Review of the Ediacaran-Lower Ordovician (pre-Sardic) stratigraphic framework of the Eastern Pyrenees, southwestern Europe

The Ediacaran-Lower Ordovician successions exposed in the Eastern Pyrenees are updated and revised based on recent U-Pb zircon radiometric ages, intertonguing relationships of carbonate-dominated strata, and onlapping patterns marking the top of volcano-sedimentary complexes. A stratigraphic comparison with neighbouring pre-Variscan outcrops from the Montagne Noire (southern French Massif Central) and Sardinia is related to i) the absence of Cadomian deformation close to the Ediacaran-Cambrian boundary interval; ii) the presence of an episodic, Cadomian-related, acidic-dominant volcanism related to carbonate production punctuating the Ediacaran-Cambrian transition, similar to that recorded in the northern Montagne Noire; and iii) the lack of Guzhangian (Late Cambrian Epoch 3) regressive shoal complexes present in the Montagne Noire and probably in Sardinia

Review of the Ediacaran-Lower Ordovician (pre-Sardic) stratigraphic framework of the Eastern Pyrenees, southwestern Europe

The Ediacaran-Lower Ordovician successions exposed in the Eastern Pyrenees are updated and revised based on recent U-Pb zircon radiometric ages, intertonguing relationships of carbonate-dominated strata, and onlapping patterns marking the top of volcano-sedimentary complexes. A stratigraphic comparison with neighbouring pre-Variscan outcrops from the Montagne Noire (southern French Massif Central) and Sardinia is related to i) the absence of Cadomian deformation close to the Ediacaran-Cambrian boundary interval; ii) the presence of an episodic, Cadomian-related, acidic-dominant volcanism related to carbonate production punctuating the Ediacaran-Cambrian transition, similar to that recorded in the northern Montagne Noire; and iii) the lack of Guzhangian (Late Cambrian Epoch 3) regressive shoal complexes present in the Montagne Noire and probably in Sardinia

Shifts in the Ediacaran to Lower Ordovician sedimentary zircon provenances of Northwest Gondwana: the Pyrenean files

Detrital zircon grains from Cambrian–Lower Ordovician sandstones and quartzites sampled in the Pyrenees were dated by LA-ICPMS in order to assess their provenance sources. Resulting age distributions are compared to other available datasets from neighbouring margins, such as Morocco, the Iberian Peninsula, southern France and Sardinia. Kolmogorov-Smirnov (K-S) test and Crystallization Age-Depositional Age (CA-DA) diagrams were used to compare zircon populations estimating their possible correlation with the arc/rift/drift geodynamic evolution of the northwestern Gondwana margin. During Terreneuvian times, zircon populations allowed the distinction of i) a southwesternmost edge (Anti-Atlas-Ossa-Morena Rift) mostly influenced by Panafrican and Anti-Atlasian sources (ca. 0.63–0.54), ii) a northeasternmost edge (Sardinia) recording the influence of the Saharan Metacraton and the Arabian Nubian Shield, with an distinct Stenian–Tonian shift (ca. 1.25–0.85Ga) and iii) an intermediate palaeogeographic transect, where lies the Central-Iberian, West Asturian-Leonese and Cantabrian Zones, the Montagne Noire and the Pyrenees sharing similar populations and a chronologically progressive influence from Anti-Atlasian/Panafrican to Saharan Metacraton/Arabian Nubian Shield sources. This gradual modification in zircon percentage populations supports similar trends based on climatically sensitive indicators, biogeographic patterns of Cambrian Epoch 2 archaeocyathan and microfossil assemblages, and laterally correlatable episodes of carbonate production, all of them pointing to a Cambrian setting for the Pyrenean Basin between the Montagne Noire (Occitan Domain) and the Sardinian margins of NW Gondwana. The Terreneuvian zircon patterns recorded in the Pyrenees gradually evolved from Cambrian Epoch 2 to Early Ordovician times, reflecting the geodynamic evolution from Panafrican and Cadomian arc-related to rift-dominant conditions. During Furongian and Ordovician times, the relative percentage of zircon populations led to a more spread age curve, characteristic of extensional settings and pointing to rift (passive margin) conditions

Hamiltonian dynamics and spectral theory for spin-oscillators

We study the Hamiltonian dynamics and spectral theory of spin-oscillators. Because of their rich structure, spin-oscillators display fairly general properties of integrable systems with two degrees of freedom. Spin-oscillators have infinitely many transversally elliptic singularities, exactly one elliptic-elliptic singularity and one focus-focus singularity. The most interesting dynamical features of integrable systems, and in particular of spin-oscillators, are encoded in their singularities. In the first part of the paper we study the symplectic dynamics around the focus-focus singularity. In the second part of the paper we quantize the coupled spin-oscillators systems and study their spectral theory. The paper combines techniques from semiclassical analysis with differential geometric methods.Comment: 32 page

On Synchronization in a Lattice Model of Pulse-Coupled Oscillators

We analyze the collective behavior of a lattice model of pulse-coupled oscillators. By means of computer simulations we find the relation between the intrinsic dynamics of each member of the population and their mutual interaction that ensures, in a general context, the existence of a fully synchronized regime. This condition turns out to be the same than the obtained for the globally coupled population. When the condition is not completely satisfied we find different spatial structures. This also gives some hints about self-organized criticality.Comment: 4 pages, RevTex, 1 PostScript available upon request, To appear in Phys. Rev. Let

Discontinuidades sedimentarias en la transición Cámbrico Inferior-Medio del manto del Esla, Zona Cantábrica

In the Esla nappe, three major discontinuities have been recognized within the Lancara Formation. Discontinuity D1 is located at the top of the white bedded limestones. It is recognized as an erosive contact and marks a sharp change from a peritidal-dominant, homoclinal ramp to a ramp with oolitic and bioclastic shoals distinguished here as the grey lenticular limestones. Discontinuity D2 is placed at the top of the grey lenticular limestones and is the boundary between the lower and upper Lancara members. A discontinuous ferruginous level or hard ground marks the boundary in the Esla nappe. Discontinuity D3 is placed at the bottom of the griotte tectofacies. It marks a major tectonic pulse and the input of fine-grained siliciclastics. In some areas, it is not sharp but gradual. D3 is a diachronous boundary, dated in some areas of the Cantabrian platform. The D3 surface is easily recognisable in SW Europe as a tectonically induced contact reflecting the diachronous and progressive breakdown of some platforms in SW Europe

The Ordovician of France and neighbouring areas of Belgium and Germany

The Ordovician successions of France and neighbouring areas of Belgium and Germany are reviewed and correlated based on international chronostratigraphic and regional biostratigraphic charts. The same three megasequences related to the rift, drift and docking of Avalonia with Baltica can be tracked in Belgium and neighbouring areas (Brabant Massif and Ardenne inliers), western (Rhenish Massif) and northeastern Germany (Rügen). The remaining investigated areas were part of Gondwana in the Ordovician. The Armorican Massif shares with the Iberian Peninsula a Furongian–Early Ordovician gap (Toledanian or Norman gap), and a continuous Mid–Late Ordovician shelf sedimentation. The Occitan Domain (Montagne Noire and Mouthoumet massifs), eastern Pyrenees and northwestern Corsica share with southwestern Sardinia continuous shelf sedimentation in the Early Ordovician, and a Mid Ordovician ‘Sardic gap’. In the Ordovician, the Maures Massif probably belonged to the same Sardo-Occitan domain. The Vosges and Schwarzwald massifs display compa-rable, poorly preserved Ordovician successions, suggesting affinities with the Teplá-Barrandian and/or Molda-nubian zones of Central Europe.This paper is a contribution to the International Geoscience Programme (IGCP) projects 653 "The onset of the Great Ordovician Biodiversification Event" and 735 “Rocks and the Rise of Ordovician Life: Filling knowledge gaps in the Early Palaeozoic Biodiversification". The authors are particularly grateful to Annalisa Ferretti, David A.T. Harper and Petr Kraft for their careful and constructive reviews, comments and suggestions, which greatly improved the quality and relevance of the paper

Dinosaur swim tracks from the Lower Cretaceous of La Rioja, Spain: An ichnological approach to non-common behaviours

The reconstruction of behavioural patterns performed by non-avian dinosaurs is an important task of palaeontology in order to globally understand how these animals interacted with their environment. Their relation with aquatic lifestyles has always been an intriguing question that has been extensively studied during the last decades, especially focused on some specific groups. The present work describes a new tracksite with 27 swimming tracks located in a fluvial setting from the Lower Cretaceous Urbion Group of La Rioja (Spain). They are preserved as natural casts with sizes between 8.5 and 29.2 cm and a predominant orientation. The tracks have been classified into 6 different morphotypes according to their morphology, and grouped into 5 different categories depending on the different pes-substrate interactions, following the proposal of Romilio et al. (2013). Some tracks were produced while the animal was moving in partial or complete buoyancy, and displacement was conducted by water and sediment impulsion, not just a mere paddling. Other tracks could be impressed in a bottom-walked, when the trackmaker touched the digit tips on the ground vertically or sub-vertically. This new tracksite confirms the capabilities of some groups of non-avian dinosaurs to interact with shallow water environments where they could print their pedes as they moved, either in complete buoyancy or during a displacement with some vertical component in the water column. It also contributes to the better understanding of swimming track morphologies as especially dependent on pes-sediment interaction and environment more than differences in pes configuration itself, causing the high variability of swimming footprints even when they belong to the same trackway. The classification of swimming tracks and footprints into categories dependent on the pes-substrate interaction could be a good guiding principle to avoid problematics about ichnotaxonomical definition.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEUniversidad de La RiojaConsejeria de Educacion y Cultura (Gobierno de La Rioja)Instituto de Estudios RiojanosMinisterio de Ciencia, Innovación y UniversidadesEuropean Regional Development FundUniversidad del País VascoMinisterio de Ciencia e Innovaciónpu

Ordovician of North Iran: New lithostratigraphy, palaeogeography and biogeographical links with South China and the Mediterranean peri-Gondwana margin

The Ordovician litho- and biostratigraphic framework of Alborz, Kopet-Dagh and the East-Central Iranian blocks is outlined and significantly updated, and a broad summary of the current state of knowledge of the Ordovician deposits and faunas across Iran is documented. Four tectono-stratigraphical units (including the Alestan, Damghan, Saluk and Talesh domains) are distinguished in northern Iran. They differ considerably from one another in their lithology, facies, fossil record and completeness of their sedimentary record. A comprehensive revision of the Ordovician stratigraphy in the eastern Alborz and the Kopet-Dagh regions leads to the definition of the (i) Simeh-Kuh Formation (new), (ii) the Qumes Formation (new) and its subdivision into the Gerd-Kuh (new) and Raziabad (new) members, (iii) the Lashkarak Formation and its subdivision into the Cheshmeh-Ali (new) and Hajiabad (new) members, (iv) the Abarsaj Formation (formalised) in the Alestan Domain, (v) the Qyzlar (new) and Pelmis formations in the Saluk Domain, and (vi) the Tatavrud Formation (new) in the Talesh Domain. The Ordovician strata of the eastern Alborz and Kopet-Dagh Mountains comprise a rifting volcanism emplaced within an active horst-and-graben palaeotopography. Despite the strong Ordovician biogeographical affinities with South China and, to a lesser extent, with Mediterranean peri- Gondwana, zircon populations analysed from Cambro-Ordovician sandstones in the area point to the Arabian-Nubian Shield of the western Arabian Peninsula and northeastern Africa as the principal continental sources. Consequently, an open oceanic communication between the Mediterranean and the northern (Alborz) margins of Gondwana and the southern margin of South China favoured the establishment of strong biogeographical affinities between these mid-latitude basins