A dearth of reliably-dated paleolake records from the southern Basin and Range has limited knowledge of past water balance changes there, precluding a more complete understanding of late Pleistocene atmospheric circulation across western North America. Paleoshorelines in closed basins throughout the region can provide accurately dated records of local effective moisture variations, representing a largely untapped source of paleohydrologic information. This dissertation presents paleohydrologic reconstructions from depositional successions in two basins at 32°N, approximately 100 km apart: Willcox basin, in southeastern Arizona, and Playas Valley, in southwestern New Mexico. Also presented are the results of ¹⁴C dating of charcoal samples from the El Fin del Mundo Clovis archaeological site, in northwestern Sonora, Mexico. In depth analysis of these results allowed constraint of the "small sample effect" on the charcoal ages, found to be smaller than 1σ of analytical uncertainty. The magnitude of the problem in ages from miniscule shell samples in the Willcox and Playas chronologies was found to be similar. The successions record moist pluvial conditions from ~20-13 ka in Playas, and>37-11 ka in Willcox, with most dates younger than 19 ka--before which there is no solid evidence for lake transgressions. There is clear evidence for overlapping highstands between ~18.3 and 17.9 ka and a brief highstand of Cochise at ~12.9 ka, coinciding with Heinrich events H1b and H0, respectively. Temporal concordance between wet periods and perturbations in the North Atlantic ocean and/or southern Laurentide ice sheet supports the idea that abrupt paleoclimatic changes in the southwestern U.S. occurred in response to large-scale atmospheric linkages to the northern high latitudes. The H1b highstands fill a hiatus in ¹⁴C dates compiled from paleoshorelines throughout the western U.S., and correspond to the first part of a lowstand in paleo-Lake Estancia (35°N), in north-central New Mexico. Anti-phasing within New Mexico suggests that the newly documented highstands resulted from an increase in southerly-sourced precipitation. This is consistent with paleoenvironmental evidence from southern Arizona and New Mexico that points toward periodic intensification of the summer monsoon during the late Pleistocene.

Stratigraphic records in Middle Park in north-central Colorado provide evidence for the late Quaternary geomorphic and environmental history of a non-glaciated Southern Rocky Mountain basin. Episodes of geomorphic instability apparent in the stratigraphic record coincide with changes in paleoenvironmental records from above 2750 m in north-central Colorado, suggesting that the western Middle Park landscape was sensitive to environmental changes affecting the region over the last ~14,000 years. Tributaries were incised prior to 14.0 ka, but deposits older than 12.0 ka are rare. Upland erosion and incision followed by rapid aggradation in alluvial settings between 12.0 and 11.0 ka coincide with evidence for regional temperatures at or above present, and is interpreted to signal the onset of Holocene summer-wet precipitation. A widespread soil-stratigraphic marker represents a long period of landscape stability between <11.0 and 6.0 ka in upland and alluvial settings. Pedologic evidence from upland settings indicates the expansion of grass and forest cover to lower elevations that today are characterized by sagebrush steppe, probably during a period of increased summer precipitation relative to present. During the late Holocene, episodes of aggradation in alluvial valleys at 6.0-1.0 ka and 0.6-0.2 ka and soil formation in uplands at 5.0-3.5 ka and 2.5-1.0 ka overlap with evidence for cooling at higher elevations. Incision of valley floors documented at 1.0-0.6 ka and during the last few centuries and episodes of erosion in uplands at 3.5-2.5 ka, after 1.0 ka, and within the last few centuries, are roughly synchronous with evidence for warming. Upland and alluvial stratigraphic records are interpreted to indicate that during cool intervals summer precipitation was diminished, resulting in relative hillslope stability and gradual valley bottom aggradation, while pulses in summer precipitation accompanying warmer episodes caused basin-wide geomorphic instability. The recent increasing frequency of geomorphic instability appears to correspond with an increase in sagebrush steppe at the expense of forest and grass cover, interpreted to represent progressive drying during the late Holocene. It stands to reason that future warming, if accompanied by similar patterns in precipitation, will result in continued erosion on a landscape already at a threshold of geomorphic instability.

In this dissertation, I examine the relationship between environmental conditions and human activity in the landscape of the Argive Plain of Greece after the collapse of the Bronze Age palatial system (1200–750 B.C.). I use evidence from four locales: the Petsas House and the Lower Town at Mycenae, to the immediate northwest and southwest of the citadel respectively; the settlement at Chania, three kilometers downstream; and the Northwest Town of Tiryns, in the lower reaches of the plain. I apply micromorphological analysis (the microscopic analysis of soils and sediments) integrated with analysis of grain-size and soil chemistry (assessed by X-Ray Fluorescence and Fourier Transform Infrared) in order to place depositional events within the context of settlement change at the end of the Bronze Age. The climate had been drying during the Late Bronze. An earthquake ca. 1200 B.C. is concurrent with the beginning of the final period of occupation on the edge of the plain around Mycenae. Some accumulation of sandy muds, destabilized sediments from the largely abandoned citadel, is observed at Petsas House as well as in the Lower Town where, additionally, remains were buried by two deposits of red muddy gravels from uncultivated mountain slopes. The gravels are separated by a brief period of stability (less than a century) marked by a weak soil formation, and reached final equilibrium in the Early to Middle Geometric period (900–760 B.C.). At the same time, three kilometers downstream, similar red muddy gravels resulted in the interruption of activity at the settlement of Chania. Meanwhile, at Tiryns, 30 cm of sandy muds, also destabilized by drier conditions, were deposited over decaying mudbrick, implying that the site was already abandoned before sedimentation occurred. The burial of both Mycenae and Tiryns demonstrates the instability in the Argive landscape and the complications of relating these changes to settlement. In the environs of Mycenae, the sudden deposition of muddy gravels certainly brought about the abandonment at Chania, and possibly also in the Lower Town; while at Tiryns abandonment preceded accumulation. This study demonstrates how intensive geoarchaeological study must be a component in properly situating sites in their particular landscapes.

This thesis reconstructs the landscape evolution of the Billy Big Spring site (24GL304, Glacier County, north-central Montana) from the last glacial maximum to present through the analysis of sediment and soil samples collected from a transect of auger tests that bisected the site and surrounding landforms. Interpretations were drawn from stratigraphy, pedologic data, sedimentologic analysis and radiocarbon dating. The site landscape came into being in the late-Pleistocene, after Wisconsin-age glaciers retreated. Glacial retreat left a meltdown depression on the land that filled with water to form a pond, which persisted through the early-Holocene. The onset of the mid-Holocene (Altithermal) occurred before ~8,415 cal. yrs. BP, when increasingly arid conditions caused the water level to drop. The first radiocarbon dated human occupation of this site occurred during the Altithermal, ~7,030 cal. yrs. BP, after the eruption of Mount Mazama (~7,633 cal. yrs. BP). Arid conditions continued until ~7,000 cal. yrs. BP, when pond water re-expanded across the basin, marking the transition to the cooler late-Holocene. Sometime before 2,100 cal. yrs. BP, dry conditions returned, and the extent of the pond water decreased again. Since this time, overland alluvial processes have deposited sediments in the basin. Many hypotheses on how the Altithermal impacted the people of the Northwestern Plains have been proposed since the 1950s, but little agreement has been reached. This is due to the fact that there was great variation in how the Altithermal expressed itself throughout the Northwestern Plains. The human reactions to this phenomena cannot be explained simplistically for the region as a whole. This study shows that the Billy Big Spring site experienced drying during the Altithermal, but despite this, people continued to occupy this site. This evidence adds to the argument that the Altithermal climate of the Northwestern Plains did not have severe enough impacts to impose much hardship on its occupants.

Geoarchaeology has had a long history within archaeology around the world, but not so much so in Gotlandic archaeology. This study is aimed at drawing attention to this by using magnetic susceptibility (MS) and phosphate (P) analysis of an Iron Age site at Ytings, Gotland. This is where a small silver hoard was discovered in 1888, and in 2009 a geophysical survey was done, via metal detector, and concluded with the theory of there being a workshop in the southern field and a farmstead in the north (ArkeoDok, 2011). The first part of this study discussed predictive modeling and whether or not the information available at the time would be enough to generate a reliable model (Coleman, 2016). The first study concluded with not being able to do so since the only discrete data available was from the metal detecting survey, which when used alone is not the most reliable instrument for archaeological prospection (Coleman, 2016). This led to this current study, which is the second part of a two-part study of Ytings. This study is aimed at using geoarchaeological methods for archaeological prospection to illustrate the benefits and need for these types of studies on Gotland, by comparing the MS and P results with the 2015 excavation report.

This research reconstructs site formation processes and activities of the inhabitants of two cave sites in south China, Xianrendong and Yuchanyan, where the earliest pottery in the world has been discovered. The goal is to broaden existing understandings of human behavior of Late Pleistocene and Early Holocene Chinese hunter-gatherers, through the production of data types rarely gathered at a Chinese Palaeolithic site. I use the geoarchaeological technique of micromorphology – microscopic observation of thin sections of oriented intact sediment samples to identify their components and nature – and micro-Fourier Transform Infrared Spectroscopy (μ-FTIR) a technique used to obtain the molecular composition of materials used here to detect changes associated with fires. In this study, I reconstruct occupational patterns over time and show how flooding events as well as cave-specific climatic patterns, such as freeze/thaw and dripping water affected human choices of living spaces. Analysis of sediments derived from human use clarify details of such activities as building and cleaning fires, and constructing clay surfaces. Analytical results indicate that the inhabitants of Xianrendong maintained fires with consistently low temperatures, while at Yuchanyan through control of oxygenation and preference of wood fuel humans could maintain their fires between 500 and 700 Co for long periods of time. The low temperatures support the hypothesis from a preliminary study of the ceramics that pottery at Xianrendong was made without the use of kilns. Thoroughly consumed wood fuel at Yuchanyan indicates sophisticated pyro-technological knowledge and a possible preference for boiling as a cooking method. Finally, micromorphological analyses confirm the undisturbed nature of the sediments and so corroborate the reliability of a recent radiocarbon date of 20 ka cal BP for the earliest pottery-bearing layers. Micromorphological research reveals these early peoples’ knowledge of the physical properties of fires and clays, as well as their behavior of separating usable space into activity areas. In combination with the published systematic analysis of the faunal and botanical remains and of the material culture from these sites, my results provide a high-resolution account of life in these two sites. This study will be an important precedent for the further, systematic use of these geoarchaeological techniques in Chinese archaeology. / 2020-02-14T00:00:00Z

Various criteria or lines of evidence have been used to identify ancient Maya marketplaces, including location near trade routes, artifactual evidence of trade, open space adjacent to transportation routes, proximity to public structures, low platforms and rock alignments to denote market spaces, and regular patterns in soil and floor chemical concentrations. Seibal and Mayapán were important economic Maya polities controlling the trade routes at the apex of their civilizations. The objectives of these studies were to apply geochemical and geospatial analyses of the soils and floors from public plazas and household patios, to discover the anthropogenic chemical residues of phosphorus (P) and heavy metals associated with the trade of foodstuffs and workshop items that may have been marketed there. Public access, causeways, reservoirs and a pattern of high P and metal concentrations are consistent with marketing of organic foodstuffs and workshop items within suspected marketplaces of each site. In contrast, geochemical patterns of the soils and floors of household structures are consistent with ceremonial and household activities.

The small number and diffuse distribution of sites with intact Late Pleistocene/Early Holocene occupations in the Southeastern United States consequently makes examining Late Pleistocene/Early Holocene settlement patterning in the region difficult (Goodyear 1999). The Hester Site (22MO569), located in northeastern Mississippi, contains intact Late Pleistocene/Early Holocene deposits that can potentially afford archaeologists with a better understanding of late Pleistocene/early Holocene settlement in the region (Brookes 1979; Goodyear 1999:463-465). Investigations at Hester by Brookes (1979) revealed a stratified site containing artifacts that represented the late Paleoindian through Woodland periods in the Southeastern United States. Burris (2006) developed an alternative typology by re-analyzing the Hester biface assemblage, which demonstrated four discrete occupations at the Hester site. I use formation theory to evaluate the degree to which post-depositional processes have impacted the deposits at the Hester site. I have determined that the Hester site has not been significantly altered by post-depositional processes.

No description available.

No description available.