Abstract Introduction Acknowledgements Material and Methods Results - Pollen Assemblages and Trends - Faunal Assemblages and Trends    - No Name Bank    - Featherbed Bank    > Card Bank Discussion Significant Findings, Implications And Future Work References Appendices PDF version

Faunal Assemblages and Trends - Card Bank

Two sets of cores have been collected from Card Bank: 1) GLW402-CBA and CBB, collected in April, 2002; and 2) SEI297-CB1, collected in February, 1997. The stratigraphy of Card Bank, in the southern part of Card Sound, consists of about 1-2 m of marine carbonate muds that have accumulated during late Holocene. Core SEI297-CB1 was taken on the southeastern flank of Card Bank and core GLW402-CBA and CBB on the northwestern flank. Two calibrated radiocarbon dates on shells from SEI297-CB1 from core depths of 81 cm and 131 cm yield ages of 1253 and 1440 AD, respectively, indicating a mean late Holocene sedimentation rate of about 0.2 cm yr^–1 at this site and a potential for decadal temporal resolution.

The ostracode assemblages (Figure 20; Appendix K) at Card Bank (SEI297-CB1) indicate changing bottom habitats and salinity conditions over the past 800-900 years with a notable change around 1700 AD when larger proportions of Thalassia-dwelling species occur. Due to the uncertainty in the age model in the uppermost 40-50 cm of the SEI297-CB1 core, the 20th century history of Card Bank cannot be determined without additional dating and analysis of the new cores, which is still underway.

Figure 20. Downcore plots of important ostracode species from Card Bank core (SEI297-CB1). Percent abundance of species plotted against year. (See Appendix K for data.) [larger version]