DEPARTMENT OF THE INTERIOR TO ACCOMPANY MAP MF-1470 UNITED STATES GEOLOGICAL SURVEY MINERAL RESOURCE POTENTIAL OF THE SAVANNAH ROADLESS AREA, LIBERTY COUNTY, FLORIDA By Sam H. Patterson1, Walter Schmidt2, and Thomas M. Crandall3 resource potential is reduced by the thickness of overburden STUDIES RELATED TO WILDERNESS above it and by its distance from markets in population centers. The Apalachicola National Forest has been explored Under the provisions of the Wilderness Act (Public Law for phosphate and reconnoitered for heavy minerals, but no 88-577, September 3, 1964) and the Joint Conference Report valuable deposits of either have been found. on Senate Bill 4, 88th Congress, the U.S. Geological Survey and the U.S. Bureau of Mines have been conducting mineral INTRODUCTION surveys of wilderness and primitive areas. Areas officially designated as "wilderness," "wild," or "canoe" when the act The Savannah Roadless Area lies in the Big Bend was passed were incorporated into the National Wilderness region of the Florida panhandle (fig. 1). The area can be Preservation System, and some of them are presently being reached by traveling about 6 mi northwest from the village studied. The act provided that areas under consideration for of Sumatra on County Highway 379. Sumatra, in southern wilderness designation should be studied for suitability for Liberty County, is located at the junction of County Highway incorporation into the Wilderness System. The mineral 379 and Florida Highway 65. The Savannah Roadless Area is surveys constitute one aspect of the suitability studies. The a three-sided tract of 1,944 acres bounded by County act directs that the results of such surveys are to be made Highway 379 on the southwest and by Forest Service roads ll5 available to the public and be sublnitted to the President and on the northwest and 123 on the southeast. The area is very the Congress. This report discusses the results of a mineral gently undulating; altitudes range from a maximum of 43 ft survey of the Savannah Roadless Area in the Apalachicola at the northern corner of the area to a low of about 25 ft National Forest, Liberty County, Florida. The Savannah where small intermittent streams cross the southwestern Roadless Area was classified as a further planning area boundary. Compared to much of the land in the surrounding (Forest Service number (08009) during the Second Roadless region the area is well drained. None of the swamps in the Area Review and Evaluation (RARE II) by the U.S. Forest roadless area that ¥e shown on the map (fig. 2, mineral Service, January 1979. resource potential map) contain standing water in the dry season. About half of the area is open grassland, which is the basis for the name Savannah. The other half is irregularly SUMMARY covered by open pine-palmetto forest. The Savannah Roadless Area is underlain by Previous Investigations sedimentary rocks having low potential for oil and gas and minerals. The low potential for oil or gas notwithstanding, No detailed geologic studies had been made in Liberty the possibilities for discovery cannot be ruled out because the County prior to thorough investigations by the Florida Bureau area and nearby lands have not been thoroughly explored. No of Geology that were begun with a drilling program in the minerals have been mined within the Savannah Roadless Area, summer of 1981. Crystalline rocks at depth in the region are and the only production nearby has been the digging of clayey discussed by Milton (1972) and outlined by Puri and Vernon sand used in stabilizing U.S. Forest Service roads. Fuller's (1964, plate l). Schmidt and Clark (1980) presented the results earth, quartz sand and gravel, clayey sand, and common clay of a thorough study of the geology of Bay County, Fla., which presently are produced elsewhere in the region, and limestone is about 20 mi west of the Savannah Roadless Area, and and peat have been produced in the past. No clay suitable for Hendry and Sproul (1966) outlined the geology of Leon County structural clay products or fuller's earth is present in the to the northeast of the area. Some information on the roadless area; however, a bed of quartz sand and gravel of stratigraphy of the region is contained in publications excellent quality was penetrated at a depth interval of 37-50 covering the entire state by Puri and Vernon (1964) and Chen ft by one drill hole. Although this bed is coarser grained-and (1965). A report by Applegate, Pontigo, and Rooke (1978) therefore is more suitable for many uses-than the sand summarizes information on the oil and gas potential of the deposits worked elsewhere in the Big Bend region, its mineral Big Bend region. 1u.s. Geological Survey ;Florida Bureau of Geology U.S. Bureau of Mines 1 31" 0 INDEX MAP OF FLORIDA. 0 50 100 MILES I I I I I 0 50 100 KILOMETERS 0 .,' ~~\§ ... 4' Key West @!'0 1}5 Figure 1.-Location of the Savannah Roadless Area, Liberty County, Fla. 2 rarely more than a foot thick. It consists chiefly of slightly Present Investigation clayey sand containing minor amounts of organic matter and root remains. Surficial soil is underlain by a blanket of Patterson reviewed the published information on the Pleistocene and Holocene unconsolidated sand, gravel, and geology of the Apalachicola National Fm·est, reconnoitered clay about 60 ft thick. The underlying Pliocene Jackson Bluff the region, and searched reports and records of the Florida Formation, which is the uppermost bedrock unit, also extends Bureau of Geology for information on oil and gas in the spring over the entire area. It, in turn, is underlain by a thick of 1980. Crandall, assisted by Frederick W. Miller of the U.S. sequence of older rocks described in the following sections. Bureau of Mines, investigated the area in February 1981. During this work soils were probed with an auger at several Stratigraphy places to make certain that no peat deposits are present. Crandall also obtained information on surface- and mineral­ Igneous, metamorphic, and sedimentary rocks ranging rights ownership from the records of the U.S. Forest Service in age from Precambrian to early Mesozoic are almost and the U.S. Bureau of Land Management. In a joint program certainly present at depth in the Savannah Roadless Area. A of the U.S. Geological Survey and the U.S. Bureau of Mines, well drilled offshore about 43 mi southeast of the area one hole was drilled in the Savannah Roadless Area and one in intersected 10 ft of diabase at a depth of 10,460 ft (Milton, the Mud Swamp-New River Roadless Area in October 1980. 1972, p. 31). This diabase is overlain by pinkish quartzitic Cores anq cuttings were logged at the drill hole sites and sandstone and underlain by diabase fragments admixed with samples were collected and later investigated in the sandstone. Sills or dikes of mafic igneous rock have been laboratory. Schmidt supervised the drilling program of the found in Triassic sedimentary rocks penetrated by a few dry Florida Bureau of Geology and correlated the rocks holes in the region (Applegate, Pontigo, and Rooke, 1978, p. penetrated, providing much of the information on which 81). One dry hole 20 mi west of the Savannah Roadless Area figure 3 and discussion in the text are based. passed into an arkose (F. A. Pontigo, oral commun., 1981). : Information on dry holes given in this report is based Another dry hole about 15 mi northwest of the area primarily on published reports and records on file in the penetrated quartzite and metamorphosed shale of probable Florida Bureau of Geology. The term "dry hole" is used Paleozoic age. The Hunt Oil Co. dry hole 20 mi south of the according to the definition meaning no significant amounts of roadless area penetrated a Precambrian granite (F. A. oil or gas were found. Pontigo, oral commun., 1981). No geochemical survey was necessary during the work leading to this report becaus.e: l) stream-sediment and soil Mesozoic Era sampling would have yielded no information of value in appraising the nonmetallic mineral potential of the area; and Mesozoic strata in the Apalachicola embayment have a 2) the metallic and other heavy minerals occurring in strata total thickness of about 10,000 ft. They generally extend near the surface are not in sufficient concentrations to form from 3,000 ft to about 13,000 ft below sea level, and include valuable mineral deposits. rocks of Triassic, Jurassic, and Cretaceous age. Triassic rocks consist of indurated micaceous Acknowledgments sandstone and shale that are commonly red. Triassic beds exceed 1,950 ft in thickness in southeastern Leon County, The authors are grateful for the cooperation of the about 50 mi east-northeast of the Savannah Roadless Area. Florida Bureau of Geology, the U.S. Forest Service, and the Five major stratigraphic units of Jurassic age occur in U.S. Bureau of Land Management. David Curry and Felipe A. the region. The lowermost, the Louann Formation, is Pontigo, Jr. of the Florida Bureau of Geology aided in irregularly distributed and consists of salt and anhydrite. One gathering information on oil and gas. Tim Smith and Larry dry hole located 6 mi east-northeast of the Savannah Thornton of the Apalachicola Ranger District, Apalachicola Roadless Area bottomed in salt after penetrating 34 ft National Forest, provided maps and storage facilities for (Applegate, Pontigo, and Rooke, 1978, p. 82), but the drilling equipment and samples. U.S. Forest Service formation is known to be much thicker farther east. The personnel-William R. Waite, soil scientist, Forest Supervisors overlying Norphlet Formation is mainly red sandstone, Office, Tallahassee, Fla.;· James Hart, soil scientist, Wakulla siltstone, and shale that has a total thickness ranging from 0- Ranger District, Crawfordville, Fla.; and Edward W.