bluuebunny/crossref_metadata_2025 huggingface dataset:
Sero-prevalence of bovine and human brucellosis on selected farms in South-western Uganda
Authors: Nanfuka BMLT Mary
Published: October 2019

Objective: To determine the seroprevalence of Brucellosis antibodies in cattle in 3 districts in South-western Uganda (Mbarara, Kiruhura and Bushenyi) and to determine the seroprevalence of Brucellosis among the cattle keepers on farms with cattle detected with brucellosis antibodies in the same districts and also to determine the level of awareness of Brucellosis disease among individuals that get in contact with livestock in the same districtsIntroduction: Brucellosis is among the zoonotic diseases that continue to afflict man and animals in Uganda. The increase in the number of disease outbreaks in animals from 1990 to 2013 and the number of human patients diagnosed with brucellosis in private clinics and hospitals has placed the infection to be among the top re-emerging diseases in the country. Brucellosis infection in humans is non-specific and caused by direct or indirect contact with infected animals or their products. Brucellosis manifests as intermittent fever, headache, weakness, profuse sweating, chills, weight loss, generalized aching that may involve multiple organ systems in the body. In animals, Brucella organisms localize in the reproductive organs, causing abortions, decreased milk yields and temporary sterility. Its effects impact negatively to the sale value of the affected animals causing financial losses to the animal owners.Methods: Purposive surveys were conducted in selected farms that were in an area with reported human cases. Ethical clearances were sought. Screening for Brucellosis was done using SAT. All positive samples were subjected to i-ELISA that detects IgM immunoglobulins. A total of 1503 cattle from 113 farms were tested for BrucellosisResults: Brucellosis test results from a total of 1503 cattle showed a sero-prevalence of 14% in Kiruhura, 18% Bushenyi and 23% Mbarara districts respectively. ELISA-positive Brucella cases from farm attendants on the sampled farms in the same districts had a prevalence of 4% in Kiruhura, 9% in Bushenyi and 12% in MbararaConclusions: Our findings underscore Brucella exposure as one of the major re-emerging diseases that should be treated with great concern by both Ministry of Health and MAAIF. We therefore recommend that the Ministries of Health and Agriculture should increase on community sensitization on the risk of Brucella infections in humans from cattle, and promote measures that can protect high risk families from getting infected. This survey indicated that Brucellosis infections are still prevalent in Uganda and continue to occur in the local communities. The public health and animal health service providers need to work together in compiling the disease epidemiological data for a concerted disease intervention measures.
Chondrichthyes Indeterminados do Membro Taquaral (Permiano, Formação Irati) no Estado de São Paulo (Brasil)
Authors: Chahud Artur
Published: October 2019

Chondrichthyes Indeterminados do Membro Taquaral (Permiano, Formação Irati) no Estado de São Paulo (Brasil) 
Action Research to Overcome the Stress Caused by the Combination of Academic and Work Life of Korean Early Childhood Education Doctoral Students
Authors: Kim Mikyung
Published: October 2019

The purpose of this action study is to take a closer look at the factors of stress with doctoral students majoring inearly childhood education and to identify changes through the process of overcoming them. As a starting point, inorder to do that, two Korean doctoral students (Park, Joo-yeon and Kwak, Ji-min) majoring in early childhoodeducation were selected, one is a nursery director and the other is a college lecturer. In - depth interviews, journalwriting, and quantitative analysis were used as data collection methods. Park Joo-yeon has chosen internal resourceto get up early in the morning to study for classes and to exercise. Kwak, Ji-min has chosen internal resource totravel, study in café, and to exercise. Park, Joo-yeon chose two methods as external resources. One pointed outemotional support as a warm word of comfort and encouragement, and the other pointed out physical support toreduce household chores through sharing with her husband. On the other hand, Kwak, Ji-min did not choose externalresources. One conclusion we can draw from this process was that not only two doctoral students' stress and stressresponse were alleviated but also overcoming power increased through the process of overcoming them. Proceedingfrom this fact, we could logically assume that overcoming power were effective in individual ability and acceptanceof life.
De raad in beraad
Authors: Verhelst Tom , Peters Klaartje , De Ceuninck Koenraad
Published: October 2019

The council under consideration. A comparison and evaluation of the formal reforms to strengthen the municipal council in Flanders and the Netherlands

Until 2002, local government in Flanders and the Netherlands had a monistic approach. In both systems, the city council was formally the head of the board. However, due to the interplay of factors and evolutions, the influence of the council in practice was increasing. This contribution compares and evaluates the institutional reforms that have been implemented in Flanders and the Netherlands over the past decades in an attempt to reassess the role and position of the council. While Flanders opted for more limited reforms within the existing monistic system (e.g. its own chairman for the council, a special committee for intermunicipal cooperation, a procedure for restoring structural unmanageability), the Netherlands opted with dualism for a radical personnel and functional separation between council and board. Although the reforms in Flanders often seem half-hearted and councilors in the Netherlands attribute more influence to themselves, research also shows that the revaluation of the council in the Netherlands is (still) incomplete too. This theme will undoubtedly remain on the political agenda in the coming years. The authors are thinking of the development of a better statute for council members, or the functioning of the council as a democratic watchdog of the network society.
Stadsleven: een pleidooi voor de ‘open stad’
Authors: Nelissen Nico
Published: October 2019

City life: a plea for the ‘open city’

This essay is written on the occasion of the appearance of the Dutch translation of Richard Sennett’s new book Building and dwelling. Ethics for the city. For more than half a century Sennett has been occupied with the position of man in the changing society in general and with the life of people in the city in particular. Apparently he doesn’t stop thinking and writing about it. His central thesis is that in the past decades, we have worked from the vision of the ‘closed city’, a city that was conceived and designed by professionals in advance, while for the future there is a need for an ‘open city’, a city where not everything is carefully planned in advance, but where there is room for unpredictability and coincidences. That sounds and is very abstract indeed, but it is a signal that is being delivered in the direction of a city nowadays controlled by state and capital, that should make room for a city that is more inspired by civil initiatives and civil involvement. A statement that is, moreover, largely at odds with the current practice of urban design and spatial planning in the present era. Does this mean that Richard Sennett’s central message has actually been said in advance against ‘deaf ears’? Is the chance that ‘his mission’ ends up in the right place already gone in advance? When we talk about the city Sennett distinguishes between two (and inseparable) dimensions: the city as a physical space (‘ville’) and the city as a whole of people of flesh and blood (‘cité’). It is a fascinating quest for the phenomenon of city: an ‘academic pilgrimage’ to an uncertain urban site, an ‘open city’, undergoing the purification of talking with the great figures in the history of (urban) sociology and urban planning.
Drewno we współczesnej architekturze. Część 3 "Plyscrapers"
Authors: Szewczyk Jarosław
Published: October 2019

W artykule opisano historię użycia drewna w najwyższych budynkach i usystematyzowano odnośne osiągnięcia dawne oraz współczesne, odnosząc je do umownych czterech kategorii wysokości budynków i do analogicznych rekordów natury. Stwierdzono istotność zjawiska jako fenomenu kulturowego ostatnich lat, opatrywanego od niemal dekady medialnym słowem „plyscrapers” („sklejkowce”) i coraz intensywniej włączanego w wielostronne zależności między światem biznesu, kultury, sztuki oraz nauki akademickiej.
DEPOSITIONAL AND DIAGENETIC HISTORY OF UPPER JURASSIC HAYNESVILLE FORMATION, TEAGUE TOWNSITE FIELD, FREESTONE COUNTY, TEXAS
Authors: FAUCETTE ROBERT C. , AHR WAYNE M.
Published: October 2019

The Upper Jurassic Haynesville Formation in Teague Townsite Field, Freestone County, Texas, consists of grainy limestones, muddy limestones, shales, and quartz conglomerates. Constituent grains in the limestones are primarily non-skeletal with ooids being the most common grain type.

Composition and textural data from petrographic studies were grouped into seven microfacies. These microfacies represent three depositional environments: (1) tidal bar, (2) open marine, and (3) restricted marine. The distribution of these environments was controlled by contemporaneous salt movement.

A major shoaling upwards sequence is present in the Haynesville Formation. Nine smaller, local cycles are also present; these local cycles were probably caused by intermittent salt movement during deposition.

Four major diagenetic environments are recognized: (1) marine phreatic, (2) mixed or brackish phreatic, (3) meteoric phreatic, and (4) subsurface environments. Dissolution of ooids in the meteoric phreatic environment created very fine, intragranular porosity in oolite grainstones. Leached zones occur at the crests of the upper shoaling cycles. Virtually all intergranular porosity has been filled by subsurface coarse, mosaic spar cement. Production is from the intragranular porosity created by early meteoric leaching.
DEPOSITION, POROSITY EVOLUTION, AND MODES OF SULFATE EMPLACEMENT IN THE UPPER SMACKOVER, EDGEWOOD FIELDS, VAN ZANDT COUNTY, TEXAS
Authors: WICKLAND DAVID C. , JACKA ALONZO D.
Published: October 2019

Cores and cuttings from the upper Smackover Formation, Edgewood fields, northern Van Zandt County, East Texas, were analyzed to determine depositional facies, diagenesis, and porosity evolution. Edgewood fields lie on an anticlinal structure formed by a salt pillow in the East Texas Basin. Structural growth began during deposition of the Smackover Formation and continued until the end of deposition of the Cotton Valley Formation.

Major lithofacies in the Smackover Formation consist of oograinstone, oopisograpestone grainstone, oobiopelwackestone-packstone, anhydrite, quartzose sandstone, and sandy carbonate, with grainstone and packstone being predominant.

Secondary oomolds and intercrystalline pores constitute the major types of preserved porosity. Although large volumes of primary intergranular porosity initially existed in the lime sands, nearly all of this porosity has been occluded first by submarine cements and later by dolomite, anhydrite, and calcite cements.

Evidence indicates that most of the anhydrite in the upper Smackover Formation is of a diagenetic origin and nonevaporitic. Some thin anhydrite layers are present in the formation and may represent sabkha deposits, but they lack certain characteristics that are typical of modern sabkhas, such as pseudomorphs of gypsum crystals, enteroliths, mud crack casts, flat pebble conglomerates, stromatolites, and fenestral cavities. No example of subaqueous evaporites was noted.

Diagenetic anhydrite occurs in the following modes and morphologies: (1) sparry or felted-lath anhydrite, which was precipitated as a cement in primary and secondary voids; (2) abundant anhydrite, which was precipitated as cement subsequently replaced outwardly, invading the surrounding matrix or grains to form nodules, porphyroblasts, or intensively replaced layers; (3) felted-lath anhydrite which occurs as scattered replacement nodules, or which coalesce to form dense mosaics or massively replaced layers; and (4) replacive sparry anhydrite which was emplaced as scattered porphyroblasts and which locally coalesced to form massively replaced intervals.

Most of the anhydrite was emplaced in grainstones and packstones which had been deposited in relatively high-energy subtidal environments. Dolostones that have been replaced intensively by anhydrite contain abundant inclusions of corroded dolomite crystals and relict fabrics of the carbonate. Initially, much anhydrite nucleated in organic-rich grains, such as ooids, shells, or peloids. In some intervals, thalassinoid burrows have been replaced selectively by anhydrite.

In most carbonate intervals, dolomitization preceded anhydritization. In many intervals, emplacement of anhydrite was followed by influx of a lower salinity fluid that dissolved the anhydrite, precipitated a calcite cement, replaced the anhydrite with calcite, and/or brought about dedolomitization.
BULK DENSITY, VELOCITY, AND POROSITY RELATIONSHIPS IN TERTIARY SANDSTONES OF SOUTHWEST LOUISIANA
Authors: JANSSEN JAMES C. , NUNN JEFFREY A.
Published: October 2019

Information from wells in Cameron and Vermilion parishes of southwest Louisiana was utilized in an empirical study of density, velocity, and porosity relationships in sandstones. Data from Oligocene to Pliocene sediments, ranging in depth from 3,000 to 17,000 feet, were compared to show the range and variability of these parameters with depth and one another. Results are compared with experimentally derived rock properties to evaluate the dominant physical and chemical factors affecting the sediments with increasing depth of burial. For comparison purposes, a smaller study of the velocity, density, and depth relationships in shales was included.

Although observations are consistent with the anticipated results of increasing density and velocity and decreasing porosity with depth, they do not follow simple linear or exponential patterns. Bulk density increases more rapidly with depth as increasing temperature and pressure weaken individual quartz grains causing greater compaction. Sonic transit time decreases (velocity increases) more slowly with depth because the rate of increase in the elastic constants of the rock becomes less as it compacts under a relatively constant rate of compression (i.e., the rate of increase in rigidity and bulk modulus decreases as the rock becomes more compact). An increase in transit time at depth observed in some sandstone units is related to a decrease in effective grain to grain pressure caused by geopressured pore fluids and possibly by increased porosity resulting from greater silicate solubility. Clean sandstone porosity decreases more rapidly with depth and shows a strong negative correlation with the bulk density-depth trend.

Relationships among density, velocity, and porosity are also complex. Although velocity is inversely proportional to density in a homogeneous solid, velocity increases with increasing bulk density in the sandstones. This phenomenon is due to the effect of increasing elastic moduli of the rock associated with porosity reduction dominating the effect of increasing bulk density. As mentioned above, clean sandstone porosity has a strong negative correlation with bulk density, indicating that the physical and chemical factors influencing them are the same.
PETROGRAPHY, RESERVOIR QUALITIES, AND DEPOSITIONAL SETTING OF THE HOWELL SAND, DEEP UPPER WILCOX, EAST SEVEN SISTERS FIELD, DUVAL COUNTY, TEXAS
Authors: D’Agostino Anthony
Published: October 2019

The deep Upper Wilcox Howell Sand was cored in two wells in the East Seven Sisters Field, Duval County, Texas. Three hundred and seven feet (15,010-15,317 feet) were recovered from the ARCO Humble Fee No. 2 and one hundred and sixty-three feet (15,183-15,346 feet) from the Exxon Farmers Life G.U. 1-3. The Howell Sand is the principal reservoir among a group of deltaic sands tested in this field. It is a wedge-shaped delta-front deposit of fine-grained sand interbedded with dark gray, slightly pyritic marginal marine and inner neritic shales. The deposit is backed up by a major growth fault which produced thickening and a rollover structure. Maximum thickness is approximately 300 feet, thinning in three directions, away from the fault and along strike.

Examination of logs and cores and interpretation of sedimentary structures, trace fossils, and grain size trends has revealed three microfacies within the Howell Sand. The facies represent three stages of deposition and subsidence of the sand body in a delta-front setting.

Examination of rock samples in thin section and with a SEM/EDs system has shown that the porosity present is attributable to secondary processes in most cases. Excellent deliverability in a limited area of the reservoir is achieved through the preservation of primary intergranular pores. Primary porosity is estimated to be 25 per cent of the total porosity in the so-called “sweet spot” of the reservoir.

The trapping mechanism is a combination of structural closure and favorable diagenetic facies as porosity and permeability slowly fade out away from the “sweet spot” which is somewhat off-structure.
INNER CONTINENTAL SHELF OFF SOUTHWEST FLORIDA
Authors: DAVIS RICHARD A. , JEWELL PLINY , SUSSKO ROGER J.
Published: October 2019

The inner continental shelf off southwest Florida is a shallow, low-energy environment that displays many of the characteristics of ancient epicontinental and pericontinental seas. The gradient is about 1:3,000, mean annual wave height is less than 0.5 m, and tides are in the lower microtidal range.

This inner shelf area contains two distinct provinces. The northern one near Cape Romano is characterized by tide-dominated quartz sand ridges, whereas the southern province contains a transition from siliciclastic to carbonate sand.

The area of WNW-trending linear sand ridges extends for about 30 km south of Cape Romano. These ridges range from a few to 10 km in length and have a relief of up to 4 m with an asymmetric profile. Sediments on the ridges are well-sorted, fine quartz sand and are covered with various types of bedforms including ripples, megaripples, and sand waves. Swales are less well-sorted with a relatively high shell content. Tidal currents in this area typically peak at 50-60 cm/sec during spring tidal cycles and about half that during neap tides. They show bidirectional patterns with little time-velocity asymmetry.

South of the linear ridge complex and north of Florida Bay is a broad, gently sloping shelf that is subjected to very low wave and tidal energies. The 10 m isobath is approximately 35 km from the coast. The transition zone from siliciclastic sediment in the north to carbonate sediment in the south is several kilometers wide and trends generally WNW.
SAND TRANSPORT KINEMATICS ON THE TEXAS CONTINENTAL SHELF DURING HURRICANE CARLA, SEPTEMBER 1961
Authors: SNEDDEN JOHN W. , NUMMEDAL DAG
Published: October 2019

Using available wind, tide, and wave data, it has been possible to reconstruct the kinematics of sand transport during Hurricane Carla, which made landfall at Pass Cavallo, Texas in September, 1961. The analysis indicates that the peak bed shear stress occurred just prior to hurricane landfall. The quasi-steady shelf flow was driven by the wind-induced sea-level slope and consequent hydrostatic pressure gradient forces. The downwelling bottom current probably was oriented obliquely offshore and along-shelf to the southwest. Integration of hindcast wave data with the proposed bottom flow patterns allows development of a descriptive model for the combined-flow transport pathway for sand and silt. This model suggests a regional transport pattern characterized by offshore transport from shoreface sources near the point of hurricane landfall and weak onshore flow on the southern part of the Texas shelf. This kinematic reconstruction is compatible with the observed strike-trending morphology of a thin (< 10 cm), regional sand bed deposited during the storm.

The shelf sand transport model developed here differs considerably from an earlier explanation for the Carla sand bed which invokes turbidity currents generated during the ebb phase of the storm surge following hurricane landfall. The combined-flow reconstruction indicates that it is unnecessary to call upon post-storm processes to explain the occurrence or areal distribution of the sand bed deposited during this storm.
ORIGIN, DEPOSITIONAL PATTERN, AND RESERVOIR CHARACTERISTICS OF MIDDLE MIOCENE SHALLOW-MARINE SANDSTONES, OFFSHORE SOUTH TEXAS
Authors: MORTON ROBERT A. , JIRIK LEE A.
Published: October 2019

Moderate volumes of dry gas are produced in the South Padre Island Area of offshore south Texas from a 120-m-thick aggregation of mixed shoreface and shelf sandstones that are interbedded with thin neritic shales. These shallow marine sediments aggraded on a broad stable shelf platform during the middle Miocene depositional episode when block faulting and basin filling within the Rio Grande Rift disrupted regional drainage patterns and caused an abrupt decrease in sediment supply to the Rio Grande Embayment. Because sediment influx to south Texas was significantly reduced, middle Miocene sandstones were deposited less than 10 km landward of the previous shelf edge, which was constructed during the early Miocene (pre-Amphistegina B) regressive episode.

Thick, widespread marine shales, containing the Cibicides opima and Textularia stapperi faunal assemblages, occur beneath and above the sequence of nearshore sediments. The Textularia stapperi transgressive shale serves as the primary seal for hydrocarbon accumulation that is preferentially trapped on the upthrown side of minor down-to-the-west faults. These reactivated early Miocene faults did not significantly influence middle Miocene sediment distribution or interval thickness except near the contemporaneous slope.

Individual sandstone reservoirs of the delta fringe and mid-shelf facies are 3 to 12 m thick and exhibit thin interbedded to upward-coarsening log responses. They form laterally-persistent but irregular sand sheets that pass landward into either thick coastal-plain sandstones or embayment mudstones, they merge updrift (northeastward) into fluvial-deltaic sandstones, and they grade seaward into slope mudstones. Progressive basinward and southwestward decreases in net sandstone thickness and sandstone percent indicate predominant sediment transport by shelf currents in the same directions. Repetitive cyclic depositional events are also indicated by the nearly uniform vertical spacing of sandstone beds near their southwestern pinchout.

Shallow reservoir depths (~ 1500 m, 5000 ft) and relatively young sediment age suggest that the hydrocarbons trapped in middle Miocene sediments originated in older Tertiary shales and migrated into the shelf sandstone reservoirs when early Miocene faults were reactivated. The presence of humic organic matter in Miocene sediments and high thermal gradients within the Rio Grande Embayment probably are responsible for the predominance of methane which results from cracking of previously generated hydrocarbons.
SEQUENCE STRATIGRAPHIC INTERPRETATION OF CONIACIAN STRATA IN THE SAN JUAN BASIN, NEW MEXICO
Authors: Nummedal Dag , Swift Donald J.P. , Kofron Bruce M.
Published: October 2019

Detailed measured sections, subsurface data and regional observations along the southern and western margins of New Mexico’s San Juan Basin provide a precise data base for testing proposed sequence stratigraphic models which describe the architecture of depositional sequences. It is concluded that Coniacian strata in this basin represent lithosomes deposited during relative sea level lowstand and subsequent transgressions. The base of the Torrivio Member of the Gallup Sandstone records the landward, unconformable Coniacian sequence boundary. The uppermost tongues (C-A) of the Gallup Sandstone and the associated upper member of the Lower Mancos Shale represent the lowstand wedge. The base of this wedge is the seaward, mostly conformable, continuation of the basal Torrivio sequence boundary. In distal shelf settings, beyond the influence of the Gallup highstand deposits (highstand systems tract), the sequence boundary merges with the condensed section of the next underlying sequence—the Juana Lopez Member of the Mancos Shale.

The Tocito Sandstone represents a set of linear shelf sand ridges which formed during transgressions associated with parasequence boundaries within this regressive lowstand wedge. Ridge-building also continued into the overlying transgressive systems tract. Dominant ridge-building currents were along-shelf tidal flows, partly modified by geostrophic storm flows.

As articulated in sequence stratigraphy, analysis of the genetic linkage between contemporaneous depositional systems and the associated relative sea level stage is a powerful tool in stratigraphic and sedimentological analysis. The many conflicting interpretations already published on the Gallup-Tocito stratigraphy partly owe their origin to a lack of appreciation for the direct connection between styles of sedimentation and patterns of relative change in sea level.
MODELING OF HYDROCARBON-RELATED CARBON ISOTOPIC ANOMALIES IN SUBSURFACE EXPLORATION WELLS OF THE NORTHERN GULF OF MEXICO
Authors: WILLIAMS DOUGLAS F. , LERCHE IAN , SPERO HOWARD J. , TRAINOR DWIGHT M. , FALLS W. FRED , GUILDERSON THOMAS , KIRSCHENMANN KYLE
Published: October 2019

Fine-grained (<63 μm) carbonate from Plio-Pleistocene exploration wells, offshore Louisiana and Trinidad, has δ13CPDB signatures of about -50 to -10 ‰. In this paper we explore two hypotheses that appear to account for these negative δ13C anomalies. The first hypothesis is that the negative δ13C signatures observed in Green Canyon block, offshore Louisiana, are due to authigenic subsurface precipitation of fine-grained carbonate as a record of past migration pathways of hydrocarbons through subsurface Plio-Pleistocene sands. The second hypothesis is that the authigenic δ13C signatures record precipitation at or near the sediment-water interface and thus record the past locations of hydrocarbon seeps on the northcentral margin of the Gulf of Mexico. Preliminary geochemical and petrographic evidence is presented to examine these hypotheses. Within the limitations of not knowing past pore fluid chemistries, we also attempt to use the δ18O signatures of the <63 μm carbonate to estimate the paleotemperatures, and perhaps paleodepths and timing, of emplacement of the negative δ13C signatures.

The potential that this isotopically negative carbonate acts as a geochemical recorder or tracer of hydrocarbon movement makes documentation of this phenomenon important to offshore exploration efforts.
Development and Stratigraphy of Three Rooker Bar; A Recently Emergent Barrier Island, Pinellas County, Florida
Authors: Gibbs Ann E. , Davis Richard A.
Published: October 2019

The emergence of Three Rooker Bar over the past 22 years has presented a unique opportunity to document, through a combination of aerial photography and field observations, the depositional processes and morphologic changes associated with the formation of the island. Three Rooker Bar is situated within the only major gap in the otherwise continuous barrier island coast of Pinellas County Florida, between Honeymoon Island and Anclote Key. The island is bounded to the west by the eastern Gulf of Mexico and by the relatively shallow St. Joseph Sound to the east. The island first became emergent in 1969, although much of its growth has occurred within the last few years. It is essentially pristine and undeveloped, approximately 2 km long and nearly 20 m at its widest spot. The island has a stable, vegetated back beach and dune complex, extensive shoals off the southern end and well developed algal covered tidal flats which overly back barrier washover deposits.

Twenty two vibracores, taken throughout the area, are the basis for three Holocene lithofacies which represent six depositional environments including barrier island, back barrier washover, nearshore bar, coastal bay, and mangrove/salt marsh. Lithofacies are defined based on mud content, shell content and taxonomy, organic content, sedimentary structures and similarity to modem surface sediment deposits. Excellent aerial photo coverage allows direct correlation of these lithofacies with the physical processes which led to their deposition. Absolute interpretation of the depositional environments of these facies is therefore possible.

Results of this method of correlation have led to the interpretation of in-place, upward shoaling of linear sand bars as the primary mode of island formation. Continued growth as well as periodic breaching of topographically lower areas, can be expected for this island in the future.
TIME-SERIES ANALYSIS OF BEACH MORPHOLOGY, PINELLAS COUNTY, FLORIDA
Authors: McKenna Kimberly K. , Davis Richard A.
Published: October 2019

Monthly beach surveys were conducted for three and one half years (1985-1989) at eleven stations along the Pinellas County, Florida shoreline from northern Clearwater Beach Island to southern Long Key. The coast is microtidal, mixed wave- and tide-energy, with a mean annual wave height of 30 centimeters and a mean wave period of four seconds. Tropical storms and low-pressure systems produce high-energy wave conditions and are prime components in eroding the beaches. Time-distance maps of beach profiles show morphologic changes of the shoreline in response to storms and “normal” wind and wave conditions. Wave refraction analyses, incorporating digitized Pinellas offshore bathymetry and common wave conditions, suggest that even low relief offshore features generate wave patterns that erode or maintain a particular beach.

The area contains a nearly continuous seawall from North Clearwater Beach to Pass-a-Grille. Armored beaches, where seawalls are located within the spring tidal range, have shown sizeable sediment loss of the subaerial beach but limited nearshore profile changes. The performance of unstabilized beaches, where the seawalls are situated above spring high tide or behind protective dunes, ranged from substantial volumetric gain at the North Clearwater Beach location to considerable loss at northern Long Key despite nourishment. Seasonal fluctuations in shoreline movement were limited due to low energy conditions. Beaches with similar shoreline orientation and nearshore gradients displayed similar morphologic trends.
MINERAL AND ORGANIC MATTER ACCUMULATION RATES IN DELTAIC COASTAL MARSHES AND THEIR IMPORTANCE TO LANDSCAPE STABILITY
Authors: Nyman John A. , DeLaune Ronald D.
Published: October 2019

Marsh deposits may occupy little of a profile, but the environments they represent may be long lived. Marsh longevity depends partly on the deposition of mineral and organic matter to counter relative sea level rise, or submergence. Understanding soil formation in Louisiana’s rapidly subsiding coastal marshes may provide insights relevant to other coastal marshes if global sea-level rise increases as expected.

Mineral and organic matter accumulation rates required to prevent flooding stress on marsh vegetation in a submerging environment are partially dependent on whether the marsh is fresh, brackish, or saline. Estimates of the rates of mineral matter accumulation required for a marsh surface submerging at 1 cm yr-1 range from 424 gr m-2 yr-1 in fresh, to 1,798 gr m-2 yr-1 in saline marsh. Mineral requirements likely vary in response to the availability of SO4-2, which reduces to a plant toxin, but which is buffered by soil iron. Estimates of the rates of organic matter accumulation required range from 1,969 gr m-2 yr-1 in fresh to 1,136 gr m-2 yr-1 in brackish marsh. Organic requirements vary because of differences in the decomposition rates of plants in the different marsh types.

Another aspect of increasing rates of global sea-level rise is increased marine influences in tidal fresh and brackish marshes, i.e., increased tidal flushing and availability of sea salts such as NaCl and SO4-2, which cause shifts in plant communities. This is important because mineral matter accumulation must almost double for Spartina alterniflora to occupy brackish marsh areas experiencing increased marine influences. Thus even though vertical accretion may initially keep pace with submergence, we hypothesize that if increasing marine influences accompanies submergence, brackish marsh may be more likely to convert to open water than to saline marsh. This may be a factor in the rapid conversion of Louisiana’s brackish marsh to open water. If the rate of global sea-level rise increases, other brackish marshes with low soil bulk density may be similarly threatened.
Rapid Erosion of A Cohesive Shoreline, Sargent Beach, Texas
Authors: Stauble Donald K. , Burke Cheryl E. , Levin Douglas R.
Published: October 2019

One of the areas of highest coastal erosion along the Texas coast is located in the deltaic headland coastal segment of the Brazos River in the vicinity of Sargent Beach. Because of this erosion, a section of the Gulf Intracoastal Waterway (GIWW) from Cedar Lakes to East Matagorda Bay is in danger of intrusion from breaching of the narrow (less than 300 m wide) shorefront. Owing to its deltaic origin, the beach is composed of cohesive fine grained clay and silt material, overlain by a narrow layer of coastal peat and topped by a thin veneer of fine grained quartz beach sand with a high percentage of shell fragments. The northeastern half of the study area has an average erosion rate of 6.7 m/yr and has a thin sandy flat sloping beach over the clay deposit. The southwestern section has up to a meter high clay bluffs outcropping into the surf zone and has an average 11 m/yr erosion rate. It is speculated that this high erosion rate is a result of intermittent wave cutting of large chunks of the clay bluff material. The overall erosion rate along this coast is due to a general lack of sand.
Subaerial Delta Development, Eastern Atchafalaya Bay, Louisiana
Authors: van Heerden Ivor L. , Roberts Harry H. , Penland Shea , Cunningham Rob H.
Published: October 2019

Subaerial expression of Atchafalaya Delta was first apparent following the major flood of 1973,10 years after the subaqueous phase was initiated. Land growth has continued to the present. A project was initiated in 1977 to monitor the plan view and morphological development of the eastern half of this delta as delta development in the Atchafalaya Bay is the only real area of land growth in Louisiana. In addition, no previous Mississippi delta complex has been studied since inception of its subaerial growth. At the present stage of delta development, two distinct phases of subaerial growth are recognizable. The first growth phase consists of channel extension, bifurcation, and initiation of narrow and sinuous overbank channels. The second stage is the more mature response of lobe fusion and upstream accretion that becomes dominant once progradation through bifurcation wanes. Channel bifurcations are initiated when midchannel bars form immediately bayward of channel mouths. As the deep, confined channel waters lose velocity on entering the unconfined, shallow bay, the coarse suspended particles are deposited. The ultimate configuration of the bifurcation reflects the influences that bay bathymetry and tidal currents have on outflow inertias. Bifurcations reduce flow efficiency such that eventually the delta channel system cannot transport sediments to areas seaward of the delta. As a result, the smallest channels of the system fill with fine-grained sediment. Channel abandonment and filling prompts the coalescence of small subaerial lobes into larger ones. Coincident with the lobe fusion is the addition of coarse sediment to the landward ends of lobes, resulting in subaerial accretion in an upstream direction.

The eastern Atchafalaya Delta should continue to grow until either all lobes have fused and the major feeder channel, East Pass, is infilled or until flow starts to bypass the system, due to the greater efficiency offered by the navigation channel.
DEFORMATION AND SEDIMENTATION ABOVE AND BELOW MIOCENE SALT DIAPIRS AND THEIR OVERHANGS, NW YEMEN
Authors: DAVISON IAN , BOSENCE DAN , ALSOP IAN , AL-AAWAH MOHAMMED H.
Published: October 2019

The Al Salif and Jabal al Milh salt diapirs of Miocene age cut through a 4 km thick overburden of Miocene to Recent sedimentary rocks in the southern Red Sea. The A1 Salif diapir is a north-south oriented diapiric wall which has caused updoming of the overburden and active extensional and minor reverse faulting. Carbonate reefs deposited at or below mean sea level, with 14C ages of 3,700 a have been raised up to an elevation of 17 m above present day sea level giving an average surface uplift rate of 4.6 mm a-1. There is no evidence for large-scale stoping or injection of salt into overlying faults and fractures, and the upward movement of the salt dome is probably caused by the overburden being forced aside and sliding off the dome.

Adjacent to the Jabal Al-Milh diapir recumbent folding and thrusting are the main deformation features observed in the siltstones and gypsum layers of the overburden. The overburden surrounding the Jabal al Milh salt neck has been rotated to the vertical at least 200 meters from the diapir walls. The folding and thrusting deformation is interpreted to be caused by flow of salt in an overlying and since eroded namakier.
SALT KINEMATICS, DEPOSITIONAL SYSTEMS, AND IMPLICATIONS FOR HYDROCARBON EXPLORATION, EUGENE ISLAND AND SHIP SHOAL SOUTH ADDITIONS, OFFSHORE LOUISIANA
Authors: HALL DAVID J. , THIES KENNETH J.
Published: October 2019

Detailed interpretation and mapping of more than 10,000 km of 80-fold 8-second recent seismic data and preliminary interpretation of 2500 km of new 15-second, 6 km streamer data provide a new understanding of the kinematic and stratigraphic development of the southern Louisiana shelf. The new data reveal elongated subsalt basins, separated by nearly vertical salt welds and residual salt walls. Sequential back-stripping of balanced depth sections suggests that the walls were initiated by differential loading of overburden depotroughs and grew primarily by down-building. Sand fairways developed between the salt walls with a primary sediment transport direction from the northeast to the southwest. Time structure maps of the MDB (Miocene D. Berggreni) sequence boundary (top of the Miocene) reveal a subsalt and subweld structure disharmonic with a much younger, extremely extended section. The younger section is characterized by backward-rotated hanging walls overlying listric growth-faults. We propose that the original extent of salt sheets emplaced near the sea floor can be defined by the current location of the extended overburden which formed as a result of secondary salt sheet withdrawal. Windows through the residual salt and salt welds, and a few key deep wells which have penetrated the welds provide biostratigraphic control on the timing of the salt/sediment interactions. The vertical welds and walls, coupled with residual salt sheets and horizontal welds, form a network of surfaces separating largely isolated basins. Each basin seems to have developed independently due to varying episodes of local salt motion. The Mahogany discovery, Ship Shoal 349, is an example of sands trapped against the flank of a northeast-trending nearly vertical salt weld. Maps of the former salt sheets associated with salt walls and welds and maps of subsalt structure below the sheets and welds define prospective areas analogous to Mahogany. Additional attractive structures were also localized by salt-sediment interactions.
HOW COMPLICATED IS THE SIMPLIFIED GEOMETRY OF SALT DIAPIRS?
Authors: KOYI HEMIN
Published: October 2019

Six rates (overburden accumulation, A’, diapiric rise, R’, extension, Ex’, shortening, Sh’, dissolution, D’, and erosion, Er’), mold the geometry of salt structures. In order to illustrate their influence on salt structures, for the first time, these parameters are shown together in a single plot. These parameters comprise three couples, A’ and Er’, R’ and D’, and Ex’ and Sh’, representing their negative and the positive end members. This work suggests that instead of conventionally representing the molding history of salt diapirs using only A’ and R’ rates, each of their profiles should be represented by a complex plot including all six parameters. To simplify this complex plot, three separate graphs could be plotted: A’ versus R’, A’ versus Ex’, and R’ versus Ex’. The weaknesses of backward modeling from single profiles of asymmetric salt structures can be overcome by using several profiles.
INTERACTIONS BETWEEN SALT TECTONICS AND SEDIMENTATION IN THE LOUISIANA OFFSHORE: PRELIMINARY RESULTS
Authors: ROWAN MARK G. , WEIMER PAUL , MCBRIDE BARRY C. , VARNAI PETER , ACOSTA ZURILMA , BUDHIJANTO FADJAR , MARTINEZ RAFAEL , NAVARRO ALONSO , VILLAMIL TOMAS , FIDUK J. CARL
Published: October 2019

Seismic profiles, well logs, biostratigraphic data, and cross section restorations were integrated to investigate the relationships between salt tectonics and sedimentation in northern Green Canyon, Ewing Bank, and southwestern Eugene Island. Preliminary results address three aspects of salt-sediment interaction.

First, minibasins have characteristic stratigraphic stacking patterns that evolve from ponded to bypass settings. The transition may occur entirely within the slope environment or be associated with shelf progradation through the minibasin. The shift can sometimes be related to salt evacuation, and in other cases to regional variations in the location and volume of clastic input.

Second, different types of salt bodies have varying bathymetric expressions that may affect sequence thicknesses and facies development: reactive diapirs are overlain by graben at the sea floor; passive diapirs usually create asymmetric highs, with smooth slopes on some flanks and steep scarps on others; and diapirs modified by contraction are marked by broad topographic highs.

Third, models of salt sheet emplacement by extrusion at the sea floor have important implications for the spatial and temporal shifting of sedimentation patterns. Salt bodies originally covered by condensed sections become major minibasins, while bathymetric lows that serve as turbidite conduits and depocenters may be overridden by allochthonous salt sheets.

Because complex salt/sediment geometries in any area are genetically linked to surrounding basins and salt bodies, the interactions between deformation and sedimentation can be understood only by reconstructing the regional evolution of both salt and sediments. Although a daunting task, such efforts will aid in the exploration for hydrocarbons, especially in the sub-salt province.
Application Of Cretaceous Interior Seaway Outcrop Investigations To Fluvial-Deltaic Reservoir Characterization: Part I, Predicting Reservoir Heterogeneity In Delta Front Sandstones, Ferron Gas Field, Central Utah
Authors: Barton Mark D.
Published: October 2019

Data collected from outcrops of the Cretaceous Ferron Sandstone, central Utah, support the theory that stratigraphic heterogeneities are predictable and can be related to position within a stratigraphic cycle (Gardner 1993; Barton 1994; Barton 1995). Specifically, strongly progradational parts of the fluvial-deltaic Ferron system are characterized by mud-rich, internally heterogeneous delta front deposits interpreted to have been rapidly deposited along a river-dominated coastline under conditions of low accommodation and high sediment supply. In contrast, aggradational to retrogradational parts of the system are characterized by sand-rich, internally homogeneous delta front deposits interpreted to have been deposited along a wave-dominated coastline under conditions of relatively high accommodation and low sediment supply.

Data collected from Ferron outcrops was integrated with borehole and production data from the nearby Ferron gas field. The Ferron gas field is located just 5 km to the northwest of outcrops studied and produces largely from the Ferron Sandstone. The description of reservoir architecture within the Ferron gas field was aided by calibrating key surfaces and facies successions identified in borehole data with nearby outcrop equivalents. The gas field is positioned near the seaward extent of the Ferron system and consists of four upward shoaling, shallow marine successions. The basal succession steps strongly basinward, the overlying succession is vertically stacked, and the upper two successions are arranged in a backstepping pattern.

A comparison of sandstone body geometry and cumulative production on a well-by-well basis for each succession illustrates areas of unrecovered gas and styles of reservoir compartmentation. Aggradational and backstepping shallow marine successions contain relatively large reservoir volumes that are effectively contacted and drained by conventional well patterns. Favorable sites for stratigraphic entrapment, however, exist near the landward pinchouts of these successions where they interfinger with lagoonal mudstones. In contrast, offlapping and downstepping shallow-marine successions are highly compartmentalized by marginal marine and marine mudstones. Past completions have contacted only small reservoir volumes. Optimal reservoir drainage within these units may require additional infill wells outside the standard field limits or at intervals less then conventional well spacing. All factors being equal, these types of shallow-marine deposits possess the greatest amount of reserve growth potential.
SEQUENCE STRATIGRAPHY, SEDIMENTOLOGY, AND RESERVOIR CHARACTERISTICS OF THE UPPER CRETACEOUS TERRY SANDSTONE, HAMBERT-ARISTOCRAT FIELD, DENVER BASIN, COLORADO
Authors: SLATT ROGER M.
Published: October 2019

With increased understanding and application of sequence stratigraphic principles to shallow marine and nonmarine strata, many hydrocarbon-producing sandstones in the Cretaceous Western Interior Seaway that were interpreted in the 1980s as offshore shelf bar sandstones have been reinterpreted in the 1990s as shoreface sandstones. The Terry (Sussex) Sandstone is such a deposit. Prior studies of the Terry Sandstone in Spindle and LaPoudre-Antelope fields suggested a shelf bar origin. This study of the Terry Sandstone in the Hambert-Aristocrat Field, which lies between Spindle and Antelope fields, indicates a shoreface origin.

In Hambert-Aristocrat Field, a sharp-based sequence boundary, interpreted as a “forced regression,” occurs at the base of the Terry Sandstone. Overlying this sequence boundary is a series of at least six stacked shoreface parasequences, each separated by transgressive marine shale. Individual parasequences are comprised mainly of upper shoreface strata toward the southwest (paleo-landward), which grade laterally toward the northeast (paleo-seaward) into lower shoreface to offshore strata. Detailed mapping of individual parasequences reveals complex northwest- and northeast-trending geometries of upper shoreface strata to the southwest, but more orderly northwest-trending geometries of lower shoreface/offshore strata toward the northeast, probably reflecting variations in marine influence. Parasequences step progressively paleo-landward indicating they record periodic relative sea level stillstands within an overall transgressive systems tract.

Permeabilities, which are rarely >5md and generally <2md, are primarily related to sedimentary facies. Upper shoreface sandstone immediately above the sequence boundary is the major oil- and gas-productive interval. Other, non-perforated upper-lower shoreface/offshore strata might constitute additional opportunities for recompletion, directional or targeted infill drilling. Transgressive shales provide the potential for stratigraphic sealing and vertical isolation of individual sandstones.