GEOLOGY AND GEOLOGICAL ENGINEERING CONSIDERATIONS FOR URBAN AND ECONOMIC PLANNING IN THE BLUE SPRINGS, MISSISSIPPI, AREA
PONTOTOC, LEE, AND UNION COUNTIES
By Charles T. Swann, R.P.G. and Jeremy J. Dew, G.I.T. Mississippi Mineral Resources Institute 111 Brevard Hall University, Mississippi 38677
MISSISSIPPI MINERAL RESOURCES INSTITUTE
OPEN-FILE REPORT 11-1S
December, 2011
Prepared in cooperation with the Three Rivers Planning and Development District On The Cover
This photo is an outcrop of the Ripley Formation northeast of Pontotoc, Mississippi, taken by Charles Swann in February of 2011, after one of several snows. This outcrop (NPQ-190) is a northern exposure of the Troy beds, an equivalent to the Coon Creek Tongue further north.
-i- TABLE OF CONTENTS
On The Cover...... i
List of Tables...... iii
List of Figures...... iii
Abstract...... 1
Introduction...... 1
Study Area...... 2
Methodology...... 3 Geological Map...... 3 Engineering Geology Map...... 4 Mineral Resources Map...... 5 GIS Map Construction...... 6
Explanation of the Maps...... 7 Geology Map...... 7 Demopolis Formation...... 8 Ripley Formation...... 9 Owl Creek / Prairie Formation...... 12 Clayton Formation...... 14 Quaternary Alluvium...... 14 Summary of Geology Map...... 15 Engineering Geology Map...... 17 Flood-prone Areas...... 18 Expansive Soils...... 19 Excess Excavation Cost Areas...... 23 Earthquake...... 24 Summary of Engineering Geology Map...... 24 Mineral Resources Map...... 25 Summary of Mineral Resources Map...... 26
Acknowledgments...... 26
References Cited...... 27
Certifications...... 30
-ii- LIST OF TABLES
Table 1 - Major Publications for the Study Area ...... 8
Table 2 - Summary of Outcrop Belt Characteristics...... 17
Table 3 - Summary of Soil Swell Evaluation Results From the Transitional Clay...... 20
Table 4 - Summary of Testing Results on Demopolis Residual and Flood Plain Soils...... 22
LIST OF FIGURES
Figure 1- Location of the study area with major geographic features...... 3
Figure 2 - Geological map of the Blue Springs area...... in pocket
Figure 3 -Picture of Mud Creek as it appeared October 15, 2010. The dry chalk channel contains beds of Pycnodonta convexa that alters erosion rates and forms a set of rapids across the channel (just above the pool of water)...... 9
Figure 4 - A photograph of the transitional clay, the basal unit of the Ripley Formation. Note the abundant fossil bivalves, This exposure (SQ-082) is just north of the Sherman city limits on a tributary of Ryan Creek (sec. 22, T8S, R4E)...... 10
Figure 5 - This exposure (NAE-079) is approximately midway between Blue Springs and the Toyota plant on the west side of Mississippi Highway 9. The grey sands are the upper portion of the Coon Creek while the red sands are assigned to the middle / upper Ripley sands (sec. 16, T8S, R4E)...... 11
Figure 6 - The Chiwapa can contain well-developed beds of limestone. Here blocks of limestone litter the slope just off of the shoulder of Miss. Highway 178 on the southern valley wall of East Branch. All of these blocks are highly fossiliferous...... 12
Figure 7 - A sample of the Owl Creek Formation from New Albany. The dark “spots” are phosphate and the white areas are clam and snail fossils (sec. 4, T7S, R3E; NAE-152)...... 13
Figure 8 - Typical Clayton Formation being utilized to construct the new Highway 15 improvement over the Tallahatchie River (sec. 4, T7S, R3E; NAE-151)...... 14
Figure 9 - This picture illustrates the flood plain along East Branch (sec. 1, T8S, R3E) west of Blue Springs. Agriculture is a well adapted land use for flood plains...... 15
Figure 10 - Engineering geology map of the Blue Springs area...... in pocket
-iii- Figure 11 - The greyish-brown zone is a thin, residual soil zone above the lighter colored chalk. Thin soils such as this can simply be removed prior to construction (SS-001; EST-016; sec. 27, T7S, R5E)...... 22
Figure 12 - Mineral resources map of the Blue Springs area...... in pocket
-iv- GEOLOGY AND GEOLOGICAL ENGINEERING CONSIDERATIONS FOR URBAN AND ECONOMIC PLANNING IN THE BLUE SPRINGS, MISSISSIPPI, AREA
PONTOTOC, LEE, AND UNION COUNTIES
ABSTRACT
The Blue Springs Mapping Project was designed to produce a set of basic information that could be used to advantage by regional planners, city planners, geologists, engineers and the general public. These data are oriented toward the area’s geology and engineering geology, although information on infrastructure and guidance regarding economic/urban development are included. The geological map includes the outcrop belts of the Cretaceous Demopolis Formation, Ripley Formation, and the Owl Creek Formation. The early Tertiary Clayton Formation also crops out in the western half of the mapped area at the highest altitudes. Most of the streams in the map area contain flood plains constructed by periodic flooding. The flood plains are mapped as a separate unit based largely on geomorphological relationships. The engineering geology map illustrates the geographical area where design, potential flooding, construction or cost concerns are likely to be encountered. Among the considerations included on the map are flood-prone areas, expansive soils, areas where cost of excavation are likely to be above normal, and areas where indurated limestone or sandstone may require heavier (and more expensive) equipment for excavation. The mineral resources map illustrates areas where useful mineral resources may be explored for. Construction sand, for example, is useful in foundations for roads and structures and is present in a north to south band near the middle of the map area and in the Clayton outcrop belt. Faulting in the map area sets up the potential for petroleum traps that could accumulate liquid hydrocarbons or natural gas. The clays of the lower Ripley Formation may have economic potential as brick clay, absorbent clays and other specialty uses. The local infrastructure is also important and maps of the power transmission lines, natural gas pipelines and roads are included in the data set. When used together these maps provide guidance to areas where development can proceed with a minimum of concerns regarding the characteristics of the natural environment.
INTRODUCTION
From 1973 to 1976 the Mississippi Office of Geology produced a series of atlas-type books aimed at presenting geological and associated data compiled in a format suited for use by a broad audience that included the general public (Green and Bograd, 1973; Green and Childress, 1974; Childress, Bograd and Marble, 1976). The Mississippi Mineral Resources Institute (MMRI) completed a similar study for the city of Ripley, Mississippi, in 1995 (Swann, Faruque, and Harding, 1995) which was intended to serve as a guide for city planning. All of these studies had a similar goal - putting technical information in the hands of planners and government officials that could use the information for improved planning.
Science and specialties within a science often develop their own set of words and terms in order to express very precise ideas and concepts. The result is sometimes referred to as the language of science and it can be quite as intimidating to the nonscientist as a foreign language. As the user reads through the following text, they will find that the technical and scientific
-1- language has been minimized and scientific terms have been explained. The purpose is, to encourage the use of the information by the nonscientist and to facilitate the “on-the-ground” application of the results of the investigation. Should the reader be interested in the science behind the maps and/or the text contained herein, they should contact the MMRI. The raw data collected during the investigation is open for public use and the MMRI staff will be pleased to discuss any issues with the public.
The goal of this study was to take the basic concept of these earlier publications, modernize the idea, add more technical data, and then supplement that technical data with an effort to place the information into the hands of the local planners, governmental leaders and developers. Included in this final step, was a set of technical briefings and training sessions that included the professionals who developed the information working closely with the local public to explain how the information was derived and could be used.
The construction of the Toyota auto manufacturing facilities in Union County, Mississippi, provided an opportunity for the MMRI to put this idea of enhanced transfer of geological data / analysis into play. The facilities are located less than a mile southwest of the small town of Blue Springs, Mississippi. Blue Springs had a population of 154 people in 2010, as well as limited infrastructure and industry. The surrounding territory is also rural, largely agricultural and sparsely populated. It was felt that when the Toyota facilities became fully functional, significant economic development was likely and along with the development would come the concerns generated by urbanization. The rural character of the area was considered an opportunity to develop a set of data that could provide guidance to planners and governmental agencies and the implications of these data could be adequately explained and discussed in the early stages of planning. The data sets included geological data, geotechnical data, infrastructure and natural resources evaluations. Data was gathered from previously published sources as well as new information such as geological maps and engineering geology maps. All pre-existing data was checked for accuracy and consistency. Internally-generated data was reviewed and examined for accuracy and reliability. All the information is available in digital form on the MMRI website.
STUDY AREA
The study area consists of four, 7.5 minute topographic quadrangles roughly centered on the town of Blue Springs, Mississippi (Figure 1). More specifically, it includes the New Albany East, Miss., Ellistown, Miss., Sherman, Miss. and Northeast Pontotoc, Miss. quadrangles. This area includes portions of New Albany, Pontotoc and Tupelo as well as Sherman, Belden, Chesterville, Cherry Creek, Blue Springs, Mound City, Center, Ellistown, Wallerville, Branyan, Alpine and Birmingham in their entirety. The Toyota vehicle manufacturing plant is located
-2- approximately one mile southwest of Blue Springs, Mississippi. The study area’s topography varies from the flat to gently rolling Black Prairie region in the east to the rolling, often steep topography in the western portions of the study area (referred to as the Pontotoc Ridge Region). Elevations vary from approximately 650 feet above sea level (Rakestraw Mountain) to approximately 280 feet (on Town Creek) for a total elevation change of 370 feet.
Figure 1 - Location of the study area with the major geographic features.
METHODOLOGY
Geological Map
Field investigations for construction of the enclosed map (Figure 2) began in March, 2010. Standard mapping technologies were utilized to construct the geological map. The process consisted of field examination and description of exposures, examination and interpretation of existing down-hole geophysical well logs, stratigraphic compilation of data sets and finally the construction of surface geologic maps. Formations appearing on the geological map are defined by lithology in accord with the provisions of the North American Stratigraphic Code (North American Commission on Stratigraphic Nomeclature, 2005). Lithology-based mapping also easily lends itself to derivative applications as described herein. All maps were finalized on a 1:24,000 relative fraction scale.
-3- A total of 547 exposures were described within the map area and additional exposures were examined in areas immediately adjacent to the map area. These exposures were described lithologically, preliminary formational assignments made and samples collected if appropriate. Each exposure was assigned a unique number consisting of a map name abbreviation and exposure number. Each exposure and its geographic position were plotted on base maps.
The primary subsurface data base consisted of well information provided by the Mississippi Office of Geology and consisted of 305 well logs and 166 well completion forms. This data set included wells in Union, Lee and Pontotoc Counties. Each log was interpreted as to the stratigraphy contained in the well log. The wells were then plotted for use in geological map construction and elevations were checked against topographic map elevations.
Remote sensing was used to evaluate specific problems and answer specific questions during field operations. Remote sensing was used, for example, to identify sand pits and exposures not immediately noticeable from roadways. Remote sensing was also used to identify exposures that were not obvious and in remote locations.
All surface and subsurface data were compiled on a single map along with elevations of formational contacts (formations are layers or “ packages” of rock and contacts are where two formations meet or are “in contact” with each other). Initially, these data were used to define the orientation of the formation over the entire map area. The next step was to construct structure contour maps to determine elevation changes of selected geological features. The result of this evaluation was the identification of a north-to-south zone near the center of the map area where the orientation appeared to be significantly altered. Based on the structure contour map, this area was interpreted as a set of normal faults resulting in horsts and grabens (blocks defined by faults that have either moved up (horst) or down (graben) that offset the regional strike and dip). After the structural interpretations were made, the structure contours were redrawn to reflect the contact elevations on each fault block. The intersection of the structure contour elevations and the ground surface elevation determined the contact location, which in turn defined the outcrop pattern. This preliminary geological map was then tested again by examination of described outcrops and then by comparison in the field. This additional field testing identified local areas where additional revisions were required due to new exposures resulting from on-going construction. The final map was digitized into a geographic information system (GIS) format.
Engineering Geology Map
The engineering geology map is based, in part, on the geological map. In the course of field investigations, indications of expansive soils were noted, as were flood plains and any indications of slope instability. Interviews were conducted with contractors and others that were
-4- experienced with excavation operations in the study area. These interviews highlighted additional concerns regarding excavation of certain geological materials, or materials that were expansive. When the interviews identified problematic materials, an on-site visit was arranged to determine the geological unit to which these materials belonged. Through these interviews and field observations, several geological units were determined to have engineering concerns that warranted further laboratory tests to verify these field and interview-derived observations.
The laboratory testing was conducted at the University of Mississippi in test facilities of either the Department of Geology and Geological Engineering or of the Department of Civil Engineering. Standard testing procedures and analyses were followed (standard ASTM procedure where applicable). The samples were uniquely labeled so they could be clearly identified as to the geological unit from which they were derived. Relating the samples back to the geological unit allowed the aerial extent of the area of concern to be identified on the engineering geology map. The Owl Creek Formation, for example, may contain expansive clays. Once this hazard has been verified, the outcrop belt of the Owl Creek Formation may then be used to map areas where construction design should include testing for expansive clay. Positive results will allow the engineer to design the foundation accordingly, or perhaps seek another site. In this respect, the engineering geology map will closely resemble the geological map, but when the same hazard or concern is present in adjacent geological units, the engineering map will identify both of these areas as one field and so it will differ from the geological map.
The map was initially constructed using the 1:24,000 scale geological maps and converted into a dititial format. Map layout followed the example of maps produced by the U.S. Geological Survey and the Illinois Geological Survey (Nichols and Yehle, 1969; Bergstrom, Piskin and Follmer, 1976, respectively). The same quality control measures were used to evaluate this map as were used with the geological map.
Mineral Resources Map
This map is a derivative product of the geological map, with the addition of information from the Mississippi Office of Geology regarding mining operations. Information regarding hydrocarbon well data was obtained form the Mississippi State Oil and Gas Board information was also derived from MMRI’s oil and gas files contained in the Institute’s Ridgway Data Center. County geology bulletins were also reviewed for useful mineral resources information.
The stratigraphic units on the geological map are based on lithology and so are directly applicable to the identification of potential mineral resources such as construction sand or clay resources. Field observations noted the presence of resources that would have potential
-5- economic value. These observations were matched with formational assignments allowing areas to be identified on the mineral resources map as having a resource of interest. Resources of potential value, construction sand for example, were verified by the presence of active mining or in the case of clay resources, laboratory tests indicating that the resource may have economic value. The potential for production of hydrocarbons was identified as areas where there exists potential hydrocarbon trapping mechanisms, trapping seals and potential source rock. As there is no current hydrocarbon production in the map area, the identified areas are speculative.
As with other maps in this report, the areas identified as having potential economic minerals should be used as a guide and are not a substitute for site-specific evaluations and economic investigations. The Mineral Resources Map was constructed on a 1:24,000 relative fraction scale map and converted into the digital format. Mississippi’s Mineral Resources Map (Booth and Schmitz, 1983) was used as a general guide to map format and design. This map is also a good reference to the distribution of mineral resources on a state-wide scale.
GIS Map Construction
In this study, ESRI’s Arc GIS, version 9.3 was used for both data manipulation and to produce the final maps. The geological map (Figure 2) is a complex map that required considerable time to complete in a digital format. The infrastructure maps, on the other hand, were largely preexisting in digital format. The following description of methodologies represents a broad set of procedures rather than a step-by-step listing. The following discussion is also more representative of the geological map.
The four U.S. Geological Survey, 7.5 minute topographic maps listed above were used as a base map for the data. The initial procedure was to scan these base maps and georeference each of them. The four maps were then joined to produce a base map coverage. Each of the contacts for the formations was digitized that were then closed and converted to closed polygons. The final map colors follow the general color scheme of the U.S. Geological Survey. The Cretaceous age formations, for example, are in shades of green and the younger Tertiary are in shades of yellow and brown. After the initial draft of the map was complete, it was followed by field checking and verification. The final map was then constructed including a legend, and other ancillary information as deemed useful.
-6- EXPLANATION OF THE MAPS
Geological Map
The formations listed on the legend of a geological map are the basic building blocks used in dividing the geological materials beneath our feet into more usable “packages”. The formation is a “package” that shares a common lithology (type of geological material, such as limestone or clay) and is sufficiently thick that it can be mapped at a scale of 1:24,000. These formations are not horizontal, but are inclined toward the east (referred to as dip) at a rate of 20 to 30 feet per mile for the formations mapped in the study area. The formations get deeper (lower elevations) to the west and higher in elevation to the east (the Demopolis Formation, for example is at the surface in Tupelo, but is several hundred feet below the surface in the New Albany area). Since the formations are inclined, at some point they will be exposed to the surface of the earth in what is referred to as the formation’s outcrop belt. Since the formations dip to the west their outcrop belts are oriented in a north - south direction. The thicker formations will have wider outcrop belts and vice versa, so the width of the outcrop belt on the geological map gives the user some idea how thick the formation may be. On the geological map (Figure 2), for example, the outcrop belt for the Ripley Formation is much more extensive than the Owl Creek Formation and so reflects a difference in thickness. Ideally, outcrop belts would appear as broad bands on the geological map, but there are two factors that make the ideal outcrop belt more complex. These factors are topography and in the case of this study, faults. Since the formations have a low angle of dip (less than one degree) the changes in elevation of the earth’s surface will result in a more complex outcrop as older or younger formations are exposed to surface because of hills or valleys. Birmingham Ridge, for example, contains a narrow outcrop of Ripley Formation because of its relatively higher elevation. Faults can be thought of as “breaks” in the earth’s surface where one side of the fault has moved relative to the other. This movement is the source of earthquakes such as the May 10, 2008, Belden Earthquake. The movement associated with faults also carries the geological materials with it and changes the elevation of the formation. This offset will result in a change in the outcrop belt and as evident in the center of the geological map result in more complex outcrop belts.
Formations vary in age with the older formations beneath the younger ones. In the legend, the Demopolis Formation is the oldest and the Quaternary Alluvium (flood plains) is the youngest. Excluding the Quaternary Alluvium, the formations get older to the east. The map legend also contains terms such as Quaternary, Tertiary, and Cretaceous. These terms denote intervals of geological time. The Cretaceous extends from approximately 140 to 65.5 million years before the present. The Tertiary extends from 65.5 to approximately 1.8 million years before the present and the Quaternary extends from 1.8 million years ago to the present. These divisions of time are often subdivided and so the Paleocene, for example, is a Tertiary subdivision extending from 65.5 to 54.5 million years ago (Dockery, 1996).
-7- The study area includes portions of three counties, all of which have published geological maps. Unfortunately, all of these maps were constructed decades ago and without the aid of topographic maps which add a vertical dimension to the maps. Without this vertical control, the details of the outcrop belt cannot be illustrated and the identification of areas that have been offset by faulting are difficult to identify. These older studies are useful as background, but with current technology and better base maps, a much more useful product can be produced. Table 1, below contains the major publications relating to the study area’s geology. Other professional papers exist that discuss various aspects of the area’s geology, but these are the ones that are most useful as a source of background geology information.
Table 1 - Major Background Publications for the Study Area
Author (s)* Date Study Area of Remarks Published Publication
R.R. Priddy and T.E. McCutcheon 1943 Pontotoc County Geology and mineral resources
F.E. Vestal 1946 Lee County Geology and mineral resources
L.C. Conant and T.E. McCutcheon 1942 Union County Geology and mineral resources
F.F. Mellen 1958 State-wide Discusses part of Ripley Fm.
L.W. Stephens and W.H. Monroe 1940 State-wide Discusses Cretaceous section
* See References Cited section for a complete bibliographic reference.
Demopolis Formation - The oldest formation in the map area is the Cretaceous Demopolis Formation. The Demopolis outcrop belt is confined to the eastern half of the geological map (Figure 2) and being a thick formation, only part of the outcrop belt is within the study area. The chalk of the Demopolis is composed of microscopic fossils with calcium carbonate shells. The Demopolis was named for exposures in Demopolis, Alabama, where the chalk is pure and is typically a bright white color. The chalk in the study area has a significant clay content, so it tends to be a very light gray color rather than a bright white. This clay content has important geotechnical characteristics that are discussed more fully in the section regarding the engineering geology map. When the chalk is fresh and unweathered, the calcium carbonate content makes it firm, but not as hard, for example, as a limestone.
The Demopolis outcrop belt is characterized by a topography that varies from flat to low rolling hills without large scale changes in elevation. This topography is due to the wet, humid environment dissolving the calcium carbonate from the chalk resulting in a low relief solution
-8- plain. The clay contained in the chalk does not dissolve as readily and will tend to accumulate as a dark colored, insoluable residue (soil zone) above the chalk. Prior to development, this solution plain contained an abundance of tall grasses typical of prairies and these tall prairie grasses and dark soil led to this area being referred to as the Black Prairie Region. An examination of the topographic maps also demonstrates the Demopolis outcrop belt is lower in elevation than the adjacent Ripley outcrop belt to the east.
Another characteristic of the chalk is the very slow movement of groundwater through the chalk. This slow groundwater movement makes it very difficult to produce water from a well reaching total depth within the chalks. Slow groundwater movement through the chalk also results in streams that tend to have very low flows in dry weather or they may become entirely dry. This situation results from a lack of groundwater contribution from the chalk to the flow of surface water within the stream channel. Fossils may be locally abundant. During field operations it was noted in several places that beds containing fossil oysters (Pycnodonta convexa Say) were so abundant that they “armored” the bottom of the stream channel and slowed channel erosion. When the channel erodes downward through the bed of oyster shells, faster erosion rates resume and the result is a small waterfall or a set of rapids. Figure 3 is a photograph of the dry channel in Mud Creek east of Birmingham in western Lee County (sec.2, T8S, R5E; map location EST- 036; EST-044). Beds of Pycnodonta Figure 3 - Picture of Mud Creek as it appeared October 15, convexa cross the channel near the 2010. The dry chalk channel contains beds of Pycnodonta center of the picture and are indicated by convexa that alters erosion rates and forms a set of rapids across the channel (just above the pool of water). faint horizontal lines across the channel. The photograph was taken on October 15, 2010, during an extended drought. South of Mud Creek the same oyster beds are exposed in Town Creek at the MS 178 bridge less than a mile north of Belden, Mississippi (sec.8, T9S, R5E; map location SQ - 001). Here the beds are also controlling stream erosion rates and have resulted in a similar set of rapids across the Town Creek channel.
Ripley Formation - The Ripley Formation is a thick formation and is subdivided into four units. An examination of the geological map in Figure 2 will indicate that the Ripley outcrop belt makes up the majority of study area. Within the Ripley, the transitional clay is the
-9- lowest subunit, the Coon Creek / Troy beds, and the middle / upper sands compose the middle of the formation, and finally the Chiwapa Sandstone interval is at the top of the formation.
The transitional clay, as the name implies, represents a transitional interval between the sands and clays of the Ripley and the Demopolis chalks below. Although the transitional clay has been mentioned in several publications, there is little detail regarding its composition or the environments in which it was deposited. The dividing line between the Demopolis and Ripley is not a well-defined bed or is there an erosional surface on which to place the boundary. The entire unit becomes more carbonate-rich as it gets deeper and so the boundary placement was in a zone of gradational change. The boundary, in this study, was placed at the base of the lowest clay bed that, although it was calcareous, was both soft and plastic. If it was hard, as above in Figure 3, it was assigned to the Demopolis.
The transitional clay is as much as 190 feet in thickness near the center of the study area. It is largely composed of a dark- to medium-gray clay that has well preserved marine fossils, it can be sandy, and often contains abundant fine-grained mica (see Figure 4). In the northeastern quarter of the Ellistown map (near the community of Parks), the upper part of the transitional clay changes from a clay to a fine-grained sand representing marine environments that were very shallow. It would also be logical that a clay this thick would contain different types of clays and this seems to be the case. Of particular note, is an area approximately one and a half miles east of Alpine (sec. 7, T7S, R5E) where the clays composing the road cuts have failed and blocks of clay have moved downward to fill the adjacent Figure 4 - A photograph of the transitional clay, road ditches. This feature is often associated with the basal unit of the Ripley Formation. Note the highly expansive clays that can pose concerns for abundant fossil bivalves. This exposure (SQ-082) structures founded on them. This concern is is just north of the Sherman city limits on a discussed in more detail in the Engineering tributary of Ryan Creek (sec. 22, T8S, R4E). Geology section.
The unit above the transitional clay is the Coon Creek Tongue/Troy beds interval. The Coon Creek and the Troy beds are considered together because they are equivalent units, but are composed of different rock types. The Coon Creek is composed of medium-gray, fine-grained sands that are often highly fossiliferous and thin, calcium (calcite)-cemented sandstone beds. The Troy beds (see Swann and Dew, 2009, for detailed descriptions of this unit) are present as calcium (calcite)-rich clays (marls), thin, sandy limestone and sandy chalk. The calcium content
-10- distinguishes this unit from the Coon Creek, but the light yellowish-grey color is often (but not always) an indicator of the Troy beds as well (see cover photo).
The Coon Creek and the Troy beds interfinger in the area south of U.S. Highway 78, so in some areas both are present in the same location. North of U.S. 78, the calcium-rich sediments of the Troy beds were not noted, so U.S. 78 can be used as an approximate line marking Coon Creek Tongue to the north and Coon Creek / Troy beds to the south. Both units contain well- cemented sandstone and limestone beds, but all are thin and should not pose a problem to construction or excavations. The Coon Creek crops out within Blue Springs area and the Toyota vehicle manufacturing plant is founded on the Coon Creek sediment. The Coon Creek is well known for it fossil content and exposures between Blue Springs and the Toyota plant are no exception. This set of exposures has produced a very diverse set of fossils including a leg bone of a dinosaur (residing Figure 5 - This exposure (NAE-079) is approximately in the Mississippi Natural Sciences Museum midway between Blue Springs and the Toyota plant on in Jackson, Mississippi). Although not the west side of Mississippi Highway 9. The grey sands often thought of as a resource, these are the upper portion of the Coon Creek while the red fossiliferous outcrops do attract rock sands at the top are assigned to the middle/upper Ripley sands (sec. 16,T8S, R4E). hounds, geologists and students into the Blue Springs area where they conduct business with the local merchants. This type of resource has value and should be considered in planning activities. Figure 5 shows the largest Coon Creek exposure situated between Blue Springs and the Toyota plant. Excluding the Coon Creek type exposures on Coon Creek in Hardeman County, Tennessee, this is considered the best Coon Creek exposure and the very best in Mississippi.
Stratigraphically above the Coon Creek and Troy beds, is a set of sands that are assigned to the middle / upper Ripley sand. The unit has a “middle / upper” descriptor due to the discontinuous nature of the Chiwapa Sandstone that lies above. If the overlying Chiwapa Sandstone is present, then these sands are referred to as the middle sand and if the Chiwapa is absent, it becomes the upper sand (since it would then extend from the Coon Creek/Troy beds to the top of the formation). In this unit, the sand is typically loose, fine-grained, contains abundant mica, and often has burrows of organisms that were living on the ocean floor 70 million years ago. This sand, unlike the Coon Creek, typically has few fossils other than burrows. Since the upper / middle sand is loose, it is not often seen in outcrop. The exposure described above (NAE-079;
-11- Figure 5) contains the lower portion of these sands (the red sands above the gray sands of the Coon Creek) overlying the Coon Creek beds. The sand is used as construction sand and while the sand pits are in use, the sands are easy to examine and sample. There are few construction / design / excavation problems associated with this unit.
The Chiwapa Sandstone Member of the Ripley Formation typically contains beds of loose sand, sand cemented together with calcium carbonate (a calcite-cemented sandstone), as well as sandy, limestone beds. The sandstone and limestone beds can be as much as five feet thick and can be hard and difficult to excavate. All of theses beds may locally contain abundant fossils such as bivalves (clams and oysters), gastropods (snails), cephalopods (extinct shellfish with a circular shell), crabs and sea urchins (echinoids). The fossil content is often the most noticeable characteristic of the unit.
The Chiwapa can have a maximum thickness of as much as 80 or 90 feet. But, the limestones and sandstones can also be completely absent and the Chiwapa interval would be represented by loose sands very nearly indistinguishable from the underlying “middle / upper” Ripley sands. The discontinuous nature of the Chiwapa limestones and sandstones makes its presence at any particular place difficult to predict. Where the Chiwapa alternates between hard limestone beds and softer sand Figure 6 - The Chiwapa can contain well-developed beds beds, small caves can develop that are of of limestone. Here blocks of limestone litter the slope enough extent to gain local notice (see just off of the shoulder of Miss. Highway 178 on the southern valley wall of East Branch. All of these blocks Mellen, 1958). When the Chiwapa is present are highly fossiliferous. in significant thickness, it can be somewhat difficult to excavate and larger and more expensive equipment is often required. This issue is discussed in detail in the Engineering Geology section of this report. Figure 6 is a photograph of large blocks of Chiwapa limestone near New Harmony Cemetery in sec. 6, T8S, R4E, approximately two miles west of Blue Springs in the valley wall of East Branch. The Chiwapa in this area is approximately 50 feet thick and exposures can be seen in road cuts along Mississippi Highway 178.
Owl Creek / Prairie Bluff Chalk - The Owl Creek Formation overlies the Ripley Formation and typically consists of dark-grey silt (silt is a grain size that is smaller than sand and larger than the microscopic clay-sized particles) and clay along with thin beds of sand. The Owl Creek in the New Albany area is somewhat different in that the upper Owl Creek contains a significant
-12- thickness of sand, sandstone, and sandy limestone. The Owl Creek, like the Coon Creek, has a chalk or calcium carbonate-rich equivalent called the Prairie Bluff Formation. Both formations are present in the study area, but the Owl Creek is the most common. The Prairie Bluff within the study area consists of calcium-rich clays and silts and is a marl rather than a chalk. In this report, we are referring all of the calcium-rich sediments to the Prairie Bluff and retaining the dark grey silts and clays in the Owl Creek. A characteristic of both formations is the phosphate content in the form of small grains the size of sand grains or as irregularly shaped “lumps” of phosphate that can be as much as two inches across. The phosphate can also take the form of fossil clams and snails. Both formations are also locally fossiliferous and can contain a wide variety of fossils.
The lower boundary of the Owl Creek represents an erosional surface and so there is a topography developed on this boundary that was subsequently buried. This buried topography makes predicting the lower boundary of the Owl Creek and Prairie Bluff more difficult. The upper boundary of the Owl Creek/Prairie Bluff with the overlying Clayton Formation also represents an erosional surface and a buried topography. This boundary, like the lower one, is also difficult to predict. The upper boundary is one of special note in that it represents the famous Cretaceous/Tertiary boundary which is the point in geologic time when the dinosaurs extinct.
Another consequence of these buried topographies at the top and bottom of the formation, is a marked variation in the thickness of the formation. Typically, it is approximately 40 to 50 feet in thickness, but in Figure 7 - A sample of the Owl Creek Formation from the New Albany area the thickness may New Albany. The dark “spots” are phosphate and the approach 90 feet. The thickening and thinning white areas are clam and snail fossils (sec. 4,T7S, R3E, translates into differences in the width of the NAE-152). outcrop belt on the geological map.
There are also some concerns associated with excavation and foundations. There are parts of the Owl Creek that can be difficult to excavate resulting in increased costs. The Owl Creek is also somewhat expansive and can cause problems with foundations if not accounted for in the design. Both of these concerns are discussed in more detail in the Engineering Geology section.
The clay/silt-rich Owl Creek and the calcium-rich Prairie Bluff tend to form relatively flat topography, so large outcrops of either unit are rare. The photograph in Figure 7 (above) is a sample of the more calcium carbonate-rich silts typical of the Owl Creek near New Albany. This
-13- specimen of Owl Creek also contains phosphate which appears as dark “lumps” in the photograph. The fossil clams and snails are also obvious as the white outlines and can be abundant.
Clayton Formation -Above the Owl Creek / Prairie Bluff Formations is the Tertiary Clayton Formation. As indicated on the geological map (Figure 2), the Clayton is present at the highest elevations in the western half of the study area. If we don’t consider the present day flood plans, then the Clayton is the youngest of the geological units in the study area. The Clayton consists of a clay-rich sand that is typically a reddish-orange color. In the study area only the lower portion of the Clayton is present, so its thickness varies, but is typically thin. There are, however, exceptions to this generalization. The faulting in the center of the study area appears to have influenced the thickness of the Clayton. Fault blocks that have moved downward seems to have unusually thick Clayton sand within them suggesting that the downward movement of the fault shielded the Clayton from erosion or that the fault was moving while the Clayton was being formed and more sand accumulated here. Regardless of the reason, there are areas of unusually thick Clayton in the center of the study area.
These Clayton sands are often used for construction and are typically well suited for road base or fill for foundations. Figure 8 is a photograph of Figure 8 - Typical Clayton Formation being utilized to the typical appearance of the Clayton in a construct the new Highway 15 improvement over the borrow pit in New Albany along with the Tallahatchie River (sec. 4, T7S, R3E, NAE-151). earth moving equipment that is being used to mine it.
Quaternary Alluvium - The geologic map (Figure 2) lists a unit referred to as Quaternary Alluvium. This unit consists of modern day flood plains associated with existing streams. Flood plains are flat areas bordering a stream channel that forms by periodic floods. The Quaternary Alluvium is still being deposited today each time a stream floods. Since the flood plains are associated with streams, the composition of the flood plain material will vary with the geological material of the area. If, for example, the stream is running through the sands of the middle / upper Ripley, then the flood plain will be composed of a large amount of sand. As can be seen from the geological map a significant amount of the area consists of the bright yellow color denoting the flood plains. See the Engineering Geology section for a more complete discussion of these uses of
-14- flood plains. The flood plain illustrated in Figure 9 is associated with East Branch, two miles west of Blue Springs.
Summary of Geology
Figure 2 (enclosed geological map) contains five mapped units including the Cretaceous Demopolis, Ripley, and Owl Creek Formations, the Tertiary Clayton Formation, and the Quaternary Alluvium. Strike for these units is nearly due north and dip is to the Figure 9 - This picture illustrates the flood plain along East west. Faulting has altered regional Branch (sec. 5, T8S, R3E) west of Blue Springs. Agriculture strike and dip, particularly in a is a well adapted land use for flood plains. northward trending area near the center of the study area. East of the fault zone dips are approximately 22 feet per mile and on the west of the fault zone the dips are approximately 30 feet per mile. The full extent of faulting in this area has not been determined, so the geometry of areas on either side of the fault zone may also be altered by faulting. This northward trending set of faults has formed a set of horsts and grabens that offsets the outcrop belts and results in outliers of several units further east than would be expected.
During field investigations, the Demopolis was found to be of a uniform lithology. It is typically a light gray, argillaceous, chalk with varying fossil content. Where the clay content is higher, very fine-grained muscovite mica is evident. Joints are present in some outcrops although they may be a result of unloading rather than a reflection of geological structure. The upper Demopolis contains increased clay content and is referred to as the Bluffport Member. The Bluffport is restricted to the upper impure chalks just below the Demopolis / Ripley contact. The Demopolis / Ripley contact is conformable (no loss of geological record) so it is chosen from within a zone of transition from the clastics of the younger Ripley Formation to the carbonates of the Demopolis. In this investigation, the Ripley / Demopolis contact was placed where the calcite content was sufficient to result in a poorly indurated section. The calcareous, plastic, clays (marls) were assigned to the transitional clay of the Ripley and the indurated section retained in the Demopolis.
The Ripley Formation contains four major subdivisions; the transitional clay, the Coon Creek / Troy beds, middle / upper sand and the Chiwapa Sandstone. In Chickasaw County the Ripley had a thickness of approximately 270 feet (Swann and Dew, 2009), while in the study area
-15- the total thickness of the Ripley is estimated to be 340 feet. This thickness increase is largely attributed to the transitional clay which is approximately 120 feet thick in Chickasaw County to 190 feet thick in the study area.
The transitional clay was defined as a gray, fossiliferous clay unit that becomes increasingly calcareous downward in the section. A sandy facies is present near the community of Parks, suggesting very near shore environments. Both contacts are conformable. The Coon Creek Tongue / Troy bed interval are facies equivalent beds. The Coon Creek consists predominately of fine-grained, fossiliferous sand and the Troy beds are composed of calcareous sands, nodular limestone and marls. These two lithologies interfinger south of U.S. Highway 78 and in this area are typically both present in the section. The upper contact is conformable and is typically marked by a nodular limestone or a thin calcite-cemented sandstone bed. The middle / upper sands are composed of fine-grained, micaceous sands that were deposited in very shallow water. There are few fossils other than burrows. The Chiwapa Sandstone consists of a series of limestones, calcite- cemented sandstones, and calcareous sands that interfinger with the upper / middle sands facies and may be as much as 80 feet in thickness or entirely absent. The upper Ripley contact is unconformable and either the Chiwapa or middle / upper sand facies can be below the contact.
The Owl Creek / Prairie Bluff Formations are the youngest formations of the Cretaceous section and are approximately 50 feet in thickness. They, like the Coon Creek / Troy beds, are also facies equivalents. The Owl Creek is composed of gray, fossiliferous silts and clays with subordinate sands. The Prairie Bluff consists of fossiliferous, marls and calcareous sands that interfinger with the more northern Owl Creek lithology. The Owl Creek is unusually thick in the New Albany area (as much as 90 feet) and there is a sandy facies at the top of the section. The upper contact is unconformable.
The Clayton Formation is the basal Tertiary unit and is it consists of massive, argillaceous sand. The Clayton is the top of the stratigraphic column in the study area and its thickness is variable. It is present at the highest elevations mostly in the western edge of the study area. There are, however, outliers of Clayton well east of its expected outcrop belt preserved in grabens in the fault zone. The Clayton is unusually thick in these grabens, suggesting fault movement and sedimentation coincided in time.
The Quaternary Alluvium is one of the larger units on the geological map. This unit consists of flood plains of tributaries in both the Tennessee and Tallahatchie River drainage basins. The low relief of the Demopolis outcrop belt contains some of the wider flood plains while the steeper topography of the Ripley, Owl Creek, and Clayton outcrops contain more restricted flood plains. The flood plain lithology is varied but most often largely clay and silt in a fining upward sequence. Table 2 below, summarizes the size of the outcrop belts in the study area as well as their composition and age.
-16- Table 2 - Summary of outcrop belt characteristics
Formation or Unit Age Composition
Alluvium Quaternary Clay, Silt & Sand
Clayton Tertiary - Paleocene Clay-rich Sand
Owl Creek/Prairie Bluff Cretaceous Silt & Clay/Limestone & Marl
Ripley Cretaceous Sand & Clay
Demopolis Cretaceous Chalk
Engineering Geology Map
Bates and Jackson (1984, p. 164) define engineering geology as the “Application of the geological sciences to engineering practice, to assure that the geologic factors affecting the location, design, and construction of engineering works are recognized and adequately provided for.” This definition points clearly to the main thrust of engineering geology - “ ... to assure that the geologic factors ... are recognized and adequately provided for”. It should be clearly stated that our purpose in this section is not to discourage any type of land use or type of development, but rather to assist local engineers and planners in recognizing potential development issues. Nor will design be discussed, as design is clearly an engineering practice and that design will likely be determined on site-specific characteristics. Many of the geological factors of concern can be mitigated by engineering design. Expansive clays, for example, cause millions of dollars of structural damage nation-wide every year. Yet, there are methods to accommodate these clays in foundation design. Siting of major structures typically include an extensive evaluation of geological / environmental concerns, but smaller structures, such as an individual home, may not. In this case, knowledge that the geologic factor exists is an effective mitigation strategy. These geological factors can also be used to advantage when planners use them to guide development where the impact of these factors are likely to be minimal.
It is important to note that the enclosed engineering geology map (Figure 10) is not a substitute for site-specific investigation. Due to the size of the study area, detailed studies were not possible and the geological materials may vary from place to place. Limestone, for example, is more expensive to excavate than loose sand and the Chiwapa Sandstone may contain significant
-17- amounts. Fifty feet of limestones in the Chiwapa at one location may be only five feet thick a mile away. Thick vegetive cover and poor exposure make it impossible know where and how quickly these changes take place. The areas identified on the map as an area of concern, are an indication that additional attention should be given to this geological factor and additional testing may be needed.
The engineering geology map is based, in part, on the geological map, so some similarities will be noted. But where adjacent geological formations or subunits of the formation contain the same geological factor of concern, the two adjacent units will be combined into one on the engineering map. Additional information from tests are included either directly on the map or in the following text, including a summary table of the characteristics of all factors of concern. As in the geological map, this table includes a column where the factor is described in nontechnical terms for use of the non-geologist. The calcium carbonate content of limestones often dissolve in humid environments resulting in collapse features that are a concern to structures at the surface. Where the Chiwapa contains thick limestone beds one would expect to see evidence of dissolution in the form of sinkholes. During field operations, however, we were unable to document a single case of sinkhole formation, therefore this factor of concern was not included on the map. We have concluded that although this concern is possible, the scale may be small enough that it is not a major issue to construction or design.
Flood-prone Areas - Flooding in the United States costs millions of dollars yearly and occurs in every state. A significant amount of flood-prone area was identified and consists of flood plains associated with perennial streams. The most extensive flood plains are developed in the northeastern quarter of the study area. The frequency, height and characteristics of a flood event is influenced by numerous factors. Urbanization, the construction of surfaces that do not allow precipitation to infiltrate into the ground surface (such as highways, parking lots and buildings) is a major factor that is likely to change stream characteristics as development progresses.
There are two approaches to evaluate the flood issue. One is the construction of flood maps referred to as Flood Insurance Rate Maps (FIRMs) which are the result of computer modeling of a stream and its tributaries to determine the elevation of a flood that is likely to occur with a set yearly probability. The other approach is to use the interpretation of the topography to identify features related to past flooding events. In other words, to identify the stream’s flood plain. Flood plains are flat areas adjacent to the stream channel that form when surface water over fills the channel and flows into the adjacent area. The sediment contained in the flood waters settle out and form a flat area adjacent to the channel. So flood plains are a result of periodic flooding and with the use of topographic maps they are relatively easy to identify. The best methodology to understand the flood concern for a given area is to use both approaches. Included in the Engineering Geology map (Figure 10) are the flood-prone areas colored in bright yellow.
-18- Although the areas identified as flood-prone in Figure 10 are subject to the flood hazard, they are not unsuitable for some uses. Those uses where flood waters will not damage the structures sited on the flood plain or cause the use of these structures to be abandoned for an extended time may be sited in flood prone areas. Some uses such as agriculture (Figure 9) is a well-suited flood plain use. Other uses may include recreational areas, particularly within urban environments, such as baseball diamonds, soccer fields, parks, bike and nature trails. In urban areas, flood plains can serve as greenways that extend into the built environment and will moderate hot summer temperatures and provide habitat to wildlife that venture into developed areas. As urbanization increases, the amount of water flowing down stream channels will also increase, leading to increased flood risk and the occurrence of flash floods. Protecting the flood plains accommodates this type of change in the stream’s flow and allows space for construction of catchment (retainment) basins to slow the water’s velocity.
The flood plain of Town Creek will be of concern should the cities of Sherman and Belden wish to expand. Yonaba Creek also has an extensive flood plain but there are few communities that are situated in or bordering on the flood plain. Ellistown and Fairfield are largely situated above the flood plain, but expansion on the available “high ground” is limited by the flood plain. So, in the future, these two communities may also need to consider flood plain issues if they need to expand.
Expansive Soils - Expansive soils (or sometime referred to as active clays or swelling soils) are a subtle geological concern that can cause property damage in Mississippi as well as across the U.S. Certain clay minerals will readily absorb water and in doing so will expand and as the clay dries, it will shrink. There are engineering tests available to identify expansive clays and specialized engineering design methods can accommodate structures on expansive clays.
Not all clay minerals are expansive, kaolin for example, is relatively nonexpansive. Thick clay beds often have a mixture of different clay minerals which means that some areas of the geological unit’s outcrop belt will be of great concern whereas other areas will not. In Figure 10 (enclosed Engineering Geology Map) the red color indicates the outcrop belts of geological units where expansive clays have been identified and these are areas where special attention should be placed on site-specific soil testing.
Two units are of major concern for expansive soils: the Owl Creek Formation and the transitional clay of the lower Ripley Formation. The expansive properties of the transitional clay was first verified by Wheeler in 2011. This study area was included within the northern limits of his regional study and a subset of his samples were from locations identified during field mapping. Wheeler (2011) used multiple methods to evaluate the swelling potential, which allows the user to compare the results. The standard Atterburg limit testing procedure was followed to derive values for liquid limits (LL), plastic limit (PL), plastic index (PI) and then used to derive a Unified Soil
-19- Classification System (USC) designation. Using these parameters, the expansiveness (or swell potential) can be evaluated and classified. This classification is found in Table 3 in the two columns on the far right of the table. From this analysis, 57 % of the samples are classed as very high or extra high swell potential and 78% are classed as having a high swell potential or above. Only one sample classed as having a low swell potential. These data suggest that the transitional clay does have some variability in its expansiveness, but is predominately an expansive clay unit that should be of concern to construction and development.
Table 3 - Summary of Soil Swell Evaluation Results From the Transitional Clay
Map Sample LL PL PI USC Designation A&T Class D&R Class No.
Ellistown EST-039 67.45 29.84 37.61 CH Very High High
Ellistown EST -043 47.42 22.36 25.06 CL Medium Medium
Ellistown EST-027 51.62 25.69 25.93 CH Medium High
Ellistown EST-040 73.2 31.05 42.15 CH Very High Very High
Ellistown EST-023 105.54 39.25 66.29 CH Very High Extra High
Ellistown EST-012 79.78 32.54 47.24 CH Very High Very High
Ellistown EST-011 93.28 34.34 58.94 CH Very High Extra High
NE Pontotoc R-41 59.46 28.71 30.75 CH Medium High
NE Pontotoc R-33 72.42 34.93 37.39 CH High Very High
NE Pontotoc R-27 72.04 32.55 39.49 CH Very High Very High
Sherman R-15 57.59 27.64 29.95 CH Medium High
Sherman R-39 40.66 22.72 17.94 CL Low Medium
Sherman R-37 45.02 20.64 24.38 CL Medium Medium
Sherman R-35 68.66 29.37 39.29 CH Very High High
Sherman R-31 61.04 27.56 33.48 CH High High
NOTES: CH = clay, inorganic, high plasticity; CL = clay, inorganic, low to medium plasticity; A&T Class = Anderson and Thomson (1969) swell potential class; D&R Class = Dakshanamurthy and Raman (1973) swell potential classification; Table 3 modified from Wheeler, 2011.
The Owl Creek Formation is another geological unit that exhibits characteristics of expansive clay in surface outcrops. Surface exposures of the Owl Creek are limited, but the better
-20- exposures contain a very plastic clay that develops an abundance of cracks upon drying (often referred to as “popcorn” texture). The expansiveness (swell potential) was examined as part of a prior investigation in adjacent Tippah County by Swann and others (1995). This study established the expansive nature of the Owl Creek and these data should apply to this study area. All of the Tippah County Owl Creek samples classified as high or very high swell potential. Limited testing in the Blue Springs field area yielded low to medium swelling potential demonstrating variability in the Owl Creek clays. These two data sets suggest that the Owl Creek contains clays that should be of a concern to construction and development, but there may also be significant differences in clay characteristics. It is more important to obtain site-specific tests when considering siting structures in the Owl Creek outcrop belt.
The Prairie Bluff Formation is the equivalent to the Owl Creek and the two units interfinger. The Prairie Bluff with its calcium-rich sediments typically does not exhibit high swell potential due to the calcium content. The intermixing of Owl Creek / Prairie Bluff sediments in parts of the study area is yet another source of variability and another reason to obtain soil tests before construction.
Another area with expansive clay soils is the Demopolis outcrop belt. The Demopolis expansive clays are of a different origin than those in the Owl Creek or transitional clay. Chalk is typically nonexpansive and makes an excellent foundation material. Yet, the insoluable residue formed in the soil zone has the appearance of an expansive soil.
Montmorillonite is a group of clay minerals that are typically very expansive. The montmorillonite group of minerals are composed largely of aluminum and silicon and they are not particularly soluble in water and persist in wet, humid climates. Chalk is composed largely of the mineral calcite (calcium, carbon, and oxygen) and does dissolve in humid, wet climates. The Demopolis contains a mixture of both calcite and montmorillonite, particularly near the top of the Demopolis. As the calcite of the chalk dissolves at the surface, it leaves the insoluble montmorillonite at the surface. The expansive soils in the Demopolis appear to be a residual soil developed by dissolving the chalk (Figure 11) rather than a characteristic inherent of the chalk. Therefore, the soil formed by weathering of the Demopolis is likely to be variable in thickness and can be moved by surface water into the flood plains of streams in the Demopolis outcrop belt. Limited testing was conducted to evaluate both the expansive characteristics of the residual soils as well as in the clays in the flood plains of Mud Creek (sec. 11, T8S, R5E) and Town Creek (sec. 9, T9S, R5E). Table 4 summarizes the results.
-21- Table 4 - Summary of Testing Results on Demopolis Residual and Flood Plain Soils
Sample L.L. P.L. P.I. USC A&T D&R Remarks No. Designation Class. Class.
SS-001 54.41 33.81 20.6 MH Medium High residual soil zone
SS-002 68.39 35.30 33.09 MH High High residual soil zone
SS-003 37.36 24.56 12.8 CL Low Medium residual soil zone
SS-004 70.81 37.15 33.66 MH High Very High residual soil zone
SS-005 39.76 23.89 39.76 CL High Medium Mud Crk. flood plain
SQ1 43.42 20.70 22.72 CL Medium Medium Town Crk. flood plain
SQ1-2 38.26 22.61 21.30 CL Medium Medium Town Crk. flood plain
NOTES: LL = liquid limit; PL = plastic limit; PI = plastic index; CL = clay, inorganic, low to medium plasticity; MH = silt, high plasticity; A&T Class = Anderson and Thomson (1969) swell potential class; D&R Class = Dakshanamurthy and Raman (1973) swell potential classification.
The testing results classify all but one residual soil (SS-003 is a low plasticity clay) as a high plasticity silt with reasonable agreement between the two swell potential classifications. These results verify the expansive nature of the residual soil and they should be of a concern to foundation designs. Sample SS-003 classified as low to medium swell potential, probably reflecting natural variability in the soil materials. The flood plain samples were more uniform, and are low plasticity clay and largely of medium swell potential.
Perhaps the major consideration with these residual soils is soil thickness. If the soil Figure 11 - The greyish-brown zone is a thin residual is thin, then the simplest mitigation method is to soil zone above the lighter colored chalk. Thin soils simply remove it down to the fresh chalk. If the such as this can simply be removed prior to soil is too thick to remove, then there are several construction (SS-001; EST-016; sec. 27, T7S, R5E). engineering designs that can accommodate the movement of the soil. A qualified engineer is best able to evaluate the different methods and make a recommendation for foundation design.
-22- Excess Excavation Cost Areas - Often major excavations are bid out based on a set of drill data. These data will contain useful information regarding materials, their extent and thickness, but it doesn’t capture any information regarding how the material may break into pieces or if it responds well to ripping. A ripper is a heavy iron bar (foot) that resembles a plow and is pulled by a bulldozer to break up hard rock layers. If heavier equipment is required than expected, then the costs will also escalate. A physical place to dispose of rock may also become problematic if it cannot be used within the project. Haulage costs can also escalate project costs if the disposal area is remote from the excavation site.
These issues played a part in a $1,228,475 cost over run when constructing the new U.S. Highway 78 north of Pontotoc at the community of Nixon. Dockery and Thompson (2011) used Mississippi Highway Department documents to illustrate that a lack of appreciation of the amount and difficulty in excavating the limestones in the Chiwapa Sandstone led to significant unexpected costs. This oversight resulted in per yard removal costs being inadequate for the removal a limestone bed approaching six feet thick.
There are two units of concern that could result in excess excavation costs; the Chiwapa Sandstone and the silts and clays of the Owl Creek Formation. Where the Chiwapa is well developed, it can contain multiple limestone beds and can result in increased construction costs. Discussions with local citizens have also resulted in accounts of excavation problems in the Chiwapa while excavating swimming pools and in construction of the basin for impoundments. Unfortunately, the Chiwapa is not uniform in thickness, but can rapidly diminish in thickness to less than two feet. This characteristic makes its presence difficult to predict. On the enclosed Engineering Geology Map (Figure 10), this thickness variation was accommodated by identifying the Ripley - Owl Creek / Prairie Bluff contact (since the Chiwapa will not be above the contact) and adding a buffer of 30 vertical feet below the contact as the area of concern. This area should encompass the majority of the Chiwapa outcrop belt, and many areas it will be in excess of the thickness of the Chiwapa section and in other areas its possible the Chiwapa could be thicker than the designated area. Our goal then, is to bring attention to this issue and to alert the user that construction in these areas should include additional attention and testing before excavating in/near these identified areas.
The Owl Creek Formation has a different set of excavation concerns. When unweathered, the silts of the Owl Creek can be cemented with calcite (calcium carbonate) that tends to make the silt and clay beds difficult to remove. Examples of this problem were identified in Ripley, New Albany and Pontotoc. The excavations in northern New Albany along the Highway 15 improvements were typical of the other problem areas. Here the clay and silt of the Owl Creek were problematic in that the bulldozer rippers would only cut a groove into the tough clay beds rather than breaking it into pieces. The solution was to cut a series of parallel grooves in the clay with the rippers. A bulldozer blade was then used to push into the grooves at a 90 degree angle
-23- causing the clay to break across from groove to groove. Once the clay was broken it could be removed, but the amount of material hauled per day diminished by approximately 60 percent. An additional complication was that zones within the clay are hard and well cemented. These zone did respond well to the rippers, but they broken into large tabular pieces. In Figure 10, the Owl Creek outcrop belt is included in excavation cost concern area along with the adjacent Chiwapa interval of the Ripley.
Earthquake - Although many don’t associate Mississippi with earthquakes, they do occur throughout the state. The major earthquake concern is the New Madrid Seismic Zone. The southern-most end of the fault zone is considered to be at Marked Tree, Arkansas, only about 100 miles from the study area. This is an active fault zone that generates many small earthquakes every year. This is also the fault zone that produced the largest set of earthquakes ever recorded in the continental United States in 1811 and 1812. This set of earthquakes was of such a magnitude that church bells rang in Washington D.C., and was felt as far north as Canada. How a structure will react to significant earthquake motion is dependent upon many variables of construction as well as the soil on which the structure is founded. In addition to the New Madrid Seismic Zone there are local earthquakes that can cause damage not because of their magnitude, but because of their close proximity to the study area. On May 10, 2008, a 3.1 magnitude earthquake occurred with its epicenter near the town of Belden. Although the damage was minor, it was felt over 97 square miles ( Swann, 2008).
Summary of Engineering Geology Map
There are four engineering geology concerns that have been identified in the map area. The most wide-spread is the presence of expansive clay as a residual soil in the Demopolis outcrop belt, in the transitional clay of the Ripley Formation, and in the Owl Creek Formation. Due to the thickness of the transitional clay, it is of most concern. The Owl Creek clays are variable and testing should be conducted to evaluate the expansiveness of these clays if constructing a structure in its outcrop belt.
There are significant amounts of flood plains in the study area and careful consideration should be given to land use in these areas. These flood plains are formed by periodic flooding and so development inside the flood plain should be suited to occasional flood waters, such as parking lots, recreational areas and green ways.
The Chiwapa Sandstone and the Owl Creek have both demonstrated the potential for being difficult to excavate. These complications can translate into increased project costs unless they are accounted for in the bidding process. The limestones of the Chiwapa can be problematic, but these limestones are of very variable thickness throughout the study area. Site-specific testing is recommended when a project is in or near the excess excavation cost area. The Owl Creek has different concerns in that the clays and silts can be tough and not respond well to ripping.
-24- Earthquakes are a potential hazard from not only the New Madrid Seismic Zone, but also from local earthquakes. The May 10, 2008, earthquake had its epicenter near Belden. Even though it had a magnitude of only 3.1, there was minor damage because of the close proximity of the epicenter. The earthquake was generated by movement along a fault that we know very little about. Without additional study, the capability of this fault to generate larger earthquakes is unknown.
Mineral Resources Map
The mineral resources map (Figure 12, enclosed) is, in part, derived from the geological map. Since many of the mineral resources are associated with certain formations, the outcrop belt can be used as a guide for exploration. As with other maps, we are seeking to bring attention to certain areas that may contain economic amounts of mineral resources. The regional scope of this project does not allow us to make detailed economic evaluations of specific sites, so the user will need to perform the tests, transportation analysis, market review and economic evaluations that are necessary to prove economic viability.
Construction sand is one of the most commonly used resources, particularly in urbanized areas. The two units that are likely sources of construction sand is the Clayton Formation and the Coon Creek and middle / upper sand of the Ripley Formation. The Clayton typically contains more clay content than the Ripley sands and are sought for as fill material. The Ripley Sands are finer-grained than the Clayton and typically have less clay. Sand borrow pits were noted during field operation from both units. The exposure in Figure 5 is within the Coon Creek and the materials removed from this area were used as fill material. So, the fine-grained sand of the Coon Creek also has potential for fill or construction material. No gravel deposits were noted during the investigation and the formations present in the study area typically do not contain significant gravel.
The transitional clay of the Ripley Formation has expansive qualities, but these characteristics that are a concern to construction are also indicators that suggest some economic potential. The highly expansive Porters Creek Formation in Tippah County, for example, is extensively used as feedstock for agricultural carriers (An agricultural carrier is clay granules processed to be absorbent. Herbicides (or other chemicals) are typically sprayed onto the carrier which is then distributed into the field. The carrier doesn’t blow about into adjacent areas as a spray would.) , absorbents, and for speciality clay products. Wheeler (2011) investigated potential uses for the clay in the transitional clay and identified potential brick clay, refactory clay, and potential use as absorbents. The methodology he used to define these potential uses are those developed by Aughenbaugh (1990; 1989; 1987). At present, there is no utilization of these potential resources. Further examination of these resources is recommended as it could potentially lead to new mining industry in the area.
-25- There is no oil or gas production in the study area, but there were oil test wells drilled in 1923, 1944 and 1947. All of these wells were drilled in sec. 36,T7S, R3E southeast of Wallerville. The Minyard Well Co., No. 1 Woodson well was drilled in 1923 and is reported to have encountered liquid hydrocarbons. The P.J. Alpine, No.1 Nabors well was drilled in 1944, but debris was accidently dropped into the well (referred to as a junked well) and so they elected to move the well site. The Cullet, No. 1-A, Ross Nabors well was drilled in 1947 and is reported to have had a show of natural gas (Ridgway Data Center, 2011). Presumably the 1944 economics were such that the amount of gas was not economic. All of these wells were drilled into the older Paleozoic rocks beneath the largely unconsolidated sediments overlying the Paleozoics.
Another potential use for the area’s natural resources would be for storage purposes. The chalks of the Demopolis are used for natural gas storage in Demopolis, Alabama. In Demopolis, Alabama, subsurface caverns have been excavated and have been storing gas for a number of years. Cavern storage has the advantage of rapid withdrawal of the product and nearly all of the product placed into the cavern can also be later withdrawn. These factors make cavern storage significantly better that depleted oil or gas field storage. This use for the area’s chalks is another area where additional research and development is needed.
Summary of Mineral Resources Map
The potential mineral resources for the study area include sand resources, particularly within the Coon Creek, the upper / middle sand of the Ripley Formation and within the Clayton Formation. These sands are currently utilized. The transitional clay of the Ripley Formation contains a thick clay section with a variety of clay with potential economic uses. These clays are currently not being utilized, but represent an area where additional research could potentially result in development of a mining industry for the area. Oil and gas is not being produced in the study area, but faulting could form a fault traps and the older Paleozoic rocks produce natural gas only a few miles south of Tupelo.
ACKNOWLEDGMENTS
The authors would like to acknowledge the assistance of Mr. A.J. Gibson, a former University of Mississippi student who helped with the clay analysis. Mr. Chap Brackett, a current University of Mississippi graduate student has provided invaluable assistance with both field and lab work. We acknowledge the assistance of Mr. Tommy Dunlap of Burns, Cooley, and Dennis of Memphis, Tennessee, who provided us not only with good practical advice regarding expansive soils but also provided us who some lab analysis for quality control. The review of the structural aspects of the geological map was provided by Dr. Terry Panhorst, University of Mississippi, Department of Geology and Geological Engineering. His advice and suggestions are appreciated. We particularly want to acknowledge the help of everyone at Talbot Brothers Construction and Grading of Nesbit, Mississippi. They gladly discussed with us their experience with excavating
-26- local materials and some of the complications they have encountered in and around the New Albany area. Our understanding of excavation issues were improved by these conversations. Mr. George Phillips of the Mississippi Museum of Natural Sciences, shared his outcrops with us and provided valuable advise throughout the project. Without exception, the local population wase generous and very willing to share local knowledge about exposures and fossil localities. This knowledge has led to a better geological map, made our work easier, and we are grateful.
REFERENCES CITED
Anderson, K.O. and Thomson, S., 1969, Modification of expansive soils of western Canada with lime, Proceedings of the Second International Research and Engineering Conference on Expansive Clay Soils, Texas A&M University, pp. 715 -182.
Aughenbaugh, N.B., 1987, Basic engineering properties of some northern Mississippi clay deposits: Mississippi Mineral Resources Institute, Open-file report 87-7F, 26p.
______, 1989, Engineering properties of Mississippi clays: Mississippi Mineral Resources Institute, Open-file Report 89-7F, 21p.
______, 1990, Clay composition of commercial clay deposits: Mississippi Mineral Resources Institute, Open-file Report 90-8F, 19p.
Bates, R.L. and J.A. Jackson, 1984, Dictionary of Geological Terms: The American Geological Institute, Anchor Books, New York, New York, 571 p.
Bergstrom, R.E., K. Piskin, and L.R. Follmer, 1976, Geology for planning in the Springfield- Decatur region, Illinois: Illinois State Geological Survey: Circular 497, 76 p.
Booth, D.C., and D.W. Schmitz, 1983, Economic minerals map of Mississippi: Mississippi Bureau of Geology / Mississippi Mineral Resources Institute, 1:500,000 scale, 1 sheet.
Childress, S. C., M. Bograd, and J.C. Marble, 1976, Geology and man in Adams County, Mississippi: Mississippi Office of Geology, Environmental Series No. 4, 188 p.
Conant, L.C. and T.E. McCutcheon, 1942, Union County mineral resources: Mississippi State Geological Survey, Bulletin 45, 158 p.
Dakshanamurty, V. and Raman, V., 1973, A simple method of identifying an expansive soil: Soils and Foundations, Japanese Society of Soil Mechanics and Foundation Engineering, v. 13, no. 1.
Dockery, D.T. III, 1996, Toward a revision of the generalized stratigraphic column of Mississippi: Mississippi Geology, V. 17, no. 1, pp. 1-9.
-27- Dockery, D.T. III, and D.E. Thompson, 2011, Geology of Mississippi: Kickapoo Press, Jackson, Mississippi, 685 p.
Green, J.W., and M. Bograd, 1973, Environmental geology of the Pocahontas, Clinton, Raymond, and Brownsville quadrangles, Hinds County, Mississippi: Mississippi Office of Geology, Environmental Geology Series, No. 1, 70 p.
Green, J.W., and S. C. Childress, 1974, Environmental geology of the Madison, Ridgeland, Jackson, and Jackson SE quadrangles, Hinds, Madison and Rankin Counties, Mississippi: Mississippi Office of Geology, Environmental Geology Series, No. 2, 64 p.
Mellen, F.F., 1958, Cretaceous shelf sediments of Mississippi: Mississippi State Geological Survey, Bulletin 85, 112 p.
Nichols, D.R., and L.A. Yehale, 1969, Engineering geologic map of the southeastern Copper River Basin: U.S. Geological Survey, Miscellaneous Geologic Investigations, Map I-524, 37p.
North American Commission on Stratigraphic Nomenclature, 2005, North American stratigraphic code, American Association of Petroleum Geologists, V. 89, no. 11, pp. 1547 – 1591.
Priddy, R.R. and T.E. McCutcheon, 1943, Pontotoc County mineral resources: Mississippi State Geological Survey, Bulletin 54, 139 p.
Ridgeway Data Center, 2011, unpublished scout card data contained in the petroleum files of the center, June, 2011.
Stephenson, L.W. and W.H. Monroe, 1940, The Upper Cretaceous deposits: Mississippi State Geological Survey, Bulletin 40, 296 p.
Swann, C.T., 2008, Summary of the investigation of the May 10, 2008, Belden, Mississippi earthquake, Pontotoc, Lee, and Union Counties Mississippi: Mississippi Mineral Resources Institute, Open-file Report 08-1S, 10 p.
Swann, C.T., F.S.M.R. Faruque, and J.L. Harding, 1995, The engineering and environmental geology of the Ripley, Mississippi area – A guide for small municipalities: Mississippi Mineral Resources Institute, Open-File Report 96-2S, 22 p.
Swann, C.T. and J.J. Dew, 2009, Geology of the Troy, Miss., 7.5 minute topographic quadrangle - Chickasaw and Pontotoc Counties Mississippi: Mississippi Mineral Resources Institute, Open-file Report 09-2S, 28p.
Vestal, F.E., 1946, Lee County Mineral Resources: Mississippi State Geological Survey, Bulletin 63, 140 p.
-28- Wheeler, R.C., 2011, Characterization of the engineering properties and economic potential of the transitional clay facies of the Ripley Formation, Northeast Mississippi: unpublished Master of Science thesis, Department of Geology and Geological Engineering, University of Mississippi, University, Mississippi, 86 p.
-29-
In Pocket Items:
Figure 2 – Geologic Map of the Blue Springs Area of MS 3-27-2012
Figure 10 – Engineering Geologic Map of the Blue Springs Area of MS 3-27-2012
Figure 12 – Mineral Resources Map of the Blue Springs Area of MS 3-27-2012
Full version of the above items are available at
http://mmri.olemiss.edu/Home/projects/docs/2011-03-30-006.aspx Figure 2
89°0'0"W 88°58'30"W 88°57'0"W R 3 E 88°55'30"W R 4 E 88°54'0"W 88°52'30"W 88°51'0"W R 4 E 88°49'30"W R 5 E 88°48'0"W 88°46'30"W 88°45'0"W 34°30'0"N 34°30'0"N Tcl 15 «¬ D «¬30 U
Qal U Kr D U Kr D New Albany «¬9 Kr Tcl
Kr 34°28'30"N 34°28'30"N
Koc/Kpb
Kd Qal ¨¦§22 £[78
Tcl U Qal D 34°27'0"N Qal 34°27'0"N Lee Co. Lee Union Co. Union Tcl
U D T 7 S Kr T 7 S
Qal 34°25'30"N U 34°25'30"N D U D
T 8 S Kd T 8 S Qal «¬9
Koc/Kpb Blue Springs 34°24'0"N Tcl 34°24'0"N
Qal
Toyota Motor Manufacturing, Mississippi Inc.
D ^ U ¨¦§22 £[78
Kr 34°22'30"N Kr 34°22'30"N Kd
Union Co. Pontotoc Co. Tcl Sherman
34°21'0"N 34°21'0"N Koc/Kpb
Qal Koc/Kpb T 8 S T 8 S «¬9
Qal
T 9 S T 9 S «¬9
34°19'30"N 34°19'30"N
¨¦§22 Kr [78 Tcl £ Pontotoc Co.
U Co. Lee D
Kr
34°18'0"N 34°18'0"N
Koc/Kpb
£[278 «¬6
Tupelo Qal «¬9 Qal 34°16'30"N 34°16'30"N
Qal Kr Tcl
U £[278 D «¬6
Qal Pontotoc
«¬6
34°15'0"N 34°15'0"N 89°0'0"W 88°58'30"W 88°57'0"W R 3 E 88°55'30"W R 4 E 88°54'0"W 88°52'30"W 88°51'0"W R 4 E 88°49'30"W R 5 E 88°48'0"W 88°46'30"W 88°45'0"W
EXPLANATION Scale 1:40000
Present flood plain deposits - Sand, silt, clay; complex set of Normal fault concealed: upthrown and downthrown blocks 0241 Qal Kr Ripley Formation fining upward cycles consisting of sand at base with silt and U indicated by “U” and “D” respectively. See Geology and Miles Upper Ripley Formation Geological Engineering Considerations for Urban and Quaternary clay overbank deposits D Sand; argillaceous, massive to poorly bedded, locally Economic Planning in the Blue Springs, Mississippi, Area for cross-bedded, coarse- to fine-grained, sparsely fossiliferous, more information. 0241 also includes discontinuous limestone; sandy, sparry, Kilometers Blue Springs, MS Clayton Formation Tcl phosphatic, fossiliferous (Chiwapa facies) Normal fault inferred: upthrown and downthrown blocks Sand; medium- to fine-grained, fossiliferous, glauconitic, indicated by “U” and “D” respectively. See Geology and Tertiary U micaceous, poorly bedded, lower section can be locally Geological Engineering Considerations for Urban and Ripley Formation / “Troy Beds” D coarse-grained Interbedded limestone, chalk, sand; limestone is sparry, Economic Planning in the Blue Springs, Mississippi, Area for more information. fossiliferous, sandy, chalk is argillaceous, sandy, fossiliferous, sand beds are fine-grained, calcareous, fossiliferous, often Koc / Kpb Owl Creek / Prairie Bluff Formation bioturbated Interbedded silt, clay, sand; medium-gray, fossiliferous, Cretaceous laminated to bedded, locally phosphatic and glauconitic; Ripley Formation / “Transitional Clay” Prairie Bluff Formation; marl; fossiliferous, phosphatic, Clay; dark to medium-gray, laminated to thinly bedded, contains fine-grained sand and argillaceous chalk in updip fossiliferous, locally sandy outcrop
Kd Demopolis Formation Marl, Chalk: Marls in top of section becoming chalks toward middle of section, massive to poorly bedded, fossiliferous, indurated, pyrite nodules in zones Geological Map of the Blue Springs Area of Mississippi Geology by Charles T. Swann, R.P.G. and Jeremy J. Dew, G.I.T. Mississippi Mineral Resources Institute Mississippi Mineral Resources Institute The University of Mississippi μ 2011 mmri.olemiss.edu [email protected] Figure 10
89°0'0"W 88°58'30"W 88°57'0"W R 3 E 88°55'30"W R 4 E 88°54'0"W 88°52'30"W 88°51'0"W R 4 E 88°49'30"W R 5 E 88°48'0"W 88°46'30"W 88°45'0"W 34°30'0"N 34°30'0"N
15 «¬ D «¬30 U
U U D D New Albany «¬9
34°28'30"N 34°28'30"N
¨¦§22 £[78
U D
34°27'0"N 34°27'0"N Lee Co. Lee Union Co. Union
U D T 7 S T 7 S
34°25'30"N U 34°25'30"N D U D
T 8 S T 8 S
«¬9
Blue Springs
34°24'0"N 34°24'0"N
Toyota Motor Manufacturing, Mississippi Inc.
D ^ U ¨¦§22 £[78
34°22'30"N 34°22'30"N
Union Co. Pontotoc Co. Sherman
34°21'0"N 34°21'0"N
T 8 S T 8 S «¬9
T 9 S T 9 S «¬9
34°19'30"N 34°19'30"N
¨¦§22 £[78 Pontotoc Co.
U Co. Lee D
34°18'0"N 34°18'0"N
£[278 «¬6
Tupelo
«¬9 34°16'30"N 34°16'30"N
U £[278 D «¬6
Pontotoc
«¬6 34°15'0"N 34°15'0"N 89°0'0"W 88°58'30"W 88°57'0"W R 3 E 88°55'30"W R 4 E 88°54'0"W 88°52'30"W 88°51'0"W R 4 E 88°49'30"W R 5 E 88°48'0"W 88°46'30"W 88°45'0"W
Scale 1:40000 EXPLANATION 0241 Expansive Soils Expansive Soil Zone Normal fault concealed: upthrown and downthrown blocks Miles Clays with subordinate sand content possessing high to An expansive soil zone formed above the chalks and marls of U indicated by “U” and “D” respectively. See Geology and medium swell potential. This area is a concern for the Demopolis. Soil zone is typically thin and can be removed D Geological Engineering Considerations for Urban and 0241 foundations and road beds. Additional engineering testing prior to construction. Additional testing is recommended to Economic Planning in the Blue Springs, Mississippi, Area for Kilometers Blue Springs, MS and design may be required prior to utilization. determine soil thickness. more information.
Excavation Costs Areas of few concerns Normal fault inferred: upthrown and downthrown blocks indicated by “U” and “D” respectively. See Geology and Clays and limestones with characteristics potentially making Areas where no geotechnical or environmental concerns U Geological Engineering Considerations for Urban and excavation more costly and time consuming. Clays can be were noted. Routine soil testing should identify any D unforeseen concerns. Economic Planning in the Blue Springs, Mississippi, Area for hard, tough, difficult to remove without heavy equipment. more information. Limestone is discontinuous and varies from 0 to 50 feet in thickness. Individual beds seldom more than five feet thick, but may be multiple beds. Typically breaks into large pieces which must be reduced in size to remove. Additional testing is recommended.
Flood Prone Area Flat areas bordering streams that are formed by flood events. Soils typically fine-grained. See http://www.fema.gov/hazard/map/flood.shtm for detailed flood maps regarding specific areas. Engineering Geologic Map of the Blue Springs Area of Mississippi Geology by Charles T. Swann, R.P.G. and Jeremy J. Dew, G.I.T. Mississippi Mineral Resources Institute Mississippi Mineral Resources Institute The University of Mississippi μ 2011 mmri.olemiss.edu [email protected] Figure 12
89°0'0"W 88°58'30"W 88°57'0"W R 3 E 88°55'30"W R 4 E 88°54'0"W 88°52'30"W 88°51'0"W R 4 E 88°49'30"W R 5 E 88°48'0"W 88°46'30"W 88°45'0"W 34°30'0"N 34°30'0"N Tcl 15 «¬ D «¬30 U
U U D D New Albany «¬9
34°28'30"N 34°28'30"N
¨¦§22 £[78
U D
34°27'0"N 34°27'0"N Lee Co. Lee Union Co. Union
ª#1 Woodson U D #1 Nabors T 7 S U ª D T 7 S
Cullet #1-A 34°25'30"N ª 34°25'30"N U D
T 8 S T 8 S
«¬9
Blue Springs
34°24'0"N 34°24'0"N
Toyota Motor Manufacturing, Mississippi Inc.
D ^ U ¨¦§22 £[78
34°22'30"N 34°22'30"N
Union Co. Pontotoc Co. Sherman
34°21'0"N 34°21'0"N
T 8 S T 8 S «¬9
T 9 S T 9 S «¬9
34°19'30"N 34°19'30"N
¨¦§22 £[78 Pontotoc Co.
U Co. Lee D
34°18'0"N 34°18'0"N
£[278 «¬6
Tupelo
«¬9 34°16'30"N 34°16'30"N
U £[278 D «¬6
Pontotoc
«¬6
34°15'0"N 34°15'0"N 89°0'0"W 88°58'30"W 88°57'0"W R 3 E 88°55'30"W R 4 E 88°54'0"W 88°52'30"W 88°51'0"W R 4 E 88°49'30"W R 5 E 88°48'0"W 88°46'30"W 88°45'0"W
Scale 1:40000
0241 EXPLANATION Miles
Sand Resources Normal fault concealed: upthrown and downthrown blocks 0241 Fine to medium-grained, quartz sand. Sands are U indicated by “U” and “D” respectively. See Geology and Geological Engineering Considerations for Urban and Kilometers Blue Springs, MS unconsolidated, often with a clay matrix and may be iron-rich D in weathered outcrop. Currently utilized for foundation or Economic Planning in the Blue Springs, Mississippi, Area for road fill. more information.
Clay Resources Normal fault inferred: upthrown and downthrown blocks indicated by “U” and “D” respectively. See Geology and Dark to medium-gray clay. Clay is often fossiliferous U D Geological Engineering Considerations for Urban and (calcareous) and expansive. Currently not utilized but may Economic Planning in the Blue Springs, Mississippi, Area for have use as absorbent or brick clay. more information.
Chalk Resources Hydrocarbon test well (dry hole) Low permeability chalk and marl is potentially useful for W underground product storage, a raw material for cement, and as industrial sites where low permeability is desirable. Not presently utilized in field area.
Mineral Resources Map of the Blue Springs Area of Mississippi Geology by Charles T. Swann, R.P.G. and Jeremy J. Dew, G.I.T. Mississippi Mineral Resources Institute Mississippi Mineral Resources Institute The University of Mississippi μ 2011 mmri.olemiss.edu [email protected]