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 2 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.

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This paper shows the results of a multidisciplinary\ud study carried out on the mortars from the Late Roman Villa\ud dell’Oratorio (fourth-sixth AD), an aristocratic mansion built\ud in the lower Valdarno (Florence, Italy). Thirty-one bedding\ud mortar and plaster samples were analysed through optical microscopy,\ud thermogravimetric analysis, X-ray powder diffraction\ud and scanning electron microscopy with energy-dispersive\ud X-ray spectroscopy for determining the chemical, mineralogical\ud and petrographic characteristics, while their main physical\ud properties were measured by geotechnical procedures. The\ud collected data indicates that the analysed mortars are made\ud up of very fine to coarse river sand aggregate mixed with\ud white to yellowish-white natural hydraulic lime binder mainly\ud consisting of mixtures of prevailing calcite and hydraulic\ud compounds. With regard to the origin of the raw materials,\ud the aggregates were recognized to be selected Arno river\ud sands, and the binders are the burning product of a local marly\ud limestone (ex Alberese). Therefore, the mortars of the Late\ud Roman Villa dell’Oratorio are one of the first uses of natural\ud hydraulic lime in the lower Valdarno

This study investigates the stratigraphical sequence of Cocina Cave (Spain) employing and testing for the first time the capability of rare earth elements as markers of human activities in caves. Located in Dos Aguas (Valencian Community, Spain), Cocina Cave is characterized by the presence of several Holocene archaeological deposits from the final Mesolithic to the present day and is a pivotal site for understanding the socio-ecological dynamics of the last hunter-gatherer inhabitants of the Iberian Peninsula and the transition to pastoral and agricultural economies in the Western Mediterranean. However, the identification of strata from particular time-periods in the cave is often difficult due to the homogeneity of layers, the poor archaeological record in some strata and the presence of severe disturbance phenomena. The methodological approach of this study consisted of crossreferencing rare earth elements and other chemical markers with the archaeological stratigraphical interpretation, in an attempt to not only support the identification of the anthropic contribution to the formation of Cocina Cave strata, but also to characterize and confirm different natural and occupational episodes, particularly those associated with hunter-gatherer, early agriculturalist, and shepherd activities. Sediments were collected from different excavation areas and analysed for major elements, trace elements, rare earth elements (REE), soil organic matter (SOM) amounts and pH. Multivariate statistics were employed to group samples according to their elemental profile, and these were then compared to the archaeological temporal interpretation. The obtained results showed that REE amount and fractionation geochemical processes were regulated by carbonates, phosphates and pH. The use of REE as markers was particularly useful as their concentrations and their calculated ratios and anomaly distributions were demonstrated to be highly consistent with the archaeological stratigraphical interpretation.

Forty-two mortar samples, from two archaeological excavations located in Sagunto (Valencian Community, Spain), were analysed by both portable energy dispersive X-ray fluorescence spectroscopy (pED-XRF) and inductively coupled plasma mass spectrometry (ICP-MS) to determine major and minor elements and traces including rare earth elements (REEs). Collected data were crossed with those previously obtained from Sagunto Castle mortars, and principal component analysis (PCA) was applied to discriminate the construction phases of the unearthed buildings. REE permitted to ascribe most of the masonries to the Roman Imperial period. Moreover, a statistical model was built by employing partial least squares discriminant analysis (PLS-DA) in order to classify the mortars from Roman Imperial period and from Islamic period due to the problematic overlapping between these two phases. Results confirmed the effectiveness of the developed indirect chronology method, based on REE data, to discriminate among historic mortars from different construction periods on a wide scale including different Sagunto archaeological sites.