bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE UPPER SMACKOVER OF THE GULF RIM: DEPOSITIONAL SYSTEMS, DIAGENESIS, POROSITY EVOLUTION AND HYDROCARBON PRODUCTION
Authors: MOORE CLYDE H. 
Published: October 2019

Abstract
A generalized stratigraphic framework for the upper Jurassic is suggested, in which the name Haynesville Formation is utilized, and the name Lower Cotton Valley Lime is suppressed in favor of the Gilmer, where appropriate. Eustatic sea-level fluctuations have resulted in patterns of sedimentation common to upper Jurassic sequences across the entire northern Gulf of Mexico region and hence indicate the wide applicability of this generalized stratigraphic framework.
The presently accepted model of the Smackover-Haynesville sedimentation must be modified to take into account sea-level fluctuations, subsidence, and sediment availability. The model developed here is simply one of lower Smackover basin fill during a rapid transgressive phase and upper Smackover regional shoaling during a sea-level stillstand in which sedimentation was in equilibrium with subsidence. The lower and upper Smackover are not necessarily time equivalent, but represent two separate sedimentologic sea-level regimens. The Haynesville Formation is thought to be a separate sedimentologic package that was deposited during the next sea-level rise; the Gilmer Limestone formed a shelf-margin barrier behind which the lagoonal Buckner evaporites were deposited. The evaporites graded landward into quartzose clastics.
Predictable regional porosity patterns have developed in the Smackover-Haynesville, in response to early diagenetic overprints, controlled largely by eustatic sea-level subsidence interactions. These patterns include: updip oomoldic porosity in a regional meteoric-water system developed during the upper Smackover sea-level stillstand; downdip porosity preservation under marine conditions along the shelf margin; regional dolomitization associated with reflux of evaporitive waters from the Buckner lagoon behind the Gilmer shelf-margin barrier.
Structural hydrocarbon traps associated with salt movement are the most common type of Late Jurassic trap. Buckner evaporites or Haynesville shales usually form the seals in the Late Jurassic reservoirs. Jurassic source rocks are probably lower Smackover limestones and Norphlet shales. Sourcing is generally local with migration into updip areas, particularly where regional dolomitization has occurred. The time of migration, which is a key factor in a viable Smackover exploration strategy, varies across the Gulf in response to the subsidence history of each individual basin.
Future Jurassic exploration will center on south Texas, the Gilmer shelf margin, and the updip Smackover along the bounding graben fault systems. Most production will be gas, but some oil should occur along the updip faulted fairways.
SUBSIDENCE AND TEMPERATURE HISTORIES FOR JURASSIC SEDIMENTS IN THE NORTHERN GULF COAST: A THERMAL-MECHANICAL MODEL
Authors: Nunn Jeffrey A. 
Published: October 2019

Abstract
The northern coast of the Gulf of Mexico contains major depositional basins in East Texas, North Louisiana, and Central Mississippi. Basin subsidence can be interpreted as resulting from the extension of continental crust by rifting related to the opening of the Gulf of Mexico during Late Triassic to Early Jurassic times. For example, subsidence of the North Louisiana Salt Basin, determined from well data, is consistent with crustal extension by a factor of 1.5 to 2. A seismic survey across the Central Mississippi Salt Basin also indicates crustal extension by about a factor of 1.6. The thermal-mechanical model presented here describes the subsidence and temperature histories of a continental margin, assuming that the lithosphere is stretched and thinned during rifting. The effects of thermal blanketing by overlying sediments are included. The observed position of strata and current thermal regime are used as model constraints. Subsidence and temperature histories for Jurassicage sediments predicted from this model are compared with observational data. The results of this comparison indicate that geothermal gradients were higher in the past and that thermal conditions in Jurassic-age sediments were favorable for hydrocarbon generation.
Geochemistry and Origin of Smackover and Buckner Dolomites (Upper Jurassic), Tay Field Area, Alabama - Florida
Authors: Vinet Marshall J. 
Published: October 2019

Abstract
The Smackover-Buckner sequence in the Jay-Big Escambia Creek area is divisible into three major lithostratigraphic units: lower Smack-over, upper Smackover and Buckner with an uppermost Smackover transitional sequence. The lower Smackover is regionally extensive, mostly high intertidal, dolomitized packstones with abundant displacive anhydrite nodules. The upper Smackover is characterized both by areas of thick oolite grainstone buildups which form the primary reservoir rock and by areas of low energy, subtidal mudstones-wackestones. The Buckner is mostly nodular mosaic anhydrite with minor amounts of dolomite mudstones-packstones. The Smack-over-Buckner contact is a transitional sequence (referred to here as uppermost Smackover) of high intertidal-low supratidal dolomitized mudstones-grainstones interbedded with nodular mosaic anhydrite layers.
A combination of stratigraphic and geochemical evidence indicate dolomites of four separate origins, three of which are early diagenetic. The dolomites of the Buckner-uppermost Smackover have supratidal stratigraphy and heavy oxygen isotopic geochemistry (means 𝔡180=+1.5‰PDB) and formed penecontemporaneously with deposition. Immediately below and separated by a sharp discontinuity in chemistry are the upper Smackover dolomitized oomoldic grainstones which were dolomitized prior to uppermost Smackover deposition. Stratigraphy, petrography and light oxygen isotopic geochemistry (mean 𝔡180= −2.0‰PDB) favor a mixed-water origin for the upper Smackover dolomites.
The lower Smackover dolomites formed in arid, high intertidal-low supratidal environments penecontemporaneously with deposition based upon petrographic similarity to those of the Buckner and trace element and oxygen isotopic values intermediate between upper Smackover and Buckner dolomite values.
Late, pore-filling saddle (baroque) dolomites precipitated under deep burial conditions.
TECTONIC EVOLUTION OF GULF COAST BASINS
Authors: WALPER JACK L. , MILLER ROBERT E. 
Published: October 2019

ABSTRACT
The Gulf of Mexico formed with the rifting and breakup of Pangaea during Triassic and Early Jurassic time. Its formation and the evolution of its tectonic framework as a passive continental margin can be viewed in terms of the interplay of two factors: (1) stresses operating during the rifting of Pangaea and (2) the inherited tectonic fabric of the rifted passive margin that formed at the divergent plate boundary.
Various aspects of continental rifting are examined and evaluated in terms of the stresses operating during the rifting process. A revised model involving double indentation tectonics is proposed to explain the suturing of North and South America and the formation of the Ouachita orogenic belt, which consists of a thrusted allochthonous subduction complex, volcanic arc and forearc basins. It also explains the relationship of this belt to the North America craton, with which it collided. This orogenic belt not only frames the Gulf but forms much of the pre-rift basement of the upper Gulf Coast where segments of the volcanic-magmatic arc terrane, possibly represented in the Sabine and Monroe Uplifts and the Wiggins Arch, are now found in the accreted continental margin and appear to have controlled or at least influenced subsequent Mesozoic rifting.
The variable aspects of both these interfacing factors are discussed and their influence on the long and active tectonic and sedimentary history of the Gulf Coast and its basins is evaluated. Also the factors that govern the thermal history of the basin sediments are identified.
The Gulf of Mexico is unique among passive margins in that the mechanism which caused uplift, rifting, crustal extension, and drift—with accretion of oceanic crust at a spreading center within the Gulf—aborted and stepped southward into the Caribbean, where it formed that plate. In the Gulf, meanwhile, salt, deposited in basins initially formed and controlled by the two interfacing factors during the early opening, became the dominant tectonic mechanism in controlling subsequent sedimentation and facies distribution.
Following deposition of the evaporites, the Gulf began rapid subsidence that resulted in formation of a thick prograding sedimentary wedge of both clastic and carbonate strata around its margin. Its final shaping came with Laramide tectonism that not only rejuvenated hinterland source areas to supply voluminous sediment but transported peninsular Mexico eastward to close the Gulf and form a huge sediment trap in which vast thicknesses of Tertiary to Recent sediment were deposited.
PETROLEUM PRODUCTION AND HYDROCARBON POTENTIAL OF ALABAMA'S COASTAL PLAIN AND TERRITORIAL WATERS
Authors: Mancini Ernest A. , Mink Robert M. 
Published: October 2019

ABSTRACTWith the discovery of oil in 1944 at the Gilbertown Field in Choctaw County, Alabama became an oil producing state. Since that discovery, Alabama’s coastal plain and territorial waters have become increasingly important areas for the exploration of oil and gas. The primary exploration targets have been the Upper Jurassic Smackover and Norphlet formations. However, the most productive oil field in the state continues to be the Citronelle Field, which produces from reservoirs of early Cretaceous age. Upper Cretaceous rocks productive in southwestern Alabama include fractured Selma chalk and sands of the Eutaw Formation and Tuscaloosa Group. The 1979 discovery of gas in Tertiary sands has resulted in the establishment of several Miocene gas fields in the state.Alabama should remain an excellent region to explore for oil and gas in the years ahead. Much of Alabama's coastal plain and territorial waters remain untested. Petroleum exploration will probably continue to be concentrated on Upper Jurassic Smackover and Norphlet prospects; however, the Haynesville Formation and Cotton Valley Group have petroleum potential in southwestern Alabama. With renewed interest in the Upper Cretaceous in the onshore northern Gulf of Mexico area, the Cretaceous in Alabama should also see additional hydrocarbon exploration. The Miocene shallow gas discoveries in coastal Alabama have demonstrated that hydrocarbons are present in Tertiary strata in the state. Other prospective Tertiary units include upper Paleocene and lower Eocene sands and Oligocene carbonates. The keys to successful prospecting in the region for Upper Jurassic and Cretaceous objectives are the delineation of petroleum traps associated with salt movement and the recognition of favorable lithofacies. Identification of favorable stratigraphy is critical to defining prospective Miocene reservoirs.
GAS COLUMNSVS.DEPTH IN TEXAS-LOUISIANA GULF COAST BASIN RESERVOIRS
Authors: WHEELER JOE O. , DAVIS JAMES M. 
Published: October 2019

ABSTRACTA plot of Gulf Coast Tertiary-Pleistocene gas columns vs. depth of burial shows that on average, columns are greater in deep reservoirs than in shallow reservoirs. Further, the plot suggests that for a given depth of burial, there is a maximum attainable gas column. Analysis of the data permits the construction of a set of probability curves, plotting depth of burial vs. gas column, which are statistically significant.
DEPOSITIONAL ENVIRONMENT OF THE QUEEN CITY FORMATION (EOCENE) IN THE HAGIST RANCH FIELD, DUVAL AND McMULLEN COUNTIES, TEXAS
Authors: SPETSERIS JERRY J. 
Published: October 2019

ABSTRACTThe Queen City Formation in South Texas has been described as a progradational wave-dominated delta system. Within this system is included a prodelta shelf and mud facies, lagoonal mudfacies, meander-belt sand facies, and stacked coastal barrier sand facies. In South Texas, Eocene deposits typically demonstrate cyclic successions of transgressive, inundative conditions followed by episodes of regression. Eocene episodes were in response to variation in relative rates of sediment supply and basin subsidence or sea level rise. Genetically related terrigenous Queen City sediments and their marine equivalent comprise a thick, regressive deltaic pulse that overlies the top of Carrizo fluvial-deltaic series of the Wilcox group. The transgressive Weches Formation, consisting of prodelta and shelf deposits, in turn overlies the Queen City section. Examination of core, thin sections, and wireline logs in the Hagist Ranch Field indicates an overall storm-dominated shelf succession. Depositional response indicates a mixture of progradational and aggradational infilling. The Queen City section is characterized by a coarsening upward sequence of very fine to fine-grained glauconitic sandstone separated by fossiliferous marine mudstone. Some sandstone intervals are quartzose, well sorted, and thinly cross-stratified. Other intervals are composed of intensely burrowed, rippled sandstones and siltstones which exhibit mixed bedding. The sandstones contain transported organic debris and exhibit wave and current-induced primary sedimentary structures, possibly as a result of combined flow. These include scour surfaces, ripples, and low-angle cross-stratification. In many instances, ripples and cross-stratification exhibit truncation surfaces. The presence of glauconite and fossiliferous mudstone suggests an open marine setting. Several feet of sand were possibly deposited rapidly, by storm activity, then followed by a period of deposition characterized by quieter conditions and intense burrowing. These sandstone units were stacked successively to create amalgamated sheet sandstones, 20 to 100 feet (6.1-30.5 m) in thickness. Overall, the Queen City section is interpreted as having been deposited in an inner shelf setting where surface waves and currents were the dominant agents.
HABITAT OF OIL AND GAS IN THE MIDDLE FRIO (OLIGOCENE) HACKBERRY
Authors: Curtis Doris M. , Echols Dorothy J. 
Published: October 2019

ABSTRACT
This paper reinterprets the stratigraphic position, depositional environments, and depositional systems in the middle Frio (Oligocene) Hackberry, and their relation to hydrocarbon accumulations. This stratigraphic unit is present in the subsurface of southeastern Texas and southwestern Louisiana, in an area known as the Hackberry embayment. The unit consists of a lower Hackberry sandstone-shale sequence, overlain by middle and upper Hackberry marine shale (the Hackberry shale “wedge”).
The lower Hackberry sandstone sequence overlies a truncated lower Frio section, but in some interdomal areas and in downdip locations, lower Hackberry sediments rest conformably on lower Frio Nonion struma beds. Planktonic foraminifers indicate that the erosional surface between lower and middle Frio coincides with a worldwide relative sea level fall approximately 30 million Ma, in planktonic foraminiferal zone P 21. Dip-oriented submarine channel systems related to this erosional surface contain lower Hackberry reservoir sands in downdip positions.
The marine shale wedge that overlies the lower Hackberry sandstones was deposited during a relative sea level rise, when rates of subsidence exceeded rates of deposition. Some strike-oriented discontinuous marine sand reservoirs are present within the shale wedge.
Production is found in the updip lower Hackberry in structural traps in reservoirs related to near-shore and fluvio-deltaic deposition (traction-transport systems), and, in downdip locations, in stratigraphic-structural traps in submarine channel systems (gravity-transport systems). Unexplored objectives related to submarine channel-fan systems may be present downdip below thick growth-faulted younger Frio sections.
MICROPALEONTOLOGICAL STRATIGRAPHIC FRAMEWORK FOR THE CRETACEOUS BLACK LIME WACKESTONE-MUDSTONE FACIES OF THE GULF OF MEXICO
Authors: McNulty Charles L. 
Published: October 2019

ABSTRACT
One of the widespread Cretaceous units of the Gulf of Mexico is characterized by dark, megapaleonto-logically poor to barren lime wackestones and mudstones, herein referred to as the Tamaulipas. The unit forms the Gulfward component of facies sets which include reef and back-reef facies. These crop out in the Sierra Madre Oriental, have been drilled in the Coastal Plain, and apparently encircle the Gulf of Mexico. Although divisible into rock units (Taraises, Tamaulipas, Cuesta del Cura, lower Agua Nueva), the lithofacies is unified by the overriding physical properties and prevalent bathypelagic paleontological aspect. The temporal span of the facies varies from one locality to another but generally extends from earliest Cretaceous into Turonian.
In spite of difficulties resulting from a biologically eccentric biota and limitations resulting from thin-section study necessitated by induration, there has been prolonged investigation of the unit. The biostratigraphic framework is well established in some oil company laboratories and in reports, particularly by Bonet, Trejo, and Longoria, but these are not always readily available, and related literature is widely scattered. Consequently, a current summary is offered here.
The most useful taxa of the Tamaulipas are calpionellids, nannoconids, calcisphaerulids, micro-calamoidids, and planktonic foraminifers. For each of these taxa, general properties, illustrative and significant species, and important ranges are given.
The distributions of the significant forms delineate detailed zonations for intervals of (1) Berriasian to Hauterivian, based on calpionellids, (2) middle Aptian to early Albian, based on foraminifers, microcalamoidids, and calpionellids, (3) late Albian to middle Cenomanian, based on foraminifers, and (4) early Turonian, based on foraminifers.
Calcisphaerulid ranges are somewhat unreliable, but calcisphaerulids provide supporting evidence, particularly for the mid-Albian. Nannoconids are very small and typically obscure in thin sections of conventional thickness, but they often help in dating, particularly for the early Aptian. Their visibility and assistance can be improved by cutting thin sections with a tapered edge or by treating a fragment of sample with calcareous nannofossil techniques. Calcareous nannofossils are present but have not been extensively reported so far, perhaps partly because of the obscuring effect of recrystallization involved in induration.
SEDIMENTARY PATTERNS AT RIDGE AND SWALE BATHYMETRY, INNER CONTINENTAL SHELF, VIRGINIA, U.S.A.
Authors: OERTEL GEORGE F. 
Published: October 2019

Abstract
A computer generated three-dimensional plot of 220 sq km of the Virginia inner continental shelf revealed three distinct bathymetric zones, not detectable on navigation charts. The survey area is characterized by broad low-relief plains, “ridge and swale” regions, and “dome and swale” regions. Low-relief plains are featureless areas of the sea floor that gently dip seaward at 0.03 to 0.06 degrees. Ridge and swale regions have linear trends in bathymetry with up to 6 m of local relief and 2 to 3 degree slopes. The dome and swale regions are differentiated from the ridge and swale areas by the lack of well-defined parallel ridges. Bathymetrically high areas stand out as individual mounds or domes.
Detailed studies were made at a ridge and swale area located 30 km east of the Chesapeake Bay entrance. Three ridges in a 3.4 sq km survey area are spaced approximately 0.75 km apart and have a maximum relief of 5.5 m. Each of the ridges is transected by shallow submarine depressions that are subnormal to the trends of the ridges. As a result, the ridge crests are undulating surfaces formed by linear trending domes and the shallow depressions.
Spatial distribution of five lithosomes in the study area corresponds with bathymetrically distinct portions of the ridge and swale system. The five areas are described as dome crests (along the ridge axis), cross-ridge depressions and upper-ridge margins, lower-ridge margins, swale floors, and scour troughs. The characteristics of these lithosomes suggest that the surface deposits are not relict, but are due to active marine processes. Grain size increases between the swale floor and the ridge crest. The only exceptions to this trend are coarse deposits at scour troughs on the swale floors. Surface sediments on domes along the ridge crests contain primary sedimentary structures in a coarse sand lag. Cross-ridge depressions contain primary sedimentary structures in fine sand, indicative of both bedform migration and storm-related sand drapes. The presence of bioturbated fine sand along the adjacent ridge-face slope, between the cross-ridge depressions, suggests that these areas are relatively stable.
STRATIGRAPHIC SEQUENCE RESPONSE TO GLACIO-EUSTATIC FLUCTUATIONS IN A RAPIDLY SUBSIDING LATE CENOZOIC BASIN, SAN FRANCISCO, CALIFORNIA
Authors: CLIFTON H. EDWARD 
Published: October 2019

Abstract
More than 1,750 m of late Cenozoic deposits are exposed in a structurally continuous section in sea cliffs south of the city of San Francisco. Well-defined facies in this succession reflect deposition in the eolian dune, alluvial, freshwater pond/swamp/marsh, embayment, backshore, foreshore, nearshore and inner-, mid- and outer-shelf environments. The facies are arranged throughout the succession in alternating regressive and transgressive sequences. The most complete regressive-transgressive cycles show the following upward progression: outer-shelf, mid-shelf, inner-shelf, nearshore, foreshore, backshore/eolian dune, embayment, inner-shelf, mid-shelf, outer-shelf. In this progression, an erosional surface separates the embayment facies from the overlying shelf facies. Although many of the cycles are incomplete, the alternating upward-shallowing and upward-deepening trends are present throughout. The upward-shallowing sequences typically are continuous, whereas upward-deepening sequences contain a distinct hiatus. Nearshore and foreshore deposits do not occur in transgresssive sequences; instead, an erosional surface marks the interval at which they would be expected. The transgressions and regressions are interpreted to reflect Pleistocene glacio-eustatic sea level oscillations.
The facies sequences in this deposit differ from some of the transgressive-regressive sequences described elsewhere. Widespread erosion seems not to coincide with relative lowstands of the sea, but rather occurs with the landward translation of the shoreface during a relative sea-level rise. This situation may be due to the rapid subsidence required to develop such a thick section in a short period of time. It may also be that, because of the high frequency of sea-level fluctuation, insufficient time existed during the lowstands to allow for widespread planation. Vertical textural trends in the regressive and transgressive sequences are more complicated than the simple upward-coarsening and upward-fining trends commonly ascribed to such sequences. These complications probably result from some combination of the effects of the high-gradient and high-energy character of this coast and the rapid rate of subsidence in this tectonically active area.