Radiocarbon age determination of a rock painting at Arnold/Tainter Cave, Wisconsin

Midcontinental Journal of Archaeology, Spring 2001 by Steelman, Karen L, Rowe, Marvin W, Boszhardt, Robert F, Southon, John R

ABSTRACT

A sample from a charcoal rock painting at the Arnold/Tainter Cave site (47Cr560) was radiocarbon dated, providing the first direct age determination for a pictograph in Wisconsin. The sample was pretreated with HCI and NaOH before organic carbon was extracted using an oxygen plasma. The painting, of a creature resembling a caribou because of the orientation of the tines on its antlers, is of interest because caribou have not been found in southwestern Wisconsin since the end of the Pleistocene. However, the accelerator mass spectrometry (AMS) radiocarbon age determination of 1260 /- 60 BP is inconsistent with such a species identification. Another sample-from a painting of a deer-was also taken but did not yield enough carbon for radiocarbon measurement.

Introduction

Arnold/Tainter Cave (47Cr560) is located in the unglaciated "Driftless Area" of southwestern Wisconsin (Figure 1). The cave is an interstratal formation within the St. Peter Sandstone and consists of three connected chambers that extend for a total of 80 m (Figures 2, 3). Ambient light reaches only the front half of the first chamber, and birch bark torches found on the floor may have been used to provide light for prehistoric activities in the darker recesses (Boszhardt 2000). Preliminary investigations have identified nearly 100 individual drawings on a series of wall panels in all three rooms. Although no effort was made to investigate the presence of mineral deposits in the pigment layer, our experience has shown that virtually all rock paintings have mineral deposits associated with them. These are usually carbonates and oxalates in limestone environments. Sampling of such paintings also inevitably involves inclusion of some of the basal rock.

The Arnold/Tainter Cave pictographs are all black and depict a variety of forms, including human, bird, deer or elk, and geometric motifs such as grids, arcs, circles, and rectangles. With the exception of that in Panel 5 in Chamber I, the animals are drawn in outline. The Panel 5 animal is unique in having a completely filled-in body (Figure 4). Close examination of the Panel 5 animal in May 1999 revealed an apparent antler rack that curved up and forward from the head. This configuration is not typical of deer and elk petroglyphs at other Driftless Area sites and resembles that of a caribou. Renderings of antlered cervids in this region depict the antlers as straight racks oriented either above or, more commonly, behind the head and over the shoulders (e.g., Gullickson's Glen [Ritzenthaler 1950:Figure 61, Samuel's Cave [Brown 1879:Figure 4], and Hole in the Wall #1 [Lowe 1987:Figure 14]). These have traditionally been interpreted as deer or elk. According to Jackson (1961:426-427), caribou historically were restricted in range to the northern margins of Wisconsin. Caribou subfossil remains have been found in southern Wisconsin but are associated with the end of the Pleistocene (West and Dallman 1980), the period of the earliest documented human occupation of the Driftless Area (ca. 10-12,000 BP). Because the Panel 5 animal resembles a caribou and differs in execution from the outlined animal figures drawn elsewhere in Arnold/Tainter Cave, it seemed plausible that Paleoindian artists might have drawn Panel 5. We decided, therefore, to collect a pigment sample for AMS dating. The age reported for this pictograph is the first "direct" radiocarbon age determination for a pictograph in Wisconsin. The nearest pictographs to Arnold/Tainter Cave that have been radiocarbon dated are those in Missouri studied by Diaz-Granados et al. (2001).

Chamber II of Arnold/Tainter Cave contains a dramatic group of pictographs consisting of sky symbols above a group of bow hunters and deer. The deer and the hunters are separated from the sky symbols by a horizontal fault line, and the scene thus conforms to a common Native American world view that segregates earth clans and their associated spirits from sky clans and their spirits (Figure 5). The scene includes nine hunters, each of whose bodies is filled in, and at least seven deer whose bodies are drawn in outline. The relatively long tails, raised as if in alarm, suggest that the animal images represent white-tailed deer. None have antlers, and three contain fetuses within their abdomens. These characteristics clearly reveal that the hunt being depicted occurred during the late winter or spring season.

Bow hunting is assumed to have been adopted by Driftless Area populations around A.D. 500, based on the dating of the earliest small chipped stone arrow tips in the archaeological record. The bow and arrow were used throughout the late prehistoric period and into historic times. Consequently, the bow-hunting scene depicted in Chamber II must postdate A.D. 500 but could have been drawn anytime thereafter. Interpretations of regional archaeological settlement patterns suggest that the portion of the Driftless Area encompassing Arnold/Tainter Cave was abandoned by about A.D. 1100. This and other circumstantial evidence suggest that the Chamber II panel is associated with the Late Woodland Effigy Mound culture, dating between ca. A.D. 600 and 1100. In order to test this interpretation, a pigment sample was collected for radiocarbon assay from one of the deer in the scene.