The Norian "chaotic carbon interval": New clues from the δ13Corg record of the Lagonegro Basin (southern Italy)

A global carbon-isotope curve for the Late Triassic has the potential for global correlations and new insights on the complex and extreme environmental changes that took place in this time interval. We reconstruct the global δ 13 C org profile for the late Norian, improving on sparse published data from North American successions that depict a "chaotic carbon-isotope interval" with rapid oscillations. In this context, we studied three sections outcropping in the Lagonegro Basin (southern Italy), originally located in the western Tethys. The carbon-isotope profiles show four negative excursions correlatable within the Lagonegro Basin. In particular, a negative shift close to the Norian/Rhaetian boundary (NRB) appears to correlate with that observed in the North American δ 13 C org record, documenting the widespread occurrence of this carbon cycle perturbation. The 87 Sr/ 86 Sr and 187 Os/ 188 Os profiles suggest that this negative shift was possibly caused by emplacement of a large igneous province (LIP). The release of greenhouse gases (CO 2 ) to the atmosphere-ocean system is supported by the 12 C enrichment observed, as well as by the increase of atmospheric p CO 2 inferred by different models for the Norian/Rhaetian interval. The trigger of this strongly perturbed interval could thus be enhanced magmatic activity that could be ascribed to the Angayucham province (Alaska, North America), a large oceanic plateau active ca. 214 ± 7 Ma, which has an estimated volume comparable to the Wrangellia and the Central Atlantic Magmatic Province (CAMP) LIPs. In fact, these three Late Triassic igneous provinces may have caused extreme environmental and climate changes during the Late Triassic

Contribution to the late triassic geochronology by magnetostratigraphic correlations between tethyan marine sections and the newark apts

Chronology of Late Triassic (last Epoch of Triassic Period) is still a debated question. Late Triassic is constrained by two U/Pb ages, one near the Ladinian/Carnian boundary (237.773±0.052 Ma; Alpe di Siusi/Seiser Alm, Italy) and the other at the Rhaetian/Hettangian boundary (201.36±0.17 Ma; Levanto, Peru). Unfortunately, any radiometric age constraints the Stage boundaries of Late Triassic. Many attempts to assign an age to the Stages have been made during the last 20 years, correlating marine sections (usually from Tethys) with the Newark Astrochronological Polarity Time Scale (Newark APTS). The ages obtained was sometimes very different, in particular for the Rhaetian, with a duration that varied from ~2 My to ~9 My depending from the correlation performed with the APTS. The options proposed in the Geological Time Scale 2012 introduced two different ages for both Rhaetian (~205.4 Ma and ~209 Ma) and Norian (~221 Ma and ~228 Ma). The Norian age of ~228 Ma seems coherent with many other correlations between marine sections and the APTS. In an effort to help resolving the issues of the Late Triassic chronology, selected Tethyan marine sections, characterized by a detailed biostratigraphy, have been analyzed for paleomagnetism. The investigation are focused on two main intervals: the Rhaetian and the Carnian. The Rhaetian have been chosen for the reasons explained before (confused chronology), the Carnian because the few magnetostratigraphic data covering this interval, in particular its middle part, must be integrated to obtain a continuous magnetostratigraphy of this Stage. The chosen sections are: Pignola-Abriola, Mount Messapion and the ODP Leg 122-Hole 761C for the Rhaetian; Pignola-2, Dibona, and ODP Leg 122-Holes 759B/760B for the Carnian. The magnetostratigraphy of these sections have been integrated with the data from other Tethyan sections in literature, obtaining a continuous magnetostratigraphy spanning the entire Late Triassic. This composite magnetostratigraphy of Tethyan section has been time-calibrated using the Newark APTS, linked to the composite through the statistical correlations with Pignola-2, Pizzo Mondello, and Pignola-Abriola. The so obtained Geomagnetic Polarity Time Scale (GPTS) has been used to assign an age to the events calibrated to the magnetostratigraphy of the Late Triassic, like the bioevents defining the Stage and substage boundaries, or climatic events as the Carnian Pluvial Event

Analisi stratigrafiche della sezione di Forcella China, Monte Clapsavon (Alpi Carniche – Udine). = Stratigraphic analyses of the Forcella Chiana section, Mount Clapsavon (Carnic Alps).

The stratigraphic research made on M. Clapsavon has the purpose of obtaining a stratigraphic column of “Forcella Chiana” section, where was surveyed the following formations: Calcari Dolomitici del M. Tiarfin: these are massive grey limestones with facies of carbonatic platform, precisely of a reef environment. Looking at the microfacies into the thin sections, is recognizable the typical configuration of a microbial boundstone with trombolitic structure, to be more precise is a bioconstructed limestone built by encrusting microbes. Into the sections can be observed several fossils organism like dasicladacean algae, foraminifers and ostracods, all encrusted into the biogenic micrite. The formation contains also some heavily dolomitizated layers, in which the substitution from calcite to dolomite obliterated the previous structures. Calcari Rossi ad Ammoniti del Monte Clapsavon: these are thin grained red limestones, deposed in a pelagic environment, enriched in re-crystallizated radiolarian, echinoderms and bivalves fragments immersed into a micritic matrix; the rock is grain-substained and can be defined like a packstone. At the bottom of the formation there is a breccias with clasts < 3 cm belonging to the underlying formation, that are the “Calcari Dolomitici del M. Tiarfin”. The clasts are immersed into a reddish matrix belonging to “Calcari Rossi” full of bivalvs and echinoderms’ flakes. Wengen Formation: these sandstones derive from terrigen material settled into a basin, enriched of volcanogenic products especially volcanic crystals. Moreover, portions of volcanic rocks can be included into these sandstones like isolated clasts. The colour of this rock is greenish for the occurrence of volcanic elements, sometimes with dark red halos caused by weathering. Looking at the thin sections is possible to see volcanic crystals within biological elements like radiolarian and sponges’ spiculas. Into a sample there is a volcanic clast that seems an effusive igneous rock, probably a basalt. The analysis with thin sections gave us more information about depositional environments. The “Calcari del Tiarfin” formation are typical rocks of reef zone, therefore during Middle Triassic a carbonatic platform was active. The presence of a basal breccias confirms the reef zone, but is possible that this rocks have been formed into an upper slope zone. The “Calcari Rossi ad Ammoniti del Monte Clapsavon” formation was deposed during the latemost Anisian to Late Ladinian; these limestones derives from a pelagic environment, that means the platform was pulled down by extensional tectonic activity, until the drowning of the platform. The presence of Wengen Formation indicates the following passage to open basin conditions, with heavy terrigen and volcanogenic contribution. Usually the Livinallongo Formation is stratigrafically lower then Wengen Formation; in Forcella Chiana the Livinallongo Formation is absent because is replaced by “Calcari Rossi ad Ammoniti”, which is stratigrafically equivalent.ope

New magnetobiostratigraphic results from the Ladinian of the Dolomites and implications for the Triassic geomagnetic polarity timescale

We investigated for magnetostratigraphy the Rio Nigra and Rio Frommer stratigraphic sections from Alpe di Siusi/Seiser Alm (Dolomites, northern Italy) in order to improve the calibration of the Triassic time scale. Both sections are characterized by ammonoid and conodont associations typical of Longobardian (late Ladinian, Middle Triassic) age. Moreover, the Rio Nigra section is constrained by a U-Pb zircon date of 237.77 ± 0.05 Ma. Building on the recently veri ed Newark-Hartford astrochronological polarity timescale for the Late Carnian–Rhaetian (plus the Hettangian) and through magnetostratigraphic correlations of an updated inventory of Tethyan marine stratigraphic sections from the literature, some of which are provided with U-Pb zircon age constraints, we propose a revised Geomagnetic Polarity Time Scale for the entire Triassic

Correction: Konidaris et al. Dating of the Lower Pleistocene Vertebrate Site of Tsiotra Vryssi (Mygdonia Basin, Greece): Biochronology, Magnetostratigraphy, and Cosmogenic Radionuclides. Quaternary 2021, 4, 1

Background and scope: The late Villafranchian large mammal age (~2.0–1.2 Ma) of the Early Pleistocene is a crucial interval of time for mammal/hominin migrations and faunal turnovers in western Eurasia. However, an accurate chronological framework for the Balkans and adjacent territories is still missing, preventing pan-European biogeographic correlations and schemes. In this article, we report the first detailed chronological scheme for the late Villafranchian of southeastern Europe through a comprehensive and multidisciplinary dating approach (biochronology, magnetostratigraphy, and cosmogenic radionuclides) of the recently discovered Lower Pleistocene vertebrate site Tsiotra Vryssi (TSR) in the Mygdonia Basin, Greece. Results: The minimum burial ages (1.88 ± 0.16 Ma, 2.10 ± 0.18 Ma, and 1.98 ± 0.18 Ma) provided by the method of cosmogenic radionuclides indicate that the normal magnetic polarity identified below the fossiliferous layer correlates to the Olduvai subchron (1.95–1.78 Ma; C2n). Therefore, an age younger than 1.78 Ma is indicated for the fossiliferous layer, which was deposited during reverse polarity chron C1r. These results are in agreement with the biochronological data, which further point to an upper age limit at ~1.5 Ma. Overall, an age between 1.78 and ~1.5 Ma (i.e., within the first part of the late Villafranchian) is proposed for the TSR fauna. Conclusions: Our results not only provide age constraints for the local mammal faunal succession, thus allowing for a better understanding of faunal changes within the same sedimentary basin, but also contribute to improving correlations on a broader scale, leading to more accurate biogeographic, palaeoecological, and taphonomic interpretations

The Run Control and Monitoring System of the CMS Experiment

The CMS experiment at the LHC at CERN will start taking data in 2008. To configure, control and monitor the experiment during data-taking the Run Control and Monitoring System (RCMS) was developed. This paper describes the architecture and the technology used to implement the RCMS, as well as the deployment and commissioning strategy of this important component of the online software for the CMS experiment

High Level Trigger Configuration and Handling of Trigger Tables in the CMS Filter Farm

The CMS experiment at the CERN Large Hadron Collider is currently being commissioned and is scheduled to collect the first pp collision data in 2008. CMS features a two-level trigger system. The Level-1 trigger, based on custom hardware, is designed to reduce the collision rate of 40 MHz to approximately 100 kHz. Data for events accepted by the Level-1 trigger are read out and assembled by an Event Builder. The High Level Trigger (HLT) employs a set of sophisticated software algorithms, to analyze the complete event information, and further reduce the accepted event rate for permanent storage and analysis. This paper describes the design and implementation of the HLT Configuration Management system. First experiences with commissioning of the HLT system are also reported

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO