HAND-HELD XRF ANALYSIS OF BASALTIC ARTIFACTS FROM JORDAN

Iron-age and later cultures utilized basalt to fashion cultural artifacts. Two recently-discovered basaltic artifacts were found near the site of the Roman Era theatre in downtown Amman, at the base of the Citadel hill. One of these is a ~2.1 m statue of what was probably an Ammonite king; the other, found nearby, is a dedication plaque with a fragmentary inscription. Our study was initiated to determine whether the statue and the plaque might have been part of an original installation in what would have been the center of ancient Amman.

A hand-held Bruker Energy Dispersive XRF instrument was used to analyze basaltic artifacts for trace elemental Rb, Sr, Zr, Y, Nb and Ni. Hand specimens of previously analyzed basalts in the Baylor collection were used to establish calibrations. Ten measurements of one minute duration were taken from standards and artifacts, and, where possible, on different places on artifacts. Average accuracy from these measurements was better than 20 percent, except for Ni, which was poorly determined by ICP in the reference standards. Precision of measurements was generally better than 10% for elements in concentrations greater than a few parts per million.

Cultural basalt was analyzed from the statue and plaque fragment, and basalt used in ancient buildings in Umm Qais and Al Hashimiyyah (north of Amman) and compared with our analyzes of basalt from Al Hashimiyyah, Wadi Mujib and Wadi Zarqa Ma’in, along with analyzes from previous work. The Amman statue and plaque are from different basalt, the statue resembling basalt from Wadi Mujib, Al Hashimeah and Karak; basalt from the buildings at Umm Qais was likely derived from the same source. The high Y value of the theatre fragment was unlike any other in our data set.

We speculate that the Amman Statue was derived from the plateau basalts near Wadi Mujib because the large cooling columns in that basalt would allow fashioning of one into an artifact of the observed size of the Amman Statue.