Strontium Isotope Systematics of Tenerife Wines (Canary Islands): Tracing Provenance in Ocean Island Terroir

Abstract

The production of fraudulent goods remains widespread and economically damaging. The high value of the wine industry makes it particularly vulnerable, and a number of geochemical methods have been developed to ensure traceability and identification of origin. Here, strontium (Sr) isotope data on wines from five defined regions in Tenerife (Canary Islands, Spain) show that the young volcanic geology imparts a clearly identifiable low 87Sr/86Sr signature (<0.7072). These values discriminate Tenerife wines from mainland Spanish and continental European produce, as these are much more radiogenic in general. However, unlike continental wine regions, wines from Tenerife show small but ubiquitous enrichments in 87Sr/86Sr above what is expected in the soils. Bentonite addition has not affected the 87Sr/86Sr signatures, with white wines at lower Sr concentrations than red wines in all regions. A number of natural contributions to the terroir are evaluated in relation to Tenerife’s unique combination of geology and geography. Atmospheric precipitation (rainfall) is likely a dominant influence on Sr isotope systematics in northern Denominación de Origen regions, and evaporation may play a role in buffering signatures in southern regions. Other natural additions of 87Sr are not precluded at a local scale, given the large range in climatic conditions of island terroir and known input of mineral dust from Africa. Despite natural explanations affecting the overall small shift observed, there are clear outliers with considerably higher 87Sr/86Sr and Sr concentration. This confirms the utility of Sr isotope systematics for oceanic-island viticulture and demonstrates the use of young volcanic soils for tracing natural inputs that may be masked in other regions.

Early transatlantic movement of horses and donkeys at Jamestown

“…Strontium isotope ratios vary greatly in West Africa (0.709 to 0.730 [23]) and the Iberian Peninsula (0.7046 to 0.735 [33,34]), though less so in the Caribbean (0.706 to 0.711 [35]), but unfortunately no bioavailable 87 Sr/ 86 Sr data are yet available for North Africa. The donkey’s 87 Sr/ 86 Sr ratios of 0.7100 exceed the range of published Sr values from the Canaries, which tend to lower values from the islands’ young volcanic geology [36,37]. Similar values are rare in the Caribbean, outside of Trinidad, and are only found in biotic samples on metamorphic rocks in small parts of the islands, but more common in southern Portugal and to a lesser extent in western Spain.…”