. Bulletins of American paleontology. Introduction: Wardlaw 11 140 n 120- 100 'Best Fit' Age E W o O c Q. 0) Q 80 £ 60 40 20-. Park Key Age Model Range in Age for a given 2 cm Sample Maximum, Median, and Minimum Age based on Sedimentation Rate 1985 1975 1965 1955 1945 1935 1925 1915 1905 1895 Year Text-figure 8.—Best Fit Age model for Russell Bank and Park Key. proxies (foraminifers, ostracodes, and mollusks). De- cadal averages are plotted at the midpoint of each de- cade (Text-fig. 6). The data for both Lignumvitae and Bob Allen Key extend back to before 1850. The Rus- sell Bank data extends
. Bulletins of American paleontology. Introduction: Wardlaw 11 140 n 120- 100 'Best Fit' Age E W o O c Q. 0) Q 80 £ 60 40 20-. Park Key Age Model Range in Age for a given 2 cm Sample Maximum, Median, and Minimum Age based on Sedimentation Rate 1985 1975 1965 1955 1945 1935 1925 1915 1905 1895 Year Text-figure 8.—Best Fit Age model for Russell Bank and Park Key. proxies (foraminifers, ostracodes, and mollusks). De- cadal averages are plotted at the midpoint of each de- cade (Text-fig. 6). The data for both Lignumvitae and Bob Allen Key extend back to before 1850. The Rus- sell Bank data extends back to 1870. Prior to 1910, the three localities show a consistent gradient from fresher to more saline values from north to south in the bay. However, following 1910, Lignumvitae shows less decadal fluctuation and slightly elevated average salinities (above mean sea average) indicating more restrictive conditions. Bob Allen and Russell Bank switch; that is, though the decadal fluctuations still track each other. Bob Allen in the center of the bay becomes consistently fresher relative to Russell Bank, disrupting the gradient noted prior to 1910. Large- scale construction connecting the Keys and filling in marine passages (building the Flagler Railroad to Key West) and initial canal construction in the Everglades occurred in the first two decades of the 20"' century. These activities may have directly affected the subtle changes seen in the salinity patterns of the Bay. The salinity values derived from faunal (foraminifer, mollusk, and ostracode) proxies for our first four Flor- ida Bay cores are shown in Text-figure 7. These are plotted against depth in core with the age model high- lighted in bold. The values for the longer cores (Bob Allen and Russell Bank) show low amplitude shifts in salinity prior to 1910 and high amplitude shifts in sa- linity after about 1940, agreeing with the curve de- veloped from shell geochemistry for Russell Bank. These faunal derivations
Size: 1998px × 1251px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookautho, bookauthorpaleontologicalresearchinstitutionithacany
