3.10 Chumash Indian Rock Art: A Study of Pictograph Pigments in the Collections of the Santa Barbara Museum of Natural History
Internal Report to John Johnson,
Head of Anthropology, Santa Barbara Museum of Natural History
David A. Scott
The Getty Conservation Institute
Period of Activity: 1988-1991
Project Abstract
The report summarizes the initial work conducted on the rock
art pigments for important, primarily Chumash Indian, sites in the
vicinity of California. The purpose of this study was the analysis
of fifteen red and yellow pigment samples by polarized light microscopy
and energy dispersive X-ray fluorescence spectroscopy energy dispersive.
Further work concerning the characterization of these pigments was
carried out by X-ray diffraction and the pigments were primarily
identified as red ochres and yellow ochres. X-ray powder diffraction
work was carried out on a number of the pigment microsamples with
the result that many of them proved to be admixtures of quartz and
haematite. Components such as goethite or lepidocrocite were comparatively
less common in this material suggesting that the source of the pigment
was either a relatively pure haematite or that some conversion to
haematite had been deliberately created. Common impurities from
the Santa Barbara Channel Island areas include albite or anorthite.
Color photomicrographs are given of the typical pigment materials
and further work is envisaged on a number of related pigment samples
in the collections of the American Museum of Natural History in
New York.