A Multi-proxy assessment of the impact of climate change on Late Holocene (ca 4500-3800 BP) Native American villages of the Georgia coast

Circular shell rings along the Atlantic Coast of southeastern North America are the remnants of some of the earliest villages that emerged during the Late Archaic Period (5000 – 3000 BP). Many of these villages, however, were abandoned during the Terminal Late Archaic Period (ca 3800 – 3000 BP). Here, we combine Bayesian chronological modeling with multiple environmental proxies to understand the nature and timing of environmental change associated with the emergence and abandonment of shell ring villages on Sapleo Island, Georgia. Our Bayesian models indicate that Native Americans occupied the three Sapelo shell rings at varying times with some generational overlap. By the end of the complex’s occupation, only Ring III was occupied before abandonment ca. 3845 BP. Ring III also consists of statistically smaller oysters ( Crassostrea virginica ) that people harvested from less saline estuaries compared to earlier occupations. These data, when integrated with recent tree ring analyses, show a clear pattern of environmental instability throughout the period in which the rings were occupied. We argue that as the climate became unstable around 4300 BP, aggregation at shell ring villages provided a way to effectively manage fisheries that are highly sensitive to environmental change. However, with the eventual collapse of oyster fisheries and subsequent rebound in environmental conditions ca. 3800 BP, people dispersed from shell rings, and shifted to non-marine subsistence economies and other types of settlements. This study provides the most comprehensive evidence correlations between large-scale environmental change and societal transformations on the Georgia coast during the Late Archaic period.

The Integration of Lidar and Legacy Datasets Provides Improved Explanations for the Spatial Patterning of Shell Rings in the American Southeast

ABSTRACTArchaeologists have struggled to combine remotely sensed datasets with preexisting information for landscape-level analyses. In the American Southeast, for example, analyses of lidar data using automated feature extraction algorithms have led to the identification of over 40 potential new pre-European-contact Native American shell ring deposits in Beaufort County, South Carolina. Such datasets are vital for understanding settlement distributions, yet a comprehensive assessment requires remotely sensed and previously surveyed archaeological data. Here, we use legacy data and airborne lidar-derived information to conduct a series of point pattern analyses using spatial models that we designed to assess the factors that best explain the location of shell rings. The results reveal that ring deposit locations are highly clustered and best explained through a combination of environmental conditions such as distance to water and elevation as well as social factors.

Towards understanding π-stacking interactions between non-aromatic rings

The first systematic study of π interactions between non-aromatic rings, based on the authors' own results from an experimental X-ray charge-density analysis assisted by quantum chemical calculations, is presented. The landmark (non-aromatic) examples include quinoid rings, planar radicals and metal-chelate rings. The results can be summarized as: (i) non-aromatic planar polyenic rings can be stacked, (ii) interactions are more pronounced between systems or rings with little or no π-electron delocalization (e.g. quinones) than those involving delocalized systems (e.g. aromatics), and (iii) the main component of the interaction is electrostatic/multipolar between closed-shell rings, whereas (iv) interactions between radicals involve a significant covalent contribution (multicentric bonding). Thus, stacking covers a wide range of interactions and energies, ranging from weak dispersion to unlocalized two-electron multicentric covalent bonding (`pancake bonding'), allowing a face-to-face stacking arrangement in some chemical species (quinone anions). The predominant interaction in a particular stacked system modulates the physical properties and defines a strategy for crystal engineering of functional materials.

Collective Action and Village Life during the Late Archaic on the Georgia Coast

This chapter examines shell rings of the Georgia Coast. I argue that the vast majority of shell rings represent co-residential village communities, and thus are some of the earliest villages in eastern North America. I identify several types of collective action problems that the formation of villages likely presented to shell ring inhabitants at both the village and landscape scales. I suggest that there were several solutions to these problems, none of which required top-down hierarchical control. Instead, I present a narrative that explains the functioning of these villages as a highly cooperative, self-organizing hunter-gatherer system, rooted in local and regional interaction through rituals and the maintenance of collective mass capture facilities and fishing technology, and management of resources in the context of surplus production.

THERMO - MECHANICAL LOADING IN BEVELLED AREA BETWEEN TWO CYLINDRICAL SHELLS WITH DIFFERENT THICKNESSES. THEORETICAL STUDY - CONNECTION LOADS

This paper addresses the problem of stress concentration in the transition area, between two cylindrical shells with different thicknesses. To reduce the intensity of the stresses and strains developed under the action of external mechanical and /or thermal loads, an original method is proposed, using method of short structural elements for shells, respectively bending moments theory and deformations continuity (displacements and rotations). In this sense, the transition between shell rings is considered linear variable in four constructive variants (with the same inner or outer surface, respectively the same median surface, or different median surfaces). Based on the evaluated intensity of the stress, it can be concluded which is the preferred variant the design stage, or deduction of the same sizes, in case of technological deviations (cutting errors, so as to result the same inner or outer surface, as in case of the same median surface). Article content refers in this configuration the setting mode related of connection loads that will be taken into account in tensions expressions.

Archaic Shell Mounds in the American Southeast

Freshwater and estuarine shellfish began to be exploited in the southeastern United States between 9000 and 7000 b.p. Shortly thereafter, shell mounds appeared in the mid-South Shell Mound Archaic, along the St. Johns River in peninsular Florida, and, somewhat later, in the Stallings Island area along the middle Savannah River. On the lower Atlantic and Gulf Coasts, shell rings arose. Until recently, all these mounds were considered middens—the accumulations of the remains of simple meals of mobile peoples who visited the same areas for hundreds or thousands of years. More recent scholarship indicates that these mounds were deliberate constructions—some of the first sculpted landscapes created by Archaic peoples to memorialize the past, celebrate the present, and provide for the future. In this chapter, recent research on shell sites in these four areas is discussed. The emphasis is on changing perspectives about the peoples who built them.