Relative dating of Hawaiian lava flows using multispectral thermal infrared images: A new tool for geologic mapping of young volcanic terranes

TLDR

Weathering of Hawaiian basalts in arid and semiarid environments alters their thermal infrared spectra, changes that can be mapped with multispectral imaging and are linked to glassy crust development, iron oxidation, and silica‑rich surface veneers. The authors propose using these quantitative multispectral measurements to estimate relative ages of lava flows in geological mapping. In Hawaii, the method most effectively distinguishes sparsely vegetated flows younger than about 1.5 ka.

Abstract

The weathering of Hawaiian basalts in arid and semiarid environments is accompanied by change in their thermal infrared emittance spectra. The spectral differences can be measured and mapped with multispectral imaging systems. The differences appear to be related to the degree of development, preservation, and alteration of glassy crusts; the oxidation of iron; and the accretion of silica‐rich surface veneers. Because the measurements are quantitative and in image format, they are useful for estimating relative ages in geologic mapping of lava flows. In Hawaii this technique is most diagnostic for distinguishing among sparsely vegetated flows less than 1.5 ka in age.