Subtropical Glacial, Deglacial and Holocene Millennial Climate Variability From Tampa Bay, Florida

Although millennial-scale intervals of cooler, drier climate have been documented in Holocene and Quaternary marine and terrestrial records of the extratropics, well-resolved subtropical records of millennial-scale variability are needed to assess the timing, amplitude, and possible modes of origin of such events. Recent coring in Tampa Bay, Florida by the R/V Marion-Dufresne (core MD02-2579) recovered 11.3 m of Quaternary marine, lacustrine and estuarine sediments containing a record of climate in a subtropical region during the last glacial maximum (LGM), deglacial and Holocene. Evidence from stratigraphy, radiocarbon chronology and micropaleontology suggests that the interval from 11.3 m to 7.4 m consists of marine sediments containing interglacial marine faunas and palynomorph assemblages deposited during marine isotope stages 11, 7 and/or 5. These are unconformably overlain by a non-marine, lacustrine unit between 7.4 m and 2.9 m deposited between about 21 ka and 11.5 ka. The glacial-deglacial interval between about 21 and 11.5 ka is characterized by a pine minimum during the LGM and herbaceous pollen during the deglaciation. The uppermost 2.9 m of estuarine sediments, deposited after the final stage of Holocene sea-level rise (3.5 ka - present), contain pollen assemblages dominated by pine, with oak and herbaceous taxa subdominant. The MD02-2579 pollen and environmental record suggests millennial climate variability related to precipitation during the LGM-deglacial transition and will be discussed in terms of broader tropical-subtropical climate patterns in the North Atlantic region.