Andrew Ivester | University of West Georgia (original) (raw)

Papers by Andrew Ivester

Previously, a large platinum (Pt) anomaly was reported in the Greenland ice sheet at the Younger ... more Previously, a large platinum (Pt) anomaly was reported in the Greenland ice sheet at the Younger Dryas boundary (YDB) (12,800 Cal B.P.). In order to evaluate its geographic extent, fire-assay and inductively coupled plasma mass spectrometry (FA and ICP-MS) elemental analyses were performed on 11 widely separated archaeological bulk sedimentary sequences. We document discovery of a distinct Pt anomaly spread widely across North America and dating to the Younger Dryas (YD) onset. The apparent synchroneity of this widespread YDB Pt anomaly is consistent with Greenland Ice Sheet Project 2 (GISP2) data that indicated atmospheric input of platinum-rich dust. We expect the Pt anomaly to serve as a widely-distributed time marker horizon (datum) for identification and correlation of the onset of the YD climatic episode at 12,800 Cal B.P. This Pt datum will facilitate the dating and correlating of archaeological, paleontological, and paleoenvironmental data between sequences, especially those with limited age control. In 2013, Petaev et al. 1 discovered an anomalously large platinum (Pt) peak in ice core samples from the Greenland Ice Sheet Project 2 (GISP2), thus providing the most compelling evidence to date for a catastrophic extraterres-trial event coincident with the onset of the Younger Dryas (YD) climate episode. In the study by Petaev et al., high-resolution (2.5–4.6 y) time-series of ice core samples were analyzed for trace and major element concentrations using inductively coupled plasma mass spectrometry (ICP-MS). Petaev et al. 1 reported the presence of a Pt peak anomaly at the Bølling-Allerød/Younger Dryas Boundary (YDB), coincident with a large shift in δ 18 O values, confirming the onset of cooler conditions at the beginning of the YD interval. This peak interval is represented by a rise in Pt concentrations over 14 years and subsequent drop during the following 7 years, consistent with the known residence time of stratospheric dust 1. This sharply defined Pt anomaly at the YD onset in GISP2 is coeval with other YDB impact-related proxies, including nanodiamonds and melted spherules, found in Greenland and across four continents and is proposed by Petaev et al. to have resulted from a highly fractionated, Ir-deficient, iron-rich, extraterrestrial impactor. However, ten additional YDB studies have reported different concentrations

Quaternary Research, 2001

Most inland eolian dunes associated with rivers on the Georgia Coastal Plain probably date to gla... more Most inland eolian dunes associated with rivers on the Georgia Coastal Plain probably date to glacial periods. Direct dating of the dune sand by optically stimulated luminescence dating, combined with limiting ages from radiocarbon dating, shows that dunes formed during isotope stage 2, stage 3, the transition between stages 4 and 5, and isotope stage 6 or earlier. Most of the dates indicate dune activity between 30,000 and 15,000 years ago. Holocene activity included limited and local reworking of the crests of some thick dunes along streams that flow from the Piedmont.

Southeastern Geology, Oct 1, 2011

ABSTRACT A small streamhead pocosin wetland at Fort Jackson, South Carolina, preserves a history ... more ABSTRACT A small streamhead pocosin wetland at Fort Jackson, South Carolina, preserves a history of late Pleistocene and Holocene plant communities in an upland habitat of the Sandhills of the upper Coastal Plain. During the late Pleistocene, the assemblage of Pinus (pine, including P. banksiana [jack pine], Picea (spruce), and Asteroideae (a subfamily of Asteraceae, the sunflower family) signals a cold, dry climate. Quercus (oak) was sparse; Liquidambar (sweetgum) and Nyssa (tupelo) were absent. During the Holocene, pine dominated except for an interval of oak dominance beginning after 9,520 cal yr BP and ending around 7,400 cal yr BP. Sediment characteristics suggest higher or more intense precipitation in the earlier segments of the Holocene record. Evidence from the pollen record is equivocal. Higher proportions of Nyssa (probably N. biflora, an obligate wetland species, or N. sylvatica, a facultative wetland species, or both) during the oak interval dominance could indicate expansion of the wetland, reduced fire fre- quency, or decreased pollen contributions from other sources, such as pine in the uplands. The rapid transition back to pine dominance was accompanied by decreases in Nyssa and Fagus (beech, prominent only in the uppermost sample of the mid-Holocene oak interval) and an increase in Gramineae (grasses), suggesting an increase in fire frequency or intensity, a decrease in moisture, or both. Asynchronies in the oak-pine transition across the Coastal Plain suggest that it is a poor proxy for Holocene climate change. The asynchronies may be in part a consequence of the importance of fire in shaping these communities.

Thesis (Ph. D.)--University of Georgia, 1999. Directed by David S. Leigh. Includes bibliographica... more Thesis (Ph. D.)--University of Georgia, 1999. Directed by David S. Leigh. Includes bibliographical references (leaves 125-131).

Recent investigation of 38AK862 provides an opportunity to examine the formation of natural and c... more Recent investigation of 38AK862 provides an opportunity to examine the formation of natural and cultural deposits on the sand rim of a large Carolina bay on the Aiken Plateau. Lying on the southeast shore of Mathis Lake, site 38AK862 contains artifacts associated with Terminal Paleoindian through Mississippian occupations. Agricultural activities and the active nature of the fine sands that constitute the site matrix have affected most of the deposits once associated with the later occupations but deposits associated with Early through Late Archaic occupations provide better contexts for the interpretation of the role of the site in the regional patterns of settlement. Geomorphological investigations of the site provide a detailed account of the formation of the eastern sand rim of the bay and the effect of the formation of the rim on human activities and archaeological deposits.

Journal of Archaeological Science, 2000

ABSTRACT New optically stimulated luminescence ages, in combination with detailed analysis of sed... more ABSTRACT New optically stimulated luminescence ages, in combination with detailed analysis of sediment from White Paintings rock shelter provide a basis for reconstructing palaeoenvironment and site formation processes at the longest archaeological sequence in the Kalahari. The new data resolve previous ambiguities related to the site’s chronology. A series of soil stratigraphic units documents changing conditions at the site over the past 100/120 ka. Millennialscale periods of increased moisture availability, occupation intensity, and landscape stability alternate with periods characterized by more arid conditions, aeolian sedimentation, and lower site occupation intensity. Broader trends in the sediment data suggest a general transition from greater moisture availability in the Pleistocene and Early to Mid Holocene toward more arid conditions in the Late Holocene. Wetter climates occurred at the time of Heinrich events in the North Atlantic due to slowing or cessation of the North Atlantic Deep Water flow (NADW) that resulted in warming of Southern Hemisphere oceans and the associated weakening of the South Atlantic and South African anticyclones.

Ongoing geomorphological fieldwork at Herndon Bay in northern Robeson County, North Carolina, has... more Ongoing geomorphological fieldwork at Herndon Bay in northern Robeson County, North Carolina, has revealed evidence for rapid bay basin scour and landform migration. LiDAR data show a regressive sequence of sand rims that partially backfill the remnant older bay basin, with bay migration of more than 600 meters to the northwest. Similarly, other bays in the region show evidence of significant migration. A series of Geoprobe® cores (n=4), basal OSL samples (n=3), and GPR data were collected along transects that cross-cut multiple bay sand rims along the bays southeastern margin. Cores were subsequently analyzed to determine basic lithologies, grain-size statistics of lithologic units (i.e., lithofaces), and magnetic susceptibly. These data, along with GPR data and OSL age estimates are used to reconstruct landform geomorphology and provide a geochronology for bay rim development. Evidence suggests bay migration, including scouring of the underlying mud facies. This migration is punct...

Southeastern Archaeology, 2010

ABSTRACT We synthesize results of extensive archaeological surveys and geoarchaeological investig... more ABSTRACT We synthesize results of extensive archaeological surveys and geoarchaeological investigations of Carolina bays and other depressional wetlands on the U. S. Department of Energy's Savannah River Site (SRS). The SRS is located along the Savannah River in the upper Coastal Plain of South Carolina. These data are augmented with data from Carolina bays elsewhere within their middle to south Atlantic Coastal Plain range. Carolina bays are shallow, oriented upland ponds that formed during the late Pleistocene under climatic conditions very different from present. Their use by prehistoric populations was most intensive during the Paleoindian and Archaic periods. Subsequent use by Woodland . and Mississippian populations tended to be ephemeral. Change through time in the prehistoric use of Carolina bays and other depressional wetlands is linked to regional-scale changes in climate, particularly to the hydrologic regime.

Journal of Archaeological Science, 1996

Anthropocene, 2015

ABSTRACT Eastern North America has seen widespread soil erosion in recent centuries. While the im... more ABSTRACT Eastern North America has seen widespread soil erosion in recent centuries. While the impact of soil erosion and feedbacks to the environment have been recognized for the period of European settlement, the period of prehistoric cultivation by Native Americans and its effect on soil erosion are largely unexplored. At the Dogwood gully system, a 820,000 m2 watershed located along the Chickasaw Bluff in southwestern Tennessee, extensive geoarchaeological investigations, which include historical data, have enabled a detailed examination of soil erosion history. The results yield insight into the relative influence on soil erosion of human activities (both prehistoric and historical) versus natural geomorphodynamic processes controlled by climate and neotectonics. Three relatively short phases of geomorphic activity occurred throughout the Holocene. In the mid-Holocene climate changes caused a change or decline in the protecting vegetation cover which triggered fires, runoff, and soil erosion. The influence of Archaic and early Woodland peoples on the landscape has remained elusive. The loss of at least 12 cm of topsoil during the Mississippi period (∼ 900 to 1400CE) may have influenced land abandonment in the 14th century. After the introduction of European agricultural techniques, a similar amount of soil was eroded but within a period of only 80 years. In the 1930s the area was reforested but runoff and gullying are still active on bare surfaces. The research shows that the impact of prehistoric land use patterns on the geomorphic system was likely generally much more important than previous studies has suggested.