Tyson Research Center is located in a rugged part of the Ozark border that is primarily underlain by Paleozoic carbonate units that dip approximately 1 degree to the northeast. Significant aquifers are the Meramec River alluvium, Mississippian limestone, and the Ordovician carbonates, but the St. Peter Sandstone is the most important source of potable water in the immediate area. Numerous springs emanate from the Burlington-Keokuk Limestone, from near the Fern Glen-Bushburg contact, and from the Kimmswick and Plattin Limestones. Karst features including springs, losing and disappearing streams, sinkholes and caves are well developed in the Burlington-Keokuk, Kimmswick and Plattin Limestones, demonstrating their high groundwater transmissivity.
Rapid vertical transport of groundwater between the Kimmswick, Decorah and Plattin formations has been reported nearby and likely also occurs in the southern part of Tyson Research Center as suggested by field data. Oxygen isotope and chemical data on various waters in the area are in some cases useful in tracing subsurface flow paths, and strongly suggest links between ponds and lakes in Lone Elk Co. Park and two springs. Field data suggest that TRC Cave and Bluegrass Spring are interconnected. The UTM northing and easting coordinates on the USGS Manchester topographic quadrangle are based on the NAD 27 datum and differ from the newer, widely used NAD 83/WGS 84 datum by being about 212 m lower and 16 m higher.
Burlington-Keokuk formations - (Mississippian; Thickness ~200 ft.) Coarsely crystalline, light gray crinoidal limestone with abundant nodules, beds and masses of white porcellaneous chert. Weathers to terra rossa clay and resistant chert soil residuum. Occurs to the northeast of the Burlington escarpment. A good exposure of the Burlington Limestone occurs on the SE side of the I-44 overpass at the Antire Road exit (Exit 269).
Fern Glen Limestone - (Mississippian; Thickness 35-60 ft.) Reddish to yellowish gray, thin bedded to massive, fine to medium grained argillaceous limestone and interbedded shales, with abundant fossils, stylolites and chert. A good exposure of the contact between the lower Fern Glen and the Bushburg Sandstone is on the north side of I-44 (Mile 268.8; see Thompson and Robertson, 1993, p. 148-9.)
Bushburg Sandstone - (Devonian; thickness 20-50 ft.) Friable, orangeish-tan, medium grained, massive to cross-bedded sandstone. Thickness variable; deposited on pronounced unconformity. Important and highly distinctive marker bed in the TVPF area. Map unit includes the underlying Glen Park formation and the overlying Bachelor formation (Mississippian), which are thin and discontinuous limestones, shales and sandstones in the TVPF area. Good exposures of the Bushburg are at Bunkers 12, 14, and 49 at TRC, and also at Mile 268.8 (see above).
Kimmswick Limestone - (Ordovician; Thickness 65-110 ft.) Light gray, coarsely crystalline, massive, sparsely fossiliferous limestone; Fisherites (formerly, Receptaculites) is diagnostic to the Kimmswick in this area. Cliff former, cavernous in places. Easily distinguished by the abundant, golf-ball sized pits in weathered surfaces. An excellent exposure is in the Mincke Hollow quarry-cave (Sec 28Aa). Depke (1973) includes the thin overlying Maquoketa Shale (Ordovician) in this map unit. Decorah Group (Ordovician; Thickness 25 ft.) Interbedded greenish-gray shales, limestones and coquinas. Highly fossiliferous in places, with some parting surfaces being almost completely covered with brachiapods and bryozoans. In the lower part of the group are two distinctive, ca. 6-8" thick beds of bentonite that are ~6 feet apart. A fine exposure of the Decorah Group and the underlying upper Plattin Limestone is on the north side of I-44 (Mile 268.2; see Thompson and Robertson, 1993, p. 147-8).
Plattin Limestone - (Ordovician; Thickness 110 ft.) Gray, medium bedded to massive, sublithographic limestone, commonly with conchoidal fracture. Abundant burrows produce a mottled surface on fresh exposures, and distinctive, cm-sized pits on weathered surfaces. Fossiliferous in lower section, particularly the thin, dark gray "Establishment Shale" member. Good exposures of the upper and lower parts of the Plattin respectfully occur along I-44 at Mile 268.1 and 267.0; see Thompson and Robertson, 1993, p. 145-8)
Joachim Limestone - (Ordovician; Thickness 140 ft.) Yellow-brown to gray, medium to wavy bedded, fine grained, argillaceous dolostone, massive in uppermost part. Basically unfossiliferous except for stromatolitic structures in upper part. A good exposure of stromatolitic structures in the upper Joachim is on the north frontage road at the Lewis Road exit (I-44 Exit 267; see Thompson and Robertson, 1993, p. 145-6).
St. Peter Sandstone - (Ordovician; Thickness 75-125 ft.) Massive to cross-bedded, friable white sandstone composed of very pure, well sorted quartz grains. Gray on weathered surfaces, occasionally with local limonite staining. The St. Peter Sandstone is an important aquifer in the TVPF but the unit does not crop out within the legal boundaries. The closest outcrop is in the southwestern corner of the Manchester quadrangle (Sec. 31B; see Depke, 1973); but the unit passes below sea level beneath eastern Lone Elk County Park (Fig. 3). Excellent exposures of the St. Peter Sandstone occur in the cliffs and glass sand mines along Business I-44 in Pacific, Missouri (Thompson and Robertson, 1993, p.131-3).