336 research outputs found

    The Mesohellenic trough and the Thrace Basin. Two Tertiary molassic Basins in Hellenides: do they really correlate?

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    Με βάση τη λιθοστρωματογραφία, την τεκτονική ανάλυση και τη γεωλογική χαρτο- γράφηση συγκρίθηκαν μεταξύ τους, οι μολασσικές λεκάνες της Θράκης (ThB) στη ΒΑ Ελλάδα (συμπεριλαμβάνονται οι Παλαιογενείς αποθέσεις της λεκάνης Αξιού) και της Μεσοελληνικής Αύλακας. Αμφότερες οι λεκάνες χαρακτηρίζονται από μια παχειά, μολασσικού-τύπου ιζηματογενή ακολουθία (3-5 km πάχος) Τριτογενούς ηλικίας, που καλύπτεται ασύμφωνα από Νεογενή και Τεταρτογενή ιζήματα. Η μολασσκή ιζηματογένεση αρχίζει σχεδόν ταυτόχρονα και στις δύο περιοχές κατά τη διάρκεια του Μέσου- Άνω Ηωκαίνου όμως σταματάει σε διαφορετικούς χρόνους, στο Μέσο-Άνω Μειόκαινο για τη ΜΗΤ και στο Άνω Ολιγόκαινο για τη ThB. Η ιζηματογένεση στη ThB συνοδεύτηκε επί πλέον από έναν ασβεσταλκαλικής και τοπικά σωσωνιτικής σύστασης μαγματισμό, Ηωκαινικής-Ολιγοκαινικής ηλικίας. Ερμηνεύσαμε τη ΜΗΤ ως μια πολυιστορική οριζόντιας μετατόπισης, piggy-back λεκάνη, που αποτέθηκε επάνω σε οφιόλιθους και στο Πελαγονικό κάλυμμα κατά την προς τα δυτικά τοποθέτησή τους πάνω στο κρύο πρίσμα επαύξησης των Ελληνίδων. Αντίθετα, η ThB αναπτύχθηκε ως μια Παλαιογενή λεκάνη, πάνω σε ρήγμα διαφυγής και στις γεωλογικές ενότητες των εσωτερικών Ελληνίδων, κατά τη διάρκεια της Ηωκαινικής-Ολιγοκαινικής έκτασης των Εσωτερικών Ελληνίδων. Ο σύγχρονος με την ιζηματογένεση μαγματισμός, πιθανόν, συνδέεται με τις ορογενετικές διαδικασίες υποβύθισης του ωκεανού της Πίνδου ή του Αξιού. Σε κάθε περίπτωση ΜΗΤ και ThB αναπτύχθηκαν κατά τη διάρκεια πλάγιας σύγκλισης της Απουλίας πλάκας και των Εσωτερικών Ελληνίδων.Based on lithostratigraphic and structural data, as well as geological mapping, the mollasic Thrace Basin (ThB) in NE Greece (including the Paleogene deposits of the Axios Basin) was compared with the Mesohellenic Trough (MHT) in NW Greece. Both basins are characterized by a thick sedimentary sequence of molassic-type strata (3-5km thickness) of Tertiary age, overlain unconformably by Miocene- Pliocene and Quaternary deposits. Molassic sedimentation started almost simultaneously in both areas during the Mid-Upper Eocene but it finished in different time, in the Mid-Upper Miocene for the MHT and the Upper Oligocene for the ThB, respectively. Sedimentation in ThB was also linked with an important calc-alkaline and locally shoshonitic magmatism of Eocene-Oligocene age. We interpreted the MHT as a polyhistory strike-slip and piggy-back basin, above westward-emplacing ophiolites and Pelagonian units on the cold Hellenic accretionary prism. In contrast to MHT, the ThB evolved as a Paleogene supra-detachment basin above the strongly extended during the Eocene-Oligocene Hellenic Hinterland. The syn-depositional magmatic products, linked possibly with subduction processes in Pindos or Axios ocean(s). In any case, MHT and ThB are related to inferred oblique convergence of the Apulia plate and the internal Hellenic units

    Observation of associated near-side and away-side long-range correlations in √sNN=5.02  TeV proton-lead collisions with the ATLAS detector

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    Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  μb-1 of data as a function of transverse momentum (pT) and the transverse energy (ΣETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∼0) correlation that grows rapidly with increasing ΣETPb. A long-range “away-side” (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁡2Δϕ modulation for all ΣETPb ranges and particle pT

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Measurement of χ c1 and χ c2 production with s√ = 7 TeV pp collisions at ATLAS

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    The prompt and non-prompt production cross-sections for the χ c1 and χ c2 charmonium states are measured in pp collisions at s√ = 7 TeV with the ATLAS detector at the LHC using 4.5 fb−1 of integrated luminosity. The χ c states are reconstructed through the radiative decay χ c → J/ψγ (with J/ψ → μ + μ −) where photons are reconstructed from γ → e + e − conversions. The production rate of the χ c2 state relative to the χ c1 state is measured for prompt and non-prompt χ c as a function of J/ψ transverse momentum. The prompt χ c cross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χ c decays. The fractions of χ c1 and χ c2 produced in b-hadron decays are also measured
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