence or possibly slight tectonic rebound in the basin. The Lewis-Fox Hills margin is considered supply-dominated, a term to denote moderately deep shelf margins (< 1000 m) that prograde at high rates (several tens of km/my) and deliver sand to deepwater areas recurrently and in large volumes even at sea level highstand.

The coal-bearing sediments of the Antelope coal field in the southcentral Powder River Basin, Wyoming were deposited in paludal and tributary subsystems of the fluvial system that existed in the basin during the early Tertiary. A depositional model for the Antelope coal field was constructed from data collected from approximately 500 drill holes that penetrated the upper 90 meters (300 feet) of the Fort Union Formation. The depositional environments were interpreted from lithologic descriptions and guidelines established in the literature. The two main coal seams at the Antelope coal field are the Anderson and stratigraphically lower Canyon coal seams. They represent poorly-drained swamp depositional environments. Each of the coal seams exhibit splits into multiple and thinner coal seams to the southwest. The parting rocks that lie between these splits, sedimentary structures, and isopach maps of the partings indicate that crevasse splaying with lacustrine and small channel development caused the observed splits in the coal seams. Distal overbank deposits occur at the top of the Canyon seam and at the base of the Anderson seam; well-drained swamp deposits and crevasse splay, lacustrine, lacustrine delta, and small channel-fill deposits occur in between the coal seams. The rocks underlying the Canyon coal seam suggest that the area of the Antelope coal field was a poorly-drained swamp that developed into a well-drained swamp with minor small channel development. The area once again digressed to a poorly-drained swamp which was the beginning of the Canyon coal swamp. The rocks overlying the Anderson seam represent a combination of the environments mentioned above with deposits from lacustrine and well-drained swamp environments dominating. The observed splits in the Anderson and Canyon coal seams to the southwest at the Antelope coal field suggest that a change in the fluvial system and/or tectonic stability of the Powder River Basin occurred and affected deposition in the southcentral portion of the basin. A combination of 1) relative basin subsidence, 2) a prograding and aggrading trunk stream with a thick levee deposit, and 3) peat accumulation that kept pace with relative basin subsidence are proposed mechanisms for the formation of the thick, continuous coal seams present in the basin and a disturbance or change in any of these processes could produce the splits observed in the Anderson and Canyon coal "Seams at the Antelope coal field. Syn- and post-depositional processes that have affected the coal quality and reserves at the Antelope coal field include compaction, erosion and deposition from modern stream action, and burning and oxidation of the coal seams. The position of the paleowater table during stream downcutting and erosion of the coal seams controlled the occurrence and extent of oxidation and burning. Exploration and development of the Antelope coal deposit can be executed in a more efficient manner by using the depositional model. Future exploration drilling programs, design of the mine site, mining and marketing the coal, and later reclamation of the mined area are all affected by the depositional model.