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Archaeological Investigations Within the Proposed U.S. 61 Corridor North of Canton in Lewis and Clark Counties Missouri, Volume II:  Environmental Reconstruction



The reconstruction of past environments focuses on indicators of prehistoric natural processes identified in current environmental contexts. These environmental indicators can be inferred from sources such as trace elements, fossil assemblages, and sediment characteristics. For the Avenue of the Saints (AOS) Project, pollen and phytolith analyses, as well as carbonisotope analysis, were conducted on sediment from cores to examine signs of prehistoric climate and vegetation change. Vegetation data from historic maps was also examined for a record of the recent past environment. Geomorphology and sedimentological analysis, along with radiocarbon dating, further provides inferences regarding prehistoric landscape change. The relevance of each specific analysis to the past environmental reconstruction of the project area vicinity is discussed in more detail in this report.

 

The AOS geo-archaeological investigation strengthened and expanded upon prior models of site potential in the upper Mississippi River valley. In general:

 

  • Late Pleistocene and early Holocene archaeological sites are the least likely types of sites to be found preserved in the valley. Sites of this age could be found in shallow deposits on the remnant terrace landforms along the valley margins and, when not eroded by later slope and stream action, they can be found preserved beneath the fans that have prograded across those landforms during the Holocene.

 

  • Middle Archaic sites are also sparse in the valley, perhaps a result of sampling bias and/or settlement patterning. These sites could be found shallowly on terrace landforms and deeply buried in small fans along the valley margins, as well as on larger fans where later erosion has not removed them. These sites could also likely be found on alluvial landforms close to the Early- Middle Holocene channel belt.

 

  • Late Archaic sites could be found in shallow deposits on proximal parts of fans, as well as more deeply buried on medial parts of fans.

 

  • Woodland sites are most common in the area and can be found buried in distal fans deposits or very shallowly buried on proximal parts of terraces and fans. Woodland deposits could also be found buried in the Late Holocene alluvium on the current Mississippi River floodplain.

AOS_Vol2_geomorph

 

Three sites (23CK57, 23CK59, and 23LE174) were sampled stratigraphically for pollen and phytoliths for the purpose of examining the past environment. The stratigraphic record was incomplete at all of the sites, so a combined paleoenvironmental history is constructed from segments at several different sites.  From oldest to most recent, the sites contribute the following to our reconstruction of the paleoenvironment:

  • Sugar Creek Site (23CK57) contained Late Pleistocene Superior clays at the base, providing a Late Pleistocene record (older than 9500 BP).
  • The time period between 8940 and 8580 BP, was represented only at the Logsdon Fan Site (23CK59), which was not examined for pollen.
  • Berhorst Site (23LE174) contains deposits between 6275 and 5515 BP, which provide information on a portion of the middle Holocene.
  • Big Branch Site (23CK302) yielded radiocarbon dates between 3510 and 2550 BP, which provides a look at a thousand-year interval of sediments that accumulated between the Indus and Vandal events (world-wide increased volcanic activity).. It is likely that the Mississippi River experienced flooding during both of these events.  This flooding might be responsible for removing sediments from many of these sites along the Mississippi River.
  • Sugar Creek Site (23CK57) provides the only evidence for examining a short interval, between 1380 and 1210 BP, during the Woodland occupation of the area. This same Woodland time period is also represented by feature samples examined from Sites 23Le178/357 and 23LE348, which are not discussed here because it was not possible to fit the results of individual features into the stratigraphic sequence.
  • Finally, sediments representing deposition post-1400 BP were examined from Berhorst Site (23LE174).

 

AOS2_table

 

While the pollen and phytolith data provided broad signs of climate change through time, archaeobotanical data from the sites provides direct evidence of nearby vegetation during the site occupations:

  • The two Early Archaic sites, Baxter Lake (23LE41) and the Logsdon Fan (23CK59) contained negligible evidence of past vegetation used by the inhabitants. At the Baxter Lake site, one wood specimen was identifiable to the white oak group and two specimens were identifiable only as indeterminate oak. Oak acorn shell was also represented, but no other plant or wood could be identified. No identifiable wood or plant taxon was found at the Logsdon Fan site. The overall lack of preserved plant remains could be related to site seasonality, but is more likely attributed to increased weathering often found at much older open-air site contexts such as these.
  • Compared with the Early Archaic sites, the Middle Archaic deposits at the Berhorst site (23LE174) yielded a larger, but still sparse, sample of identifiable wood and nuts. Wood taxa included oak and elm. Hickory nuts were also identified in features and likely represent additional trees in the site vicinity, as well as a likely source of food.
  • During the Late Archaic occupation at the Big Branch Fan site (23CK302), plant remains from features indicated a mixed subsistence strategy involving both native plant food gathering (principally hickory nuts and to a lesser extent walnuts) and the use of sumpweed.  Several weedy plant taxa, including those of a ruderal chenopod, suggested a relatively open and disturbed environment, at least in the vicinity of the site. The identified tree taxa, including hickory, red oak, white oak, and walnut, represent high quality fuel woods and would have been available in the immediate site area.
  • The three larger Woodland period sites investigated for the AOS project (23LE178/357, 23LE348, and 23CK57) had more extensive wood and seed assemblages. Wood charcoal at all three sites included a prevalence of oak, followed by much lower percentages of hickory, elm, ash, walnut, and cherry/plum. Willow, honey locust/coffee tree, sycamore, maple, mulberry, and sassafras wood were also identified at most of these sites. Possible cultigens at these Woodland sites included chenopod, knotweed, little barley, marshelder, maygrass, and sunflower. A variety of available fruits, including wild grape, plum, and blackberry/raspberry, were also suggested in the site vicinities.

Faunal remains recovered from the sites also provide a record of local environmental conditions, as well as seasonality of the occupations:

 

  • The faunal material from the early and Middle Archaic sites was sparse, and largely included highly weathered indeterminate specimens or material from poor context. Little more than presence of faunal remains could be inferred from the assemblages at these Archaic sites.

 

  • In contrast, a wide variety of species (fish, mammal, bird, reptile, and amphibian) were identified at the Middle Woodland component at the Carskadon Site (23LE348). The most abundant species found in features at this site was white-tailed deer. Fish were also very abundant and included both river and backwater slough species.

 

  • The Late Woodland sample from the Carskadon Site was much smaller than the Middle Woodland assemblage. Mammals were the mostabundant class utilized. Birds included the family Anatidae (ducks, geese and swans), wild turkey, and perching birds. Fish comprised a high proportion of the sample and included numerous species from backwater slough and river ecotones.

 

  • The faunal materials were also recovered from three Late Woodland components at the Artesian Branch site (23LE178/357). Inhabitants of the site consumed animals from terrestrial settings, including prairie and upland areas, as well as from aquatic environments. Species in the assemblages included white-tailed deer, the dog family, raccoon, prairie chicken, a venomous snake, soft-shelled turtle, mud or musk turtle, bowfin, gar, several species of catfish, sucker, freshwater drum, and sunfish. Fish could have been obtained during any season, but the presence of reptiles in the assemblage suggests spring or fall occupation(s).

 

  • The Late Woodland South Branch and Ralls Phase samples from the Sugar Creek site (23CK57) consisted primarily of mammal (deer), withsmaller amounts of reptile, bird, and fish. These likely indicate that terrestrial resources were more of a focus here. The presence of aquatic species such as fish and waterfowl indicates the local streams and/or backwater lakes and ponds were also being secondarily exploited. The recovery of migratory birds and reptilian specimens within the assemblages suggests use of the site area during the late spring/early summer and/or fall months during the Late Woodland occupations.

 

  • Based on the wide variety of faunal taxa represented, the occupants of these Woodland sites exploited a variety of ecotones, including uplands, bluff base, riverine/floodplain, and backwater/slough areas. All of the faunal remains recovered from the Woodland components are species typically found in a temperate climate currently in the region.
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