Silurian-Devonian pelecypods and Paleozoic stratigraphy of subsurface rocks in Florida and Georgia and related Silurian pelecypods from Bolivia and Turkey

Abstract

The subsurface sedimentary Paleozoic rocks beneath northern Florida and adjacent parts of Georgia and Alabama comprise a .sequence of quarlzitic sandstones and micaceous shales, dark-gray shales, and red and gray siltstones ranging in age from Early Ordovician to Middle Devonian. The Silurian-Devonian pelecypod faunas from four wells (three of which, the Ragland, Cone, and Tillis wells, are in Florida, and one of which, the Chandler, is in Georgia) are described and illustrated. Also described are Silurian pelecypods from one locality in Bolivia and one in Turkey. Biostratigraphically, the faunas from the American wells range in age from Wenlockian or Ludlovian (Silurian) to Middle Devonian; the Bolivian specimens are probably Ludlovian (Late Silurian); and the Turkish specimens are probably Wenlockian or Ludlovian (Silurian). Paleoecologically, the strata in the American wel1s represent shallowwater normal marine environments, and all pelecypods known from them belong to one of three life-habit groups-'byssally attached, burrowing, or reclining. The Bol,ivian and Turkish pelecypods likewise belong only to these three life-habit groups. Analysis of the geograpMc distribution of the Florida Paleozoic pelecypod genera shows that they are closest to the forms found in central Bohemia and Poland; elements of this fauna also occur in Nova Scotia, North Mrica, and South America.

The Grenville orogenic cycle of southern Laurentia: Unraveling sutures, rifts, and shear zones as potential piercing points for Amazonia

“…Characteristics of Paleozoic sutures of the Appalachian orogen: Accreted-terrane sutures and the suture between Laurentia and the West Africian craton Speculation that a piece of Africa remained attached to Laurentia after opening of the Atlantic Ocean developed from paleontological (e.g., Cramer, 1973;Pojeta et al, 1976;Chowns and Williams, 1983), paleomagnetic (Opdyke et al, 1987) and geochronologic evidence (e.g., Dallmeyer, 1987Dallmeyer, , 1989aDallmeyer, , 1989b. Confirmation of a suture between the West African craton and Laurentia ( Fig.…”

“…With application of plate-tectonic models to the Appalachians (e.g., Bird and Dewey, 1970;Hatcher, 1972) came the realization that rifted or marginal fragments along the eastern geographic part of the Grenville orogen were involved in Appalachian orogensis. Some other older Precambrian fragments, including much of northern and central Florida and southernmost Georgia and Alabama, are now known to be pieces of Africa (e.g., Pojeta et al, 1976;Mueller et al, 1994).…”

Devonian miospores of North America

“…However, generally available palynological information is sparse from many of the areas in which spore-bearing strata occur, e.g. eastern Greenland (Friend et al, 1976); the Grand Banks (GSC files); Maine (Andrews etal., 1972;Schopf, 1964); the subsurface of Florida, Alabama and Georgia (Pojeta et al, 1976;McLaughlin, 1970;Carrington, 1972) southern Ontario (McGregor, 1961; GSC files); Manitoba (GSC files); Wyoming and Montana (Brush, 1966;Sandberg, 1965Sandberg, , 1967; Yukon and western District of Mackenzie (Audretsch, 1968;McGregor and Owens, 1966;McGregor, 1969;Staplin and Jansonius, 1964;Norris, 1968); and eastern Alaska (Scott and Doher, 1967). Some significant studies remain unpublished, e.g.…”

Untitled

“…The Appalachians and all other crustal blocks in the subsurface of Alabama are truncated along the boundary with the Suwannee terrane, a huge mass of Gondwanan crust sutured to the Laurentian margin and left orphaned here as the modern Gulf of Mexico (Early Jurassic) and Atlantic oceans (Early Triassic) began to form (Applin, 1951;Barnett, 1975;Neathery and Thomas, 1975;Pojeta et al, 1976;Chowns and Williams, 1983;Horton et al, 1984Horton et al, , 1989Horton et al, , 1991Guthrie and Raymond, 1992). The discovery in the late 1950s of Lower Ordovician through Devonian sedimentary rocks containing Gondwanan faunal assemblages from exploration wells penetrating the pre-Jurassic basement (here meaning either or both Gondwanan and crystalline Appalachian basement) beneath Gulf Coastal Plain sedimentary rocks in south Alabama (Applin, 1951) was a critical piece of the puzzle that Wilson needed to help solidify his thoughts on cycles of ocean basins opening and closing and continents colliding.…”