Isotopic features of rivers and groundwater of the Parma Province (Northern Italy) and their relationships with precipitation

The Enza, Parma, Baganza, Taro and Po rivers and several waters from aquifers of the area of the Parma town (northern Italy) have been investigated for oxygen and hydrogen isotopes. Enza, Parma, Baganza and Taro differ from Po in having higher isotope ratios and the Taro River exhibits an isotope ratio higher than those of Enza, Parma and Baganza. The low values of Po are due to the dominant contribution of waters coming from glaciers and precipitation occurring along the Alps. The high values of the Taro River are probably due to the fact that its catchment basin extends close to the Tyrrhenian sea and is well opened to perturbations coming from the west. The isotopic values of the present day precipitations occurring along the northern Apennine piedmont area are lower than in rivers. On the contrary, the rivers resemble waters issuing from springs located close the Apennine ridge; the isotopic values of the last waters probably approach those in the precipitation occurring at present along the Apennine ridge. Reasonably, the low isotope values recorded in precipitation of the Apennines piedmont area are due to cold air masses invading the Po plain from N or NE rather than only to the change in the regime of precipitation (higher amount in cold periods, lower amount in the hot periods). Waters of the aquifer of the Po plain have been investigated in the Priorato, Parola and Parma fields (Parma Province). The aquifers are largely fed by the surface hydrographic system: their waters have constant isotopic composition and resemble waters of the Apennines rivers. They are also isotopically similar to the average precipitation occurring from 1995 to 2006, but differ largely from recent (2003–2005) precipitation. Minor isotopic variations recorded in a well of the Priorato field suggest that this well is partly fed by local precipitation.     

Geochemistry and potential use of groundwater in the Rocca Busambra area (Sicily, Italy)

In the Rocca Busambra area (mid-west Sicily, Italy), from November 1999 to July 2002, 23 water points including wells and springs were sampled and studied for their chemical and isotopic compositions. Two rain gauges were also installed at different altitudes, and rainwater was collected monthly to determine the isotopic composition. The obtained results revealed the Rocca Busambra carbonate complex as being the main recharge area on account of its high permeability value. From a chemical view point, two main groups of water can be distinguished: calcium–magnesium–bicarbonate-type and calcium–magnesium–chloride–sulphate-type waters. The first group reflects the dissolution of the carbonate rocks; the second group probably originates from circulation within flyschoid sediments. Three water wells differ from the other samples due to their relatively high Na and K content, which probably is to be referred to a marked interaction with the “Calcareniti di Corleone” formation, which is rich in glauconite [(K, Na)(Fe³⁺, Al, Mg)₂(Si, Al)₄O₁₀(OH)₂]. In accordance with WHO guidelines for drinking water (2004), almost all the samples collected can be considered drinkable, with the exception of four of them, whose NO₃ ⁻, F⁻ and Na⁺ contents exceed the limits. On the contrary, the sampled groundwater studied is basically suitable for irrigation.     

Isotopic composition and origin of the precipitation in Northern Chile

A 3 a data set of isotopes in precipitation from northern Chile show a very distinct pattern, with δ¹⁸O values ranging between −18 and −15‰ at high altitude stations, compared to δ¹⁸O values between −10 and −6‰ at the lower altitude areas. The ¹⁸O-depleted values observed in the high altitude area, the Altiplano, are related to processes that affect the air masses that originated over the Atlantic, cross the Amazon Basin (continental effect), ascend the Andes (altitude effect) and precipitated (convective effect) in the Altiplano. It is postulated that a second source of moisture, associated with air masses from the Pacific, may contribute to the ¹⁸O-enriched values observed in the lower altitude areas. Similar isotopic patterns are documented in springs and groundwater indicating that the data presented in this paper are an accurate representation of the long term behavior isotopic composition of rain in northern Chile.     

Chemistry and sulfur isotopic composition of precipitation at Bologna, Italy

Individual and monthly precipitation samples from the polluted atmosphere of Bologna (Emilia-Romagna province) were collected during March 1996 to May 1997 and analyzed for major ions in solution and S isotopes in dissolved SO₄.Weighted mean enrichment factors relative to seawater are found to be 1.0 for Na, 15.2 for K, 105 for Ca, 3.3 for Mg, 17.3 for SO₄ and 663 for HCO⁻₃. Very good positive correlations are observed for the Ca²⁺–Mg²⁺–HCO⁻₃–SO²⁻₄–NO⁻₃ system, indicating that dissolution of Ca (±Mg)-carbonate particles by H₂SO₄ and HNO₃ from combustion of oil and gas is a major process controlling the chemical composition of rain and snow. Na⁺ and Cl⁻ in monthly precipitation derive essentially from sea spray, but the contribution of Na⁺ from continental sources is appreciable in a number of individual rains. NH⁺₄ appears to be on average more abundant in spring and summer precipitation, its main sources being microbial activity in soils and application of fertilizers. K⁺ is probably of continental origin from soil dust.The S isotopic composition of SO₄ is systematically positive, with mean δ³⁴S values of +3.2±1.6‰ (n=40) in individual precipitation and +2.8±1.4‰ (n=12) in monthly precipitation. These isotopic compositions are interpreted in terms of a dominant contribution of S from anthropogenic emissions and subordinate contributions from biogenic and marine sources. Pollutant SO₄ is estimated to have a δ³⁴S value in the range +2.5 to +4.5‰, whereas a distinctive δ³⁴S of −4.5‰ or lower indicates SO₄ from oxidation of biogenic gases.The isotopic and chemical compositions of SO₄ do not depend on wind direction, thus testifying to a mostly local source for pollutant S in the Bologna atmosphere.     

Isotopic composition of rain- and groundwater at Mt. Vesuvius: environmental and volcanological implications

The present work reports on the isotopic characterization of rainfall and groundwater at Mt. Vesuvius. Values of δ ¹⁸O, monthly measured on rain samples collected during the period 2002–2004 in a rain-gauge network composed of 10 stations, were compared with meteorological and DEM data. Air temperature, controlled by the local orographic structure, was identified as the main factor influencing rain isotopic composition. Another important role is played by orographic clouds, whose condensation over the top of Mt. Vesuvius is responsible for anomalously high δ ¹⁸O values recorded in rain samples from the summit area of the volcanic edifice. A spatial model of rain isotopic composition, based on a 3D distribution of temperature derived by a 1 × 1 km DEM, was implemented and used for calculating the theoretical isotopic signature of seepage, further compared with data measured in the groundwater monitoring network. The analysis evidenced the role of local meteoric recharge as the main source feeding Mt. Vesuvius aquifers. The unique exception is the Olivella drainage gallery, located on the north-eastern flank of the volcanic edifice, whose isotopic composition is slightly more positive than the one expected for its altitude, likely caused by both evaporation processes and mixing with condensed hydrothermal vapor.     

Mud volcano eruptions and earthquakes in the Northern Apennines and Sicily, Italy

The relations between earthquakes and the eruption of mud volcanoes have been investigated at the Pede–Apennine margin of the Northern Apennines and in Sicily. Some of these volcanoes experienced eruptions or increased activity in connection with historical seismic events, showing a good correlation with established thresholds of hydrological response (liquefaction) to earthquakes. However, the majority of eruptions have been documented to be independent of seismic activity, being mud volcanoes often not activated even when the earthquakes were of suitable magnitude and the epicentre at the proper distance for the triggering. This behaviour suggests that paroxysmal activity of mud volcanoes depends upon the reaching of a specific critical state dictated by internal fluid pressure, and implies that the strain caused by the passage of seismic waves can activate only mud volcanoes in near-critical conditions (i.e., close to the eruption). Seismogenic faults, such as the Pede–Apennine thrust, often structurally control the fluid reservoirs of mud volcanoes, which are frequently located at the core of thrust-related folds. Such an intimate link enables mud volcanoes to represent features potentially suitable for recording perturbations associated with the past and ongoing tectonic activity of the controlling fault system.     

Chemical composition of precipitation at Mt. Vesuvius and Vulcano Island,Italy: volcanological and environmental implications

Natural precipitation and water samples from passive devices were collected at Mt. Vesuvius and Vulcano Island, Italy, during the period 2004–2006, in order to investigate its possible interactions with fumarolic gases. Evidence of chemical reactions between fumarolic fluids and rain samples before and after its deposition into the sampling devices was found at Vulcano Island. Very low pH values (down to 2.5) and significant amounts of chlorine and sulfate (up to 22 mEq/l) were measured at sampling points located close to the fumarolic field. In contrast, anthropogenic contributions and/or dissolution of aerosols (both maritime and continental) influence the chemistry of rainwaters at Mt. Vesuvius, which show inter-annual variations that are highly consistent with those recorded at the coastal site at Vulcano Island. Chemistry of waters directly exposed to fumarolic fluids may then give useful information about its temporal evolution, holding the signal of the “maximum” chemical event occurred in the meanwhile. In addition, the observation of the health status of vegetation colonizing the immediate surroundings of the fumarolic fields, due to its strong dependence on the interactions with these fluids, may work as a possible biomarker of volcanic activity.     

Isotopic tracing of perchlorate sources in groundwater from Pomona,California

The groundwater of Pomona, California, is contaminated with perchlorate (${\text{ClO}}_4^{-}$). This water is treated to reduce the ${\text{ClO}}_4^{-}$ concentration to less than 6 μg L⁻¹ for compliance with California Department of Public Health drinking water regulations. A study of the isotopic composition of oxygen and chlorine in ${\text{ClO}}_4^{-}$ has been conducted to determine the source of the contamination. Isotopic compositions were measured for ${\text{ClO}}_4^{-}$ samples extracted from 14 wells, yielding ranges of δ¹⁸O values from −10.8‰ to −8.0‰, Δ¹⁷O values from +4.6‰ to +7.5‰, and δ³⁷Cl values from −12.8‰ to −8.9‰. Evaluation of mixing proportions using published isotopic data for three ${\text{ClO}}_4^{-}$ end-members (synthetic, Atacama, and indigenous natural ${\text{ClO}}_4^{-}$) indicates that contamination is dominantly (85–89%) Atacama ${\text{ClO}}_4^{-}$ derived from past use of imported Chilean nitrate fertilizer in citrus cultivation. This interpretation is consistent with (1) aerial photography archives showing extensive citrus fields surrounding Pomona in the early- to mid-20th century, (2) mass-balance estimates for ${\text{ClO}}_4^{-}$, and (3) numerical hydrologic models yielding travel-times for ${\text{ClO}}_4^{-}$ from fields to wells that are in the range of 15 to >100 years. The hydrologic models predict that ${\text{ClO}}_4^{-}$ contamination of Pomona groundwater will persist for decades into the future.     

Garnet-spinel-pyroxenite xenoliths from hyblean plateau (South-eastern Sicily, Italy)

Summary Rare garnet-spinel pyroxenite xenoliths occur in some basaltic tuff-breccia levels of Miocene age from the Valle Guffari (Hyblean Plateau, Sicily), together with a number of spinel-bearing mantle xenoliths. The garnet-bearing pyroxenites may be divided into two groups (a and b) on textural and mineralogical bases. Garnet-bearing spinel websterites with a fully recrystallized texture represent the first group (a). Here the garnet (Py_54.5 A1m₃₂ Gr_13.5), with a diffuse kelyphitic alteration, forms a reaction corona between coarse spinel grains and the in contact pyroxenes. The transition from the spinel-pyroxenite to the garnet-pyroxenite field may depend on isobaric cooling from higher (magmatic?) temperatures. Garnet-pyroxene geothermometry indicates that the last equilibration most probably occurred at P = 1.0 GPa (ca.), T = 750 °C (ca).The second lithotype (b) is an orthopyroxene-bearing garnet-spinel clinopyroxenite, exhibiting a complex texture. It consists of zones of coarse clinopyroxene grains enclosing euhedral spinel passing to zones where tiny rounded crystals of the same pyroxene and spinel are enclosed in relatively large patches of extensively kelyphitisized garnet (Py_64.8 Alm_25.6 Gr_9.6). Garnet also occurs as inclusion-free grains up to 4 mm in diameter. P-T calculations give significantly higher values than for the former case (a). The origin of the b-type garnet may also depend on subsolidus reaction of spinel and pyroxenes after an isobaric cooling from still higher temperatures, but a primary magrnatic origin might also be possible, especially for the granular garnets.P-T estimates for both the pyroxenite types closely match a steady geotherm for 100 mW/m² surface heat flow. Such a relatively intense heat flow may suggest the occurrence of huge masses of hot magma intruding the Hyblean lithospheric mantle and lower crust at different levels.

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Granat-Spinell-Pyroxenit-Xenolithe aus dem Iblei-Plateau (Südost-Sizilien, Italien)

Zusammenfassung Seltene Granat-Spinell-Pyroxenit-Xenolithe kommen in einigen basaltischen Tuff-Breckzien Horizonten miozänen Alters aus dem Valle Guffari (lblei-Plateau, Sizilien) zusammen mit einer Anzahl von Spinell-führenden Mantel-Xenolithen vor. Aufgrund textureller und mineralogischer Kriterien können die Granat-führenden Pyroxenite in zwei Gruppen (a und b) unterteilt werden. Granat-führende Spinell-Websterite mit vollkommen rekristallisierter Textur repräsentieren die erste Gruppe (a). Hier bildet Granat (Py_54.5 Alm₃₂ Gr_13.5) mit einer diffusen kelyphitischen Umwandlung, einen Reaktionssaum zwischen grobkörnigem Spinell und Pyroxenen, mit denen er in Kontakt ist. Der übergang vom Spinell-Pyroxenit- zum Granat-Pyroxenit-Feld kann auf isobarische Abkühlung von höheren (magmatischen ?) Temperaturen zurückgehen. Granat-Pyroxen-Geothermometrie zeigt, dass die letzte Equilibrierung sehr wahrscheinlich bei P = 1.0 GPa (ca.), T = 750°C (ca.) erfolgte.Der zweite Typ von Granat-führenden Pyroxeniten ist ein (b) Orthopyroxenführender Granat-Spinell-Klinopyroxenit, der komplexe Texturen zeigt. Er besteht aus Zonen von grobkörnigem Klinopyroxen mit Einschlüssen von idiomorphem Spinell, der in Zonen übergeht, wo kleine gerundete Kristalle des gleichen Pyroxens und Spinells in relativ große Bereiche von extensiv kelyphitisiertem Granat (Py_64,8 Alm_25,6 Gr_9,6) eingeschlossen sind. Granat kommt auch als einschlußfreie Körner mit bis zu 4 mm Durchmesser vor. P-T Berechnungen geben wesentlich höhere Werte als für die Gesteine des Types (a). Die Entstehung der b-Typ-Granaten kann auch durch Subsolidus-Reaktion von Spinell und Pyroxen nach isobarischer Abkühlung von noch höheren Temperaturen beeinflußt sein; ein primärer magmatischer Ursprung könnte auch möglich sein, besonders für die körnigen Granate.P-T Abschätzungen für beide Pyroxenit-Typen sind gut einer Geotherme für 100 mW/m² Wärmefluß an der Oberfläche zuzuordnen. Ein solcher, relativ intensiver Wärmefluß könnte auf das Vorkommen von großen heißen Magmenkörpern hinweisen, die den lithosphärischen Mantel unter dem Iblei-Plateau und die untere Kruste in verschiedenen Niveaus intrudierten.

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With 4 Figures     

Isotopic composition of zinc, copper, and iron in lunar samples

We determined by ICP-MS the concentrations and isotopic ratios of Fe, Cu, and Zn in the Ti-rich lunar basalt 74275, in the lunar orange glass 74220, and in up to 10 lunar soils, namely, 14163, 15231, 64501, 66041, 68841, 69941, 70011, 72501, 75081, and 76501. Two analyses of zinc in lunar basalt 74275 give δ⁶⁶Zn = 0.17‰ and 0.75‰, values within the range of those measured in terrestrial basalts; copper in lunar basalt 74275 has δ⁶⁵Cu  +1.4‰, which is isotopically heavier than values observed in terrestrial basalts. In the orange glass, we measured δ⁵⁶Fe = −0.24‰, δ⁶⁵Cu = −0.42‰, and δ⁶⁶Zn  −3.6‰. These values of δ are more negative than those obtained for 74275 and for typical lunar basalts, but for Cu, comparable to those observed in terrestrial sulfides and meteorites. In lunar soils we found 0.11‰  δ⁵⁶Fe  0.51‰, 2.6‰  δ⁶⁵Cu  4.5‰, and 2.2‰  δ⁶⁶Zn  6.4‰. Insofar as we can generalize from a small sample set, S, Fe, Cu, Zn, and Cd show similar trends in isotopic fractionation on the Moon. Lunar basalts have nearly terrestrial isotopic ratios. Relative to the lunar basalt 74275, the pyroclastic glass 74220 is enriched in the lighter isotopes of Fe, Cu, and Zn, and the soils are enriched in the heavier isotopes of Fe, Cu, and Zn. The patterns in the basalts are likely inherited from the source material; the light-isotope enrichments seen in the orange glass originated during lava fountaining or, less probably, during partial condensation of vapor; and the heavy-isotope enrichments in the lunar soils were likely created by a combination of processes that included micrometeorite vaporization and sputtering. In the orange glass, the light-isotope enrichments (relative to lunar basalts) of Zn are larger than those of Cu. If these enrichments reflect accurately the isotopic composition of the gas, they suggest that Cu is more volatile than Zn in the liquid from which the gas derived. A simple model built on the known flux of micrometeorites to the lunar surface and a published estimate that micrometeorites generate 10 times their own mass of vapor, predicts heavy-isotope enrichments comparable to those observed in soils but only if the regolith gardening rate is set at about one twentieth of the generally accepted value of 1 cm/My. This discrepancy may reflect the difference in the time constants for micrometeorite milling and decimeter-scale gardening, or the importance of sputtering.     

Morphometric and landsliding analyses in chain domain: the Roccella basin,NE Sicily,Italy

The dynamic interaction of endogenic and exogenic processes in active geodynamic context leads to the deterioration of the physico-mechanical characteristics of the rocks, inducing slopes instability. In such context, the morphometric parameters and the analysis of landslide distribution contribute to appraise the evolutive state of hydrographic basins. The aim of the study is the morphometric characterization of the Roccella Torrent basin (Rtb) located in South Italy. Landsliding and tectonic structure dynamically interact with the drainage pattern that records these effects and permits the definition of the evolutive geomorphic stage of the basin. The Air Photograph Investigation and field surveys permitted to draw the main geomorphic features, the drainage pattern of the Rtb, to calculate the morphometric parameters and to delimit the landslides’ bodies. Detailed analysis about the landslide distribution within a test site 17 km² wide were carried out to elaborate indicative indexes of the landslides type and to single out the lithotypes that are more involved in slope instability phenomena. The morphometric parameters indicate the rejuvenation state within the Rtb where the stream reaches show the effects of increased energy relief in agreement with the geological settings of this sector of the Apennine–Maghrebian Chain.     

Arsenic and fluorine in the Etnean volcanics from Biancavilla,Sicily, Italy: environmental implications

Mineralogical and geochemical studies were undertaken in the volcanic area of Biancavilla (Catania, Italy) with the aim of explaining the nature of the high As and F contents of the area’s rocks. As and F contents in soils and groundwater were also investigated. The metasomatised benmoreite lavas show fluorine and arsenic concentrations up to about 3,000 and 1,000 mg/kg, respectively. Mineralogical analyses show that fluorine occurs mostly in fluoro-edenite and apatite-(CaF) crystals, both abundantly present in the altered rocks, while As is exclusively attributed to the apatite-(CaF) crystals. Specifically, arsenic was observed only at the borders of these apatite crystals. Leaching tests and sequential extraction procedures were carried out to evaluate the potential remobilisation of As and F by the mineral phases and the eventual risks induced by their spreading. The results of the leaching tests suggest that As is almost totally associated with the ‘easily reducible’ fraction and that it is released by the preferential dissolution of the arsenic enriched rims of apatite-(CaF) crystals. In soils, As concentration is relatively low (about 15 mg/kg, on average), while F ranges from 236 to 683 mg/kg. The underground waters supplying the town of Biancavilla show As and F contents lower than the allowed limits for drinking water, (As:10 μg/L, F:1–1.5 mg/L). The limited distribution of these rocks and the relatively limited mobilisation by the minerals both contribute to maintain low As and F values, in soils and groundwaters, despite the high values in metasomatised lava samples.     

Isotopic composition of silicon in meteorites

Samples of bulk meteorites show only mass-dependent fractionation of silicon isotopes. No isotopic anomalies were found. The variation of the ratios ²⁹Si/²⁸Si and ³⁰Si/²⁸Si over the meteorite classes is small; 1%. per mass unit difference. The average Si isotopic composition for each class of meteorites is identical, within analytical uncertainties. This is quite unlike O, whose anomalous isotopic abundances in bulk samples differentiate among the classes of meteorites. The overlapping abundance ranges of Si isotopes among many classes of meteorites suggest closed-system behavior for this element prior to meteorite accretion and allow calculation of an average solar system Si isotope composition.     

Submarine groundwater discharge into Venice Lagoon, Italy

Venice Lagoon, Italy, rests on a series of aquifers that are 1,000 m thick. Measurements of submarine groundwater discharge (SGD) were made in Venice Lagoon using benthic chambers vented to a plastic collection bag. Two hundred measurements taken in a pristine northern lagoon site (Isola la Cura) revealed flow rates as high as 200 cm d⁻¹ with an average of 30 cm d⁻¹. Over 100 measurements taken adjacent to a bulkhead shoreline in the Porto Marghera industrial zone (Fusina) showed flow rates as high as 30 cm d⁻¹ and averaging 6 cm d⁻¹. These flow rates, if representative of even a fraction of the lagoon floor, are easily able to account for the 15% deficit previously calculated between precipitation and runoff for the entire Venice Lagoon drainage basin. Land elevation surrounding the Venice Lagoon is < 10 m within 20 km of the shoreline and is unable to support any substantial onshore water table. Submarine groundwater discharge most likely represents upward artesian discharge from deeper partially confined aquifers. Over 60 samples were collected in total from both sites for nutrient analysis. Ammonium concentration was found to be 2–8 fold higher in the device water than in the lagoon water at the northern site depending on season, and 10–30 times higher at the industrial zone site. These numbers suggest that SGD may be the primary pathway for nutrients and perhaps other contaminants to enter Venice Lagoon.     

Cyclostratigraphy and astrochronology of the Tripoli diatomite formation (pre-evaporite Messinian, Sicily, Italy)

The ongoing debate about the Messinian salinity crisis in the Mediternean is fuelled in part by the lack of an adequate time control. The most accurate and, at the same time, detailed constraints are nowadays provided by the astronomical dating technique. Here we present an astronomical age model for the cyclically bedded Tripoli diatomite Formation on Sicily (pre-evaporite Messinian, Italy) based on an integrated stratigraphic study of three key-sections, Falconara, Gibliscemi and Capodarso. Characteristic sedimentary cycle patterns allow (i) the sections to be cyclostratigraphically correlated, the 'bed-to-bed' correlations being confirmed by high-resolution planktonic foraminiferal biostratigraphy, and (ii) the Tripoli cycles to be calibrated to the astronomical record. Despite minor misfits the correctness of the tuning is evident from the match between precession-obliquity interference in the astronomical target and its reflection in the sedimentary cycle record. The tuning provides absolute astronomical ages for all sedimentary cycles and planktonic foraminiferal events. The base of the Tripoli is astronomically dated at 7.005 Ma, indicating that the onset of diatomite formation is diachronous in the Mediternean since it started 300 000 years earlier on Sicily than on Gavdos, south of Crete. The top of the Tripoli, and thus the onset of the salinity crisis proper on Sicily, arrives at 5.98 Ma.     

Gabbroic xenoliths in tuff-breccia pipes from the Hyblean Plateau: insights into the nature and composition of the lower crust underneath South-eastern Sicily, Italy

Summary Crust-derived xenoliths hosted by Miocene basaltic diatremes in the Hyblean Plateau (south-eastern Sicily, Italy) provide new information regarding the nature of a portion of the central Mediterranean lower crust. These xenoliths can be divided into three groups: gabbros (plagioclase + clinopyroxene + Fe–Ti oxides ± apatite ± amphibole ± Fe-rich green spinel), diorites (An-poor plagioclase, clinopyroxene ± Fe–Ti oxides ± orthopyroxene) and mafic granulites (plagioclase + clinopyroxene + green spinel ± orthopyroxene ± Fe–Ti oxides). Gabbros form the main subject of this paper. They represent cumulates whose igneous texture has been locally obliterated by metamorphic recrystallization and shearing. They were permeated by Fe–Ti-rich melts related to tholeiitic-type fractional crystallisation. Incompatible element ratios (Zr/Nb = 5–26; Y/Nb = 1.4–11) indicate that these cumulate gabbros derived from MORB liquids. Late-stage and hydrothermal fluids caused diverse, sometimes important, metasomatic trasformations. Petrographic and geochemical comparison with gabbroids from well-known geodynamic settings show that the Hyblean lower crustal xenoliths were probably formed in an oceanic or oceanic-continent transition environment.