Astrochronostratigraphic polarity time scale (APTS) for the Late Triassic and Early Jurassic from continental sediments and correlation with standard marine stages

Paleomagnetic and cycle stratigraphic analyses of nearly 7000 m of section from continuous cores in the Newark basin and an overlapping 2500 meter-thick composite outcrop and core section in the nearby Hartford basin provide an astrochronostratigraphic polarity time-scale (APTS) for practically the entire Late Triassic (Carnian, Norian and Rhaetian) and the Hettangian and early Sinemurian stages of the Early Jurassic (233 to 199 Ma in toto). Aperiodic magnetic polarity reversals make a distinctive pattern of normal and reverse chrons for correlation, ideally paced by the periodic timing of orbital climate cycles, and anchored to million years ago (Ma) by high-precision U-Pb zircon dates from stratigraphically-constrained basalts of the Central Atlantic Magmatic Province (CAMP). Pinned by the CAMP dates, the Newark-Hartford APTS is calibrated by sixty-six McLaughlin cycles, each a reflection of climate forcing by the long astronomical eccentricity variation with the stable 405 kyr period, from 199.5 to 225.8 Ma and encompassing fifty-one magnetic polarity intervals, making it one of the longest continuous astrochronostratigraphic polarity time-scales available in the Mesozoic and Cenozoic. Extrapolation of sediment accumulation rates in fluvial sediments in the basal Newark section extends the sequence an additional fifteen polarity intervals to 232.7 Ma. The lengths of the 66 polarity chrons vary from 0.011 Myr (Chron E23r) to 1.63 Myr (Chron H24n) with an overall mean duration of 0.53 Myr. The oldest CAMP basalts provide a zircon U-Pb-based estimated age of 201.5 Ma for the base of the stratigraphically superjacent McLaughlin cycle 61 and 201.6 Ma using cycle stratigraphy for the onset of the immediately subjacent Chron E23r. The calibration age of 201.5 Ma for the base of McLaughlin cycle 61 is remarkably consistent with the calculated phase of the 498th long eccentricity cycle counting back using a period of 405 kyr from the most recent peak at 0.216 Ma. Accordingly, we suggest a nomenclature (Ecc405:k, where k is the cycle number or fraction thereof) to unambiguously assign ages from the astrochronostratigraphy. Magnetostratigraphic correlation of key Tethyan sections with diagnostic marine biostratigraphic elements to the Newark-Hartford APTS allows determination of numerical ages of standard marine stages, as follows: 227 Ma for the Carnian/Norian boundary, 205.5 Ma for the Norian/Rhaetian boundary (using a chemostratigraphic criterion, or about 4 Myr older for alternative criteria), 201.4 Ma for the Triassic/Jurassic boundary, and 199.5 Ma for the Hettangian/Sinemurian boundary. These age estimates are in excellent agreement with available constraints from high-precision U-Pb zircon dating from the Pucara Basin of Peru and along with the presence of the short Chron E23r in several basins argue strongly against suggestions that millions of years of Rhaetian time is missing in a cryptic hiatus or unconformity that supposedly occurs just above Chron E23r in the Newark Supergroup basins. It is more parsimonious to explain the apparent temporal delays in appearances and disappearances of palynoflora, conchostracans, and other endemic taxa in continental deposits as a reflection of demonstrated continental drift across climate belts and the misinterpretation of ecostratigraphy as chronostratigraphy. The Newark-Hartford APTS provides a chronostratigraphic template for continuing efforts at correlation of Late Triassic and Early Jurassic continental and marine sections throughout the world, including integration with atmospheric pCO2 measurements from paleosol carbonates and carbon isotopic measurements from marine carbonates to better understand the global carbon cycle as well as understanding the causes of and recovery from the end-Triassic mass extinction

Ecce Homo in Milan

Come ogni essere vivente anche l\u2019uomo ha colonizzato gli habitat solo nel momento in cui questi presentavano le condizioni favorevoli alla sua sopravvivenza. La colonizzazione del continente europeo \ue8 avvenuta molto probabilmente da Est verso Ovest e l\u2019ingresso in Italia pu\uf2 essere avvenuto solo dal punto pi\uf9 comodo in cui si poteva superare la catena Alpina, ossia passando dai Balcani (Figura 2). Dal record geologico si deduce il susseguirsi di periodi caldi a periodi freddi durante tutto il Pleistocene, tuttavia non ci sono evidenze di un passaggio ad un clima glaciale nel nostro paese prima del Pleistocene Superiore. Questo cambiamento ha come prima conseguenza l\u2019espansione delle calotte glaciali legata all\u2019intrappolamento dell\u2019acqua degli oceani e il conseguente abbassamento del livello del mare che provoca il passaggio di molte zone precedentemente sommerse prima ad un ambiente litorale e inne emerso. Questo \ue8 quanto si \ue8 vericato in Pianura Padana. Il cambiamento di ambiente ha provocato una variazione nel materiale che si stava depositando: prima si avevano limi e sabbie marine, poi ciottoli legati al trasporto uviale e materiale ne legato alle esondazioni dei umi. La dierenza nel materiale deposto \ue8 stata riconosciuta lungo tutta la Pianura Padana ed \ue8 stata nominata Discontinuit\ue0 R. La Discontinuit\ue0 R \ue8 quindi legata a un cambiamento nel clima, e all\u2019istaurarsi delle grandi glaciazioni nel continente europeo. Mediante lo studio di diverse carote prelevate in Pianura Padana \ue8 stato possibile creare un modello di et\ue0 che ha permesso di associare la Discontinuit\ue0 R al MIS22, datandola a circa 870.000 anni fa (Figura 1). Il MIS22 corrisponde inoltre alla ne della cosiddetta \u201cRivoluzione del Pleistocene Medio\u201d, un momento in cui si \ue8 assistito ad un cambiamento nella ora con la comparsa delle prime piante legate all\u2019ambiente glaciale, ma anche ad un cambiamento nella fauna legato all\u2019arrivo di specie come il mammuth (Mammuthus meridionalis), l\u2019elefante antico (Elephas antiquus), e il rinoceronte lanoso (Coelodonta antiquitatis). La nostra ipotesi \ue8 che l\u2019arrivo dell\u2019uomo in Europa e in Italia sia stato legato alla sua tendenza a seguire le onde migratorie degli animali che costituivano le sue principali prede (Figura 2), e che sia avvenuto in concomitanza con l\u2019instaurarsi delle grandi glaciazioni Pleistocenica, ossia attorno all\u2019et\ue0 del MIS22

Organic Carbon Burial following the Middle Eocene Climatic Optimum (MECO) in the central - western Tethys

We present trace metal geochemistry and stable isotope records for the middle Eocene Alano di Piave section, NE Italy, deposited during magnetochron C18n in the marginal Tethys Ocean. We identify a $\sim$ 500 kyr long carbon isotope perturbation event we infer to be the middle Eocene Climatic Optimum (MECO) confirming the northern hemisphere expression and global occurrence of MECO. Interpreted peak climatic conditions are followed by the rapid deposition of two organic rich intervals ($\le$3\% TOC) and contemporaneous positive $\delta^{13}$C excursions. These two intervals are associated with increases in the concentration of sulphur and redox-sensitive trace metals, and low concentrations of Mn, as well as coupled with the occurrence of pyrite. Together these changes imply low, possibly dysoxic, bottom water O$_{2}$ conditions promoting increased organic carbon burial. We hypothesize that this rapid burial of organic carbon lowered global {\it p}CO$_{2}$ following the peak warming and returned the climate system to the general Eocene cooling trend

A Virtual CAD Model of the LHC

Integrating the large and complex LHC machine into the existing LEP tunnel is a major challenge. Space was not really a problem to fit the LEP machine into its tunnel, but LHC cryostats are much larger than the LEP quadrupoles and the external cryogenic line fills even more the tunnel. Space problems lead to small clearances. Possible conflicts, or at least the most penalising ones, between installed equipment or with transport, must be solved beforehand in order to avoid unacceptable delays and extra costs during the installation. Experience gained with LEP has already shown the help that Computer-Aided Engineering tools could provide for the integration. A virtual model of the LHC is presently prepared. The actual LEP tunnel, known with a quite good accuracy (centimetre level), has been modelled and all the elements of the machine constructed as 3D objects with the CAD system are positioned accurately on the basis of data generated from the theoretical definition. These layouts are used to generate the reference sections and to check the clearances. Examples of this powerful approach applied to engineering for accelerators are given

Integrated bio- and magnetostratigraphy of the Tithonian \u2013 Berriasian interval in the Tethys Ocean: implications for the definition of the Jurassic/Cretaceous boundary.

The Jurassic/Cretaceous boundary time interval is characterized by a major calcareous nannofossil speciation episode: several successful genera and species first appear and rapidly evolve, particularly nannolith genera show a progressive increase in diversity, abundance and degree of calcification through time (Roth, 1989; Bralower et al., 1989; Erba & Quadrio, 1989; Bornemann et al., 2003; Bown et al., 2004; Tremolada et al., 2006; Casellato & Erba, 2007). In the Tethys ocean this event is associated with a major change in pelagic sedimentation from predominantly siliceous to mostly calcareous (transition from Rosso ad Aptici /Rosso Ammonitico Superiore to Maiolica). Magneto- and calcareous nannofossil biostratigraphy, and nannofloral relative and absolute abundances have been investigated on selected Tethyan land sections (Monte Pernice, Torre de Busi, Foza, Colma di Vignole, Frisoni - Southern Alps, Italy) in order to integrate calcareous nannofossil events with the polarity chron sequence and, where available, with calpionellid biostratigraphy. Biostratigraphic investigations have been performed directly on un-heated magneto-core end pieces: calcareous nannofossil biostratigraphy, relative and absolute abundances have been performed on simple smear slides and ultra-thin sections (7-8 \ub5m thick), calpionellid biostratigraphy has been investigated on thin sections. All known calcareous nannofossil Zones and Subzones (Bralower et al., 1989) have been recognized. Differences in some taxa ranges have been also pointed out, due to the high-resolution sampling (one sample every 5 - 40 cm). Chitinoidella, Crassicollaria and Calpionella Zones have been identified across the Jurassic/Cretaceous boundary (Remane, 1986; Pop, 1994b; Reh\ue1kov\ue1 & Michal\uedk, 1997). Nine polarity chrons (from CM24 to CM17) have been identified. Quantitative nannofossil studies indicate that nannolith taxa (firstly F.multicolumnatus, then C.mexicana, finally P.beckmannii) increase significantly in abundance, size and degree of calcification gaining lithogenetic proportion. The abundance acmes are reached in discrete steps between calcareous nannofossil Zones NJ-20B and NJK-A, in the interval marked by the first occurrence of calcified calpionellids. Nannoconids also appear and rapidly evolve across the Tithonian/Berriasian boundary, reaching lithogenetic abundances from calcareous nannofossil Subzone NJK-C to NK-1. High nannoconid abundances are concomitant with the well known Acme of Calpionella alpina spherical forms, both contributing to most Maiolica micrite. Calibration with magnetostratigraphy indicates that these trends could be very useful as additional bio-horizons in the Tithonian and for locating the Jurassic/Cretaceous boundary, especially when ammonites are absent, as in the Tethyan Maiolica. In particular, the speciation of highly-calcified nannofossil forms, and the remarkable abundance and size increase, could provide new reliable stratigraphic events for the Jurassic/Cretaceous boundary interval in low latitudinal pelagic and hemipelagic sequences. We emphasize that integrated stratigraphy based on calcareous nannofossil and capionellid events and magnetostratigraphy, is a powerful tool for characterizing the Jurassic/Cretaceous boundary interval at enhanced resolution

Decompressive craniectomy in paediatric traumatic brain injury: a systematic review of current evidence

Introduction Paediatric traumatic brain injury (pTBI) is one of the most frequent neurological presentations encountered in emergency departments worldwide. Every year, more than 200,000 American children suffer pTBIs, many of which lead to long-term damage. Objectives We aim to review the existing evidence on the efficacy of the decompressive craniectomy (DC) in controlling intracranial pressure (ICP) and improving long-term outcomes in children with pTBI. Methods A comprehensive search of the MEDLINE and EMBASE databases led to the screening of 212 studies, 12 of which satisfied inclusion criteria. Data extracted included the number and ages of patients, Glasgow Coma Scale scores at presentation, treatment protocols and short- and long-term outcomes. Results Each of the nine studies including ICP as an outcome reported that it was successfully controlled by DC. The 6–12 month outcome scores of patients undergoing DC were positive, or superior to those of medically treated groups in nine of 11 studies. Mortality was compared in only two studies, and was lower in the DC group in both.Very few studies are currently available investigating short- and long-term outcomes in children with TBI undergoing DC. Conclusion The currently available evidence may support a beneficial role of DC in controlling ICP and improving long-term outcomes

Late Paleocene to Early Eocene Magneto-Biostratigraphy from the Cicogna section (Belluno Basin, NE Italy): A record of continental weathering

During the Late Paleocene-Early Eocene (\u30360 Ma to 50 Ma), Earth's climate experienced a warming trend that culminated at the Early Eocene Climatic Optimum (EECO). The EECO was characterized by warm conditions at even extreme high latitudes, subdued latitudinal temperature gradients, and virtually nonexistent polar ice sheets. The early Paleogene long-term climate was punctuated by several short-lived hyperthermal events, the most prominent of which is the Paleocene Eocene Thermal Maximum (PETM). Here we present paleomagnetic and calcareous nannofossil data from the Tethyan marine Cicogna section (Belluno Basin, NE Italy). The paleomagnetic results, integrated with calcareous nannofossil biostratigraphy, indicate that the Cicogna section extends from Chron C25r to Chron C23r spanning the NP7/NP8-NP12 nannofossil Zones with a relatively constant sediment accumulation rate of \u30318 m/My. Rock-magnetic data show sediment enrichment in hematite-maghemite respect to magnetite generally across the PETM and from \u30354 Ma up to the section top. We observed a correlation between rock-magnetic properties and global climate as revealed by a standard benthic oxygen isotope record from the literature. Our interpretation is that the warm and humid conditions typical of the PETM and the EECO enhanced continental weathering with the consequent production, transport, and sedimentation of more oxidized iron oxide phases (e.g. hematite-maghemite) relative to less oxidized phases (e.g., magnetite). Our temporal coupling between oxidation state of sedimentary magnetic phases and global climate therefore demonstrates the existence in the Paleocene-Eocene of the silicate weathering negative feedback mechanism for the long-term stabilization of the Earth's surfaces temperature as proposed by various authors

Magnetostratigrafia della serie Pleistocenica di Castell’Arquato (PC)

Abbiamo presentato i risultati preliminari relativi all'indagine magnetostratigrafica della sezione affiorante nel torrente Arda (PC) da cui \ue8 poi stato ricavato l'articolo Monesi et al., (21016

Tethyan magnetostratigraphy from Pizzo Mondello (Sicily) and correlation to the Late Triassic Newark astrochronological polarity time scale

We present the magnetostratigraphy and stable isotope stratigraphy from an expanded (∼430-m-thick) Upper Triassic marine limestone section at Pizzo Mondello, Sicily, and review published biostratigraphic information that can be used to define the location of the conodont Carnian-Norian and Norian-Rhaetian boundaries in this section. Pizzo Mondello offers good potential for magneto-stratigraphic correlation of marine biostratigraphic and chemostratigraphic data with the continental Newark astrochronological polarity time scale (APTS) for development of an integrated Late Triassic time scale. The relatively stable average values of δ18O centered on 0‰ are a strong indication that the Cherty Limestone at Pizzo Mondello suffered very little diagenetic overprinting. The conodont Carnian-Norian boundary is located 12.5 m above a positive shift of δ13C. A statistical approach was applied to evaluate various Pizzo Mondello to Newark magnetostratigraphic correlations. Two correlation options have the highest correlation coefficients. In option #1, the base of Pizzo Mondello correlates with the middle part of the Newark APTS, whereas in option #2, the base of Pizzo Mondello starts toward the early part of the Newark APTS. We prefer option #2 in which the Carnian-Norian boundary based on conodonts, as well as its closely associated positive δ13C shift, correspond to Newark magnetozone E7 at ca. 228–227 Ma (adopting Newark astrochronology), implying a long Norian with a duration of ∼20 m.y., and a Rhaetian of ∼6 m.y. duration. These ages are in fact not inconsistent with the few high-quality radiometric dates that are available for Late Triassic time scale calibration. Based on its good exposure, accessibility, stratigraphic thickness and continuity, and multiple chronostratigraphic correlation possibilities, we propose Pizzo Mondello as global stratigraphic section and point for the base of the Norian

Tethyan magnetostratigraphy from Pizzo Mondello (Sicily) and correlation to the Late Triassic Newark astrochronological polarity time scale

We present the magnetostratigraphy and stable isotope stratigraphy from an expanded (∼430-m-thick) Upper Triassic marine limestone section at Pizzo Mondello, Sicily, and review published biostratigraphic information that can be used to define the location of the conodont Carnian-Norian and Norian-Rhaetian boundaries in this section. Pizzo Mondello offers good potential for magneto-stratigraphic correlation of marine biostratigraphic and chemostratigraphic data with the continental Newark astrochronological polarity time scale (APTS) for development of an integrated Late Triassic time scale. The relatively stable average values of δ18O centered on 0‰ are a strong indication that the Cherty Limestone at Pizzo Mondello suffered very little diagenetic overprinting. The conodont Carnian-Norian boundary is located 12.5 m above a positive shift of δ13C. A statistical approach was applied to evaluate various Pizzo Mondello to Newark magnetostratigraphic correlations. Two correlation options have the highest correlation coefficients. In option #1, the base of Pizzo Mondello correlates with the middle part of the Newark APTS, whereas in option #2, the base of Pizzo Mondello starts toward the early part of the Newark APTS. We prefer option #2 in which the Carnian-Norian boundary based on conodonts, as well as its closely associated positive δ13C shift, correspond to Newark magnetozone E7 at ca. 228–227 Ma (adopting Newark astrochronology), implying a long Norian with a duration of ∼20 m.y., and a Rhaetian of ∼6 m.y. duration. These ages are in fact not inconsistent with the few high-quality radiometric dates that are available for Late Triassic time scale calibration. Based on its good exposure, accessibility, stratigraphic thickness and continuity, and multiple chronostratigraphic correlation possibilities, we propose Pizzo Mondello as global stratigraphic section and point for the base of the Norian