Lawrence L. Loendorf

AMS Radiocarbon and Cation-Ratio Dating of Rock Art In the Bighorn Basin of Wyoming and Montana

Samples of organic matter and rock varnish from seven rock-art sites in the Bighorn Basin of Wyoming and Montana were collected for dating purposes. Petroglyphs sampled include Dinwoody-style figures, shield-bearing warriors, and other well-known Plains rock-art motifs. Accelerator mass spectrometry (AMS) dating of 10 petroglyphs yielded dates from the Early Archaic to the Protohistoric periods. A strong numerical relation between varnish leaching and time was found for petroglyphs older than 1,000 years, permitting the derivation of a cationleaching curve (CLC) and calibrated cation-ratio (CR) ages for 15 different petroglyphs. No clear numerical relation between varnish leaching and time was found for petroglyphs less than 1,000 years old, possibly due to historical damage or past environmental conditions. As a result, calibrated CR ages could not be derived for six petroglyphs, and they are considered to be only younger than 1,000 years. Although further research is needed to establish whether one CLC can be used for all petroglyphs in the region, these studies constitute the first numerical chronology for rock art in the Bighorn area. Results indicate the occurrence of spatially discrete, but temporally concurrent styles in the Bighorn Basin during the last 800-900 years.

Dated Rock Art Panel of Shield Bearing Warriors in South Central Montana

The use of traditional archaeological excavation to recover the tools used to complete a pictograph or petroglyph is one way rock art can be dated. Two sandstone abraders, used to smooth the rock face prior to painting a shield bearing warrior motif, were recovered in a datable context beneath a rock art panel in south central Montana. One of these abraders still hadpaint pigment adhering to it that matched one of the colors in the pictograph. The numerical age of the rock art panel was established by radiocar bon at A.D. 1104. Some researchers believe the shield bearing warrior motif was a product of Shoshonean speaking groups, but A.D. 1100 is two to four centuries older than their arrival to the area. Another can didate for the makers of the motif is the Avonlea, who are thought to represent Athapaskan movements through the site area at this time. Rock art was a topic of considerable study in North America a century ago (Mallery 1886; 1893) and has become the subject of renewed in vestigations today. Recent studies have focused on methods for establishing chronological con trols (Dorn and Whitley 1983; Wainwright 1987). One significant new method of determin ing the age of rock art is designed to date the rock varnish over petroglyphs (Dorn et al. 1986; Whitley and Dorn 1987). Other attempts have been made to date lichens growing over rock art and to date small amounts of carbon in the paint pigments (Wainwright 1987). Over the past five years, research has been under way in Montana and Wyoming to estab lish the age of rock art through experimental and traditional archaeological techniques. The primary focus of the research has been to recover the tools used in production of rock art. Initially a series of experimental petroglyphs were made by researchers to learn something about tool effectiveness and wear in petroglyph production. This work offered insights regard ing the sort of tools or fragments of tools one might expect to find at the petroglyph site. The most important research results were obtained through a series of excavation units placed at the base of rock art panels to search for the tools used in rock art production (Loendorf 1984). Rock art panels that were partially buried or very close to the ground surface were sought for the research. Ten rock art panels meeting these criteria were subjected to excavation using traditional techniques. Eight of these excava tions produced cultural debris directly as sociated with the rock art, and two were sterile. Six of the eight productive excavations con tained chipped stone flaking debris, charcoal, heat cracked stones, and broken bone. This is the sort of debris one would expect in an occupa tion site in Montana or Wyoming. In no instance was there any assurance the debris represented the makers of the rock drawings. The rock art could be the product of individuals who visited the site either before or after the time of the oc

Bird Rattle's Petroglyphs at Writing-On-Stone: Continuity in the Biographic Rock Art Tradition

Abstract Writing-On-Stone is well-known for its Plains Biographic rock art, characterized by distinctive motifs and narrative compositions. Biographic rock art flourished from the Late Prehistoric period throughout the nineteenth century. Although related images were drawn on hides and paper well into the twentieth century, it was unclear whether Biographic rock art also persisted this late. The recent discovery of photographs and narrative of a 1924 trip by Roland Willcomb and Pi egan elder Bird Rattle demonstrates that a well-known historic petroglyph at Writing-On-Stone was carved by this Plains warrior as part of the Biographic rock art tradition. Aside from showing a continuity of Biographic rock art well into the twentieth century, the positive attribution of these glyphs to an Indian artist supports the use of stylistic criteria to identify rock art ethnicity. Finally, the photographs and notes that Willcomb took on this trip provide significant insight into the sacred nature of Writing-On-Stone

Dating a Pictograph in the Pryor Mountains, Montana

We have dated a sample of red paint taken near an anthropomorphic pictograph in Elk Creek Cave in the Pryor Mountains, Montana. The radiocarbon date obtained, 840?50 years BP, is in agreement with expectations based on archaeological inference.

Rainy Buttes Silicified Wood:: A Source of Lithic Raw Material in Western North Dakota

An extensive lithic workshop and raw material procurement site was discovered near West Rainy Butte, Slope County, North Dakota, in 1982 during the University of North Dakota archaeological field school. The site covers over 500,000 m2 on a small ridgetop approximately 2 km southwest of West Rainy Butte (Fig. 1). Pebble, cobble, and small boulder-sized pieces of silicified material (chert) are scattered as probable erosional lag throughout the surface of the site. Numerous artifacts of this material include cores, flakes, pieces of shatter, and bifacially and unifacially modified tools. While no evidence is available to suggest that the material was quarried (actually dug out), evidence from the West Rainy Butte site suggests procurement of surface-available deposits. Similar material has been observed in artifact form on several other ar chaeological sites in the Rainy Buttes area (Stan Ahler, personal communication 1983; Loendorf 1982), and at other sites in western North Dakota (Ahler and Christensen 1983; Root 1983; Simon et al. 1982).

Radiocarbon dating a pictograph at Medicine Lodge Creek, Wyoming

Wyoming State Parks recovered a large chunk of the Medicine Lodge Creek Archaeological Site cliff wall, which had fallen away, with rock paintings on it. A sample from one of the paintings was dated to 800 BP with the Plasma Oxidation dating method. Comparison to regional sites suggests the dated painting is part of the Foothills Abstract tradition or a variant of the Columbia Plateau tradition.

Examination of Tipi Rings In the Bighorn Canyon - Pryor Mountain Area. In From Microcosm To Macrocosm: Advances In Tipi Ring Investigation and Interpretation

AbstractFrom 1968 through 1974, approximately 500 archaeological sites were recorded in the Pryor MountainBighorn Canyon area of south-central Montana. One hundred and twenty-two of these exhibited...