PETROGLYPHS – DATING THE OTHER 95% OF ROCK ART

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(Slide 20) I chose the concave-faced Double Spiral petroglyph boulder because art debris would have funnelled into our test soil. (Slide 21) I also wanted motifs where flying hammerstone chips would have been deflected back into the soil below the art. Soil below the Double Spiral motif was tested down 12 levels to 6 cm. Possible sharp quartz hammerstone chips were in four levels, with rhyolite chips in two levels that had fallen naturally from its boulder. Carbon samples were in all levels, as was rock flour.

(Slide 22) The Single Spiral motif was completely enclosed by high boulders. Soil below the Single Spiral motif contained 21 levels to a depth of 10.5 cm. Sharp quartz chips, possibly from hammerstones, were only in levels 6 and 7, but quartz chips in levels 12 may have originated likewise. Naturally fallen rhyolite chunks were in most levels, as were carbon samples. Rhyolite flour was absent because line grinders were not used. (Slide 23) As motif visibility differs with sun angle, we enhanced the Double & Single Spiral motifs using software, revealing older motifs. These findings correspond to our multi-levelled art debris in showing older art applications.

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Slide 20
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Slide 21
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Slide 22

(Slide 24) I chose the Bear Paw petroglyph because its main motif was surrounded by dart throwers pre-dating the 800 AD bow and arrow. A deflecting boulder and its sloping rock face would have directed art debris to the soil where we tested. The Bear Paw motif had 10 levels to a depth of 5 cm. Possible quartz hammerstone chips were found only in levels 5 and 7. Rock flour was in most levels, with quartz crystals from hammerstones absent. Carbon samples were in all levels except 7, with much organic material in four levels.

(Slide 25) In conclusion, all five petroglyphs tested at Gabriola and Coso were likely made in stages. Gabriola’s deeply ground motifs were repeatedly visited over the last 1000 years. Coso’s shallow pocked motifs barely penetrated the desert varnish, yet were likely done in stages, especially complex panels. Hammerstones were used, with little sign of line grinders. The motifs enhanced on the same panel as the Single Spiral motif were likely done much earlier. The slightly and evenly weathered Bear Paw panel with its dart throwers was likely jointly done more than 1000 years ago. Dating several soil levels under a panel will help us comprehend the true length of art traditions.

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Slide 23
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Slide 24
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Acknowledgements:

Mary Wohlleben, Eva Linklater, Midge Gordon and Robbie Robinson assisted in testing the Gabriola petroglyphs. Both pairs of landowners Glenna Borsuk & Don Gatley and Dave & Keni Lorette provided access to the art, and Don and Mary covered three petroglyph boulders a week before our arrival to keep their soil dry for sieving. Duaine and Vieno Lindstrom, Michael and Richard Heath, Pete McQueen and Bruce Thompson tested the Single Spiral and Bear Paw tests. Kish LaPierre and Sandy Rogers were helpful in guiding us to Little Petroglyph Canyon and assisting in testing the Double Spiral motif with Midge Gordon. At the Museum, Don Gribble, Alicia Ghadban and Frank Bayerl separated samples using sieving, flotation and microscopy. Frank and Alicia proofread this paper. Archaeological permits were issued through the Archaeology Branch of the British Columbia Ministry of Tourism, Culture and the Arts, and the United States Navy.


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