Correlation of Silurian Strata Between Georgia, Alabama, and Florida Based on Chitinozoan Biostratigraphy: ABSTRACT

Abstract

Silurian chitinozoans have been described previously from 4 wells in north-central Florida. These wells also have been correlated previously with each other as well as with known Silurian sections. The youngest assemblage is of Ludlovian age; the oldest is of late Llandoverian age. Outcrop samples were collected from the Silurian Red Mountain Formation in Alabama and Georgia. This formation has been dated as Llandoverian on the basis of megafossil evidence. Four Red Mountain Formation sections are divided into biostratigraphic zones on the basis of chitinozoan assemblages. Attempts at correlating the well and outcrop samples on the basis of frequency of chitinozoan taxa proved unsuccessful, because only a few taxa are abundant throughout the sections. Instead, correlations are made on the first or last occurrence of certain taxa. A comparison of the assemblages in the oldest (Ludlovian) Florida well section and the youngest (late Llandoverian) Red Mountain Formation section indicates that they have only 2 taxa in common. A comparison between the other parts of the Florida and Alabama-Georgia sections was not feasible because of the great age differences. The general aspect of the Florida assemblages is quite different from those in Georgia and Alabama. It is concluded that the sections in Georgia and Alabama are of ages different from those in Florida. The rocks are not different faunal facies of isochronous strata because chitinozoans are planktonic and are therefore not lithofacies dependent. One problem encountered in this study was that 3 wells did not penetrate very deeply into Silurian strata. Three of the Florida wells only penetrated the Upper Silurian, and only one went as deep as the Lower Silurian. Future work in correlating the Silurian rocks from these 3 states must depend on new wells being drilled to greater depths. End_of_Article - Last_Page 1784------------