Investigation on weathering and surface depositions on marble Cycladic figurines

Abstract

The island of Keros and the islet of Dhaskalio are two of the most important archaeological sites in the Cyclades, dating to the Bronze Age. According to Prof. Colin Renfrew these two sites are considered as the first maritime sanctuary in the world. This theory is based on the hundreds figurine fragments and marble vessels found in the Special Deposits South and North (looted) as well as the settlement of Dhaskalio. In this work, a brief report on the history of the excavations and surveys at these areas is presented, as well as, the typology of the figurines and the geology of Keros Island and the geology and soil micromorphology of the Special Deposit South. A theoretical chapter of the marble weathering is discussed and the results of the preliminary research by Maniatis and Tambakopoulos in 2015 are reported. The experimental part of the study is focused on the scientific examination and analysis of the weathering state of the marble and the depositions on the surface of a representative number of marble figurines and the red deposition of a fragment of a marble basin. The analyses were performed using a stereoscopic microscope, a petrographic microscope and a Scanning Electron Microscope with analytical equipment. The samples were examined and analyzed in two forms: (1) as received (ASR) and (2) in polished cross-sections. The examination and analysis showed cracks of different size going through whole marble grains and soil depositions formed at the surface of the grains entering at places inside the grain boundaries. A sequence of weathering events could also be detected. These indicate that the figurines were severely weathered under different environmental conditions and episodes. The intense red depositions on the interior of the marble basin were identified as the valuable mercury sulfide pigment Cinnabar. For future research it is suggested that more figurines from Special Deposit South as well as from Special Deposit North, in combination with marble objects from Dhaskalio, should be examined and analyzed to see the difference in weathering in relation to the geological environment and soil. Other techniques such as FTIR, could give more details about the organic depositions on the grain surfaces.