Date Approved

2006

Degree Type

Open Access Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

Committee Member

Ruth Ann Armitage

Abstract

A black coating of unknown origin obscures the pictographs in Little Lost River Cave, Idaho. We utilized x-ray photoelectron spectroscopy (XPS) to characterize the outermost surface of the black coating to understand how it was formed. Carbon and oxygen predominated in the XP spectra, whereas nitrogen was detected at varying levels in different samples. High-resolution carbon 1s XP spectra showed that carbon was present in at least three different forms: hydrocarbon C, carbonyl C, and carbonate C/ amide C. The N 1s peak was observed at ~399-400 eV binding energy, which is usually attributed to aromatic or amide N. The surface composition of the coating was variable throughout the cave. The XPS results are consistent with the coating’s being a water-deposited layer of humic substances from the overlying soil.

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Chemistry Commons

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