Lower Ohio River Research Articles

Characterizing variation in late precontact diets using dental microwear texture analysis: a Caborn-Welborn example

ABSTRACT The Caborn-Welborn phase identifies late precontact and early postcontact (ca. AD 1400–1700) peoples of the lower Ohio River valley in Indiana, Kentucky, and Illinois who coalesced following the collapse of the Angel chiefdom. Our current understanding of Caborn-Welborn foodways is that they, like their contemporaries in other parts of eastern North America, subsisted largely on maize and wild game, supplemented by a wide range of other wild and cultivated foods. While technically accurate, this generic picture of late precontact diets does not do justice to the many microclimatological and cultural nuances that characterized local native southeastern and midwestern diets. Dental microwear texture analysis (DMTA) is a method to understand diet by analyzing the microscopic scratches and pits left on teeth during mastication. Combining DMTA with other lines of evidence, we confirm previous studies that indicate that at least some Caborn-Welborn peoples consumed less maize than their ancestors living at the Angel site. Rather than understanding Caborn-Welborn peoples as practicing a generic late precontact subsistence strategy, our study highlights how Caborn-Welborn peoples chose to eat less maize and consume more hard wild foods such as nuts compared with their contemporaries.

Large floods on the lower Ohio River inferred from slackwater deposits

Slackwater deposits representing past flood events provide a robust means to extend systematic gage records further back in time, place historic floods in a longer-term context, and reduce uncertainties in flood hazard analysis. The identification and application of slackwater deposits in riverine paleoflood hydrology has traditionally been limited to arid bedrock-controlled environments and periglacial environments. In this study, we utilize methods developed in humid alluvial settings and apply them to slackwater deposits, one of the first studies to do so. This novel approach uses sediment texture and geochemistry to distinguish slackwater deposits from in situ material in a temperate alluvial setting. We identify multiple slackwater deposits in two rock shelters situated on bluffs adjacent to the lower Ohio River. Flood age estimates are based on optically stimulated luminescence (OSL) dating, and discharge estimates are based on a 1D HEC-RAS model. The uppermost slackwater deposit at both sites corresponds to the AD 1937 historic flood of record (∼31,400 m3/s), while another slackwater deposit identified only at the lower elevation site corresponds to a paleoflood that occurred around AD 1650 with a discharge of ∼23,900 m3/s. Our findings imply that the AD 1937 flood represents the largest magnitude flood on the lower Ohio River in at least the last 400 years. Inclusion of the paleoflood into a flood frequency analysis for the Ohio River at Louisville reduces uncertainties in large flood quantiles by ∼50%.

Molecular species delimitation reveals hidden endemism in Faxonius placidus (Hagen 1870) (Decapoda: Astacidea: Cambaridae) in southeastern USA

Abstract Molecular surveys are critical for understanding species boundaries and evolutionary relationships of North American crayfishes, as traditional morphological characters used for taxonomy frequently misrepresent crayfish diversity. The bigclaw crayfish, Faxonius placidus (Hagen, 1870), is currently described as a widely distributed crayfish that is common throughout the Cumberland, Tennessee, and Lower Ohio river drainages. The geographic distribution of F. placidus is based on identifications using traditional morphological characters including the first-form male gonopod, chelae, and rostrum. Within F. placidus, color pattern variation is specific to populations separated by hydrogeographic barriers. We used DNA barcoding data (mtDNA-COI) and genome-wide molecular markers (nuclear SNPs) to examine geographic patterns of genetic variation in F. placidus within the Cumberland and Tennessee river drainages. The federally endangered Nashville crayfish, F. shoupi (Hobbs, 1948), was included in our analyses, as previous phylogenetic reconstructions suggest F. placidus is paraphyletic with respect to F. shoupi. Phylogenetic reconstructions and molecular species delimitation identified four genetically distinct lineages within F. placidus that are paraphyletic with respect to F. shoupi. Our results add to numerous studies demonstrating the utility of robust molecular analyses for understanding the biodiversity of North American crayfishes.

Systematics of the Stripetail Darter, Etheostoma kennicotti (Putnam), and the Distinctiveness of the Upper Cumberland Endemic Etheostoma cumberlandicum Jordan and Swain

The Stripetail Darter, Etheostoma kennicotti (Putnam), is widely distributed in tributaries of the lower Ohio River, the upper Green River system, the Clarks River system, throughout the Tennessee River system, the Laurel River system, and the upper Cumberland River system. Etheostoma cumberlandicum Jordan and Swain was described in 1883 from a population sampled in the Clear Fork system that drains to the upper Cumberland. A previous morphological analysis led to the placement of E. cumberlandicum into the synonymy of E. kennicotti. Results from molecular phylogenetic and relaxed molecular clock analyses, genetic variation at 25 microsatellite loci, morphological disparity in meristic traits, and variation in pigmentation from specimens sampled throughout the geographic distribution of E. kennicotti (s.l.) indicate E. cumberlandicum is a distinct species and there are multiple undescribed species masquerading as E. kennicotti. We elevate Etheostoma cumberlandicum out of synonymy and propose Moonbow Darter as the common name for the species. The results of the phylogenetic analyses are discussed in the context of the historical biogeography of rivers draining the Eastern Highlands of North America.

Fluvial responses to late Holocene hydroclimate variability in the midcontinental United States

Long-term relationships between mean-state climatic conditions and flood frequencies in the midcontinental United States (US) are not well established because instrumental records of fluvial processes are limited to the current warm period (CWP; the last ca. 150 years) and continuous paleo-flood records are exceedingly rare. Here, we investigate climate-flood relationships in the midcontinental US by reconstructing flood frequencies at Half Moon Pond, a 1600-year-old oxbow lake on the lower White River, Indiana (watershed = ca, 29,000 km2). We used sediment accumulation rates and clastic fluxes constrained by high-resolution radiocarbon (14C) dating. Frequent flooding, as indicated by high sedimentation rates and clastic fluxes to Half Moon Pond, occurred leading up to and during the Medieval Climate Anomaly (MCA; 950–1250 CE) when paleoclimate records suggest the predominance of ocean-atmosphere mean states resembling the negative phases of the Pacific Decadal Oscillation (-PDO-like) and Pacific North American Mode (-PNA-like). Reductions in sedimentation rates and clastic fluxes, indicating reduced flooding, subsequently occurred during the transition out of the MCA and into the Little Ice Age (LIA; 1250–1830 CE) as ocean-atmosphere conditions shifted to + PDO-like and +PNA-like mean states. Sedimentation rates and clastic fluxes increased again after ca. 1800 CE, indicating increased flooding during the CWP as ocean-atmosphere conditions returned to -PDO-like and -PNA-like mean states. The White River trends were notably antiphased with sedimentation-rate-based flood frequencies for the lower Ohio River (500,000 km2 watershed) prior to 1830 CE. This antiphased relationship is consistent with flooding in moderate to small watersheds in the Midwest being sensitive to the occurrence of rainstorm events, which were more frequent leading up to and during the MCA, and flooding in large watersheds being more sensitive to large spring melts associated with extensive snowpacks, which characterized the LIA. That both the White and Ohio rivers experienced their most frequent flooding during the CWP suggests deforestation and changing land use practices increased flooding on Midwestern watersheds across scales despite a current climatic mean state that in the past only resulted in increased flooding on moderate to small watersheds. Continued increased in midcontinental rainfall are therefore likely to enhance the occurrence of floods in Midwestern watersheds across different geographic scales.

Early Archaic landscape use, cultural transmission, and aggregation in the lower Ohio River valley

ABSTRACT In this paper, we use GIS and 2D geometric morphometrics to explore landscape use and social interaction among Kirk Cluster populations in the lower Ohio River valley. Using cultural transmission as a theoretical foundation, we develop models for identifying assemblages produced by macroband aggregations. We show that two distinct populations occupied northern Indiana and southwestern Kentucky. Intensively occupied sites in these areas are situated in near-upland settings in close proximity to a variety of resources including chert, higher order rivers, and sinkholes. In contrast, the Butterfield site in central Kentucky lies in the lowlands with the Green River as the only obvious resource. Analyses reveal that Butterfield was a macroband aggregation site visited by populations from Indiana, but groups from southwestern Kentucky only minimally participated in aggregations at Butterfield. Results further show that the Ohio River was not a barrier to social interaction in the Early Holocene.

A brief history of modeling Early Holocene landscape use in the American Southeast

ABSTRACT The Early Holocene is a critical period in the American Southeast and represents the time between the end of the Pleistocene and emerging cultural complexity of the Mid-Holocene. Due to the limitations imposed by a relative lack of site preservation, an important avenue of inquiry for understanding this period has been connecting the few reported, well-dated sites with the distribution of surface finds to explore how people organized their mobility across landscapes. The most widely cited examples of studies examining Early Holocene landscape use in the region are Anderson and Hanson (1988), Daniel (2001), and Hollenbach (2009). In this article, we discuss the historical development of these three approaches to modeling landscape use and explore the impacts of these works in Southeastern archaeology. Finally, we introduce four articles that explore the applicability of these three approaches in Virginia (Gingerich, this issue), Florida (Halligan et al., this issue), the lower Ohio River valley (Jennings et al. this issue), and the upper Tombigbee River valley (Strawn et al., this issue).

Using sediment accumulation rates in floodplain paleochannel lakes to reconstruct climate-flood relationships on the lower Ohio River

Late Holocene flood frequencies on the lower Ohio River were investigated using 14C-based sedimentation rates from three floodplain lakes located in Illinois (Avery Lake), Kentucky (Grassy Pond), and Indiana (Goose Pond). Changes in sediment accumulation rates were attributed to variability in the delivery of overbank sediment to each site as controlled by the frequency of Ohio River flooding. Sedimentation rates reached their lowest values in all three lakes between 400 and 1230 CE, indicating a regional reduction in flood frequencies on the lower Ohio River during a period that included the Medieval Climate Anomaly (MCA; ca. 950–1250 CE). Sedimentation rates increased after ca. 1230 CE and remained moderately high through the Little Ice Age (LIA; 1350–1820 CE) until the onset of extensive land clearance during the early 1800s CE. After 1820 CE, sedimentation rates increased further and were higher than any other time during the late Holocene. A comparison of regional paleoclimatic proxies with the above floodplain sedimentation records shows that Ohio River flooding during the late Holocene was responsive to mean-state changes in atmospheric circulation. During the MCA, when clockwise mean-state atmospheric circulation advected southerly moisture from the Gulf of Mexico into the Ohio River Valley primarily in the form of convective rainstorms, flooding on the Ohio River was least frequent. During the LIA, meridional mean-state atmospheric circulation increased the proportion of midcontinental moisture that was sourced from the northern Pacific and Arctic and delivered as snowfall, hence increasing flooding on the Ohio River. We attribute the increase in Ohio River flooding during the LIA to an increase in snowpack volume across the Ohio River Valley and the watershed-scale integration of runoff during spring snowmelt. Following Euro-American land clearance in the early 1800s, flood frequencies decoupled from this relationship and the lower Ohio River became susceptible to frequent flooding, despite a return to southerly and clockwise synoptic atmospheric conditions. These modern climate-flood dynamics are fundamentally different than those of the paleo-record and suggest that land-use changes – such as deforestation, tile draining, and landscape conversion to intensive row crop agriculture – have fundamentally altered the modern Midwestern hydrologic cycle.

Description of a new species of crayfish in the genus Faxonius (Decapoda: Cambaridae) from the Lower Ohio River Drainage, with evidence of glacial influence on the distribution of some crayfish species throughout the Ohio River basin.

Variation in morphology of Faxonius jeffersoni has been documented since the 1960s. However, a taxonomic review of the species had not been conducted. In order to clarify if F. jeffersoni exhibited a variety of character traits, or was comprised of multiple taxa, genetic and morphological analyses were conducted. As a result, we revealed that F. jeffersoni sensu lato was comprised of two non-sister taxa. A new species of crayfish, Faxonius elix n. sp., is described herein. Further analysis shows evidence of glacial influence on the distribution of crayfish species of the genus Faxonius throughout Kentucky, Illinois, and Indiana along the glacial maximum.

Genetic and morphological characterization of the freshwater mussel clubshell species complex (Pleurobema clava and Pleurobema oviforme) to inform conservation planning.

The shell morphologies of the freshwater mussel species Pleurobema clava (federally endangered) and Pleurobema oviforme (species of concern) are similar, causing considerable taxonomic confusion between the two species over the last 100 years. While P. clava was historically widespread throughout the Ohio River basin and tributaries to the lower Laurentian Great Lakes, P. oviforme was confined to the Tennessee and the upper Cumberland River basins. We used two mitochondrial DNA (mtDNA) genes, 13 novel nuclear DNA microsatellite markers, and shell morphometrics to help resolve this taxonomic confusion. Evidence for a single species was apparent in phylogenetic analyses of each mtDNA gene, revealing monophyletic relationships with minimal differentiation and shared haplotypes. Analyses of microsatellites showed significant genetic structuring, with four main genetic clusters detected, respectively, in the upper Ohio River basin, the lower Ohio River and Great Lakes, and upper Tennessee River basin, and a fourth genetic cluster, which included geographically intermediate populations in the Ohio and Tennessee river basins. While principal components analysis (PCA) of morphometric variables (i.e., length, height, width, and weight) showed significant differences in shell shape, only 3% of the variance in shell shape was explained by nominal species. Using Linear Discriminant and Random Forest (RF) analyses, correct classification rates for the two species' shell forms were 65.5% and 83.2%, respectively. Random Forest classification rates for some populations were higher; for example, for North Fork Holston (HOLS), it was >90%. While nuclear DNA and shell morphology indicate that the HOLS population is strongly differentiated, perhaps indicative of cryptic biodiversity, we consider the presence of a single widespread species the most likely biological scenario for many of the investigated populations based on our mtDNA dataset. However, additional sampling of P. oviforme populations at nuclear loci is needed to corroborate this finding.

Evaluation of Recently Implemented Harvest Regulations in a Data‐Limited Catfish Fishery with Bayesian Estimation

AbstractIn 2015, the Illinois Department of Natural Resources changed size and harvest limits for catfishes (Blue Catfish Ictalurus furcatus, Flathead Catfish Pylodictis olivaris, and Channel Catfish I. punctatus) in the lower Ohio River to match those of neighboring states. The new regulations imposed a daily limit of one 88.9‐cm (35‐in) or larger Blue or Flathead Catfish per fisher, one 71.1‐cm (28‐in) or larger Channel Catfish per fisher, and a 33.0‐cm (13‐in) minimum length limit for all species, with no harvest restrictions between these limit lengths (permissive slot). When these management regulations were implemented, potential efficacy was unknown. The goal of this study was to evaluate the potential effects of these regulations using the limited data for baseline demographic parameters. Bayesian modeling was used to estimate growth and mortality because of the ability to estimate derived functions of parameters and associated uncertainty (as credible intervals). Yield‐per‐recruit (YPR) modeling was used to estimate and evaluate the fishing mortality rates (F) that would induce growth overfishing (FMAX) and the yield at FMAX (YPRMAX) for three management scenarios: no harvest restrictions (former regulation), a 33.0‐cm minimum length limit, and the enacted permissive slot limits. Model results suggested that catfish stocks are unlikely to benefit from current regulations given the near‐complete overlap of YPRMAX credible intervals for all estimable scenarios and the small significant differences (1–3%) based on FMAX between the most permissive and most restrictive scenarios. Despite the existence of significant differences in FMAX, they are likely biologically irrelevant based on the life histories of these species. Although modeling results suggested that the implemented harvest regulations will not likely affect catfish population demographics or fishery yield in the lower Ohio River, a post hoc evaluation examining the accuracy of these predictions is needed and would improve the accuracy and precision of parameter estimates.

Evaluating ground‐penetrating radar antenna performance for investigating Mississippian mound construction compared with data from solid‐earth cores and magnetometry

AbstractMississippian mounds in the south‐eastern and mid‐continental United States often contain multiple construction stages and a diverse array of features. Investigating mound construction with excavation is expensive, logistically challenging, and sometimes politically impossible. Three mounds at the Angel site (12VG1), a Mississippian village (ca ad 1100–1450) in the lower Ohio River Valley, were investigated with non‐invasive geophysical and minimally invasive geoarchaeological methods. We compare the efficacy of two different ground‐penetrating radar (GPR) antenna frequencies (250 and 500 MHz) for detecting elements of mound construction previously identified with solid‐earth cores, magnetometry, and electrical resistance tomography. Solid‐earth cores provide stratigraphic information about mound layers and construction soils and materials with low horizontal spatial resolution. Surface magnetometry provides information on shallow features, such as buried building walls and floors at high resolution, but little information about depth. Radar profiles taken with 500 MHz and 250 MHz antennae were evaluated to determine which antenna frequencies are most suitable for detecting features and strata that had been documented using the other methods. Utilizing the solid‐earth cores for velocity correlations, the 500 MHz antenna provided the most useful information about prehistoric structures near the mound surface, but was limited by its relatively shallow penetration depth. The 250 MHz antenna was not able to resolve shallow features as clearly as the 500 MHz antenna. However, it was able to detect possible interior mound platforms and features, although without providing many details about possible buried structures. In combination, GPR, solid‐earth cores, and magnetometry provided new information about the construction of mounds at the Angel site.

Reweaving river food webs through time

Abstract Our project sought to determine ecological effects of adding low‐head dams and levees to large rivers by examining potential changes to aquatic food webs over a 70‐year period in the Lower Ohio River (LOR) and Upper Mississippi River (UMR). We employed museum collections of fish and compound specific stable isotope analysis of amino acids to evaluate long‐term changes in primary food sources for multiple species of fish in each river. Fishes in both rivers depended more on autochthonous than allochthonous carbon sources throughout the 70‐year period (based on measurements of isotopic signatures of algae, C3 plants, C4 plants, cyanobacteria, and fungi), but the relative use of different carbon sources differed between the UMR and LOR. Significant but opposite shifts in trophic positions (TP) between rivers over time (higher TP in the UMR; lower in the LOR) were correlated with major anthropogenic changes to habitat structure (e.g. slight decrease in abundance of side channels in the UMR; increase in pool water depth in the LOR) resulting from low‐head dam construction. They may also have been influenced by likely increased primary productivity in the UMR from agricultural nitrogen inputs and by possible shifts in the importance of phytoplankton versus benthic algae in the LOR from changes in water depth. Shifts in trophic position and reliance on various food sources were not correlated with variation in discharge, gage height, or temperature. Although these two rivers have contrasting hydrogeomorphic complexity (UMR is an anastomosing river, while the LOR is a constricted channel river) and different discharge patterns (seasonal versus yearly operation in some cases), both differ substantially from rivers having hydrogeomorphic changes resulting from construction of high dams (>15 m). It is not surprising, therefore, that factors controlling trophic position and reliance on different carbon sources vary among different types of dams and river structures.

Pre-Columbian lead pollution from Native American galena processing and land use in the midcontinental United States

Abstract The presence and sources of pre-Columbian (before 1492 CE) lead (Pb) pollution in the midcontinental United States were investigated using geochemical and Pb isotope analyses on sediment cores recovered from Avery Lake, a floodplain lake located directly adjacent to the Kincaid Mounds archaeological site on the lower Ohio River, Illinois. Geochemical results indicate the presence of Pb pollution during the Baumer (300 BCE to 300 CE) and Mississippian (1150–1450 CE) occupations, and since the 1800s. Pb isotope results link Mississippian Pb pollution to the processing and use of galena primarily from southeastern and/or central Missouri, and to a lesser extent the upper Mississippi River valley, with ∼1.5 t (metric tons) of galena-derived Pb deposited in Avery Lake during this time. Pb pollution during the Baumer phase, equating to ∼0.4 t of Pb, was not accompanied by a Pb isotope excursion and most likely originated from local biomass burning. These results provide new information about the environmental impacts associated with pre-Columbian Native Americans’ interaction with and utilization of their landscape and its resources.

Late-Holocene floodplain development, land-use, and hydroclimate–flood relationships on the lower Ohio River, US

Floodplain development, land-use, and flooding on the lower Ohio River are investigated with a 3100-year-long sediment archive from Avery Lake, a swale lake on the Black Bottom floodplain in southern Illinois, US. In all, 12 radiocarbon dates show that Avery Lake formed at 1130 BCE (3100 cal. yr BP), almost 3000 years later than previously thought, indicating that the Black Bottom floodplain is younger and more dynamic than previously estimated. Three subsequent periods of extensive land clearance were identified by changes in pollen composition, corresponding to Native American occupations before 1500 CE and the current Euro-American occupation beginning in the 18th century. Sedimentation rates prior to 1820 CE changed independently of land clearance events, suggesting natural as opposed to land-use controls. Comparison with high-resolution paleoclimate data from Martin Lake, IN, indicates that lower Ohio River flooding was frequent when cold-season precipitation originating from the Pacific/Arctic predominated when atmospheric circulation resembled positive Pacific North American (PNA) conditions and the Pacific Decadal Oscillation (PDO) was in a positive mean state (1130 BCE to 350 CE and 1150–1820 CE). Conversely, Ohio River flooding was less frequent when warm-season precipitation from the Gulf of Mexico prevailed during negative PDO- and PNA-like mean states (350 and 1150 CE). This flood dynamic appears to have been fundamentally altered after 1820 CE. We suggest that extensive land clearance in the Ohio River watershed increased runoff and landscape erosion by reducing interception, infiltration, and evapotranspiration, thereby increasing flooding despite a shift to negative PDO- and PNA-like mean states. Predicted increases in average precipitation and extreme rainfall events across the mid-continental US are likely to perpetuate current trends toward more frequent flood events, because anthropogenic modifications have made the landscape less resilient to changing hydroclimatic conditions.

Population Demographics of Sauger and Simulated Effects of Minimum Length Limits in the Kaskaskia and Ohio Rivers

Abstract Sauger Sander canadensis are a popular sport fish native to large turbid midwestern rivers and are in decline across much of their range due to habitat loss and exploitation. Specifically, within the lower Kaskaskia and Ohio rivers, Sauger are managed under different harvest regulations and a knowledge gap exists regarding the current status of both populations as well as the effects of the harvest regulations on the size and age structures of both populations. We collected Sauger by nighttime boat electrofishing during early winter 2014–2016 and used otoliths to age all fish. Sauger stocks in both rivers exhibited fast growth rates and high annual mortality rates. Yield-per-recruit modeling indicated that the current 356-mm minimum size limit for Sauger in the Kaskaskia River is sufficient to prevent growth overfishing and likely explains the consistently larger size structure (greater proportion of fish ≥356-mm total length) of Sauger sampled from the Kaskaskia River compared with the Ohio River. Modeling suggested that growth and recruitment overfishing of Sauger are likely occurring in the Ohio River with no minimum length limit based on available exploitation estimates for Sauger in the lower Ohio River. Implementing a 356-mm minimum length limit for Sauger in the lower Ohio River is predicted to prevent growth and recruitment overfishing based on available exploitation rate estimates and would be consistent with the statewide minimum length limit for Sauger in Illinois and minimum length limits on two major tributaries (Tennessee and Cumberland rivers downstream of Kentucky and Barkley lakes, respectively).

Carbon Sources in Riverine Food Webs: New Evidence from Amino Acid Isotope Techniques

A nearly 40-year debate on the origins of carbon supporting animal production in lotic systems has spawned numerous conceptual theories emphasizing the importance of autochthonous carbon, terrestrial carbon, or both (depending on river stage height). Testing theories has been hampered by lack of adequate analytical methods to distinguish in consumer tissue between ultimate autochthonous and allochthonous carbon. Investigators initially relied on assimilation efficiencies of gut contents and later on bulk tissue stable isotope analysis or fatty acid methods. The newest technique in amino acid, compound specific, stable isotope analysis (AA-CSIA), however, enables investigators to link consumers to food sources by tracing essential amino acids from producers to consumers. We used AA-CSIA to evaluate nutrient sources for 5 invertivorous and 6 piscivorous species in 2 hydrogeomorphically contrasting large rivers: the anastomosing Upper Mississippi River (UMR) and the mostly constricted lower Ohio River (LOR). Museum specimens we analyzed isotopically had been collected by other investigators over many decades (UMR: 1900–1969; LOR: 1931–1970). Our results demonstrate that on average algae contributed 58.5% (LOR) to 75.6% (UMR) of fish diets. The next highest estimated contributions of food sources were from C3 terrestrial plants (21.1 and 11.5% for the LOR and UMR, respectively). Moreover, results from 11 individually examined species consistently demonstrated the importance of algae for most fish species in these trophic guilds. Differences among rivers in relative food source availability resulting from contrasting hydrogeomorphic complexity may account for relative proportions of amino acids derived from algae.

Late Quaternary chronostratigraphic framework of terraces and alluvium along the lower Ohio River, southwestern Indiana and western Kentucky, USA

The lower Ohio River valley is a terraced fluvial landscape that has been profoundly influenced by Quaternary climate change and glaciation. A modern Quaternary chronostratigraphic framework was developed for the lower Ohio River valley using optically stimulated luminescence (OSL) dating and allostratigraphic mapping to gain insights into the nature of fluvial responses to glacial–interglacial/stadial–interstadial transitions and Holocene climate change. River deposits, T0 (youngest) to T7 (oldest), were mapped along a 75 km reach of the lower Ohio River and were dated using 46 OSL and 5 radiocarbon samples. The examination of cores combined with OSL and radiocarbon dating shows that fluvial sediments older than marine oxygen isotope stage (MIS) 2 are present only in the subsurface. Aggradation during MIS 6 (Illinoian glaciation) filled the valley to within ∼7 m of the modern floodplain, and by ∼114 ka (MIS 5e/Sangamon interglacial) the Ohio River had scoured the MIS 6 sediments to ∼22 m below the modern floodplain surface. There were no fluvial sediments in the valley with ages between MIS 5e and the middle of MIS 3. The MIS 3 ages (∼39 ka) and stratigraphic position of T5 deposits suggest the Ohio River aggraded 8–14 m during MIS 4 or MIS 3. Near the end of MIS 3, the Ohio River incised the mid Last Glacial (mid-Wisconsinan) deposits ∼10 m and began aggrading again by ∼30 ka. Aggradation continued into MIS 2, with maximum MIS 2 aggradation occurring before ∼21 ka, which is coincident with the global Last Glacial Maximum (LGM). As the Ohio River adjusted to changing fluxes in sediment load and discharge following the LGM, it formed a sequence of fill-cut terraces in the MIS 2 outwash that get progressively younger with decreasing elevation, ranging in age from ∼21 ka to ∼13 ka. From ∼14 ka to ∼13 ka the Ohio River rapidly incised ∼3 m to form a new terrace, and by ∼12 ka at the onset of the Holocene, the Ohio River established a meandering channel pattern. The river formed a broad floodplain surface from ∼12 ka to ∼6 ka, and then incised ∼1 m and formed a fill-cut terrace from ∼6 ka to ∼5 ka. After ∼5 ka, likely in response to mid-Holocene drought in North America, the Ohio River incised ∼5 m, and by ∼4 ka the river began aggrading again. The Ohio River has aggraded ∼4 m since aggradation began at ∼4 ka. The chronostratigraphic framework and reconstructed history developed here suggest that the lower Ohio River is highly sensitive to glacial–interglacial transitions and abrupt Holocene climate change and responds rapidly to these allogenic forcings.

Short term occupation surfaces in the lower Ohio River Valley: Exposing more of the late Holocene hidden record

As in other larger river valleys, Holocene alluvial deposition in the lower Ohio River Valley created a sampling bias towards certain prehistoric archaeological sites by burying them too deep to be accessed by conventional archaeological methods. Alternatively, archaeological site types that do not leave a large signature (i.e. a large sample of artifacts) may also be obscured since they are not associated with recognizable geomorphic or soil development features, such as a buried A horizon. This obscuration has led to an incomplete record of the region's prehistory. To better understand the age and type of prehistoric sites that may be buried within this alluvial landscape, it is necessary to understand the structure and history of the alluvium in the valley. This can be done by reconstructing the chronological development of alluvial deposits and the soils that formed in them. Regional models for the age and development of Ohio River Valley alluvium, and the cultural deposits they may contain, have been previously developed, but must be continuously reviewed and revised as to their applicability to all and any alluvial packages found within the lower Ohio River Valley. This study tests and expands some of these models through the investigation of an alluvial landscape near the confluence of the Ohio and Great Miami Rivers in Indiana. An age-based landscape reconstruction, which focuses on late Holocene alluvium, is presented. Cultural deposits can be linked to brief stability periods within alluvial packages, stability periods that were too brief to have formed an A horizon. This study shows that short-term or ephemeral prehistoric occupations may co-occur with periods where the surface of an alluvial landscape or landform was geomorphically stable for a brief period. Identifying these short-term stable surfaces could likely lead to the better identification of underrepresented prehistoric cultural components or archaeological site types and help to reduce sampling bias in the regional prehistoric record.

The Distribution of Negative Painted Pottery in the Caddo Area

Negative painted pottery (NPP) is one of the most distinctive kinds of pottery made by Mississippian peoples during the Middle Mississippian period (ca. A.D. 1200-1500) in eastern North America. This pottery is decorated with a “resist painting technique, which creates a lighter-colored design outlined by a black pigment” over an underlying slip/wash. Principal production areas for NPP include the lower Ohio River valley, the Nashville Basin, and the Bootheel of southeast Missouri, and there are four main types: Kincaid Negative Painted, Nashville Negative Painted, Sikeston Negative Painted, and Angel Negative Painted. This NPP has been found in several sites in the southern and northern Caddo areas, and its occurrence in Caddo sites constitutes compelling evidence for some form of contact and interaction between Caddo peoples and peoples from various Mississippian polities, most particularly Mississippian polities in the Nashville basin.