Weathering Characteristics, Age, and Provenance Determinations on Ancient Greek and Roman Marble Artifacts

Abstract

Surface weathering crusts and patinas on ancient Greek and Roman sculpture and other artifacts have been investigated by stable isotope mass spectroscopy, scanning electron microscopy, electron microprobe and PIXE techniques. Analysis of polished cross-sections made from cores taken from fresh interior marble to outer weathered sculpted surfaces on pieces of Early Cycladic Greek to 3 rd. century A.D. Roman age indicate that there are progressive alterations of the carbonate minerals with age. The chemical, isotopic and petrographic characteristics of the weathering crusts vary with marble type, age and weathering environmental histories. These crusts, however, appear to be excellent indicators of antiquity and authenticity.

These techniques, when applied to analyses of fresh, unweathered marble from cores taken from ancient artifacts, can also be used for provenance determinations. Oxygen and carbon isotope, petrographic and Sr/Ca analyses yielded good correlations with ancient quarries for several Archaic Greek marble sculptures.