Kinematics of the Southern Rhodope Core Complex (North Greece)

The Southern Rhodope Core Complex is a wide metamorphic dome exhumed in the northern Aegean as a result of large-scale extension from mid-Eocene to mid-Miocene times. Its roughly triangular shape is bordered on the SW by the Jurassic and Cretaceous metamorphic units of the Serbo-Macedonian in the Chalkidiki peninsula and on the N by the eclogite bearing gneisses of the Sideroneron massif. The main foliation of metamorphic rocks is flat lying up to 100 km core complex width. Most rocks display a stretching lineation trending NEâ SW. The Kerdylion detachment zone located at the SW controlled the exhumation of the core complex from middle Eocene to mid-Oligocene. From late Oligocene to mid-Miocene exhumation is located inside the dome and is accompanied by the emplacement of the synkinematic plutons of Vrondou and Symvolon. Since late Miocene times, extensional basin sediments are deposited on top of the exhumed metamorphic and plutonic rocks and controlled by steep normal faults and flat-ramp-type structures. Evidence from Thassos Island is used to illustrate the sequence of deformation from stacking by thrusting of the metamorphic pile to ductile extension and finally to development of extensional Plio-Pleistocene sedimentary basin. Paleomagnetic data indicate that the core complex exhumation is controlled by a 30� dextral rotation of the Chalkidiki block. Extensional displacements are restored using a pole of rotation deduced from the curvature of stretching lineation trends at core complex scale. It is argued that the Rhodope Core Complex has recorded at least 120 km of extension in the North Aegean, since the last 40 My

Characterisation of igneous terranes by zircon dating: Implications for UHP occurrences and suture identification in the Central Rhodope, northern Greece

2siThe occurrence of ultra high pressure (UHP) and high pressure (HP) relicts associated with oceanic material suggests the presence of a suture zone within the Rhodope Massif. Characterisation of the accreted igneous terranes and their relationship with the UHP/eclogite occurrences provide new constraints on the location of this suture. Single-zircon evaporation and sensitive high-resolution ion microprobe dating of orthogneiss protoliths define two groups of intrusion ages: Permo-Carboniferous and Late Jurassic–Early Cretaceous. Structurally, the Late Jurassic gneissic complex overthrust a unit with Permo- Carboniferous orthogneisses. A ‘‘melange zone’’ marked by mylonites, eclogites, amphibolites, and UHP micaschists separates these two units. We interpret these observations in terms of two distinct igneous terranes, the Thracia (Permo- Carboniferous) and Rhodope (Late Jurassic) terranes, separated by the Nestos suture, and assembled during the closure of an oceanic basin of the Tethys. Geochemically, the Late-Jurassic rocks are akin to subduction magmatism, possibly the same subduction that caused the UHP metamorphism of metasediments within the ‘‘melange zone’’. Observed UHP–HP relicts are restricted to the tectonic contact zone, suggesting that a single subduction/collison event can explain the occurrences of UHP relicts and eclogites in the Central Rhodope, and that subducted rocks are exhumed only within the Nestos suture.nonenoneTurpaud, Philippe; Reischmann, ThomasTurpaud, Philippe; Reischmann, Thoma

Dissemination through InFEA Project: the water, an inalienable right

6noWhile drawing up the Water Protection Plan, the Water Resources Department of the Friuli Venezia Giulia Region jointly with the Mathematics and Geosciences Department of the Trieste University has carried out a three-year study aimed at assessing the sustainability of the groundwater use in the Friuli Venezia Giulia Region. In this territory is still very common to get water from artesian wells for domestic purposes and to leave them flowing free. These so called “fountains”, widespread located in the Low Plain, can be considered an integral part of the popular culture, a sort of cultural heritage to be preserved. Their density varies considerably according to the geographic settlements distribution and to the boundary conditions. The withdrawals interest the artesian aquifer systems and being free flowing, withdrawals are real and much more than the needs. The unsustainability lies in the fact that, high quality waters, withdrawn from medium to high depths, end up in the sea through irrigation and drainage canals or go to feed the shallow phreatic aquifer system of the Low Plain without producing any recharge for the groundwaters. The study highlighted that more than 50% of the total used groundwaters come from the domestic wells that get the waters from the deep aquifer systems. These withdrawals are approximately 70 times more than the estimated demand (250l/day per person, for a European citizen). In the Friuli Venezia Giulia Region, even if do not exist a problem of water quantity, going on with the same way of living, there will be, for sure, a quality problem. In the system in fact, through the effective infiltration, worse quality waters go into the water cycle. Furthermore, this great discharge that reaches the drainage system causes malfunctions in sewage plants and an increase of the pumping costs. Then comes the need to raise awareness on this specific subject. Thanks to the national InFEA Project, Friuli Venezia Giulia Region, jointly with researchers of the Trieste University, started a dissemination program in the hydrogeology field. The foreseen activities, within the time, will involve all the Low Plain municipalities. The methodological approach involve all the primary schools (class 4 and 5), teachers, local administrators and citizens. To the scholars, after a starting front lecture (two hours for each class), a field daily activity is offered. At the end of the cycle, all the students are involved in an active cooperation allowing to realize posters, models, poems and short stories that are later presented during an evening dedicated to a discussion among researchers, politicians/administrators and citizens. The involvement of the young students (9-11 years old) with the constant and active participation also of the teachers, authorities, parents and citizens, can be considered an educational experience for everybody. At the same time, this creates a conscious awareness of the critical issues of our fragile territory.nonenoneCalligaris, C.; Zini, L.; Turpaud, P.; Iervolino, D.; Lippi, F.; Cucchi, F.Calligaris, Chiara; Zini, Luca; Turpaud, Philippe; Iervolino, D.; Lippi, F.; Cucchi, Franc

Capire il ciclo idrologico per una migliore gestione dell'irrigazione in viticoltura: dalle precipitazioni al suolo e di nuovo alla vite

The Project Acquavitis investigated soil water recharge and its utilization by grapevines in 6 vineyards belonging to 3 contexts characterized by different geological, hydrogeological and climatic characteristics during the growing seasons of 2020 and 2021. Here, we present the results obtained in 3 vineyards, each one representing a different context. The soils of each vineyard have been characterized from a granulometric and mineralogic point of view. Soil samples were collected at least three times during summer 2020 and 2021 to measure the soil water content and water potential and to analyze the oxygen and hydrogen isotopic composition of soil water. Together with soils, precipitations, surface water and groundwater (from wells or caves in proximity of the studied areas) were also sampled. For understanding which water, the grapevines exploit during the growing season, the isotopic composition of the waters was compared to xylem sap extracted from grapevine branches during the same sampling periods. In the Ceroglie vineyard (in the Italian Karst), sampling frequency was incremented during 2021 for determining the influence of single precipitation events on soil water recharge and soil water use from vines. Geophysical surveys were also conducted to Capire il ciclo idrologico per una migliore gestione dell’irrigazione in viticoltura determine soil depth in the area. The obtained results suggest that, in general, grapevines mainly utilize water from the upper soil layers. This was influenced by the good water availability in soils due to the relatively abundant rainfall in spring and/or summer during the two years of this study

Fluid circulation related to post-messinian extension, Thassos Island, North Aegean

International audienceIn the North Aegean Domain, Thassos Island contains a Plio-Pleistocene basin controlled by a large-scale flat-ramp extensional system with a potential décollement located at depth within a marble unit. Numerous mineralizations associated with normal faults of Plio-Pleistocene age are the sign of fluid circulation during extension. Two main generations of fluid flow are recognized, related to Plio-Pleistocene extension. A first circulation under high-temperature conditions (about 100­200°C) resulted in dolomitization of marbles near the base of the Plio-Pleistocene basin. The dolomites are characterized by low d18O values (down to 11 versus Standard Mean Ocean Water). Some cataclastic deformation affected the dolomites. Hydrothermal quartz that crystallized in extension veins above a blind ramp also has low d18O values (about 13). This shows that high-temperature fluids moved up from the décollement level toward the surface. A second downward circulation of continental waters at near-surface temperature is documented by calcite veins in fault zones and at the base of the Plio-Pleistocene basin. These veins have O isotope values relatively constant at about 23­25 and C isotope values intermediate between the high d13C value of the carbonate host rock (about 1­3 versus Peedee Belemnite) and the low d13C value of soil-derived carbon (-10). The calcites associated with the oxidative remobilization of primary sulphide Zn­Pb mineralization of Thassos carbonates have comparable O and C isotope compositions. Hot fluids, within the 100­200°C temperature range, have likely contributed to the weakening of the lower marble unit of Thassos and, thus, to the process of décollement