gulf coastal plain
Recently Published Documents

Architectural remains, especially domestic architecture, are essential for understanding the ways in which households organized themselves socially and economically in the past. Unfortunately, these remains are infrequently identified from Woodland period (1000 BC–AD 1000) archaeological sites along the Gulf Coast, an area home to well-known ceramic and mortuary traditions during this time. As a result, our knowledge of Woodland period households in the region is scant. In this article I present a newly discovered house from Letchworth (8JE337), a large Woodland period ceremonial center in northwest Florida, and compare it to the few published examples of houses from this region. I show that domestic architecture along the Gulf Coast during the Woodland period is diverse, suggesting differences in the organization of households and the historical development of ceremonial centers.

ABSTRACT Detrital-zircon U-Pb geochronology documents a regional- to continental-scale drainage reorganization along the eastern Gulf Coastal Plain (USA) from the Late Cretaceous (Cenomanian) to the Paleocene–Eocene. We present detrital-zircon U-Pb ages and Th/U values from the Maastrichtian Ripley Formation to determine the sedimentary provenance and to provide spatiotemporal resolution of drainage reorganization. The Ripley Formation contains a 12.7% overall average abundance of detrital zircons with low (< 0.1) Th/U values relative to the underlying Cenomanian Tuscaloosa Group (3.6%), the overlying Paleocene–Eocene Wilcox Group (2.8%), an Appalachian foreland composite (2.1%), and the laterally equivalent McNairy Sandstone in the northern Mississippi Embayment (3.8%). Multidimensional scaling of detrital-zircon U-Pb spectra shows that the Ripley Formation is dissimilar from underlying and overlying Gulf Coastal Plain units, the McNairy Sandstone, and an Appalachian foreland composite sample because of differences in proportions of Appalachian (490–270 Ma) and Grenville (1250–900 Ma) zircons. We interpret the southern Appalachian Piedmont province as the principal sediment source region for the Ripley Formation to account for the elevated abundance of grains with low (< 0.1) Th/U values and unique detrital-zircon U-Pb age spectra. Results suggest a regional-scale (105 km2) drainage network, which delivered sediment to the Maastrichtian coast followed by northwestward littoral transport and eventual mixing with Appalachian foreland-derived sediment in the northern Mississippi Embayment. This study further brackets drainage reorganization along the eastern Gulf Coastal Plain and demonstrates how simple chemical–age relationships, such as zircon Th/U values coupled with U-Pb ages, can be used to evaluate sediment provenance.

Dendroarchaeology is under-represented in the Gulf Coastal Plain region of the United States (US), and at present, only three published studies have precision dated a collection of 18th–19th-century structures. In this study, we examined the tree-ring data from pine, poplar, and oak timbers used in the Walker House in Tupelo, Mississippi. The Walker House was constructed ca. the mid-1800s with timbers that appeared to be recycled from previous structures. In total, we examined 30 samples (16 pines, 8 oaks, and 6 poplars) from the attic and crawlspace. We cross-dated latewood ring growth from the attic pine samples to the period 1541–1734 (r = 0.52, t = 8.43, p < 0.0001) using a 514-year longleaf pine (Pinus palustris Mill.) latewood reference chronology from southern Mississippi. The crawlspace oak samples produced a 57-year chronology that we dated against a white oak (Quercus alba L.) reference chronology from northeast Alabama to the period 1765–1822 (r = 0.36, t = 2.83, p < 0.01). We were unable to cross-date the six poplar samples due to a lack of poplar reference chronologies in the region. Our findings have two important implications: (1) the pine material dated to 1734 represents the oldest dendroarchaeology-confirmed dating match for construction materials in the southeastern US, and (2) cross-dating latewood growth for southeastern US pine species produced statistically significant results, whereas total ring width failed to produce significant dating results.

Abstract West Gulf Coastal Plain provenance loblolly (Pinus taeda L.), longleaf (Pinus palustris Mill.), shortleaf (Pinus echinata Mill.), and slash pines (Pinus elliottii Engelm.) were planted in December 2015 on three east Texas sites to compare initial growth and survival. Three years after planting, survival ranged from 26.4% to 76.4%. Damage by Texas leafcutter ants (Atta texana) caused significant mortality on one site, and feral hog (Sus scrofa) herbivory and uprooting greatly affected survival at two other sites. Tree heights were greater in loblolly and slash pine than in shortleaf and longleaf pine, whereas diameters were greater in loblolly than in slash, shortleaf, and longleaf. Height and survival rates were greater in Shelby County and were lowest in Cherokee County. Midday leaf-level water potentials were most negative for shortleaf and loblolly pines and varied across the three sites. Tree heights were significantly but weakly (R = −0.23) correlated to leaf-level water potentials. Study Implications Based on these results, loblolly pine is recommended for planting on sites where soil moisture is adequate, if early growth and survival are a concern. Slash pine can outcompete other pines on sites where soils are poorly drained. On soils that are excessively drained with low moisture, shortleaf may be considered. Given longleaf pine’s ability to retain needle moisture and surface area during periods of low soil moisture, longleaf pine is suggested for planting on the same sites. Longleaf pine will require more active management on any soil type in order to decrease herbaceous plant competition. Continued measurements are required to determine whether these growth and survival trends will continue over a full rotation.

Abstract Interspersed inputs of wood and sediment brings about morphological change at confluences and the extent to which these processes are modified by anthropogenic disturbance has ramifications for stream fish assemblages. In this study, we use three functional groups of headwater fishes to assess the influences of confluence size and land cover on habitat stability, distance moved, movement rate, and assemblage change in a Gulf Coastal Plain drainage in the southeastern United States using a 2X2 design. Our results suggest that differences in habitat stability were described by a hydrogeomorphic gradient, and urban reaches characterized by a confluence size > 0.6 displayed the greatest habitat instability. Water-column specialists in urban reaches were more likely to move when habitat change was limited, whereas movement by this functional group in forested reaches was more likely in response to greater habitat instability. Therefore, the distance moved by water-column specialists was related to land cover. Assemblage change also occurred at a more constant rate in urban reaches in response to habitat instability. There was little evidence that confluence size influenced movement or assemblage stability in these headwater assemblages. Our understanding of the extent to which land cover alters the geomorphic and ecological gradients associated with headwater confluences will be critical to ensure the conservation of sensitive species whose fitness is dependent on the integrity of these habitats.

ABSTRACT We used our previously published Lg-wave spectral ratio model to develop a model of pseudospectral acceleration (PSA) response ratios at sites in the Atlantic and Gulf Coastal Plain, relative to a reference site condition defined as the mean response for site locations outside the Coastal Plain. The model is strongly dependent on sediment thickness. The results of this study can be used to predict PSA response, for linear behavior, at sites in the Atlantic or Gulf Coastal Plain with a known thickness of Coastal Plain sediment, given a ground-motion model for reference site conditions outside the Coastal Plain region of the central and eastern United States.