Description:
A glossy, black deposit covers much of the ceiling and walls of Little Lost River Cave No. 1, Idaho. This site is of particular interest because of the red, orange, and yellow pictographs underlying the coating. Carbon and nitrogen stable isotope analysis has allowed us to better understand the nature and origin of the deposit. With a δ13C value of −20·1‰, δ15N value of +14‰, and a C/N ratio of 5·6 after the removal of inorganic carbon from the sample matrix, the deposit appears to have been derived from animal tissue, not plant. Plasma chemical extraction of carbon from the organic material in another sample of the deposit, followed by accelerator mass spectrometric analysis, yielded a minimum uncalibrated radiocarbon age of 2990±50 bp for the paintings. This preliminary evidence suggests that the deposit may be cooking residue.
Saiz-Jimenez and Hermosin [18] used pyrolysis-gas chromatography-mass spectrometry (py-GC-MS) and thermally assisted hydrolysis methylation (THM) on a black coating in Cueva del Encajero, Spain, which probably originated from decomposing olives in the overlying soil. Based on charcoal and faunal evidence, Steelman et al. hypothesized that the black coating in the Idaho cave may be a residue from cooking animals within this enclosed space. To test the cooking residue hypothesis, Steelman et al. [19,20] used elemental and stable isotopic analysis to determine the proportions of C and N; C/N ratios of 5.6 and d 13 C = À20.1% and d 15 N = +14.9%.
Based on charcoal and faunal evidence, Steelman et al. [19,20] hypothesized that the black coating in the Idaho cave may be a residue from cooking animals within this enclosed space. To test the cooking residue hypothesis, Steelman et al. used elemental and stable isotopic analysis to determine the proportions of C and N; C/N ratios of 5.6 and d 13 C = À20.1% and d 15 N = +14.9% fall within expected ranges for animal tissue, and have been interpreted as supporting a cooking residue origin for the coating in 10BT1
