William A. Wescott

The Wagwater Trough is a fault-bounded basin which cuts across east-central Jamaica. The basin formed during the late Palaeocene or early Eocene and the earliest sediments deposited in the trough were the Wagwater and Richmond formations of the Wagwater Group. These formations are composed of up to 7000 m of conglomerates, sandstones, and shales. S...

The Wagwater Trough is a fault-bounded basin which cuts across east-central Jamaica. The basin formed during the late Palaeocene or early Eocene and the earliest sediments deposited in the trough were the Wagwater and Richmond formations of the Wagwater Group. These formations are composed of up to 7000 m of conglomerates, sandstones, and shales. S...

ABSTRACT The Wagwater Trough is a fault-bounded basin which cuts across east-central Jamaica. The basin formed during the late Palaeocene or early Eocene and the earliest sediments deposited in the trough were the Wagwater and Richmond formations of the Wagwater Group. These formations are composed of up to 7000 m of conglomerates, sandstones, and...

An overview of the morphological characteristics of the Rosetta, Abu Madi, and Kafr el Sheik submarine valley/channel complexes is given. The processes that formed these channels are interpreted within a sequence stratigraphic context. Further, the analysis is used to infer sand/shale ratios of the sediments that were transported by these channel c...

From its inception during the early Miocene, the Suez Rift has been dominated by marine sedimentation. New high-resolution biostratigraphic and sedimentologic analyses of synrift deposits have resulted in the recognition of late Burdigalian-early Langhian brackish water and lacustrine deposits in the Wadi Abu Gaada-Gebel Gushia area, Sinai Peninsul...

The stratal architechture of the Gulf of Suez can be discriminated on several different orders. There are the sequences that can be defined paleontologically: however, since biostratigraphically detectable lacunae can be caused by several different processes, graphic correlation time gaps do not always correlate to true depositional sequence bounda...

Paleontological data derived from well cuttings and outcrop sections shed light on the chronostratigraphy and sequence stratigraphy of Miocene syn-rift rocks in the Gulf of Suez (GOS), and magnetostratigraphy of Miocene outcrop sections enhances the resolution of correlations. Graphic correlation of microfossil datums reveals that the Neogene secti...

The Karoo Supergroup in Madagascar is subdivided into three lithostratigraphical units: the Late Carboniferous-Early Permian Sakoa Group; the Late Permian-Middle Triassic Sakamena Group; and the Triassic-Early Jurassic Isalo Group. The Sakamena Group is fairly well exposed in the southern Morondava Basin, where it is approximately 4000 m thick. The...

Paleontology has played a long and distinguished role in the petroleum industry. Traditionally, paleontology has been used for two main purposes: dating of sedimentary rocks and stratigraphic correlations. The primary method for achieving both objectives was the recognition of index fossils. Based on the observed ranges of these index fossils, the...

The establishment of a robust, paleontologically defined chronostratigraphic framework coupled with detailed facies analysis of outcrops resulted in the development of a sequence stratigraphic model for the Miocene synrift of the Gulf of Suez. Application of this model, along with 3-D seismic, has had a major impact on the ability to recognize stra...

The wide acceptance and application of sequence stratigraphic principles by exploration and production (E&P) professionals has been accompanied by frequent misuse of the associated terminology—such as indiscriminately interchanging the terms channel and valley. In reality, channels and valleys are distinct paleogeomorphic features. There are signif...

The Sakoa Group is the lowermost stratigraphical succession of the Karoo Supergroup and the oldest sedimentary unit in Madagascar, spanning the Late Carboniferous through Early Permian epochs. The Sakoa Group is exposed in the southern Morondava Basin. It is predominantly a siliciclastic sequence comprising seven lithofacies associations: (1) diami...

Unconformity-bounded sequences within the Miocene strata of the Suez Rift reflect a complex interplay between tectonism and sea level fluctuations. Analyses of Miocene outcrops along the Sinai margin of the Gulf of Suez provide new insights into the sequence stratigraphy of this basin. The Miocene strata can be subdivided into seven major sequences...

Graphic correlation of paleontological data from wells and outcrops in the Gulf of Suez reveals that the Neogene section consists of at least eight biostratigraphic sequences (S10-S80) separated by graphic terraces (T00-T70) (geologic lacunae or hiatuses). Field analysis in the Sinai of terraces T00 to T30 and their associated fossil assemblages in...

The Lotikipi plain, located in the northwestern corner of Kenya, is a broad saucer-shaped depression surrounded by, and mainly filled by, volcanic rocks. Recently acquired geophysical surveys (gravity, magnetic, and seismic) show for the first time the structural configuration of this area and has resulted in an interpretation of its geological his...

The East Texas basin is a prolific, mature hydrocarbon province, producing oil and gas from several reservoirs and a variety of trap types. Many of the liquid hydrocarbons discovered in the basin are trapped in structures related to movement of the underlying Louann Salt. By determining the structural evolution of the basin, we constructed a framew...

The onset of tectonism in the northern Kenya Rift is believed to be recorded by the deposition of immature, arkosic sandstones generally referred to as Turkana Grits. These sandstones have been interpreted by various workers as either Cretaceous or Miocene in age. Detailed re-mapping of the Turkana Grits in the Mount Porr (Kajong) area and a new ma...

First-generation sequence stratigraphic models have dealt in a very rudimentary fashion with the response of fluvial systems to eustasy. A major element of presently accepted models is that rivers incise when sea level falls and aggrade during the ensuing rise. Geomorphic principles state that fluvial systems are complex, process-response systems t...

The East Texas basin is a prolific mature hydrocarbon province, producing oil and gas from several reservoirs and a variety of trap types. Much of the liquid hydrocarbons discovered in the basin are trapped in structures related to movement of the underlying Louann Salt. By determining the structural evolution of the basin, a framework was construc...

Deltas have proven to be important worldwide oil and gas provinces for two main reasons. First, they are point sources from which sediment is introduced onto continental shelves and into marginal basins, where the interaction of fluvial and basinal processes frequently results in favorable associations of reservoir, source, and seal facies. Second,...

Recent geological fieldwork, radiometric age dating of volcanic rocks, gravity and seismic reflection surveys have considerably refined our understanding of the tectonic evolution of the northern Kenya Rift. These data reveal that deep, half-graben basins up to 7 km thick were initiated west of Lake Turkana probably during Late Oligocene-Early Mioc...

Deltas have proven to be important worldwide petroleum provinces for two main reasons. Firstly, they are point sources from which sediment is introduced onto continental shelves and into marginal basins, where the interaction of fluvial and basinal processes frequently result in favorable associations of reservoir, source, and seal facies. Secondly...

Exploration in the Rukwa rift, using gravity and seismic reflection surveys, fieldwork, and drilling has defined the structure and stratigraphy of the basin in greater detail than any other part of the Western rift. The stratigraphy comprises Precambrian basement, Karroo sandstones, shales and coals, upper Miocene red beds, and Miocene-Recent lacus...

Three major stratigraphic units have been recognized in the basin (from oldest to youngest): Karroo Supergroup, the Red Sandstone, and the Lake Beds. These units have traditionally been assigned the following ages, respectively, based upon lithologic correlations: Permian-Triassic, Jurassic-Cretaceous, and Tertiary. Recently, microfloral assemblage...

The East Texas basin is a prolific, mature hydrocarbon province, producing oil and gas from several reservoirs and a variety of trap types. Many of the liquid hydrocarbons discovered in the basin are trapped in structures related to movement of the underlying Louann Salt. By determining the structural evolution of the basin, we constructed a framew...

There are three major geomorphic zones on fan deltas: the subaerial fan, which is essentially an alluvial fan; the transitional zone, where fluvial processes and deposits interact with and are modified by littoral processes; and the subaqueous fan delta whose characteristics are least well known and can be quite variable. At least three depositiona...

The Yallahs fan delta on the southeastern coast of Jamaica is a classical example of a wave-dominated, slope-type fan delta complex which has developed in a humid tropical climate. Three distinctive morphological zones make up the fan delta; the subaerial fan, the transitional zone, and the submarine delta front. Environments composing the subaeria...

A trace-fossil assemblage is exposed in the uppermost portion of an interpreted tidal sand-flat deposit in the Upper Mississippian Tar Springs Sandstone in southwestern Illinois. Sedimentary structures, indicative of a tidal origin for this unit, include herringbone crossbeds, flaser and lenticular beds, reactivation surfaces, small channel scours,...

The Upper Jurassic Cotton Valley Sandstone is a thick siliciclastic unit in the East Texas basin. Along the eastern flank of the basin, natural gas is produced from Cotton Valley reservoirs characterized by low porosity and permeability, which have been stimulated by massive hydraulic fracturing. Cotton Valley sandstones are generally very fine-gra...

Conglomerates originating in coastal environments represent mainly beachface, shoreface, fan-deltaic or deltaic mouth bar, andGilbert-type delta sequences. They show structures, textures and otherfeatures created mainly by the varied influence of waves and fluvialoutput in the shallow marine setting. Transitional, alluvial/marine systems show a bro...

The Upper Jurassic Cotton Valley sandstone comprises a thick siliciclastic sequence in the East Texas basin. These sediments were deposited in a dominantly progradational sequence of shallow marine and fluvial-deltaic environments. Along the eastern flank of the basin, natural gas is produced from low porosity and low-permeability reservoirs which...

The shallow offshore Yallahs fan delta serves as a model for the interaction of littoral processes and bathymetry and how they influence sedimentation on steep submarine slopes and in deep marine basins in tectonically active areas. Bottom reflection profiles show that the Yallahs delta front is characterized by two bathymetric zones, a narrow isla...

The Tar Springs Sandstone (Upper Mississippian) crop out in a thin belt around the southern margin of the Illinois Basin. The formation is composed of fine-grained, well-sorted quartz arenites and sublitharenites. Four facies are recognized. They represent deposition by prograding fluvial-deltaic and paralic sedimentary environments. The distributi...

The Yallahs River debouches from the Blue Mountains and has built a 10.5-sq km lobate fan delta composed of sand to boulder-size detritus. The morphology of the delta is controlled in part by the foothills of the Blue Mountains which bound the delta on 3 sides and by a steep offshore profile which causes waves to break and expend most of their ener...

Fan deltas have been defined as alluvial fans that prograde into a standing body of water from an adjacent highland. Most large Holocene fan deltas are located at the edge of active continental margins and island-arc systems where high-gradient braided streams deposit their sediment load of coarse detritus. Such coastlines are usually wave dominate...

The vertical and lateral succession of specific subaerial, transitional, and submarine environments associated with the Yallahs fan delta system provides the data for the development of a stratigraphic model for truncated, coarse-grained, humid region fans that build directly onto relatively steep submarine slopes. This model should prove useful in...

Thesis (M.S.)--Southern Illinois University at Carbondale, Dept. of Geology. Vita. Includes bibliographical references (leaves 93-102).