Paleoindian Societies of the Coastal Southeast by Dunbar James S.;

Author:Dunbar, James S.;
Language: eng
Format: epub
Publisher: University Press of Florida
Published: 2019-08-15T00:00:00+00:00

Figure 5.2. Reconstructed bathymetry of the Page-Ladson site, ~14,400 cal BP, Aucilla River, North Florida.

The hiatus between U4 and U5 appears to be from an erosional event. The age of U5 is only partially dated, with its uppermost level ~12.2 ka cal BP. It is a smectite level identified by Sylvia Scudder (2006) as a very shallow, possibly intermittent water environment. This represents yet another unique sediment level of the site because of its sediment type and the artifacts that it holds. Though additional radiocarbon dating is needed, it dates to the Late Paleoindian and yielded a different lithic artifact assemblage compared to the Bolen artifact assemblage that was recovered above it in U6 and on the Unit 5 surface.

Shortly after the Holocene onset during the Preboreal Oscillation ~11.5 ka cal BP (an average of seven radiocarbon dates expressed in actual calendar years), the surface of U5 was subaerially exposed and a human site activity was established in the sinkhole on the Unit 5 surface. Bolen artifacts lost or abandoned at the site included diagnostic side-notched and corner-notched Bolen points, adzes, dimple stones (inaccurately referred to as bola stones by some), bone tools, two fire hearths, two wooden stakes, and one tree fragment chopped by an adze or ax (Carter and Dunbar 2006;

Muniz and Hemmings 2006). That component of the site became informally known as the Bolen surface, which is now located about -5 m below present sea level. The Preboreal Oscillation was arid at a time when mesic forests had already been replaced by more xeric, fire-adapted species (Hansen 2006) that had migrated north from their south Florida refugia by that time. The water level in the Page-Ladson sinkhole began rising slowly after ~11.3 ka cal BP, and the site was inundated and unsuitable for further human use by ~11.2 ka cal BP.

In sum, water-table fluctuations at the Page-Ladson site also appear to reflect variations of local habitats that influenced animal and human usage patterns through time. During the GS-3, in the LGM, and again during GS-2a, the H1a interval botanical peat accumulations reflect refugia of species in the sinkhole during episodes of low water tables. During the latter half of Heinrich 1 (H1b), the water level dropped even more, leaving the sinkhole bottom subaerially exposed at elevations that are now more than -10 m below present sea level. Units 1L and U2 yielded virtually no mammal remains or evidence that they existed nearby; thus habitat opportunities in the area appear to have been unfavorable.

In contrast, when Units 1U and U3 were accumulating in the Page-Ladson sinkhole, both represented intervals when large land mammal activity around the rivers was abundant. The sinkholes were watering places. The bones of the animals that died became incorporated with the deposition process. During GS-2b, the Pleniglacial warming episode Unit 1U accumulated and both proboscideans (mammoths and mastodons) accessed the river channel when the river maintained either seasonal or perennial flow. GS-2b was the only prolonged period during the last glacial recession when biogenetic shell marls were being deposited in the Half Mile Rise section.

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