This report presents results of re-excavation and reanalysis of unit 5276N 4790E, located on Ridge West 3 (RW3) at the Poverty Point site. Jon Gibson excavated this unit and others in 1991 and argued that RW3 was constructed rapidly. We test the fast construction hypothesis by applying new methods (micromorphology, magnetic susceptibility, sequential loss-on-ignition) and by obtaining new radiocarbon dates. Before construction, the ground surface beneath RW3 was cleared and occupied. Preconstruction deposits are composed of anthropogenically enriched sediments. RW3 was constructed in layers of mixed heterogeneous natural and anthropogenically enriched sediments. The surfaces of these layers were used briefly during construction. The goal of the builders was to quickly raise the ridge to its full height. Magnetic susceptibility measurements and artifact density data show that the top of the constructed ridge is buried 10 to 30 cm below the modern surface. The construction of this section of RW3 was exceptionally rapid. The ridge was built after 3355-3210 cal BP and was under construction by at least 3450-2975 cal BP. Analysis of existing excavations offers great opportunity for pursuing vital research questions while having a limited effect on the integrity of archaeological deposits at Poverty Point.
A multistaged geophysical methodology was recently used at site 15Ck10, a state-protected Middle Woodland period Adena (500 BCE to CE 250) conical burial mound in Central Kentucky, USA. Data from this research are used to develop anthropological interpretations on the nature of burial mound construction and regional interaction between separate mortuary traditions in Kentucky. Methods utilized in this research include magnetic gradiometry, electromagnetic induction, ground-penetrating radar, electrical resistivity tomography and downhole magnetic susceptibility. Together, these methods helped identify a circular ditch-and-embankment earthwork enclosing the burial mound, as well as possible off-mound activity areas commonly reported in the Adena literature. Within the mound, multiple anomalies were discovered that are consistent with hypothesized geophysical responses of mound stages and funerary features. A review of burial mounds excavated by the University of Kentucky during the depression-era work relief programmes (i.e. the Works Progress Administration -WPA) of the 1930s and early 1940s provide a vehicle with which to interpret these features. Comparisons of our data with length and width dimensions of known mortuary facilities documented in WPA excavations suggest that two distinct burial types were used at 15Ck10. These data are used to build a comprehensive site interpretation and create a relative dating context for the site. We use the site-level model to evaluate regional interaction on Kentucky's Middle Woodland social landscape. Figure 2. (a) Gradiometer imagery from 15Ck10. Data were collected with a Bartington Grad601-2 at a sampling density of 0.5 m by 0.25 m. Processing was performed in Geoplot 3 with zero-mean-traverse and destagger functions applied to the data. (b and c) Electromagnetic imagery from 15Ck10. Data were collected with a Geonics, Inc. EM38B in dual-phase mode at a sampling density of 0.5 by 0.5 m. (b) Results of the q-phase EM survey and conductivity features discussed. (c) Results of the in-phase EM survey and corresponding gradiometer anomalies.
Magnetic gradiometry and in-phase electromagnetic induction (EM) instruments were employed during a geophysical survey to identify archaeological features at an Adena circular ditch and embankment earthwork site. Three features identified in the geophysical survey were selected for further geophysical examination because of their shape, spatial arrangement, and differences in the gradiometer and EM data. Downhole magnetic susceptibility was used to explore the subsurface shape of these features and to identify the presence of magnetic variations within them. Excavation of these features exposed a buried ground surface below the earthwork's embankment, a midden-like soil in the ditch, and a large pit situated over a spring/seep inside the earthwork. Magnetic susceptibility data were collected on open wall profiles of excavation units with a KT9 kappameter. Pairing the geophysical results and excavation profiles helped separate a lightly burned ground surface from a buried A horizon below the embankment, map the buried A horizon beneath areas where the embankment is now destroyed, and separate natural from cultural fill episodes inside the pit feature. Correlations between the magnetic susceptibility data and drawn profiles identified specific cultural contexts for radiocarbon dating. The radiocarbon chronology of the site indicates the earthwork was constructed during Middle Adena ritual development (150BC to AD 1), a time marked by increasing ritual diversity and the appearance of circular structures used in mortuary ritual. This research also demonstrated that the Woodland earthwork was reused by Late Fort Ancient peoples after approximately AD 1450 .
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