The palynology of Upper Pleistocene and Holocene sediments from the eastern shoreline and Central Depression of St. Catherines Island, Georgia, USA

Abstract

Sediment samples from the Hoke's Landing area of St. Catherines Island, Georgia, were analyzed for their pollen and spore contents, and were further analyzed for their clay mineralogy and time of deposition. Samples were retrieved from a core collected in July, 2013, and were recovered from a site lying near an early-twentieth-century oyster boiler on the eastern side of the island, the Hoke's Landing oyster boiler. The continuous core was more than 4.5 m long, representing one of the longest continuous cores collected on the island. Palynological and radiocarbon analyses provide significant information concerning the Late Pleistocene and Holocene evolution of the island; one of the most ancient finite radiocarbon ages (31,990 § 230 years BP) came from the Hoke's Landing site. Clay analyses indicate the presence of montmorillonite, kaolinite and illite, indicating sediment contributions from marine and terrestrial environments. Palynological data show that the freshwater fern Woodwardia grew in abundance at the site nearly 32,000 years ago. Investigation of other strata from the island, and comparison with data derived from other locations on the Georgia coastal plain, were undertaken. Emphasis was placed on the timing and topographic extent of the Pleistocene sea level lowstand along the eastern seaboard of North America. The effects of the eastward migration of the Georgia coastal zone during the lowstand are preserved in sediments at Hoke's Landing, and provide a convincing new source of information concerning the nature of Pleistocene lowstand terrestrial communities in that region.

Ecological niche modelling and phylogeography reveal range shifts of pawpaw, a North American understorey tree

“…While there are no fossil pollen records for Asimina because it is zoophilous, there are records for other warm temperate, anemophilous tree species that occupy present‐day habitat similar to A. triloba . Fossil pollen of Liquidambar from ~22,000 YBP has been documented in low abundance in Louisiana and southwestern Mississippi (Jackson & Givens, 1994; Kolb & Freudlund, 1981), southeastern Alabama (Delcourt et al., 1980), the panhandle of Florida (Watts et al., 1992) and St. Catherine's Island, Georgia (Rich et al., 2015). Nyssa appears to have been more widespread, with very low abundance pollen records all along the southeastern coastal plain from Texas (Potzger & Tharp, 1947) north to the Chesapeake Bay (Willard et al., 2005), and more inland records from Tennessee (Delcourt, 1979) and Georgia (Watts, 1975).…”

The Neogene-Quaternary palynological record of Castanea in the American southeast

“…The Gray's Reef sample was one of three recovered from shallow cores recovered from the reef, and the palynological contents of samples from the three cores are discussed in Rich et al (2015). Cook Hale et al (2012) undertook archaeological analyses of sediments from the reef, and were able to constrain the ages of the artifact-bearing sediments to between ∼8000 – ∼ 5000 YBP.…”

“…it is anemophilous), so its pollen are readily blown from the catkins that bear many individual male flowers, and the pollen might fall freely in large amounts if the trees are abundant. The post-blight strata of eastern North America clearly contain many fewer pollen than those sediments that accumulated before introduction of the chestnut blight parasite; in fact, post-blight strata normally contain none, though Rich et al (2015) did identify <1% Castanea pollen in a surface sample identified as Hibiscus Meadow (aka. Hibiscus Bog) from St. Catherines Island, GA. (Figures 2 and 3).…”

“…The trees were present and persistent but were never abundant at the sample site. At Hoke’s Landing (Figure 3), a site located a short distance north of the Cracker Tom sites, Rich et al (2015) recovered sediments from 4.3 m depth that dated to 31,990 ± 230 YBP (BETA 372,216). Two samples each had <1% Castanea , but the identity of the grains was, again, certain.…”

The late Pliocene palaeoenvironments and palaeoclimates of the western Iberian Atlantic margin from the Rio Maior flora

“…Modern species of Nyssa inhabit temperate to tropical climates; many have a preference for humid environments and have adaptations to survive seasonal flooding (Eyde, 1997). Nyssa pollination is predominantly entomophilous (though limited anemophilous pollination does occur in some species) and thus any significant accumulation of its pollen in the fossil record is normally autochthonous -indicating a wetland environment (Eyde, 1997;Sun et al, 2009;Rich et al, 2015). A second peak in Nyssa pollen is found in Pollen Zone RM6, together with a significant amount of Leitneria pollen (Fig.…”