Sara Marchionni

High-precision 87Sr/86Sr analyses in wines and their use as a geological fingerprint for tracing geographic provenance.

The radiogenic isotopic compositions of inorganic heavy elements such as Sr, Nd, and Pb of the food chain may constitute a reliable geographic fingerprint, their isotopic ratios being inherited by the geological substratum of the territory of production. The Sr isotope composition of geomaterials (i.e., rocks and soils) is largely variable, and it depends upon the age of the rocks and their nature (e.g., genesis, composition). In this study we developed a high-precision analytical procedure for determining Sr isotopes in wines at comparable uncertainty levels of geological data. With the aim of verifying the possibility of using Sr isotope in wine as a reliable tracer for geographic provenance, we performed Sr isotope analyses of 45 bottled wines from four different geographical localities of the Italian peninsula. Their Sr isotope composition has been compared with that of rocks from the substrata (i.e., rocks) of their vineyards. In addition wines from the same winemaker but different vintage years have been analyzed to verify the constancy with time of the (87)Sr/(86)Sr. Sr isotope compositions have been determined by solid source thermal ionization mass spectrometry following purification of Sr in a clean laboratory. (87)Sr/(86)Sr of the analyzed wines is correlated with the isotopic values of the geological substratum of the vineyards, showing little or no variation within the same vineyard and among different vintages. Large (87)Sr/(86)Sr variation is observed among wines from the different geographical areas, reinforcing the link with the geological substratum of the production territory. This makes Sr isotopes a robust geochemical tool for tracing the geographic authenticity and provenance of wine.

Tracing 87Sr/86Sr from rocks and soils to vine and wine: an experimental study on geologic and pedologic characterisation of vineyards using radiogenic isotope of heavy elements. Science of the Total Environment

In this paper we report an experimental study to assess the process of Sr-isotope uptake from the soil and its transfer to the grapevine and then to the wine made through micro-vinification. The experimental work has been carried out with a deep control of the boundary conditions (i.e., type of soil, geologic substratum, ground water supply, etc.) on 11 selected vine-plant sites over a period of four harvest years. Sr-isotopes have been determined on grape-bunches, grapevine sap, on the bioavailable fraction of the soil, on bulk soil, and on the rocks of the substratum. No significant Sr-isotope variability has been observed among micro-vinifications from different harvest years. A slight but significant Sr-isotope variability occurred among wines from rows embedded on different soil type. The Sr-isotope data on micro-vinifications well match those of grapevine sap and bioavailable fraction of soils, all of them falling well within the whole geological range of the bedrock, despite an evident decoupling between bioavailable fraction, whole soils and bedrocks does exist. This decoupling has been ascribed to differential geochemical behaviour of minerals in response to pedogenetic processes. The findings of our experiments indicate that the biological activity of the vine is not able to change the original 87Sr/86Sr composition up-taken from the bio-available fraction of the soil. Thus, the 87Sr/86Sr of the wine is an unadulterated feature of the terroir.

Geologic map, volcanic stratigraphy and structure of the Cabo de Gata volcanic zone, Betic-Rif orogen, SE Spain

The geologic map of the Neogene Cabo de Gata volcanic zone is presented together with a comprehensive volcanic stratigraphy and structure based on logging, correlation and mapping. Volcanic rocks are interbedded with sedimentary rocks throughout the Cabo de Gata volcanic zone. The volcano-sedimentary succession of Cabo de Gata has been divided into formations according to lithology, age, composition and stratigraphic position. The contacts between sedimentary units and volcanic units and between formations are unconformities. Sedimentary units were deposited during periods of volcanic repose. The depositional environment of volcanism in Cabo de Gata is characterized as shallow-water submarine to emergent based on lithofacies of volcanic rocks and on fossil content and sedimentary structures of sedimentary rocks. The eruptive style in Cabo de Gata is dominantly effusive, although small-volume explosive eruptions due to magma-water interaction processes and to explosions of lava flow and domes complexes occurred.

Geochronology, Geochemistry and Geodynamics of the Cabo de Gata volcanic zone, Southeastern Spain

New 40Ar/39Ar ages and major and trace element geochemistry ofthe middle-late Miocene Cabo de Gata volcanic complex, southeastSpain, indicate that the volcanic activity of the Cabo de Gata volcaniczone developed over a short period through several pulses of geochemicallyand isotopically different parental magmas. The oldestvolcanic rocks exposed in the Cabo de Gata volcanic zone are theshoshonite and high-K calc-alkaline rocks of Bujo group, which cry -stallised from a parental magma transitional from calc-alkaline toalkaline potassic generated through large degrees of partial melting,and then affected by a minor contribution from metasomatised veinsand a larger one from the surrounding mantle wedge, in comparisonto ultrapotassic melts. Subsequent partial melting of the mantlesource produced typical calc-alkaline parental magmas belonging tothe Rodalquilar and Agua Amarga groups. Sr-Nd-Pb isotope andincompatible trace element distributions of Cabo de Gata rocks arein agreement with a mantle-wedge source affected by a two-foldmetasomatism. The data suggested that mild potassic to sub-alkalinesubduction-related parental magmas (i.e., high-K calc-alkaline andcalc-alkaline) were generated in the Cabo de Gata sector within amantle wedge metasomatised by a fluid-dominated agent. In contrast,the enrichment in K2O of shoshonitic to ultrapotassic magmaswas achieved through recycling of subducted sediments throughmelts that enriched the mantle wedge in K and related elements.Such a scenario can be easily reconciled with a geodynamic settingat the edge of a destructive plate margin with the subducted slabresponsible for the recycling of sediments within the mantle wedge.

Strontium Isotopes in Biological Material: A Key Tool for the Geographic Traceability of Foods and Humans Beings

This chapter discusses the application in geology of the isotope ratio 87Sr/86Sr, where 87Sr is the long-lived radiogenic daughter of 87Rb (t1/2 = 48.8 billion years), and its use as geologic fingerprint for geographic traceability in food, forensic, and archaeological sciences. The 87Sr/86Sr ratio of any geological material (i.e. minerals and rocks) on Earth depends on its time integrated 87Rb/86Sr ratio and thus it is related to three main parameters: (1) the initial radiogenic isotopic abundance, (2) the age of the rock/mineral, and (3) the parent/daughter isotope ratio. Being a ratio between two nuclides of the same element 87Sr/86Sr is not modified during the uptake of the plant and it is transferred unchanged to all living beings of the food chain, thus remaining identical to that of the substratum from which the original plant or vegetable grew.

From vine to wine: Data on 87Sr/86Sr from rocks and soils as a geologic and pedologic characterisation of vineyards

This data article describes the soils characterisation, bedrock geochemical composition and descriptive statistics of 87Sr/86Sr in wines, grape saps, labile fractions of soils (bio-available), whole soils, and bedrocks used to explore the Sr isotope conservation from rocks and soils to vine and wine. These data also describe the reproducibility of the isotopic composition of wine over four harvest years (2008–2011) on 11 selected experimental parcels (sampling point). The data reported in this paper are related to the research article (Braschi et al., 2018) [1].

High-Precision In Situ 87Sr/86Sr Analyses through Microsampling on Solid Samples: Applications to Earth and Life Sciences

An analytical protocol for high-precision, in situ microscale isotopic investigations is presented here, which combines the use of a high-performing mechanical microsampling device and high-precision TIMS measurements on micro-Sr samples, allowing for excellent results both in accuracy and precision. The present paper is a detailed methodological description of the whole analytical procedure from sampling to elemental purification and Sr-isotope measurements. The method offers the potential to attain isotope data at the microscale on a wide range of solid materials with the use of minimally invasive sampling. In addition, we present three significant case studies for geological and life sciences, as examples of the various applications of microscale 87Sr/86Sr isotope ratios, concerning (i) the pre-eruptive mechanisms triggering recent eruptions at Nisyros volcano (Greece), (ii) the dynamics involved with the initial magma ascent during Eyjafjallajökull volcanos (Iceland) 2010 eruption, which are usually related to the precursory signals of the eruption, and (iii) the environmental context of a MIS 3 cave bear, Ursus spelaeus. The studied cases show the robustness of the methods, which can be also be applied in other areas, such as cultural heritage, archaeology, petrology, and forensic sciences.

87Sr/86Sr isotopes in grapes of different cultivars: A geochemical tool for geographic traceability of agriculture products

87Sr/86Sr was determined on fresh red and white grapes, soils and rocks from three selected vineyards to verify the isotopic relationships between the fruit of the vine and geologic substrata of vineyards. 87Sr/86Sr were determined on sampled grapes of four different harvest years and different grape varieties, on bioavailable fraction of soils, on whole soils, and on bedrocks from the geo-pedological substratum of the vineyards. The vineyards chosen for the experimental works belong to an organic farming winery and thus cultivation procedures were strictly controlled. Grapes were sampled during the harvests of four different but consecutive years with 87Sr/86Sr that does not change reflecting the values of the soil bioavailable fraction. No variations among grapes from different vine cultivars were observed. A strict isotope relationship with soil bio-available fraction was observed. These findings demonstrate the reliability of 87Sr/86Sr, even at a very small scale, for food products geographic origin assessment.

Inverse modelling to unravel the radiogenic isotope signature of mantle sources from evolved magmas: the case-study of Ischia volcano

The active volcano of Ischia, the well-known island off-shore the city of Naples, has had a discontinuous volcanic activity characterised by caldera-forming paroxysmal eruptions, lava flows, and lava domes for >150 kyr. The overall geochemical composition of erupted magmas includes shoshonite, latite, and trachyte/ trachyphonolite. In a complementary study, we demonstrated that the evolution of Ischia trachytes with Sr