Geology and Geography.
Vice-chair: Stan Galicki, Millsaps College
8:45 Divisional Poster Session
FORAMINIFER AND ARCELLACEAN ASSEMBLAGES OF MISSISSIPPI AND LOUISIANA MARSHES APPLIED TO THE HOLOCENE PEARL RIVER DELTA
Charlotte A. Brunner*, Marco J. Giardino, and Ervin G. Otvos, University of Southern Mississippi, Stennis Space Center, MS 39529; NASA, Stennis Space Center, MS 39529; and University of Southern Mississippi, Ocean Springs, MS 39566
Trends in surficial foraminifer and arcellacean assemblages are related to the environment of low-lying, microtidal marshes of coastal Mississippi and Louisiana in order to interpret paleoenvironment of late Holocene marsh sections from the region. Five locales were selected along a
salinity gradient from 2 to 25 psu in the Mississippi Sound and Pearl River delta. At each locale, five samples of the top 10 cm were taken from the subtidal channel, unvegetated low-intertidal zone, the grassy marsh border, levee crest, and marsh interior. Samples were split by settling to >300 foraminifers, and a census was made of all foraminifers and arcellaceans >45 [micro]m. Assemblages vary with both salinity and subenvironment-elevation. The high-salinity locales are dominated by Ammotium spp. and Miliammina fusca and are similar to those of many meso- to polyhaline, clastic marshes of the northern Gulf of Mexico. In contrast, the low-salinity locales host abundant arcellaceans with common Trochamminita irregularis and Tr. salsa. The unusual assemblage resembles those reported from oligohaline, upper marshes of a handful of locales in the world. Based on analogy with surface samples, assemblages from a vibracore from the lower Pearl River marsh show a clear succession from estuary to channel, followed by mesohaline lower marsh. The section is capped by the Trochamminita assemblage starting at about 1500 yBP, which appears to coincide with a drastic local decrease in native American residents in the delta.
9:00 WILLIAM DUNBAR AND THE EXPLORATION OF THE SOUTHERN PART OF THE LOUISIANA PURCHASE
Michael B.E. Bograd, Mississippi Office of Geology, Jackson, MS 39289
Two hundred years ago, President Thomas Jefferson was organizing surveying and scientific expeditions to send into the newly acquired Louisiana Purchase. The story of the Lewis and Clark expedition in the north is well known. The exploration of the southern part of the Louisiana Purchase is not as well known. President Jefferson asked his correspondent William Dunbar (1749-1810) of Natchez to assist in planning the exploration of the Red and Arkansas rivers. Dunbar, a native of Scotland, had become a successful planter in the Natchez District and was interested in science and natural history. Planning difficulties included finding a suitable officer with surveying skills as leader, enlisting a scientist, concerns about Spanish troops under orders to stop Americans, and concerns about hostile Indians. The expedition was to acquire information about terrain, geography, soils, mineral resources, plants with medicinal properties, and the animal kingdom "from the mammoth down to the field mouse." Due to delays in starting the main expedition, Dunbar and naturalist George Hunter departed in October 1804 on a 3-month trip up the Ouachita River and to the hot springs (in what is now Arkansas). They made scientific observations of the flora and fauna, mineral resources, and the hot springs. The main Red River expedition did not depart until 1806, with Thomas Freeman and Peter Custis as scientists, and was only partially successful.
9:20 THE GOSPEL, THE SILURIAN, AND THE SLAVE TRADE: THE MURCHISON-LIVINGSTONE CONNECTION
David T. Dockery III, Mississippi Office of Geology, Jackson, MS 39289
In the spring of 1865, Dr. David Livingstone was in need of a sponsor for his third missionary/expeditionary trip to Africa. Livingstone was not only a missionary and explorer but was also an experienced naturalist with an understanding of geology. On his first African tour, he was the first European to travel across the African Continent from the east coast to west coast and back again (in the years 1854-1856), and was honored in England as a national hero. At that time, Livingstone reported to Sir Roderick Murchison the occurrence of "strong beds of coal and iron-stone on the affluents of the Zambesi, and to the north-west of the Portuguese settlement of Tete." This statement was published in Murchison's third edition of Siluria (1859) with the conclusion that if Devonian and Carboniferous strata were present in Africa, the Silurian must be there as well. The Silurian System was not only described and named by Murchison (his greatest scientific achievement), but was promoted by him; he gratefully acknowledged those who found Silurian rocks in other lands. As president of the Royal Geographical Society in 1865, Murchison funded Livingstone's third and last trip to Africa, a trip that focused the world's attention on that continent and which helped fulfill Livingstone's career-long wish of ending the Arab-Portuguese slave trade (as the British fleet did in 1870).
9:40 AN UPDATED GROUND WATER ASSESSMENT OF CAMP MCCAIN TRAINING SITE AND ENVIRONS, GRENADA COUNTY, MISSISSIPPI
John McCarty* and David M. Patrick, University of Southern Mississippi, Hattiesburg, MS 39406
Since the 1943 study of Camp McCain, both the size and objectives of the training site have enlarged significantly. There have been increased requirements to identify and protect natural resources, including shallow and deep groundwater. In the area of Camp McCain the shallow aquifers are protected from surface contamination by near-surface clay and shale layers. The principal aquifers in the area are in the Claiborne and Wilcox Groups. In the Claiborne the Tallahata Formation is a minor source of ground water. The basal member of the Tallahata Formation, the Meridian Sand Member, is in direct contact with the underlying upper Wilcox sands. The undifferentiated Meridian Sand--upper Wilcox sand is one of two primary aquifers in the area. The boundary between the two is difficult to determine with available electric logs and nearly impossible to distinguish using driller's logs. The middle Wilcox sands of the Wilcox Group, although regionally a minor source of ground water, in the area of Camp McCain is one of the consistent aquifers. The other primary aquifer in the area of Camp McCain is the lower Wilcox sands. Below the Wilcox is the Midway Group, an aquiclude that also serves as the basement for fresh water in this area. With Camp McCain converting to the City of Grenada water system in the early 1970s, the flow direction of the subsurface waters is now to the northwest, toward the large volume wells of the City of Grenada and the industrial water consumers south of the city.
10:00 LANDSCAPE EVOLUTION IN SOUTHEASTERN MISSISSIPPI: IMPLICATIONS FROM A QUATERNARY SOIL CHRONOSEQUENCE
David Ufnar*, Amy L. Seiter, and J. Heath Harwood, University of Southern Mississippi, Hattiesburg, MS 39406
The soils of southeastern Mississippi are generally classified as Ultisols, and exhibit characteristics of extensive weathering such as: rubification, prominent illuvial clay accumulations, depletions in alkaline earth metals, and acidic pH values. These deeply weathered soils are restricted to the higher elevation interfluves, and transition into less mature soils in the Quaternary terraces and alluvial soils of the valleys. The soils developed in recent (Holocene) alluvium are poorly developed and characterized by A/C horizonation. The terrace soils however, are in an intermediate stage of development, and the origin, development and age of these terraces is the focus of this study. A soil chronosequence based upon a transect near Estabuchie in Forrest Co., MS contains ridge soils with an Ap, E, Bw, Bs, Bts, Cox profile developed in sands and gravels of the Plio-Pleistocene Upland Complex. The profile is thick, with prominent structure, a thick argillic horizon (prominent clay coatings), reddening to 10R 4/8, and prominent sesquioxide coatings. The Quaternary terrace soils are poorly drained, and characterized by an Ap, Bw, Bg, Cg profile. This soil exhibits moderate development in medium-grained sands with some faint to distinct mottling, moderate illuvial clay accumulations, few concretions, and gleying in the lower portions of the profile. The age of the Quaternary terrace deposits is poorly constrained, and the sandy parent materials are easily eroded. Thus, it seems unlikely that these terraces formed prior to the last glacial sea-level lowstand. We hypothesize that the terraces developed during a slightly higher than present sea-level stand during the early Holocene.
10:40 GEOLOGIC MAPS AND HIGHWAY CONSTRUCTION--THE HIGHWAY 76 BYPASS AT PONTOTOC, MISSISSIPPI
David T. Dockery III, Mississippi Office of Geology, Jackson, MS 39289
Priddy (1943), in the Pontotoc County geology bulletin, placed the thickness of the upper Ripley sandstone, subsequently named the Chiwapa Sandstone, in Section 23, T. 9 S., R. 3 E. in Pontotoc County as 12.6 to 18.4 feet thick. Here, Priddy's geologic map showed the upper Ripley to outcrop in the valley of Miller Creek below an elevation of about 450 feet above sea level. In the 2003 construction of the Highway 76 Bypass at Pontotoc, Mississippi, the Chiwapa Sandstone was unanticipated. A supplemental rock removal estimate of $360,000 was based on an average rock thickness of 6 feet over an area of 30,000 yard[s.sup.2] for a total volume of 60,000 yard[s.sup.3] at a cost of $7.45 per yar[d.sup.3], less $1.45 per yar[d.sup.3] for the cost of unconsolidated soil removal. Soil borings showed the top of the sandstone to vary from 447.6 to 450.1 feet above sea level between stations 136 and 146 with an average elevation over the 1,000-foot interval of 448.5 feet. The actual volume of sandstone removed was 164,896 yard[s.sup.3], and the true cost of removal was $7.45 per yar[d.sup.3] for a total cost of $1,228,475. This volume would have been used for highway fill if it were unconsolidated sand. The additional volume encountered indicated an average thickness of 16.5 feet, vindicating the original thickness reported by Priddy.
11:00 IMAGE CREATION USING LIGHT DETECTION AND RANGING INTENSITY DATA: AN INTRODUCTION TO A NEW PRODUCT
Fazlay Faruque*, Abu O.A. Khan, and Marcel Frigon, University of Mississippi Medical Center, Jackson, MS 39216; Jackson State University, Jackson, MS 39217; and Waggoner Engineering, Jackson, MS 39211
Light Detection And Ranging(LIDAR) is a relatively new airborne laser mapping technology. A typical LIDAR unit consists of a near-infrared laser system operating at a preset frequency, a Global Positioning System (GPS), and an Inertial Measurement Unit (IMU) for recording rotational angle. The post-processed final digital output consists of geo-referenced co-ordinates, and returned laser shots with elevation and intensity values. LIDAR applications focus primarily on creating Digital Elevation Models (DEM) and other topographic mapping products without using intensity values. The potential for using intensity data for image creation has yet to be fully explored. Intensity is a measure of the peak amplitude of return pulses reflected from the target. These values are relative and vary with data acquisition and target conditions, which makes feature extraction difficult. Although useful digital orthophotograph-type products or images have recently been created, commercial products are yet to emerge. This study focuses on studying the variables that impact the quality and reproduciblity of LIDAR generated orthophotographs.
11:20 A SEA FLOOR MONITORING STATION, NORTHERN GULF OF MEXICO
J.R. Woolsey*, T.M. McGee, and C.B. Lutken, University of Mississippi, University, MS 38677
A Consortium designed to assemble leaders in gas hydrates research has been established at the University of Mississippi's Center for Marine Resources and Environmental Technology, CMRET. The primary objective of the group is to design and emplace a remote monitoring station on the sea floor in the northern Gulf of Mexico by the year 2005, in an area where gas hydrates are known to be present at, or just below, the sea floor. This mission necessitates assembling a station that will monitor physical and chemical parameters of the sea water and sea floor sediments on a more-or-less continuous basis over an extended period of time. Development of the station allows for the possibility of expanding its capabilities to include biological monitoring, as a means of assessing environmental health. Establishment of the Consortium has already succeeded in fulfilling the critical need to coordinate activities, avoid redundancies and communicate effectively among researchers in this relatively new research arena. Complementary expertise, both scientific and technical, has been assembled to innovate research methods and construct necessary instrumentation. Advances, so far include new in-situ porewater sampling techniques, new seismic data-acquisition systems and processing techniques, progress on methane sensors, and a host of advances in geochemical analyses of gas hydrates, their formation, and their distribution in the Gulf of Mexico.
1:30 A TECHNIQUE FOR DETERMINING POROSITY OF UNDISTURBED MARINE SEDIMENT
Conrad W. Curry (1)*, Richard H. Bennett (1), Matthew H. Hulbert (2), Kenneth J. Curry (3), and Richard W. Faas (4), (1) SEAPROBE, Inc., Picayune, MS 39466; (2) Research Dynamics, West Chester, PA 19380; (3) University of Southern Mississippi, Hattiesburg, MS 39406; and (4) University of Southern Mississippi, Stennis Space Center, MS 39529
Porosity is a fundamental property of marine sediment to be measured from which wet bulk density can be easily determined and used in a variety of geoacoustic, geotechnical, and sedimentological studies, analyses, and models. However, methods of sampling marine sands suffer from the common problem of core disturbance making the in situ porosity difficult to obtain. Embedding the sediment within an epoxy resin matrix will minimize the disturbance to the microfabric and preserve the in situ sedimentary structure for subsequent study. Image analysis can then be used on thin sections to study the microfabric and porometry. A simple, accurate, and nondestructive technique is described for preparing and measuring the porosity of marine sediment (siliciclastic sand) that has been infiltrated with agar aboard ship immediately upon sample collection and later embedded in epoxy resin. The average porosity of 36 samples of marine sand collected offshore Fort Walton Beach, Florida and embedded with resin was determined to be 41.30%.
1:50 MISSISSIPPI COASTAL DATA NODE AND VALUE ADDED GIS DATA PRODUCTS
Keil Schmid* and Barbara E. Yassin, Mississippi Office of Geology, Jackson, MS 39289
The Coastal Geology Section of the Mississippi Office of Geology has been actively involved in gathering and disseminating coastal data to interested users since it was formed in 1990. During the ensuing 13 years a large amount of data and local expertise has been developed. Concomitant to the data development, significant progress has been made in bringing Geographic Information System (GIS) technologies to the end user. GIS data and technologies are now staples for physical and biological scientists and have facilitated significant data sharing across disciplines. To expand use of the Coastal Geology Section's data inventory, an online data node has been developed to disseminate the collected data. As a key goal of the project is to share data across scientific boundaries, a composite product has been developed. It is a geospatial feature (coastline) with attributes that depict the natural features and historic evolution that defines its present character; it is, to a large degree, a presentation of the data and expertise gathered during 13 years of coastal research. To create this single feature with multiple attributes a systematic approach has been developed to conflate data from multiple sources and formats. The outcome is a product, with documentation on source data and methodology that can be used by a wide group of researchers and policy makers on federal, state and local levels.
2:10 MAKING HISTORIC MISSISSIPPI COASTAL T-SHEETS ACCESSIBLE ON THE INTERNET
Barbara E. Yassin* and Keil Schmid, Mississippi Office of Geology, Jackson, MS 39289
The Mississippi Office of Geology received a grant from NOAA Coastal Services to make our Mississippi Coastal Data available on the Internet. A unique part of our collection are Mylar Coast and Geodetic Survey Topographic sheets from 1849 to 1920. At present no georectified T-sheets from this period are available and ready to use in a GIS mapping program. These valuable maps depict structures such as homes and piers, and natural features such as bluffs, beaches, and marshes. The T-sheets are beautifully hand drawn; they are a curiosity to the public and a scientific tool for the researcher. These maps have been used in tidelands court cases and are the best available data for depicting the shoreline character when Mississippi became a state in 1817. To make the maps available to the public, Mylar maps were scanned at 150 dpi, 8-bit gray scale. The Tif images were georectified in ArcMap using previously digitized shorelines in Mississippi Transverse Mercator projection and coordinate system. The resulting files were compressed using MrSid, and FGDC-compliant metadata was created for each image. Georectified map images will be available to the public in the summer of 2004 in many forms: (a) users can search for the data using keywords or location, (b) they can view the data with other layers in a GIS Internet Map Server, or (c) they can download the files to their own PC.
2:50 MISSISSIPPI MIOCENE OPAL
James E. Starnes (1)*, D. Kenneth Davis (1), and David Abbott (2)*, (1) Mississippi Office of Geology, Jackson, MS 39289, and (2) Mississippi Department of Archives and History, Jackson, MS 39202
A newly described orthoquartzite-bearing exposure in the Miocene Upper Catahoula Formation of Claiborne County has yielded something rare and special to both Geologists and Archaeologists. At this exposure above a sandy-clay, which makes up the creek floor, is a two-foot-thick conglomeratic sandstone. The sand fraction includes medium to coarse-grained quartz and black chert sands with disseminated angular to sub-rounded black chert and quartz pea gravel in a matrix of vibrant multi-colored opalescent opal cement. Artifacts of opalescent and common orthoquartzite, as well as chert, were also associated with this outcrop. This discovery was the result of geologic surface mapping efforts by the Mississippi Office of Geology to better understand the geology and stratigraphy of the Miocene Aquifer system. The hydro-silica-rich Miocene deposits of the Catahoula Formation of Mississippi create interesting landforms and rock types that are petrologically different from other Tertiary units. Commonly, hard sandstones, as well as orthoquartzites, occur in the coarser grained lithologies as a near-surface diagenetic feature due to leaching of silica. Recent archaeological finds of both historic and aboriginal cultural artifacts have been found associated with these well lithified Miocene exposures. These finds include pre-historic quarry sites containing an orthoquartzite type new to archaeology, the remains of previously unrecorded pre-Civil War mill sites, and a culvert built of Miocene orthoquartzite on one of Mississippi's first railroads.
3:10 DISSOLVED TRACE ELEMENTS IN TWO CONTRASTING RIVERS SYSTEMS: THE MISSISSIPPI AND YUKON RIVERS
Alan Shiller, University of Southern Mississippi, Hattiesburg, MS 39406
We have been examining the temporal variability of dissolved and colloidal trace element chemistry in two contrasting major river systems: the Mississippi and Yukon Rivers. These two systems are similar in that they both have high suspended loads and moderately alkaline pHs. However, they differ greatly in climate and the extent of human engineering. In the lower Mississippi River, seasonal variability in many dissolved metals follows a seasonal "redox pump." This pump is caused by inputs from seasonally stratified lakes and reservoirs as well as by the temperature dependance of microbial manganese oxidation. In the Yukon River there is additionally evidence of a spring pulse of trace elements associated with early season soil flushing. The spring pulse has been observed in certain headwaters of the Mississippi River system, so its absence in the lower river may reflect the effects of impoundments in damping out this signal. Thus, the timing of river delivery of some dissolved and colloidal materials to the coastal region is likely different in these two systems, reflecting both differences in hydrology and chemistry. We also observe greater amounts of colloidal Fe in the Yukon relative to the Mississippi which may reflect the greater DOC of the Yukon. This colloidal Fe could represent a significant pool of reactive Fe delivered to the coastal system. Finally, we note that permafrost-dominated basins in the Yukon system show relatively little concentration variability. Long-term changes in the seasonal concentration variability of such basins may thus provide an indicator of the effects of climate change on the landscape.
3:30 Divisional Business Meeting
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|Publication:||Journal of the Mississippi Academy of Sciences|
|Date:||Jan 1, 2004|
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