Geology and geography.

Chair: Ezat Heydari, Jackson State University 

Vicechair: Keil Schmid, Mississippi Office of Geology

THURSDAY MORNING

Petit Bois Room

9:00 LEWIS HARPER--A COLORFUL CHARACTER TN THE HISTORY OF GEOLOGY IN MISSISSIPPI

Michael B.E. Bograd, Mississippi Office of Geology, Jackson, MS 39289

Lewis Harper (born Ludwig Hafner in Hamburg, Germany) was professor of geology and agriculture at the University of Mississippi (1854-1856) and the third State Geologist of Mississippi (1854-1857). His colorful tenure was characterized by disputes with the chancellor, his colleagues, and his assistants. Little is known of his previous history, except that he taught at an academy in Alabama and claimed to have an LL.D. Harper moved the Geological Survey to rooms in the state penitentiary in Jackson when he was dismissed from the University. Harper's most significant accomplishment as State Geologist was publication in 1857 of Preliminary Report on the Geology and Agriculture of the State of Mississippi. This report generated widespread dissatisfaction, adversely affecting the Survey. It was colorfully criticized by Harper's former assistant and successor Eugene Hilgard. The report's geologic map reversed the Eocene and Miocene outcrop belts, but otherwise was the best produced to date. A reading of the book re veals it to be a pretty good report, with carefully reasoned scientific arguments supporting Harper's interpretation of the geology. A colorful misuse of the report occurred in the 1980s, when an article in Mother Earth News misquoted Harper as reporting gold in northeastern Mississippi; this generated many inquiries. Harper's history after leaving Mississippi is poorly known. His great-granddaughter reported that he moved to the New York area and later returned to Germany, where he died in 1874.

9:15 AQUEOUS FAUNA DISCOVERED IN THE LATE PLEISTOCENE (PEORIAN) LOESS OF VICKSBURG, MISSISSIPPI

Michael Williams, Millsaps College, Jackson, MS 39210

A large outcrop of loess containing aqueous fauna has been discovered in Ballground Creek in Vicksburg, Mississippi. Nearly all of the fauna are freshwater mollusks and include small clams, snails, and a large washboard mussel. The only non-molluscan fauna include two small crayfish gastroliths. All Loess deposits are considered strictly eolian in origin. However, this discovery suggests a much more complicated depositional history for this particular loess deposit than one of strictly eoloian origin.

9:30 THREE NEW FOSSIL REPORTS FROM TESHEVA CREEK, YAZOO COUNTY, MISSISSIPPI 

Michael Williams, Millisaps College, Jackson, MS 39210

Several fossil collecting trips by the writer to Tesheva Creek in Yazoo County, Mississippi between the years of 1997-2001 have produced numerous fossil bones and teeth of Late Pleistocene (Rancholabrean age) land mammals including mastodon, horse, tapir, mammoth, deer, and llama which are derived from the loess deposits of the area. This study concentrates on three new reports from Tesheva Creek. (1) A tooth has been identified as the Pliocene three-toed horse, Nannippus minor. This may be the first and only record of a Pliocene vertebrate fossil from Mississippi. (2) A complete proximal phalanx has been identified as the rare Pleistocene llama, Hemiauchenia macrocephala. Only about six reports of this llama have been made in Mississippi. (3) A nearly complete left rear metatarsal has been identified as the common Pleistocene horse, Equus complicatus. The bone is crushed on one side and has an iron oxide stain on the other side. This bone is extremely rare because most Pleistocene fossils found in Tesheva Cr eek usually occur as broken or fragmented remains showing heavy transportation abrasion.

9:45 MINERALOGY OF FINE GRAIN SEDIMENTS ALONG SODA BUTTE CREEK, GREATER YELLOWSTONE ECOSYSTEM 

Jessie [Kneupper.sup.*] and Lori G. Eversull, Millsaps College, Jackson, MS 39210

Soda Butte Creek has its headwaters in the heavily mineralized terrain of the New World Mining District in southwest Montana. Beyond the uppermost reach of the stream, Soda Butte Creek flows for approximately 25 miles through the northeast section of Yellowstone National Park. Over a century of metal mining and milling has left an impact on the stream's ecosystem. Heavy metal contamination of Soda Butte Creek is well documented. Furthermore, previous research by Millsaps College indicates that these metals are mostly concentrated in the stream's fine-grained (<200 micron) sediments. As part of an on-going study, sediment samples were collected from 24 sites along Soda Butte Creek. The sites are representative of the entire length of the stream, from its headwaters to its confluence with the Lamar River inside Yellowstone National Park. The mineralogy of the fine-grain fraction was determined by X-ray diffraction (XRD). Results indicate that quartz, plagioclase, smectite, calcite, and dolomite are major consti tuents of all samples. Kaolinite and mica are primarily present in samples taken from sites closest to the McLaren Mine tailings. Ore minerals indicated by XRD are magnetite, pyrite, and hematite. Magnetite is detected in all samples; however pyrite and hematite are restricted to samples taken from tributaries to Soda Butte Creek. This mineralogical analysis has implications for the mobility and transport of metals in Soda Butte Creek.

10:00 MINERALOGICAL AND TEXTURAL ANALYSIS OF DIFFERENTALLY WEATHERED DEMOPOLIS CHALK: MACON, MISSISSIPPI

Jason T. [Wilson.sup.*] and Stan J. Galicki, Millsaps College, Jackson, MS 39210

The Demopolis Chalk exposed east of Macon, Mississippi on Highway 14 at the intersection with Highway 45 has differentially weathered to produce several resistant layers separated by intervals that are more prone to slope formation. Samples taken from both ridge and slope forming intervals were analyzed using insoluble residue, X-ray diffraction, and scanning electron microscopy to investigate the mineralogy and the textural relationship between components of the chalk in relation to the weathering profile. Insoluble residue tests indicate that the chalk is composed of approximately 70 to 80% calcium carbonate. The ridges appear to be more enriched in calcium carbonate than the slopes. The insoluble mineral components are kaolinite, montmorillonite, illite and quartz. Textural relationships between the calcium carbonate and the insoluble fraction were observed using the scanning electron microscope and aid in the interpretation of the diagenetic history of the unit which can be used to explain the current top ographic expression.

10:15 Break

10:30 DECLINES IN POTENTIOMETRIC SURFACES OF NEOGENE AQUIFERS, PERRY COUNTY, MISSISSIPPI 

Kai [Roth.sup.*] and David M. Patrick, The University of Southern Mississippi, Hattiesburg, MS 39406

The purpose of this ongoing study is focused on the nature and condition of Miocene and younger aquifers underlying Camp Shelby and Perry County. Also, there was a need to establish the presence of adequate confining layers between these aquifers and between the aquifers and the surface. A database was constructed from driller's log, electric logs, and monitoring well information, which included well depth, location, well number, ground elevation, screened interval, water level elevation, and lithology. Cross-sections and potentiometric surfaces maps were then constructed for the principal aquifers for different years. There are approximately five principal aquifers combined in the Catahoula and Hattiesburg Formations. These aquifers exhibit approximate depths between 200 to nearly 1100 ft, and well-defined confining layers were present. Water level monitoring data showed a potentiometric surface decline of almost thirty feet between 1943 and 1996 in one 416 ft-deep Hattiesburg Formation aquifer on Camp Shelb y, and similar declines in this aquifer elsewhere in Perry County. Of the twenty monitoring wells in this area, only three were monitored on a consistent basis and for longer than one year. The declines in this aquifer are believed to be the result of pumping on Camp Shelby as well pumping in the Hattiesburg area, which is experiencing similar declines.

10:45 SOIL MINERAL ANALYSIS AT MULTIPLE LAUNCH ROCK SYSTEM (MLRS) FIRING POINTS, CAMP SHELBY

Misty D. [Savell.sup.*] and David M. Patrick, The University of Southern Mississippi, Hattiesburg, MS 39406

The MLRS utilizes a solid fuel propellant which, upon firing, emits aluminum and chloride. The effects of these emissions on the biota are unknown. In order to determine effects, pre-and post-firing soil and vegetation samples are being collected at existing and new firing points and control sites and the soil mineralogy and chemistry are being determined. Ultimately, both the mineralogy and chemistry investigations are aimed at determining the amount, if any, of aluminum and chloride taken up by the soil and vegetation in comparison to pre-firing data. Most firing points are located in upland areas having sandy soils derived from the Citronelle Formation and samples were taken from the upper ten centimeters of the soil. In general, these soils are dark, organic rich, silty or clayey, fine to medium sand consisting of over 90 percent quartz with degraded clay minerals. Field pH, CEC, and extractable aluminum, respectively, for all samples ranged from 4 to 8; 0.9 to nearly 20 Me/100 g; and less than one to 448 ppm. After firing 328 rockets over a four-year period at one site, field pH, CEC, and extractable aluminum, respectively, were 4.3 to 6.1,3 to 17.2 Me/100 g, and 5 to 177 ppm. Based on these preliminary data, there does not appear to appreciable differences between soils exposed to firing and soils not exposed to firing.

11:00 WHAT IS THE RELATIONSHIP BETWEEN GEOLOGY AND ENVIRONMENTAL ENHANCEMENT FROM DEVELOPMENT?

Suzanne A. [Boyd.sup.*] and David M. Patrick, The University of Southern Mississippi, Hattiesburg, MS 39406

Military training and ancillary activities are often suspected or accused of adversely impacting the environment. Based upon empirical study, however, these activities may, under certain circumstances, actually enhance certain wetland areas, such as pine flatwoods, and increase wetland biodiversity. For instance, at Camp Shelby, certain training areas which have either been cleared or successively burned were found to contain wetlands which had anomalously high numbers of pitcher plants and a number of rare plant species. These same wetlands also contain the habitat for a threatened and endangered species, the Camp Shelby burrowing crayfish. Significantly, adjacent areas with similar stratigraphic and geomorphic characteristics, which have not been modified by training activities, exhibited lower quality wetlands, less biodiversity, and no significant numbers of rare or sensitive plant species. A review of the data reveals that the training areas which exhibited these environmental enhancements included firin g points, the Impact Area, and the Air-to-Ground range. These training areas are located within pine flatwoods in or near low-order riverine or slope wetlands characterized by reduced silt loam soils formed upon fine-grained Miocene sediments which have contributed to the high water tables and have been the subject of frequent, although inadvertent burning caused by range firing, prescribed burning, and mechanical clearing for training purposes have reduced canopy cover in these areas which, in turn, has resulted in increased sunlight and higher water tables.

11:15 SOLID-PHASE GEOCHEMICAL SURVEY OF THE STATE OF MISSISSIPPI: ON THE NATURE AND DISTRIBUTION OF AS, SE, HG, CU, PB, AND ZN IN STREAM SEDIMENTS AND SOILS

Over 1500 samples were collected statewide on a 100-[km.sup.2] grid-cell-based survey to determine baseline geochemical values for a suite of metallic elements in stream sediment (drainage basins up to 10 [km.sup.2]) and soil samples (about 300) from the "Delta" and Black Prairie regions, and to prepare statistically reliable geochemical maps. Samples were analyzed by a number of analytical techniques as detailed by Thompson and others (1998). Salient statistics for stream sediment and soil samples are given below in parts per million. The "Delta" and Gulf Coast regions have significantly higher baseline values of these potentially toxic elements with respect to adjacent terranes, in part because soils were the sampled media. A strong spatial correlation is shown to exist between regions of elevated values of these metals and land (broadly) classified as agricultural, irrespective of media sampled. Cretaceous sediments in the State, as throughout the continent, also exhibit higher baseline geochemical values than adjacent geologic units.

David E. [Thompson.sup.*] (1), Andrew E. Grosz (2), Paul G. Schruben (2), and Jeffrey N. Grossman (2), (1.) Office of Geology, Jackson, MS 39289, and (2.) U.S Geological Survey, Reston, VA 20192

                      SEDIMENTS                          SOILS

           MIN         MEDIAN    MAX        MIN      MEDIAN    MAX

As        -0.6          2.3      137        1.7       8.6      27.9
Se        -0.2          -0.2     2.5       -0.2       0.4      4.1
Hg        -0.02        -0.02     0.08      -0.02      0.03     0.20
Cu         -2            3       517        -2         10       62
Pb         -4            13      101        -4         17       50
Zn         -2            14      220         6        49.5     222

11:30 MINERALOGY OF THE TWIGGS CLAY FORMATION NEAR WRENS, GEORGIA

Lori G. Eversull, Millsaps College, Jackson, MS 39210

The Twiggs Clay Formation, a thick marine clay of the Barnwell Group, was deposited in neretic environments during a late Eocene highstand. Three zones are discerned near Wrens, Georgia. The lower two represent a highly absorbent fuller's earth. The upper stratum has no commercial value. Samples described herein represent the fuller's earth, and the less absorbent upper stratum. Identification of the minerals in the <2 micron fraction as well as the bulk sample was accomplished by XRD procedures supplemented with the profile fitting function of MacDiff to resolve overlapping peaks. The relative abundance of mineral constituents was determined by peak-area percentage calculations. A typical fuller's earth sample comprises quartz (17%), opal-CT (59%), smectite (24%), and mica (<1%). The less absorbent upper stratum is composed of quartz (34%), smectite (43%), kaolinite (21%), and mica (2%). Ethylene-glycol saturation reveals the smectite component of both strata to be fully expanding. The Twiggs Formation near Wrens has been described as a slightly opaline smectite, and at its type locality the Twiggs is described as comprising up to 30% cristobalite-tridymite and 15% quartz. Results of this work suggest that silica accounts for a much greater proportion of the fuller's earth facies of the Twiggs Formation.

THURSDAY AFTERNOON

Petit Bois Room

1:00 BAR MORPHOLOGY AND RELATIONSHIP TO SHORELINE CHANGE ON A RENOURISHED BEACH: HARRISON COUNTY, MISSISSIPPI 

Keil Schmid, Mississippi Office of Geology, Jackson, MS 39289

A long-term pattern of erosion, especially in specific and discontinuous areas, along the wholly renourished beach in Harrison County, Mississippi, prompts the need to periodically renourish the entire beach. These 'Hot Spots' along with a varying pattern of shoreline change have been documented; however, a definitive cause is elusive. Variables such as shoreline orientation, culvert locations, harbor structures, and profile morphology have all received attention. While bar morphology on the Harrison County beach has been studied, it has not been compared to shoreline change patterns. In the present research, bar morphology has been categorized using four basic morphologies as both primary and secondary patterns. In addition, the offshore distances of the nearshore bars and shoreline structures were mapped. Bar morphology categories were classified at 50 m intervals and then compared to shoreline change patterns from 1993 to 2000. Initial results from the western portion of the study area suggest highly erodi ng areas are associated with wide nearshore bar zones and a dominance of widely spaced transverse bars (bars oriented at high angles to the shoreline) that together may indicate higher offshore sediment transport. Structures, both large (harbors) and small (culverts) have localized effects on bar type; the highest levels of erosion are associated with these structures and/or the bar morphology that they create.

1:15 LATE PLEISTOCENE NORTHERN GULF OF MEXICO COASTAL PLAIN SURFACES AND VALLEY TERRACES--TOWARD AN IMPROVED CHRONOLOGY

Ervin G. Otvos, University of Southern Mississippi, Ocean Springs, MS 39566

Ever since H. Fisk (1940), ages of Gulf coastal alluvial surfaces; the Bentley, Montgomery, and Prairie were restricted to interglacial high sea-level (= base level) phases. Even the upper Prairie interval was associated with a late Wisconsin interstade. Contrary to early assumptions, it was unrelated to any highstand. The revised Pleistocene subdivision, new dating methods and numerous recently acquired luminescence dates now prove that coastal and valley terrace aggradation between SE Texas and south Mississippi occurred throughout the Sangamon Interglacial (135-116 ka B.P.), the Eowisconsin (116-80 ka) and glacial Wisconsin (80-10 ka) intervals. Aridity-related sediment increase compensated for low base-levels. Ongoing regional uplift raised coastal surfaces. While terrace aggradation involved at least five stream valleys between 65-30 ka B.P., erosional (strath) terraces also formed frequently. They were cut in early and late Wisconsin times from older alluvial units.

1:30 SURFACE MAPPING EFFORTS TOWARD DIFFERENTIATING THE MIOCENE IN MISSISSIPPI

Ken Davis and James E. [Starnes.sup.*], Mississippi Office of Geology, Jackson, MS 39289

Surface geologic mapping in the Stronghope, Hazlehurst, Shady Grove, and Wesson quadrangles of Copiah and Lincoln counties by the Office of Geology has recognized the following mapping units: (1) the Miocene age Catahoula Formation, (2) the Miocene Hattiesburg Formation, (3) the Pliocene Citronelle Formation, and (4) the Holocene alluvium. The Catahoula Formation contains generally light-colored sands and clays as well as sandstones and opal-cemented orthoquartzites derived diagenetically from volcanic ash. The Catahoula Formation has marine and nonmarine members as characterized by foraminifera and glauconite, and silicified and lignitized wood that is often associated with orthoquartzites. Thinly bedded pea gravel consisting of black chert and metaquartzite clasts are commonly associated with indurated sandstones and orthoquartzites. The Hattiesburg Formation contains the typical Hattiesburg clay section but also contains sands similar to those in the Catahoula Formation as well as lutites and opaline-cemen ted sandstone. A sand at the base of the Hattiesburg Formation having a regional extent was chosen as the marker for the Hattiesburg-Catahoula contact. The Citronelle is characterized by coarse brown chert gravel and oxidized sands, quite different from the pea gravel of the Catahoula Formation and of a different source. The Citronelle contains ironstone-cemented gravel and sand at its base and locally contains goethite and other from-hydroxide leachate deposits where springs are present.

1:45 PARALIC SANDS OF THE COAL BLUFF MEMBER OF THE NAHEOLA FORMATION IN MISSISSIPPI, AN OUTCROP OF THE ANCIENT SHORELINE

David T. Dockery [III.sup.*] and David E. Thompson, Mississippi Office of Geology, Jackson, MS 39289

Stearns (1957), in his study of the Cretaceous and Tertiary stratigraphy of the northern Mississippi Embayment, noted that near-surface Paleocene sands, below the basal "1,400-foot sand" of the Wilcox Group, graded downdip (toward the Embayment axis) into shales like those of the underlying Porters Creek Formation. This observation has been reinforced by the Mississippi Office of Geology's mapping and drilling programs. In particular, the sands of the Coal Bluff Member of the Naheola Formation (upper Midway Group) are restricted largely to the member's north-south trending outcrop belt and grade downdip (to the west) into shales. In this case, erosion has exhumed the Late Paleocene shoreline so that it and the present outcrop belt are in the same place. Hughes (1963) studied orthoquartzite boulders along the Coal Bluff outcrop in southwestern Union County, Mississippi, which he recognized as weathered remnants resting on unconsolidated "Wilcox" sands. He believed the depositional environment of the quartzites to be that of a beach and/or offshore bar and noted the underlying sands to form a series of north-south hills along the border of the "North Central Plateau" and the Flatwoods physiographic provinces, and, in places, to form detached outliers within the Flatwoods Province. Large quartzite formations have since been observed in place within the Coal Bluff sands of Union County.

2:00 EVALUATION OF THE WHITE RIVERFAULT ZONE UTILIZING TRANSVERSE TOPO-GRAPHIC SYMMETRY

Terry [Panhorst.sup.*] and Emily Strack, University of Mississippi, University, MS 38677

The White River Fault Zone (WRFZ), a zone of fault sets approximately 16 kilometers wide, poses potential seismic hazards for northwest Mississippi. Calculations of drainage basin symmetry are used to detect preferred river migration in areas suspected of neotectonic activity. The technique used to assess drainage basin symmetry is best utilized in areas defined by dendritic drainage, unconsolidated bedrock, and low regional bedrock dip, all of which characterize conditions in northwest Mississippi. Drainage basins randomly chosen in the study area followed two criteria: (1) stream order of three or larger and (2) distance from the proposed fault boundary. Because of uncertainty in precisely defining edges of the WRFZ, drainages within a 2-mile distance from the projected WRFZ boundary were considered within the WRFZ. Drainage basins outside this area established regional symmetry values to compare with symmetry value calculated for the WRFZ. The transverse topographic symmetry was calculated for linear segme nts of each selected drainage basin. Polar plots generated to compare the migration direction of the regional trend against the WRFZ boundary yielded a scatter of data, suggesting river basins in the area do not follow a preferred river migration direction. Rose diagrams produced for the study area indicate river channel orientations, both inside and outside the projected WRFZ, follow the regional lithologic trend of the Mississippi Embayment. Any tectonic influences of surface drainages appears subtle enough to be concealed by regional lithologic controls.

2:15 SHALLOW SEISMIC REFLECTION IMAGING OF THE IDALIA HILL FAULT ZONE, SOUTHEASTERN MISSOURI

William F. Reid, [Jr..sup.*] (1), Robert D. Cosentino (1), James B. Harris (1), and John N. Baldwin (2), (1.) Millsaps College, Jackson, MS 39210, and (2.) William Lettis & Associates, Inc., Walnut Creek, CA 94596

Shallow seismic reflection imaging was used to characterize the significance of near-surface tectonic deformation associated with the northeast-trending Idalia Hill fault zone in southeastern Missouri. The fault zone is expressed by topographic escarpments, photolineaments, and subsurface faulting in Paleozoic through Quaternary deposits. Two shear-wave seismic reflection profiles (IDAL 1 and IDAL 2) were collected (in July, 2001) across the fault zone in order to identify the location and style of neotectonic deformation and help guide the placement of subsequent paleoseismic trenches. The processed seismic profiles show coherent seismic reflection energy to depths greater than 100m. Based on correlation with local borehole data and previously acquired compressional-wave seismic reflection data, reflections from the Tertiary/Cretaceous and Cretaceous/Paleozoic boundaries have been identified on the S-wave profiles. Changes in reflection amplitude and coherency suggest the presence of high-angle faults in the subsurface. Deformation features identified in a paleoseismic trench excavated in October, 2001, correlate with the updip projection of a fault interpreted on seismic line IDAL 2. Future seismic investigations are planned in the area to image very shallow (<10 m deep) subsurface (Quatemary) deposits that do not show a geomorphic expression of recent faulting.

2:30 Divisional Business Meeting and Meeting of the Mississippi Stratigraphic Names Committee

2:45 Divisional Poster Session

SEDIMENTOLOGY OF A DELTA FED BY CONSTRUCTION-ENHANCED RUNOFF AND ASSOCIATED SEDIMENT POLLUTION: HENN1NGTON LAKE, LAMAR CO., MISSISSIPPI

Clare Falcon, Mississippi Office of Geology, Jackson, MS 39289

This study was done as part of an investigation into local construction-sourced sediment pollution in a small bay in eastern Hennington Lake. The extent of the subaerial portion of the delta was mapped using GPS and detailed topographic maps. The subaqueous extent of the delta was delineated by the presence or absence of the delta sediments found in the six push cores taken. Six sedimentary facies were identified: Red colored moderate to well sorted sands; red colored mud; green colored mud; compacted dark grayblack mud; pale gray moderately sorted sand; 'gooey' dark gray mud with plant material. The facies were grouped into facies associations and interpreted as representing deposition in a deltaic environment, natural lacustrine environment, and sediments that were at the surface prior to lake dam construction. The detailed sedimentology made it possible to delineate between the deltaic sediments that had been sourced from the nearby construction site and those that were naturally occurring sediments. The g rainsize of the sediment pollution changed depending on the location's relationship to the input point. This study will be useful for other lakes with similar problems in order to help predict sedimentation patterns and the type of sediments expected to be found at different locations. These redeposited construction-sourced sediments have very different and variable textural characteristics from the original source material.

MERCURY IN ENID, SARDIS, AND GRENADA LAKES: PRELIMINARY INVESTIGATIONS

Carol Blanton [Lutken.sup.*] (1), Cathy A. Grace (1), and Stephen L. Ingram (2), (1.) Mississippi Mineral Resources Institute, University, MS 38677, and (2.) P0 Box 5233, Oxford, MS 38655

In 1996, the Mississippi Mineral Resources Institute began field investigations designed to isolate the source of mercury in Enid Lake, North Mississippi. Mercury levels in fish taken from Enid Lake by the Mississippi Department of Environmental Quality, in 1994, included many samples that exceeded state (0.75 ppm) and federal (1.00 ppm) guidelines. Initial investigation included collection and analysis of water and sediment. Water parameters affecting methylation of mercury--depth, temperature, dissolved oxygen, total dissolved solids, oxygen reduction potential, pH, conductance--were measured at the surface and at total depth at each sample site. No obvious source of mercury was discovered, though Enid was found to be slightly acidic, a condition which promotes methylation of mercury. The following year, lakes to the north (Sardis) and south (Grenada) of Enid were added to the investigation. The Mississippi Office of Geology's 1999-2000 geological investigation of the area, results of the US Geological Surv ey's background mercury sampling, and more fish data were incorporated into the study. All results support persistence of a problem, not evident in the water or substrate, producing levels of mercury in fish that make them unacceptable for human consumption. Mercury concentrations in Enid fish remain consistently high; those from Sardis and Grenada appear to have increased from 1994 through 1997. Few specimens from elsewhere in the Yazoo River drainage basin exhibit concentrations of mercury that exceed state or federal guidelines.

HIGH-RESOLUTION SEISMIC PROFILES IN SARDIS LAKE--PANOLA COUNTY, MISSISSIPPI

Charles T. [Swann.sup.*] (1), Anthony S. Gossett (1), Carol Blanton Lutken (1), and Thomas M. McGee (2), (1.) Mississippi Mineral Resources Institute, University, MS 38677, and (2.) Center for Marine Resources and Environmental Technology, University, MS 38677

The Seistec high-resolution seismic profiling system has been used in inland water ways, lakes and reservoirs extensively in Europe, but seldom in the United States. This boomer sourced, line-in-cone receiver system was recently used in Sardis Lake to acquire highly detailed shallow subbottom data regarding the lake's stratigraphy. The objectives of the investigation were to identify sedimentation accumulated since impoundment in 1939, investigate lineaments of the local fluvial systems, and fine-tune technical aspects of the system for work in Mississippi. Data were acquired from a grid of nine seismic lines oriented along the long axis of the lake (northeast) and at approximately 90[degrees] to this axis. Preliminary analyses indicate that a well preserved bottom topography is present representing the pre-1939 Little Tallahatchie River channel. Flood plain and apparent elevated terrace deposits associated with the Tallahatchie River were also identified. A discontinuous bed up to one meter thick is interpre ted to be sedimentation accumulated since 1939. This bed is absent over some bottom highs and in some channels. The reason for the discontinuous distribution is presently unclear.

SEISMIC IMAGES OF STRUCTURES ASSOCIATED WITH GAS HYDRATES NEAR THE SEA FLOOR: INITIAL RESULTS

Thomas M. [McGee.sup.*] (1), Carol Blanton Lutken (1), Vaughn S. Goebel (2), and J. Robert Woolsey (1), Mississippi (1.) Mineral Resources Institute and Center for Marine Resources and Environmental Technology, University, MS, 38677, and Lookout (2.) Geophysical Company, Dillon, CO 80435

Obtaining very-high-resolution seismic images of structures immediately below the sea floor in deep water is problematic. The conventional approach involves towing a subbottom profiler near the sea floor. However, in water a kilometer or more deep, restraints in vessel speed and maneuverability increase dramatically and energy levels of seismic sources deployed at these depths are so restricted that subbottom penetration is limited to tens of meters. Research at the University of Mississippi, designed to overcome these difficulties utilizing various seismic sources and receivers and special software to process the data, has produced seismic images of structures near the sea floor in deep water of the Gulf of Mexico. With the objective to image structures associated with gas hydrates, seismic profiles have been produced demonstrating decimeter-scale resolution near the sea floor in a kilometer of water. One profile, with resolution better than three meters, crosses a well in which shallow flowing sand had been encountered at about 300 m depth. Several profiles cross what are apparently mud diapers with one documented to contain gas hydrates; others display intriguing patterns within the shallow sediment layers. Data analyses reveal the acoustic structure of one such pattern and provide a basis for interpretation.

MABEN FIELD GAS PRODUCTION FROM THE ORDOVICIAN STONES RIVER IN OKTIBBEHA COUNTY, MISSISSIPPI 

Stephen D. Champlin, Mississippi Office of Geology, Jackson, MS 39289

Maben Field is located in northeastern Mississippi on the southwestern flank of the Black Warrior Basin, approximately 10 miles west of Starkville in townships T18N-R12E and T19N- R12E, northwestern Oktibbeha County, Mississippi. It is one of only three fields which have produced oil or gas from the Ordovician Stones River Dolostone or "Knox-Ordovician" in Mississippi. Maben Field was discovered in July 1971 with the completion of the Texaco Inc., #1 Clyde Q. Sheely well, located in Section 28, T19N-R12E. The #1 Sheely was drilled to a total depth of 17,442 feet. The well was completed flowing 599 MCFGPD on a 9/64-inch choke with 1,000 lbs. psi flowing tubing pressure from perforations at 14,690-784' and 14,904-15,036'. The Stones River Dolostone in the #1 Sheely well is approximately 420 feet thick; the top is picked at 14,670 feet and the base at 15,090 feet. In December 1997, cumulative gas production at Maben Field was over 1.1 BCF of gas. In September of that same year Fina Oil & Chemical began a drillin g program, which has resulted in the completion of four Stones River gas wells and a dramatic increase in production. As of 12/31/2000, cumulative gas production for the field was over 7.8 BCF. The new producing wells are fault separated from the original well and production is believed to be enhanced by fault-induced fractures present in the Stones River reservoir. In October 2001, Fina was actively drilling or testing two new wells and had two additional locations permitted.