Hawthorn Group, Peace River Formation, Bone Valley Member

The Bone Valley Member (originally the Bone Valley Formation of Matson and Clapp, 1909), Peace River Formation occurs in a limited area on the southern part of the Ocala Platform in Hillsborough, Polk and Hardee Counties. Throughout its extent, the Bone Valley Member is a clastic unit consisting of sand-sized and larger phosphate grains in a matrix of quartz sand, silt and clay. The lithology is highly variable, ranging from sandy, silty, phosphatic clays and relatively pure clays to clayey, phosphatic sands to sandy, clayey phosphorites (Webb and Crissinger, 1983). In general, consolidation is poor and colors range from white, light brown and yellowish gray to olive gray and blue green. Mollusks are found as reworked, often phosphatized casts. Vertebrate fossils occur in many of the beds within the Bone Valley Member. Shark's teeth are often abundant. Silicified corals and wood are occasionally present as well. The Bone Valley Member is an extremely important, unique phosphate deposit and has provided much of the phosphate production in the United States during the twentieth century. Mining of phosphate in the outcrop area began in 1888 (Cathcart, 1985) and continues to the present.
State Florida
Name Hawthorn Group, Peace River Formation, Bone Valley Member
Geologic age Miocene/Pliocene
Lithologic constituents
Major
Unconsolidated > Fine-detrital > ClayThe lithology is highly variable, ranging from sandy, silty, phosphatic clays and relatively pure clays to clayey, phosphatic sands to sandy, clayey phosphorites. In general, consolidation is poor and colors range from white, light brown and yellowish gray to olive gray and blue green.
Unconsolidated > Coarse-detrital > SandThe lithology is highly variable, ranging from sandy, silty, phosphatic clays and relatively pure clays to clayey, phosphatic sands to sandy, clayey phosphorites. In general, consolidation is poor and colors range from white, light brown and yellowish gray to olive gray and blue green.
Sedimentary > Chemical > PhosphoriteClastic unit consisting of sand-sized and larger phosphate grains in a matrix of quartz sand, silt and clay. The lithology is highly variable, ranging from sandy, silty, phosphatic clays and relatively pure clays to clayey, phosphatic sands to sandy, clayey phosphorites (Webb and Crissinger, 1983). In general, consolidation is poor and colors range from white, light brown and yellowish gray to olive gray and blue green. The Bone Valley Member is an extremely important, unique phosphate deposit and has provided much of the phosphate production in the United States during the twentieth century. Mining of phosphate in the outcrop area began in 1888 (Cathcart, 1985) and continues to the present.
Minor
Unconsolidated > Fine-detrital > SiltThe lithology is highly variable, ranging from sandy, silty, phosphatic clays and relatively pure clays to clayey, phosphatic sands to sandy, clayey phosphorites. In general, consolidation is poor and colors range from white, light brown and yellowish gray to olive gray and blue green.
References

Scott, T.M., Campbell, K.M., Rupert, F.R., Arthur, J.D., Missimer, T.M., Lloyd, J.M., Yon, J.W., and Duncan, J.G., 2001, Geologic Map of the State of Florida, Florida Geological Survey & Florida Department of Environmental Protection, Map Series 146, scale 1:750,000.

Scott, Thomas M.P.G. #99, Text to Accompany the Geologic Map of Florida, Open-file Report 80, Florida Geological Survey, 2001.

Matson, G.C. and Clapp, F.G., 1909, A preliminary report on the geology of Florida: Florida Geological Survey Second Annual Report, p. 23-173, 1 plate.

Webb, S.D., and Crissinger, D.B., 1983, Stratigraphy and vertebrate paleontology of the central and southern Phosphate District of Florida: in Central Florida Phosphate District, Geological Society of America, Southeast Section Field Trip Guidebook, p. 28-72.

Cathcart, J.B., 1985, Economic geology of the Land-Pebble Phosphate District of Florida and its southern extension: in Cathcart, J.B., and Scott, T.M., eds., Florida Land-Pebble Phosphate District: Geological Society of America Annual Meeting, Orlando, Florida, field trip guidebook, p. 4-27.

NGMDB product
Counties Hardee - Hillsborough - Manatee - Polk