nonfuel mineral value, followed by cement ($110 million), and stone ($118 mil- 

 lion). The total value of crude oil, natural gas liquids, and natural gas was 

 $709,053,000, about 39% of the value of all minerals mined. In terms of the 

 State's economy, the principal mineral products in order of value are phos- 

 phate rock, crude petroleum, and limestone. 



Northwest Florida, located on the northeastern edge of the Gulf of Mexico 

 coastal oil reserves, has several oil wells in production in Santa Rosa County 

 and northern Escambia County. Although offshore exploration in the Destin 

 Dome (approximately 40 miles southwest of Panama City) has not yielded any 

 important finds, the potential still exists for substantial offshore produc- 

 tion. 



The seven-county area of Northwest Florida has produced few minerals 

 (mostly sand, gravel, titanium ores, and magnesia) until the relatively recent 

 inland oil and gas find in Santa Rosa and Escambia Counties. There have been 

 no important OCS oil and gas discoveries; consequently, much of the data and 

 observation on OCS oil and gas exploration and development in this chapter is 

 generic and relevant to western Florida as a whole. 



REGIONAL GEOLOGY 



INLAND 



Florida has a land area of over 151,800 km^ (58,600 mi^), and is the 

 second largest state in the Southeast. It lies entirely within the coastal 

 plain province, a major physiographic division of the United States. It is 

 underlain by sedimentary rock with a thickness of more than 1,200 m (4,000 

 ft). The surface mantle over much of the State is composed of oils and sands 

 up to 61 m (200 ft) deep (Calver 1957). The location and variety of mineral 

 deposits and industries in Florida are shown in Figures 1 and 2. 



The counties in Northwest Florida are underlain by a thick sequence of 

 sedimentary formations. The oldest formation is the Hatchetigbee Formation 

 (Wilcox Group, early Eocene) consisting primarily of clay, with some shale, 

 siltstone, and shaly limestone. The formation averages 96 m (315 ft) and 

 slopes from a depth of over 820 m (2,700 ft) at the Alabama/Florida State 

 line, to less than 305 m (1,000 ft) in the eastern part of the region (Marsh 

 1966). 



The physiography of Northwest Florida is divided into coastal lowlands 

 and uplands. The uplands portion is comprised primarily of gently rolling 

 areas called "sand hills" because of their marine origin (The Planning Design 

 Group et al . 1977). The basic geology of the region consists of relatively 

 young sedimentary formations and most of the coastal lowlands are covered by 

 unconsolidated marine and estuarine terrace deposits of the Pleistocene. 



Oil and gas reservoirs in Northwest Florida may be attributed to the 

 Smackover Formation of Jurassic age. The depth of this formation is about 

 4,633 m (15,200 to 15,300 ft). There are three producing fields and one 

 plugged field in Escambia and Santa Rosa Counties. The largest of these is 

 the Jay-Little Escambia Creek field. 



134 



