Three late‐glacial pollen and plant Macrofossil assemblages from Iowa

Abstract

Late-glacial pollen and plant macrofossil assemblages from the Brayton gravel pit in southwestern Iowa, Nichols silts in southeastern Iowa, and Summer Bog in northeastern Iowa indicate that a spruce-larch forest was present between about 12,500 and 11,500 radiocarbon years before present (RCYBP). Some forest openings probably existed at Brayton and during the lower zone recognized at Sumner Bog, but not at Nichols. All Sites contain pollen of thermophilous species; macrofossils of Quercus rubra (northern red oak) and Corylus cornuta (beaked hazel) at Brayton and of Acer negundo (box elder) at Nichols indicate that some thermophilous plants were locally present. Fir trees were present in small numbers, but pine was absent.

Late‐glacial vegetational and climatic history of the Allegheny Plateau and the Till Plains of Ohio and Indiana, U.S.A.

“…A red oak (Quercus rubra) acorn (a species with a northern range) dating to c. 13,000 B.P. was reported from Iowa (Baker et al 1980). M. Davis (1981) observes that the two points of oak pollen expansion in Midwest pollen diagrams probably reflect the varied autecology of the many oak species.…”

Biogeography of Pleistocene conifer species from the Ziegler Reservoir fossil site, Snowmass Village, Colorado

“…Ovulate cones of Picea and other conifers have been found in many Quaternary deposits (Baker et al, 1980;Jackson et al, 1986, Givens and Givens, 1987Warner and Chmielewski, 1987;Miller, 1988;Jackson and Givens, 1994). Because taxonomy of conifers relies heavily on ovulate cone morphology (Florin, 1954;Hart, 1987;Farjon, 2010), such occurrences provide unique opportunities for understanding biogeographic history of individual conifer species (Jackson et al, 1997).…”

Accelerator Radiocarbon Date Indicates Mid-Holocene age for Hickory Nut from Indiana Late-Glacial Sediments

“…Because precise dates can be achieved using a strongly advocate wider application of the Grootes, P. M. (1983). blages of considerable significance because of the mixture of boreal and temperate elements they contain (e.g., Baker et al, 1980;Delcourt and Delcourt, 1977;Delcourt et al, 1980). Because these assemblages are from alluvial sediments, questions have been raised concerning the contemporaneity of the components of these assemblages (Watts, 1983).…”