SOUTHERN AND CENTRAL APPALACHIANS 



119 



ENGLISH MTN 



Chilhowee gr 

 v\ ^ Cochron SonasucA 



GftEAT SMOKY PITS (COST END) 



SECTION 5A 





Fig. 8.27. Northeast part of Great Smoky Mountains and adjacent foothills on north. 

 After P. B. King, 1950a. The Great Smoky conglomerate, the Nantahala slate, the Pigeon 

 siltstone, and the Sandsuck shale, are part of the Ocoee series (Late Precambrian) which 

 forms most of the Great Smokies. The Cochran conglomerate is basal Cambrian. For location 

 see Fig. 8.22. 



Infolded Belts of Metasedimentary Rocks 



Besides the gneisses, the metamorphic and plutonic belt contains other 

 metamorphic rocks that are clearly of sedimentary origin. These characteristi- 

 cally form narrow belts or bands of considerable linear extent. The principal 

 belts of metasedimentary rocks are: 



1. The Arvonia slate belt, near the James River, and the Quantico slate belt, 

 near the Potomac River, in Virginia. These are synclines of fossiliferous Ordovi- 

 cian rocks, lying uncomformably on older schists and granites. 



2. A belt of quartzite, schist, and marble in North and South Carolina, which 

 has been mapped by Keith (1931) in the Kings Mountain area. Further details 

 have been given by Kesler (1944), whose interpretations differ from those of 

 Keith. 



3. The Brevard schist belt [Figs. 7.1 and 8.30], which is by far the longest, 

 and extends from central North Carolina through South Carolina, Georgia, and 

 Alabama to the Gulf Coastal Plain. Jonas (1932) states that similar rocks con- 

 tinue northeastward from central North Carolina into southern Virginia. The 

 rocks of the Brevard belt consist of contorted dark slates and schists, with 

 lenses of limestones, apparently of a somewhat lower grade of metamorphism 

 than the rocks which flank them on either side. 



4. The Murphy marble belt of western North Carolina and Northwest 

 '■ Georgia (Fig. 8.22), has many features similar to the others just described, but 



differs in that it is not flanked by crystalline rocks, but by altered sedimentary 

 i rocks of the Ocoee series. 



No fossils have been found in the belts south of Virginia and the age of the 

 ! rocks which compose them is unknown. They have been variously assigned to 



the Paleozoic and the Precambrian (King, 1950a). 



Carolina Slate Belt 



In the southeast part of the Piedmont province, highly metamorphosed 

 rocks give place to less metamorphosed sedimentary and volcanic rocks 

 which make up the Carolina slate belt (Fig. 7.1). Granite intrusions are 



present, but they appear to be small and widely scattered and also cross- 

 cutting rather than concordant. The most extensive rock unit is the 

 "volcanic series." It is composed of flows, breccias, and bedded tuffs of 

 volcanic origin with some interbedded slates and sandstones. To the 

 southwest in southwestern Georgia and northeastern Alabama is the 

 shorter and narrower Pine Mountain belt. It is composed of quartzite, 

 marble, and schist clearly of sedimentary origin and intruded bv a 

 gneissic granite. The beds are broadly rather than steeply folded. The 

 age of both the rocks of the Carolina slate belt and the Pine Mountain 

 belt is uncertain; they have been assigned to both the Precambrian and 

 Paleozoic. 



Paleozoic of Florida 



Within the area embracing northern Florida and adjacent parts of 

 southern Alabama and Georgia, recent drilling has shown that the Meso- 

 zoic rocks are underlain by volcanic rocks and by sedimentary rocks of 

 Paleozoic age (Applin, 1949). 



In the Ocala uplift, pre-Mesozoic rocks are reached in places at depths 

 of less than 4000 feet, but elsewhere they may lie as much as 10,000 

 feet below the surface. Penetration of the pre-Mesozoic rocks has not 

 been sufficient to establish a sequence; in other words, different rock 

 types have been found in different wells, but have not been found in 

 superposition. 



The sedimentary rocks are mainly sandstones and shales. Some of the 

 sandstones contain worm tubes of Scolithus type, not unlike those found 

 in the older Paleozoic rocks of the Appalachians; others contain large 

 quantities of detrital mica. The shales are gray, black, and even red. 

 Graptolites have been found in places, as well as various other fossils. 

 The only Paleozoic systems whose existence has been definitely proved 

 paleontologically are the Ordovician and Silurian, although others might 

 be present. The volcanics may be related to the "volcanic series" of the 

 southeast part of the Piedmont area, but like this series, their age has 

 not been established. 



Well cores show that these rocks are little deformed. Metamorphic 

 effects, such as cleavage and recrystallization, are lacking. Bedding dips 



