Lignitic Material Research Articles

Petrologic Discrimination Between the Neogene Formations in Adams and Wilkinson Counties, Southwestern Mississippi

ABSTRACT The outcropping Neogene sediments of Adams and Wilkinson Counties, Mississippi, include the Miocene(?) Hattiesburg Formation,the Plio-Pleistocene(?) Citronelle Formation, the Pleistocene Natchez Formation, and Quaternary terrace deposits, overlain by a now erosionally dissected loess blanket that thins eastward away from the Mississippi River. These units can be distinguished both on the basis of outcrop characteristics (which were used to identify them in the field) and petrologic parameters (which may be useful for determining lithostratigraphic relationships between units during detailed geologic mapping, as well as for identifying units in the subsurface). Samples of the pre-loess Neogene section have been studied utilizing grain size (sieve and pipette) analysis, thin-section petrography of sands, and X-ray diffraction analysis of the clay-sized fraction. The Hattiesburg Formation consists primarily of clay and silt; the coarsest bed sampled is a fine-grained sand. Smectite is the dominant clay mineral in the Hattiesburg, but kaolinite is the only clay present in all samples of this formation. The Hattiesburg is increasingly siltier southward, and this increase in grain size coincides with a decline in smectite abundance. The coarsest unit is the Citronelle, which is commonly graveliferous near its unconformable basal contact with the Hattiesburg Formation, fining upward to sands. This contact is found consistently at an elevation of about 300 feet. Gravel is also present in the Natchez Formation and terrace deposits, and fining upward sequences were observed in both units. The Citronelle, Natchez, and terrace deposits also include beds of fine-grained sediments, the Citronelle even having a relatively well indurated shale. Kaolinite is the dominant clay mineral in the Citronelle, and in most of the samples is the only clay detected. Whereas Hattiesburg, Citronelle, and terrace deposit sands can be classified as quartz arenites or sublitharenites, the markedly greater feldspar content of the Natchez Formation gives it a subarkose to arkose composition. Additionally, it is the only unit displaying volcanic rock fragments, as well as the only unit with illite identified in all samples; kaolinite is also abundant in the Natchez Formation. Unfortunately, the Natchez is essentially a local unit, the remnant of a Mississippi River terrace constructed of glacial debris from a northern mid-continent provenance area; thus, the diagnostic characteristics of the Natchez Formation do not have regional applicability. Terrace deposits lie unconformably on the Hattiesburg Formation, and likely have been derived mostly from Citronelle, and to a lesser extent, Hattiesburg sediments. Kaolinite is present in all terrace deposit fine fractions; illite and smectite are important but less frequently occurring. Miscellaneous sedimentary features that may be useful for distinguishing between units are also present. Lignitic material, calcite nodules, and trace fossils are found within the Hattiesburg section. Large-scale crossbedding, rip-up clasts composed of clay, and manganese oxide-encrusted gravel clasts occur in the Citronelle Formation; and armored clay balls were noted in the Natchez Formation.

New Oil Exploration Play in Florida: The Upper Fredericksberg Dollar Bay Formation: ABSTRACT

ABSTRACT The Fredericksburg of South Florida has been overlooked as a primary oil target. Previous exploration in the area has emphasized the Lower Cretaceous oil-producing Sunniland formation which is lower in the stratigraphic section. Many wells in the Fredericksburg Dollar Bay formation yield hydrocarbon shows in limestone biohermal deposits and in an upper dolomitic section. The Dollar Bay formation is part of the Big Cypress Group of the Comanchean Series of the Lower Cretaceous. The Lower Cretaceous is composed of evaporite-carbonate cycles consisting of anhydrites, dolomites, and limestones. Also present are calcareous shales, mudstones, salt, lignitic material, and carbonaceous material, especially in the anhydrite and limestone intervals. The limestones are usually micritic, chalky, calcarenitic, sometimes argillaceous, and contain skeletal particles of gastropods, pelecypods, ostracods, algae, and forams, along with vadoids, ooids, oncolites, grapestones, and fecal pellets. The color of the limestone ranges from white to gray to tan to dark brown. The anhydrite is nodular, microcrystalline, or crystalline and is usually bedded. The dolomite crystals are euhedral to sucrosic and occur in about 30% of the formation. The expected production in the Dollar Bay formation will be from a leached calcarenite or a dolomite. Examination of cores and cuttings suggests a trapping mechanism and reservoir quality and content similar to the oil pay-zone of the Sunniland formation in Felda field. In the wells examined, the reservoir porosities range from 13.6% to 28.7%, with permeabilities ranging from 4.9 md to 119.0 md in a dolomite section, while in the limestone the porosities range from 9.2% to 32.7% with permeabilities from 5.2 md to 59.0 md. More than twenty wells have been evaluated for lithology, porosity, diagenesis, cementation, and for evidence of the direction of hydrocarbon migration. All indicators suggest that the Dollar Bay formation should produce oil similar to that of the Sunniland formation but from an area updip and northeast of the existing oil producing trend.

An investigation of carbonaceous materials reducing ferric ions in aqueous solution

By substituting the ferrous to ferric oxidation for anodic oxygen evolution in an electrowinning cell, it is possible to reduce the cell voltage by about 1 V. However, it is then necessary to reduce the ferric back to ferrous and, depending on the circumstances, acid needs to be cogenerated. Various possible reductants are discussed, and experiments are described on the use of lignite and other carbonaceous materials to reduce the ferric ion. It was found that lignite was able to reduce the ferric ion,in situ in the electrowinning cell, but that the rate of reduction was compatible only with a maximum current density of about 40 Am-2. The efficiency was increased by periodically interrupting the current flow.

WATER REPELLENCY OF DEGRADED LIGNITE IN A RECLAIMED SOIL

Lignitic material located in a reshaped mine spoil at a depth of 35–53 cm was extremely water-repellent and no root growth was observed in or below this layer. The material is black (10YR 2/1) when dry and is easily identifiable. It is postulated that this layer may influence water movement and nutrient uptake because of the water repellency. Key words: Lignite, reclamation, strip mining, water repellency

The geochemistry of the Fox Hills‐Basal Hell Creek Aquifer in southwestern North Dakota and northwestern South Dakota

The Late Cretaceous Fox Hills Formation and the basal portion of the overlying Hell Creek Formation constitute an important aquifer in the Fort Union coal region. Throughout most of southwestern North Dakota and northwestern South Dakota the aquifer is at depths ranging from 1000 to 2000 ft, except for exposures along the Cedar Creek anticline. Water flows in the aquifer from southwest to northeast, with flow rates of a few feet per year. The recharge and discharge areas of the aquifer are separated by a north‐south trending transition zone in which significant changes in water chemistry occur. Dissolved constituents in the recharge area (the western part of the study area) are Na+ = 18 mmol/l, Cl− = 0.7 mmol/1, SO42− = 2.7 mmol/1, and HCO3− = 13 mmol/l (δ13C = −12‰) with pH = 8.5. Ca2+, Mg2+, and K+ are each less than 0.1 mmol/l, dissolved O2 = 0, and traces of H2S and CH4 are present. Computer modeling and carbon isotope data suggest the following reactions in the recharge area. CO2 derived from lignitic carbon reacts to dissolve carbonate minerals, with cations then being exchanged for Na+ on clay minerals. The high pH in the aquifer is the result of buffering by carbonate‐ion exchange equilibria. In the discharge area, pH values have declined to 8.3, Cl− has increased from 0.7 to 5.5 mmol/l, with a parallel increase in Na+ SO42− has essentially disappeared, HCO3− has increased from 13 to 21 mmol/l (δ13C = −9‰), CH4 has attained concentrations greater than 0.5 mmol/l, and small amounts of He are present. Traces of H2S are present, and Ca2+, Mg2+, and K+ concentrations remain low throughout the aquifer: These changes can be accounted for by reactions in the aquifer: (1) sulfate reduction to pyrite with lignitic material as the carbon source and (2) continuous buffering of pH by the carbonate‐ion exchange equilibria. Chemical and hydrologic data suggest that the increase in NaCl results from upward movement of small volumes of water into the Fox Hills aquifer from the transition zone eastward. Redox reactions in the aquifer are closely analogous to those observed in pore waters of reducing marine sediments. Reactions approach but do not achieve true thermodynamic equilibrium. Measurements of redox potential suggest a downgradient decrease in redox potential. The measurements are not amenable to quantitative interpretation.

Nonmarine Depositional Environments and Uranium Exploration in Lower Cretaceous Antlers Formation, North Texas: ABSTRACT

Detailed geologic and geochemical investigations of the Sherman quadrangle for the National Uranium Resource Evaluation (NURE) program have included fluvial deposits of the Antlers Formation which are exceptionally well exposed in cliffs along the shores of Lake Texoma, Grayson County, Texas. These deposits accord with the classical mixed-load, meandering-river model, with erosively based pebbly sandstones grading upward into silty sandstones and carbonaceous mudstones with sporadic lignitic material. Lateral-accretion bedding of presumed point-bar origin is inclined at angles up to 10°. Thickness of these lateral accretion units permits estimates of channel depth of as much as 12 m. Distinct channel forms, some of which are clay filled, are up to 100 m wide, but sub tantially lower estimates of channel width are obtained from dimensions of the point-bar stratification. Flanking and overlying the in-channel sands are inclined levee deposits, chutes and chute bars, proximal to distal crevasse splays, and organic-rich backswamp clays. Preliminary radiometric analyses show low to very low readings for the major channel sands, with a general trend of increasing radioactivity with decreasing grain size, decreasing bed thickness, and increasing organic content. Thus the most distal, or sediment-starved, overbank facies composed of dark laminated clays and lignites show the highest values. These analyses indicate substantial local epigenetic enrichment, but the deposits encountered to date are too small to be considered a potential resource. End_of_Article - Last_Page 831------------

Influence of Jackson Dome on Sedimentary Facies and Effect on Water-Bearing Properties of Claiborne in Jackson Area, Mississippi: ABSTRACT

This paper summarizes the importance of diastrophic uplift of the Jackson dome, which occurred during pre-Tertiary time and may have continued more or less active in the middle Eocene, and its influence on the sedimentary cycles in the Claiborne. The uplifting together with compaction of underlying sediments in the rim-syncline area affected the thickness, character, and attitude of the formations and established controls on the occurrence and quality of the ground waters. Isopachous maps and stratigraphic sections are presented to show the thicknesses of the Sparta sand and Cockfield formation on and around the dome; they indicate facies and thickness distribution of the sediments in these and several other units, and the size of the structure. Local concentration of lignitic material in the aquifers causes various degrees of straw-colored water affecting its usefulness for certain specific purposes. The pertinent stratigraphic units and the two principal aquifers are described. End_of_Article - Last_Page 2516------------

L'ile Bach Long Vi (golfe du Tonkin)

Abstract The island of Bach Long Vi in the middle of the Gulf of Tonkin (South China sea) is underlain by late Tertiary continental sandstones, containing lenses of lignitic material, which indicate that submergence of the gulf was relatively recent. The island is bordered by Quaternary marine terraces (at elevations of 2, 4, and 10 meters) and beveled on top, at 55 meters, by a remnant of a more extensive peneplain.

Coal as a Possible Petroleum Source Rock: GEOLOGICAL NOTES

In recent years, considerable thought has been given to sources of hydrocar­ bons available in the United States which might be developed when our petroleum reserves decline. Attention has been paid principally to (a) hydrogenation of commercial coals, (b) extraction of oil shales, and (c) tar sands. Comparatively little attention has as yet been given to the large reserves of extractable hydro­ carbons in peat, brown coal, lignite, and subbituminous coal. Table I summarizes the information given in United Stales Bureau of Mines Bulletin 482 on the wax yields of various peats and lignitic to subbituminous coals of the United States and other countries. From Table I it is evident that the attrital lignites are the most prolific source of wax, although the total reserves of wax available in lower concentrations in the xyloid lignites and subbituminous coals in the United States are probably greater because of the larger amounts of the two latter fuels. Some peats mayhave even higher concentrations of wax than the attrital lignites, but information on peat is very fragmentary. Attrital lignites are made up chiefly of finely divided vegetable debris, washed or blown into the swamp or shallow-water body where the lignite material ac­ cumulated. This type of lignite is rich in the more decay-resistant components of plants, such as cuticular fragments, seeds, spores, pollen, el cetera. Attrital lig­ nites indicate swamp or shallow-water conditions where the oxidation and dis­ integration of the internal cells of plants, and of the woody tissues, were relatively rapid. Highest wax yields would be expected from attrital lignites derived from tropical or subtropical plants, which generally produce more cuticular wax than do plants growing in cooler latitudes.

Clay-Pellet Conglomerates at Hobart Butte, Lane County, Oregon

ABSTRACT Ovate pellets of kaolinite from .05 to 15 millimeters in length occur in conglomerates interbedded with pyroclastic materials and waterlaid sediments in the Eocene Calapooya formation at Hobart Butte, Oregon. Although Miocene hydrothermal solutions invaded these rocks, altered welded tuffs to clay, and deposited kaolin minerals together with realgar, stibnite, pyrite, quartz, and other minerals, a hydrothermal or a volcanic origin for the pellets is considered unlikely. The sizes and shapes of the pellets, the presence of pellets and lithic fragments within pellets, the lack of radial and concentric structures, the presence of charcoal, lignitic material, and diatoms in the matrix suggest fluvial deposition of clay flakes, broken from thin clay layers that had dried on Eocene flood pl ins. The arrangement of the long axes of the pellets parallel to the bedding and the molding of pellets against quartz, lithic fragments, and pellets support the interpretation of a sedimentary origin for the pellets and the clays containing them.

Metasomatism of a Coaly Sediment into an Igneous-Appearing Rock

In the southeastern portion of Mount Rainier National Park seams of lignitic material occur locally in a thick series of arkosic sandstones and shales which can probably be correlated with the Puget series of the Eocene. Some members of this series, however, have been so altered by low-temperature metasomatic replacement that they resemble portions of the Keechelus andesitic series of the Miocene as described by Smith and Calkins in the Snoqualmie folio. This type of metamorphism is especially well developed in the incompetent carbonaceous material which is replaced locally by a fine-grained, igneous-appearing dacitic groundmass containing porphyroblasts of quartz and plagioclase.

Contributions to the Anatomy of Mesozoic Conifers No. I. Jurassic Coniferous Woods from Yorkshire1

DURING been investigated the last few anatomically, years, a large and number found to of throw Cretaceous considerable woods have light e investigated anatomically, and f und to throw considerable light on the inter-relationships of the various families of Conifers. Structurally preserved material from the Jurassic is comparatively rarer and less known, but seems to be of even greater value than the Cretaceous from this standpoint. Especially interesting are those specimens described by Professor Seward from Yorkshire, England (1), by Gothan from King Karl's Land (2) and the island of Spitzbergen (3), and by Lignier from Normandy (4). The woods to be described in this article are all from the Jurassic of Yorkshire. They are in two conditions of preservation petrified and lignitic. With a few exceptions, the petrified material was sent by Mr. James Lomax to Professor Jeffrey, to whom the writer is indebted for an opportunity to study it. All the lignite, on the other hand, and a small number of petrified specimens, were obtained by the writer from various localities on the Yorkshire coast. All the sections from Mr. Lomax, and representative ones of the lignitic material, are now at the University Museum, Harvard College, Cambridge, Massachusetts. Before entering on the descriptive part, it will be apposite to consider briefly those features which have been found to be of greatest significance in diagnosing woods, especially in differentiating between the two great groups of Conifers Araucarian and nonAraucarian, or Abietineous. The earliest classification, that of Kraus (5), was based entirely on the character of the radial pitting of the tracheides the pits being alternating and compressed in the Araucarineae, and opposite and separated in the Abietineae and other tribes. This is the criterion used by both Seward and Lignier. Jeffrey (6), however, has shown that in the Cretaceous there were woods which combined the Araucarian type of pitting with that characteristic of