A ‘Geo-Pedo-Fingerprint’ (GPF) as a tracer to detect univocal parent material-to-wine production chain in high quality vineyard districts, Campi Flegrei (Southern Italy)

An interdisciplinary study, involving geologists, chemists and pedologists, started aiming at identifying a “Geo- 23Pedo-Fingerprint” (GPF) univocally linking the wine to its origin, namely, the Piedirosso vineyards growing in 24the Campi Flegrei volcanic area. The focal point of this research was the characterization of the whole parent 25material–soil–vineyard–wine system, achieved by correlating the elemental pattern – with special reference to 26micro-nutrients and Rare Earth Elements (REEs) – and Sr isotopic ratios, to identify a reliable and convenient 27GPF as a guaranteed indicator of wine provenance. A representative soil/Piedirosso vineyard system was identi- 28fied and characterized. Samples from each soil horizon as well as from vine branches, leaves, grapes and wine 29were collected and analyzed. All samples were analyzed by multi-collector inductively coupled mass spectrom- 30etry (MC-ICPMS) to determine their 87Sr/86Sr isotopic composition, by ICP-Quadrupole MS to measure multi- 31elemental composition including REE, and by X-Ray Powder Diffraction (XRPD) for the quantitative evaluation 32of the mineral phases occurring in soil samples. 33Statistical analysis (Hierarchical Cluster Analysis, Factor Analysis) revealed the existence of separate correlations 34of element distribution between: i) soil, as nutrient pool source, and vegetative compartments, i.e. branches and 35leaves, as biochemical yards for nutrient elaboration and marshaling, ii) vegetative compartments and the pro- 36ductive compartment, i.e. grapes as the metabolic outcome of the vine, and, iii) the productive compartment 37and its artifact produced by man, i.e. wine. However, no sequential correlation of elements from soil to wine 38did appear, likely because clusters of elements were discriminated due to the varying takeup and fractionation 39processes in plants, as well as during vinification processes. 40Therefore, none of the investigated elements was a liable ‘GPF’ as a candidate tracer from soil to wine. 41In contrast, the use of a petrogenetic tracer such as 87Sr/86Sr isotopic composition provided satisfactory 42responses. In fact, the values of such a ratio within the entire studied chain vary in a very small range from 430.7076 to 0.7084, thus falling within the typical range for volcanites of Campi Flegrei (0.7065–0.7086). These 44results currently represent the only study focusing on a geotracer, such as the 87Sr/86Sr isotopic ratio, linked with 45a pedological survey to identify the volcanic Campanian wine-producing chains fromsoil parentmaterial-to-wine