SEQUENCE STRATIGRAPHY OF A SOUTH FLORIDA CARBONATE RAMP AND BOUNDING SILICICLASTICS (LATE MIOCENE-PLIOCENE)

METHODS

A total of 89 coreholes and cuttings from 18 test wells were used to map lithostratigraphic boundaries and to develop facies associations and sequence stratigraphy (Fig. 1). The cuttings were described using a binocular microscope. Descriptions of the cores are from Causaras (1985), Causaras (1987), Fish (1988), Fish and Stewart (1991), McNeill et al. (1996), Missimer (1997), Weedman et al. (1997), Cunningham et al., (1998), Edwards et al., (1998), Guertin (1998), Weedman et al. (1999), Reese and Cunningham (2000, in press), and from the data archives of the Florida Geological Survey and U.S. Geological Survey. Co-authors David Bukry and Tokiyuki Sato identified coccolith taxonomy, and John Barron determined diatom taxonomy. Bukry and Barron conducted identifications by standard U.S. Geological Survey methods. Sato identified coccoliths for each sample by counting 200 nannofossil specimens for quantitative analysis. The terms abundant (greater than 32 percent of specimens in total assemblage), common (32 to 8 percent of specimens in total assemblage), rare (less than 8 percent of specimens in total assemblage) and present (found but not counted)were used to describe quantitatively coccolith populations defined by Sato. Coccolith taxonomy has been assigned to the biostratigraphic zones of Okada and Bukry (1980) as calibrated to the coccolith datums of ODP Leg 171 B from the Blake Nose east of northern Florida (Shipboard Scientific Party, 1998) with normalized modifications from Bukry (1991).

Figure 1. Location map of test wells used in this study. Data from this study, Florida Geological Survey lithologic data base, Causaras (1985, Causaras (1987), Fish (1988), Fish and Stewart (1991), McNeill et al. (1996), Missimer (1997), Weedman et al. (1997), Edwards et al. (1998), Guertin (1998), Weedman et al. (1999), and Reese and Cunningham (2000, in press). The dashed polygon shows the area used to develop facies associations for the upper part of the Peace River Formation (Table 1), and the stippled box indicates the area used for development of the facies associations of the Ochopee Limestone Member of the Tamiami Formation and an unnamed sand (Tables 6 and 7). Locations of cross-sections A-A' (Fig. 5) and B-B' (Fig. 6) are shown. [larger image]

Co-author Laura Guertin identified benthic foraminifera at the genus level using data from Bock et al. (1971), Poag (1981), and Jones (1994). Paleoenvironmental interpretations are based on grouping of individual benthic foraminiferal associations and species into the broad depth categories of inner and outer shelf, defined as mean sea level to an approximate water depth of about 305 feet and from about 305 to 610 feet, respectively (Murray, 1991). Ages are reported in accordance with the integrated magnetobiochronologic Cenozoic time scale of Berggren et al. (1995).