Prospects and problems in the use of hyperspectral imagery for archaeological remote sensing: a case study from the Faynan copper mining district, Jordan

Hyperspectral (multiple, narrow band) satellite imaging provides a useful discovery and analytical tool for archaeologists. The Hyperion instrument, flying on the Earth Observer 1 (EO-1) satellite, was launched from Vandenberg Air Force Base on November 21, 2000. Unlike 7-band Landsat or 15-band ASTER imagery, Hyperion provides 242 (196 calibrated) narrow bands in the visible (VIS) to shortwave infrared range (SWIR), enabling much more detailed archaeological and geological analyses. It was designed as a spectrometer specifically geared to mineralogical analysis, and the imagery is freely available via data acquisition (targeting) requests from NASA. We requested a Hyperion image swath targeted on Khirbat en-Nahas (KEN), an ancient copper smelting site along the Wadi al-Ghuwayb (WAG), a part of Jordan’s Faynan district, where extensive ore processing occurred from the 3rd millennium BCE to industrial scale production over several centuries in the early 1st millennium BCE (Iron Age) and continued until Medieval Islamic times. We use a combination of Principal Components Analysis (PCA), similarity matrices, and Spectral Mixture Analysis (SMA) on a single image swath to help locate additional ore processing sites, distinguish different areas at KEN that drew on different ore deposits, and discern depositional differences that may help illuminate issues related to the organization of production at KEN. Extensive field surveys in the research area provide a unique opportunity to ‘ground-truth’ the results of the hyperspectral research. The results of our study show considerable promise for future work with Hyperion data sets, and illuminate new aspects of the copper smelting industry at Khirbat en-Nahas. However, the low spatial resolution of the imagery and the nature of weakly reflective bands in the near infrared (NIR) limit the utility of the results.

► We use Hyperion imagery to examine the ancient copper mining region of Jordan.
► Copper smelting sites are detected with PCA and compared to known site distributions.
► We develop a similarity matrix for analyzing 156 bands of the Hyperion image cube.
► Spectral mixture analysis isolates areas using copper ores from different sources.
► The SMA may provide insights into the organization of production at the site.