A combination of techniques was applied to the problem of dating recent intertidal deposits from eastern Long Island. Careful separation of important indicator pollen types allowed identification of regional changes in vegetation. Comparison of pollen profiles and historic documents supplied three dated horizons: (1) a 1640-1680 rise in agricultural indicator at the time of settlement, (2) an 1800 decline in oak pollen with the initiation of the cordwood industry, and (3) a 1920 decline in chestnut pollen following the chestnut blight. Pb-210 provided chronologies for the last 100-150-year sections of cores. Chronologies from each were compared and used to date a 1900 rise in industrially derived opaque spherules independently. Results showed that a combination of techniques could be used to obtain detailed chronologies from intertidal sediments deposited within the last 300-350 years and to interpret salt marsh and barrier island dynamics. Although Pb-210 may be restricted in its application due to erratic sedimentation, pollen analysis can be used to date strata from high-energy marshes where sediment-accumulation rates fluctuate.

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