Indirect chronology method employing rare earth elements to identify Sagunto Castle mortar construction periods

A novel indirect chronology method has been developed to identify Sagunto Castle construction periods. The method is based on the use of inductively coupled plasma mass spectrometry (ICP-MS) to determine rare earth elements (REE) and other trace elements in mortars. Additionally, a no destructive geochemical analysis based on X-ray fluorescence (XRF) was employed for major elements determination. Collected chemical data were processed through Principal Component Analysis (PCA) to highlight any differences among the mortars belonging to different buildings and construction periods. The results show that PCA analysis permits to discriminate construction periods according to mortar sample REE contents. Major elements and trace elements show just coarse differences related to the mortar composition. The proposed method permitted to clarify important issues about wall stratigraphy and its effectiveness on a novel indirect chronology developed method.