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The Lower and Upper Cretaceous turbidites cover large areas in the central Pontides (north-central Turkey). The Lower Cretaceous turbidites are over 2 km thick and are exposed in an area of 400 x 90 km. The Upper Cretaceous (Campanian-Maastrichtian) forearc turbidites are up to 1,200 m thick and crop out in NW-SE trending elongate basins about 40 km wide, extending along the central and eastern Pontides. We present new detrital zircon U-Pb ages, petrography, and paleocurrent measurements from the Campanian-Maastrichtian turbidites and compare them to those from the Lower Cretaceous turbidites. The Campanian-Maastrichtian sandstones are dominated by carbonate and magmatic lithic grains. The paleocurrents indicate paleoflow directions parallel to the axis of the basin. The sandstones are dominated by Late Cretaceous zircons indicating derivation mainly from the coeval magmatic arc. In contrast, the Lower Cretaceous sandstones are dominated by quartz and feldspar, and paleocurrents indicate southward transport. The detrital zircons in the Lower Cretaceous sandstones are mainly Archean and Paleoproterozoic, indicating that in the Early Cretaceous, the source of turbidites was from the Archean-Paleoproterozoic Ukrainian Shield to the north. After the opening of the Black Sea in the Late Cretaceous, the connection between the Pontides and the East European Platform was severed and the Campanian-Maastrichtian turbidites were sourced principally from the magmatic arc in the Pontides. Our results indicate that the Campanian-Maastrichtian turbidites represent the first turbiditic sequence deposited after the opening of the Black Sea.

The Central Pontides of N Turkey represents a mobile orogenic belt of the southern Eurasian margin that experienced several phases of exhumation associated with the consumption of different branches of the Neo-Tethys Ocean and the amalgamation of continental domains. Our new low-temperature thermochronology data help to constrain the timing of these episodes, providing new insights into associated geodynamic processes. In particular, our data suggest that exhumation occurred at (1) similar to 110 to 90Ma, most likely during tectonic accretion and exhumation of metamorphic rocks from the subduction zone; (2) from similar to 60 to 40Ma, during the collision of the Kirehir and Anatolide-Tauride microcontinental domains with the Eurasian margin; (3) from similar to 0 to 25Ma, either during the early stages of the Arabia-Eurasia collision (soft collision) when the Arabian passive margin reached the trench, implying 70 to 530km of subduction of the Arabian passive margin, or during a phase of trench advance predating hard collision at similar to 20Ma; and (4) similar to 11Ma to the present, during transpression associated with the westward motion of Anatolia. Our findings document the punctuated nature of fault-related exhumation, with episodes of fast cooling followed by periods of slow cooling or subsidence, the role of inverted normal faults in controlling the Paleogene exhumation pattern, and of the North Anatolian Fault in dictating the most recent pattern of exhumation.

Geophysical Research Abstracts. - 20 EGU General Assembly 2018, Vienna, Austria, 8 Apr 2018 - 13 Apr 2018; Katlenburg-Lindau : European Geophysical Society, Geophysical Research Abstracts 20, EGU2018-12718, 1 Seite (2018)., Published by European Geophysical Society, Katlenburg-Lindau

The Camaná-Mollendo Basin is an active-margin depression ~NW-SE elongated, which is located in the forearc of southern Perú and extends from the Coastal Cordillera to the Perú-Chile Trench. This basin consists of a grabens and half-graben complex, filled with deltaic and fluvial sedimentary rocks of the Oligocene-Pliocene Camaná Formation (~500 m thick). An integration of compiled onshore stratigraphic logs, reinterpreted 2D seismic offshore information, sediment provenance data, and previous zircon U-Pb geochronology on volcanic reworked ash supports a refined tectono-chronostratigraphic framework for the whole Camaná-Mollendo Basin fill. To complete this integration we needed firstly to elaborate a geological reinterpretation of seismic offshore data and highlight their most prominent features (i.e., erosive surfaces). This step allowed establishing a first correlation between onshore and offshore deposits of Camaná Formation by means of their sequence boundaries, giving as result a consistent division for Camaná Formation: (i) “CamA Unit” (coarse-grained deltas) and (ii) “CamB Unit” (fluvial deposits). CamA Unit is further subdivided into three subunits based on minor erosive surfaces (i.e., A1: Oligocene, A2: Early Miocene, and A3: Middle Miocene). CamA reflects prograding geometry (subunits A1 and A2) as well as onlapping geometry (subunit A3). CamB Unit (Late Miocene to Pliocene) consists of high-energy hyperpycnal flows composed of fluvial conglomerates in onshore, which very possibly changes to progradational deltaic in offshore. Each one of these units and subunits extends offshore and preserves similarities in depositional geometry and sequence boundaries with Camaná Formation onshore. Subunits A1 and A2 observed in offshore are grouped in this paper as “A1+A2” (Oligocene to Middle Miocene) because they show similar progradational geometry and it is difficult to differentiate them from each other. A regressive systems tract (RST) represents these subunits. These deposits reach up to ~2.5 km thick, and they are intensely affected by normal faulting associated to pinch-out depositional geometry. Strata of subunit A3 (Middle Miocene) reflect a transgressive systems tract (TST), and blanket the entire basin with fine-grained sediments. These deposits are up to ~1 km thick, being less affected by synsedimentary tectonic and show minor effects of synsedimentary tectonics. Finally, deposition of CamB Unit (Late Miocene to Pliocene) occurred during a new regressive systems tract (TST), which turned to progradational geometry similar to deltaic deposits in offshore, and according to seismic lines they are much less affected by synsedimentary faulting. Stratigraphic boundaries between “A1+A2” and A3, and between A3 and CamB observed in onshore outcrops are used here as tools to differentiate, correlate and predict the main depositional geometries in offshore. High-frequency seismic reflectors represent such boundaries and support divisions and subdivisions within Camaná Formation. These boundaries are also used to define depocentres of Camaná Formation along the entire Camaná-Mollendo Basin, where the thickests are located in the proximity of the large river mouths (e.g., Planchada, Camaná, and Punta de Bombón). Strata of subunits “A1+A2” are considered as potential reservoir for hydrocarbon due to their high rate of sediment accumulation. Deposits of A3 are transgressive and they are considered as potential potential seal rock. Structurally, Camaná-Mollendo Basin is composed of graben and half-graben components ~NW-SE-oriented, typical of a trantensional tectonic regime. © 2017, Servicio Nacional de Geologia y Mineria. All Rights Reserved.

This contribution explores several issues arising in the measurement of a (geo)chemical composition, specially in the case that the quantities of interest are linear functions of (log)-ratios. This is the case of multi-isotopic geochronological analyses, where an age of a geological material is inferred as a function of several logratios in the isotopic system (Hg202, Pb204, Pb206, Pb207, Pb208, Th232, U235, U238), by using several ratios (e.g., Pb208/Pb206, Pb206/Pb204, Hg202/Pb204, U238/U235), quantities that are scaling invariant and subcompositionally coherent, but which in general cannot be estimated without taking into account additive noise effects incompatible with a purely compositional approach. The proposed ways to a solution heavily build upon the multi- Poisson distribution, higlighting the counting nature of the readings delivered by these measuring machines.

These work contribute understanding a large scale Oligocene and Neogene tectonic processes in the southeastern Alps and northwestern Dinarides, based from new (U-Th-Sm)/He apatite ages.

Cenozoic gneiss domes—exposing middle-lower crustal rocks—cover ~30% of the surface exposure of the Pamir, western India-Asia collision zone; they allow an unparalleled view into the deep crust of the Asian plate. We use titanite, monazite, and zircon U/Th-Pb, mica Rb-Sr and 40Ar/39Ar, zircon and apatite fission track, and zircon (U-Th)/He ages to constrain the exhumation history of the ~350 × 90 km Shakhdara-Alichur dome, southwestern Pamir. Doming started at 21–20 Ma along the Gunt top-to-N normal-shear zone of the northern Shakhdara dome. The bulk of the exhumation occurred by ~NNW-ward extrusion of the footwall of the crustal-scale South Pamir normal-shear zone along the southern Shakhdara dome boundary. Footwall extrusion was active from ~18–15 Ma to ~2 Ma at ~10 mm/yr slip and with vertical exhumation rates of 1–3 mm/yr; it resulted in up to 90 km ~N-S extension, coeval with ~N-S convergence between India and Asia. Erosion rates were 0.3–0.5 mm/yr within the domes and 0.1–0.3 mm/yr in the horst separating the Shakhdara and Alichur domes and in the southeastern Pamir plateau; rates were highest along the dome axis in the southern part of the Shakhdara dome. Incision along the major drainages was up to 1.0 mm/yr. Thermal modeling suggests geothermal gradients as high as 60°C/km along the trace of the South Pamir shear zone and their strong N-S variation across the dome; the gradients relaxed to ≤40–45°C/km since the end of doming.

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Στο Πελαγονικό κρυσταλλοσχιστώδες στο δυτικό Βόρα, αναγνωρίστηκε ένα D1 τεκτονικό γεγονός κάτω κρητιδικής ηλικίας συν-μεταμορφικό ως προς μία, υψηλής πρασινοσχιστολιθικής-χαμηλής αμφιβολιτικής φάσης Mj-μεταμόρφωση (~135εκ. χρ. ηλικία ψύξης). Στο Μέσο-Άνω Κρητιδικό οι Ό1 δομε'ς επηρεάζονται από ένα, κυρίαρχο, ϋ2-τεκτονικό γεγονός, με κύρια έννοια της κίνησης προς τα ΝΑ. To D2 συνοδεύτηκε από μια ανάδρομη πρασινισχιστολιθικής φάσης Μ2-μεταμόρφωση (~90εκ. χρ.). Η 82-σχιστότητα πτυχώνεται συχνά από ασύμμετρες πτυχές ΒΔ-ΝΑ ανάπτυξης. Ένα νεώτερο τεκτονικό γεγονός, που χαρακτηρίζεται από την ανάπτυξη ημιπλαστικών ζωνών διάτμησης με κύρια προς τα ΝΑ έννοια της κίνησης, επηρέασε σε ακόμα ψυχρότερες Ρ-Τ συνθήκες στο Άνω Κρητιδικό (~60εκ. χρ.), κυρίως, τα ανώτερα τμήματα του κρυσταλλοσχιστώδους. Επίσης σε πλουτωνικά σώματα, που διεισδύουν το κρυσταλλοσχιστώδες υπόβαθρο, προσδιορίσθηκε ηλικία διείσδυσης 300±3εκ. χρ., The kinematic of the Cretaceous deformation and the relationship between deformation and metamorphism of the Pelagonian crystalline was studied in Voras Mt (northern Greece). The Pelagonian crystalline in this area has been subdivided into a lower, core part, consisting mainly of gneissic rocks and schists and an upper, cover part, consistine of schists and quartzites with marble intercalations. Intensely deformed granitic rocks of Upper Paleozoic age intrude the Pelagonian crystalline basement. An S j foliation is the oldest fabric recognized in the Pelagonian crystalline. Sj is mainly defined by syn-Sjgarnet(Gr1), biotite(Btj), white mica (Wnij), chloritoid, kyanite and plagioclase in the metapelitic rocks and green amphibole, epidote, plagioclase, and biotiteiBtj) in the amphibolite. Garnet grows also in some cases post-kinematically. Ilmenite and tourmaline are often found in the pelitic rocks as well. S is overprinted by an S2 foliation that developed as a crenulation cleavage. In most places, however, S2 has destroyed all earlier fabrics and a single S2 fabric is present related to, isoclinal or sheath folds intrafolial in places. S2 in the metapelitic rocks is characterized by the syn-S2 development of chlorite, white mica(Wm2) and plagioclase. In the amphibolite S2 is mainly defined by the syn-kinematic development of actinolite, plagioclase, biotite(Bt2), white mica(Wm2) and chlorite. During D2 garnet(Gr1) and biotiteiBtj) are partially replaced by chlorite, while green amphibole is replaced by actinolite and chlorite. Chloritoid remains generally stable along the S2-planes but in some places transforms to chlorite and sericite. Furthermore, D2 was locally followed by a static post-kinematic annealing indicated by polygonal quartz microfabrics with equilibrated grain boundaries and triple points. The overall orientation of S2 is dome shaped with a gentle SW-ward and NE-ward dip in the southwestern and northeastern flanks of the dome respectively. Syn-S2 minerals defined a very well exposed NW-SE trending stretching lineation. Kinematic indicators show a main top to the SE sense of movement. An S3 crenulation cleavage associated with asymmetric NW-SE trending folds is also present in most parts of the core and cover rocks, possibly, related to a constrictional type of deformation. A well developed, S4 shear band cleavage is mainly present in the upper parts of the metamorphic dome and formed under cooler conditions. S4 shear bands are associated with a NW-SE developed stretching lineation defined by elongated and dynamically recrystallized quartz grains and a preferred orientation of white mica and chlorite. Along the S4 shear bands a transformation of garnet, biotite, chloritoid and amphibole into chlorite is always observed. S4 shear bands indicate a main top to the SE sense of movement. The P-T metamorphic conditions were derived from textural equilibria and mineral assemblages, as well as from the spatial distribution of the metamorphic minerals. Syn-Dj metamorphism reached the conditions of the boundaries between greenschist and amphibolite facies. Syn-D2 retrogression took place under greenschist facie conditions. K/Ar radiometric datings on coarse-grained syn-St and younger fine-grained syn-S2 micas define an Early Cretaceous cooling age ('135Ma) for the older event and a Mid- to Late Cretaceous age ('90-80Ma) for the second event. A white mica age of ca. 65Ma correlates with S4 shear band clevage. Furthermore, the intrusion age of a granitic body into the Pelagonian crystalline is dated using the Pb/Pb single zircon evaporation method. The estimated intrusion age of 300±3Ma suggests that the Pelagonian crystalline was affected by a pre-kinematic magmatic activity relative to its Cretaceous deformation.