U-Pb sensitive high resolution ion microprobe (SHRIMP) zircon geochronology, combined with REE geochemistry, has been applied in order to gain insight into the complex polymetamorphic history of the (ultra) high pressure [(U)HP] zone of Rhodope. Dating included a paragneiss of Central Rhodope, for which (U)HP conditions have been suggested, an amphibolitized eclogite, as well as a leucosome from a migmatized orthogneiss at the immediate contact to the amphibolitized eclogite, West Rhodope. The youngest detrital zircon cores of the paragneiss yielded ca. 560 Ma. This date indicates a maximum age for sedimentation in this part of Central Rhodope. The concentration of detrital core ages of the paragneiss between 670-560 Ma and around 2 Ga is consistent with a Gondwana provenance of the eroded rocks in this area of Central Rhodope. Metamorphic zircon rims of the same paragneiss yielded a lower intercept

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The microscopic characteristics of soot particulate matter (PM) in gas turbine exhaust are critical for an accurate assessment of the potential impacts of the aviation industry on the environment and human health. The morphology and internal structure of soot particles emitted from a CFM 56-7B26/3 turbofan engine were analyzed in an electron microscopic study, down to the nanoscale, for ∼ 100%, ∼ 65%, and ∼ 7% static engine thrust as a proxy for takeoff, cruising, and taxiing, respectively. Sampling was performed directly on transmission electron microscopy (TEM) grids with a state-of-the-art sampling system designed for nonvolatile particulate matter. The electron microscopy results reveal that ∼ 100% thrust produces the highest amount of soot, the highest soot particle volume, and the largest and most crystalline primary soot particles with the lowest oxidative reactivity. The opposite is the case for soot produced during taxiing, where primary soot particles are smallest and most reactive and the soot amount and volume are lowest. The microscopic characteristics of cruising condition soot resemble the ones of the ∼ 100% thrust conditions, but they are more moderate. Real time online measurements of number and mass concentration show also a clear correlation with engine thrust level, comparable with the TEM study. The results of the present work, in particular the small size of primary soot particles present in the exhaust (modes of 24, 20, and 13 nm in diameter for ∼ 100%, ∼ 65% and ∼ 7% engine thrust, respectively) could be a concern for human health and the environment and merit further study. This work further emphasizes the significance of the detailed morphological characteristics of soot for assessing environmental impacts.

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Metabasic rocks from different parts of the Antrona ophiolites, Western Alps, as well as from the Misox zone, Central Alps, were dated using ion microprobe (SHRIMP) U-Pb analyses of zircon, in association with cathodoluminescence (CL) imaging. HP metamorphism must have affected at least the major part of the Antrona ophiolites, although HP relics are rarely preserved, probably due to the Lepontine metamorphic overprint. HP metamorphism has affected also the area of the Misox zone. The origin of the Antrona ophiolites is arguable. They were interpreted as part of both the Piemont-Ligurian (PL) and the Valais ocean, the two main oceans in the area of the Alps before Alpine convergence. SHRIMP-analyses of co-magmatic zircon domains from the Antrona ophiolites (Guggilihorn, Passo del Mottone and Quarata areas) yielded identical (within uncertainty) weighted mean 206 Pb/ 238 U ages of 155.2±1.6 Ma, 158±17 Ma (or 163.1±2.4 Ma: one analysis; 1r error) and 155.6±2.1 Ma, respectively, interpreted as the time of crystallization of the magmatic protoliths. These Late Jurassic ages fit well to the time span considered for the formation of Piemont-Ligurian oceanic crust. The metagabbro of the Misox zone (Hinterrhein area), for which a Valaisan origin is generally accepted, gave also a Late Jurassic, PL protolith age of 161.0±3.9 Ma. The metamorphic zircon domains from the amphibolitized eclogite of Mottone yielded an age of 38.5±0.7 Ma, interpreted as the time of HP metamorphism. This age is in good agreement with the time of metamorphism reported from previous zircon SHRIMP-data for eclogites and amphibolites of other parts in the Valais domain. In order to bring in line the PL protolith ages with the Valaisan metamorphic ages, we suggest a scenario involving emplacement of part of the PL oceanic crust to the north of the newly formed Brianc¸onnais peninsula, inside the Valais geotectonic domain. This paleotectonic configuration was probably established when younger Valaisan oceanic crust formed by spreading and re-rifting, partly within PL oceanic crust.