ABSTRACT
The present study gathers mineralogical and isotopic geochemical data of 45 soil samples collected from the La Guardiense and Cantina di Solopaca wineries (Southern Italy) in order to provide useful information for the geotraceability of Falanghina white wine terroir. Mineralogical analyses show the ubiquitous presence of quartz, frequent and moderate contents of feldspars and phyllosilicates (i.e., illite/mica, kaolinite, and smectite). Rhizosphere soils from La Guardiense vineyards show a strontium isotope signature (87Sr/86Sr) ranging from 0.708604 to 0.711234 (average 0.710334; 1σ = 0.000943; n = 7) for the total fraction and a narrower range (from 0.706907 to 0.708807; average 0.708120; 1σ = 0.000641; n = 7) for the bioavailable one. For the rhizosphere soils collected from the vineyards of Cantina di Solopaca winery, 87Sr/86Sr ratios range from 0.708268 to 0.712413 (average 0.710145; 1σ = 0.001622; n = 8) and from 0.707968 to 0.709157 (average 0.708384; 1σ = 0.000409; n = 8) for the total and the bioavailable fraction, respectively. Actually, the bioavailable Sr fraction shows a narrower range of 87Sr/86Sr ratios compared to that of the total fraction, making the former more suitable for any study of wine traceability.
ABSTRACT
This paper presents a detailed review of the use of 87Sr/86Sr isotope systematics for wine provenance studies. The method is based on the principle that the Sr isotope ratio in wine reflects that of the labile fraction of the vineyard soil from which the wine is produced. The review encompasses 87Sr/86Sr data from wine samples published between 1993 and 2021 from terroirs in 22 different countries. The analytical procedures and techniques adopted by the different authors and the range of isotope ratios obtained in the different studies are discussed and evaluated. This study provides a bibliometric analysis of the 87Sr/86Sr isotope approach for wine authentication at different scales. Although limitations are evident when implemented at large (global) scales, we demonstrate that the 87Sr/86Sr isotope tracing technique remains a powerful and reliable tool for determining the geographical origin of wine when combined with detailed knowledge of the geological and soil characteristics of the substrata. For example, this combination of data allows the wines grown in the volcanic soils of Central and Southern Italy to be unambiguously fingerprinted. We present a detailed protocol for the application of the Sr isotope technique to wine authentication.
ABSTRACT
Many calderas show repeated unrest over centuries. Though probably induced by magma, this unique behaviour is not understood and its dynamics remains elusive. To better understand these restless calderas, we interpret deformation data and build thermal models of Campi Flegrei caldera, Italy. Campi Flegrei experienced at least 4 major unrest episodes in the last decades. Our results indicate that the inflation and deflation of magmatic sources at the same location explain most deformation, at least since the build-up of the last 1538 AD eruption. However, such a repeated magma emplacement requires a persistently hot crust. Our thermal models show that this repeated emplacement was assisted by the thermal anomaly created by magma that was intruded at shallow depth ~3 ka before the last eruption. This may explain the persistence of the magmatic sources promoting the restless behaviour of the Campi Flegrei caldera; moreover, it explains the crystallization, re-melting and mixing among compositionally distinct magmas recorded in young volcanic rocks. Our model of thermally-assisted unrest may have a wider applicability, possibly explaining also the dynamics of other restless calderas.