Matteo Maron

. We investigated the geochemical and rock magnetic properties of the magnetostratigraphically-calibrated Pignola-Abriola section (Italy) in order to understand the climatic perturbations that characterize the late Norian–early Rhaetian interval (Late Triassic). We performed experiments on anhysteretic and isothermal remanence (ARM, IRM), and on magnetic susceptibility (χ), to obtain the rock magnetic parameters necessary for our paleoclimatic investigation. An episode of increase in relative quantity of hematite, suggesting enhanced subaerial oxidation of iron minerals, was identified in the Norian from ~217 Ma in the Alaunian up to ~211 Ma in the early Sevatian, followed by a decline up to 207–206 Ma at the end of the Norian (late Sevatian). The results of geochemical and multivariate statistical analyses support a long-term increase and reduction in rock weathering, confirming and extending previous 87Sr/86Sr data from the Pizzo Mondello section (Italy). Possible causes of these long-term weathering trends are the multiphase uplifting of the Cimmerian orogen, occurring at mid northern latitudes along the southern margin of Asia in the Late Triassic, and/or the northward motion of Pangea across the equatorial humid belt. Rapid excursions in oxidized iron minerals have also been observed across the Norian/Rhaetian boundary, the origin of which has still to be determined.

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.

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...

The Norian/Rhaetian section of Pignola-Abriola (Southern Apennines, Italy), consisting in ca. 60 m of pelagic sediments (cherty limestones and shales), provided new magnetostratigraphic data for the upper Norian (Sevatian) and the lower Rhaetian. The magnetostratigraphic sequence, subdivided in 10 magnetozones, is calibrated with conodont and radiolarian biostratigraphy. The Norian/Rhaetian boundary in Pignola-Abriola is defined by the first appearance of conodont Misikella posthernsteini, within the Proparvicingula moniliformis radiolarian Zone 1. Other Norian and Rhaetian magneto-biostratigraphic sections from the Tethys realm such as Brumano-Italcementi Quarry, Oyuklu, Pizzo Mondello and Steinbergkogel have been successfully correlated with the Pignola-Abriola section. According to our correlations, the oldest occurrences of M. posthernsteini at Steinbergkogel and Oyuklu, used to place the Norian/Rhaetian boundary in these sections (e.g. Krystyn et al., 2007), correspond at Pigno...

In order to improve the magnetostratigraphy of the Carnian, we studied the sections of Pignola 2 (Southern Apennines, Italy) and Dibona (Dolomites, Italy), both covering the Julian/Tuvalian boundary (lower/upper Carnian). This boundary is characterized by an important climate change to more humid conditions called Carnian Pluvial Event (Simms & Ruffell, 1989), affecting the sedimentary record. In a pelagic contest, i.e. the Pignola 2 section, the CPE appears as a condensed sequence of shales and radiolarites called the “green clay-radiolaritic horizon” (Rigo et al., 2007). In a shallow-water environment, i.e. the Dibona section, the CPE manifests with the deposition of a thick, expanded sequence of various-grained sandstone and silty-clayey levels within the Heiligkreuz Fm. By comparison of palynomorphs record, the magnetostratigraphy of the Dibona section can be considered coeval to the shaley level of the “green clay-radiolaritic horizon” in Pignola 2, filling the lack in magnetos...

We present a summary of previously published Olenekian–Anisian boundary magnetostratigraphic and biostratigraphic results from the Kçira area of northern Albania. We focus on the stratigraphically complete Kçira-A section that represents a potential candidate Global Boundary Stratotype Section and Point (GSSP) for the base of the Anisian Stage of the Triassic System. The previously published conodont biostratigraphy from Kçira-A and ancillary sections located nearby has been updated using modern taxonomic criteria and correlated to the available ammonoid and benthic foraminifera biostratigraphy. Previously published magnetobiostratigraphic data reveal the occurrence at Kçira-A, and ancillary sections, of a well-defined magnetic polarity reversal pattern of primary origin that allows global correlations ensuring the exportability of biostratigraphic datums (e.g., the first occurrence of conodont Chiosella timorensis) falling close to the Kclr/Kc2n polarity transition. A suite of pilo...

Supplementary Table S1: ChRM components from Rio Nigra and Rio Frommer stratigraphic sections. Data are in core, in situ, and tilt-corrected coordinates. Legend of the header is at the end of the table. Supplementary Table S2: Ages and durations of the chrons of the GPTS. The name of the chrons refers to the name of the magnetozones of origin. The mean polarity reversal rates for Early, Middle and Late Triassic (reversal/Myr) have been obtained through linear regression. Figure S1: Anisotropy of Magnetic Susceptibility carried out on the samples from Rio Nigra and Rio Frommer sections. Figure S2: Detail of the Middle Triassic interval of the GPTS/Age plot showing the error bars of the U-Pb zircon ages from Seceda (Wotzlaw et al., 2018) and Rio Nigra (Mietto et al., 2012).

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...

The onset of the Acheulean, marked by the emergence of large cutting tools (LCTs), is considered a major technological advance in the Early Stone Age and a key turning point in human evolution. The Acheulean originated in East Africa at ~ 1.8–1.6 Ma and is reported in South Africa between ~ 1.6 and > 1.0 Ma. The timing of its appearance and development in North Africa have been poorly known due to the near-absence of well-dated sites in reliable contexts. The ~ 1 Ma stone artefacts of Tighennif (Algeria) and Thomas Quarry I-Unit L (ThI-L) at Casablanca (Morocco) are thus far regarded as documenting the oldest Acheulean in North Africa but whatever the precision of their stratigraphical position, both deserve a better chronology. Here we provide a chronology for ThI-L, based on new magnetostratigraphic and geochemical data. Added to the existing lithostratigraphy of the Casablanca sequence, these results provide the first robust chronostratigraphic framework for the early North Af...

We present a summary of previously published Olenekian–Anisian boundary magnetostratigraphic and biostratigraphic results from the Kçira area of northern Albania. We focus on the stratigraphically complete Kçira-A section that represents a potential candidate Global Boundary Stratotype Section and Point (GSSP) for the base of the Anisian Stage of the Triassic System. The previously published conodont biostratigraphy from Kçira-A and ancillary sections located nearby has been updated using modern taxonomic criteria and correlated to the available ammonoid and benthic foraminifera biostratigraphy. Previously published magnetobiostratigraphic data reveal the occurrence at Kçira-A, and ancillary sections, of a well-defined magnetic polarity reversal pattern of primary origin that allows global correlations ensuring the exportability of biostratigraphic datums (e.g., the first occurrence of conodont Chiosella timorensis) falling close to the Kclr/Kc2n polarity transition. A suite of pilo...

New Norian/Rhaetian magnetostratigraphic data have been obtained from the Pignola-Abriola section cropping out in the Southern Apennines (Potenza, Italy), and composed of ~60 m of hemipelagic-pelagic sediments in stratigraphic continuity (Calcari con Selce Fm). More than 160 samples have been analyzed for the NRM but only 45 gave back the primary magnetic component; successively the VGP has been defined from the principal component analysis. Using the VGP latitude was settled a sequence of 3 normal (MPA-1n, -2n, -3n) and 2 reverse (MPA-1r, -2r) polarity magnetozones, well calibrated by using an integrated conodont/radiolarian biostratigraphy, which provide a detailed Norian/Rhaetian age of the studied succession. In order to identify the magnetozones containing the Norian/Rhaetian boundary, here recognized as FAD of the Misikella posthernsteini, these results have been correlated to published magnetobiostratigraphic data from two other Tethyan marine sections that are Oyuklu (Turkey...

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...

Abstract This paper investigates the magnetostratigraphy of the ~750 m-thick Costa Grande Member (lower Miocene) from the Castagnola Basin of NW Italy, which represents the turbidite fill of a structurally confined basin where flow ponding resulted in a complete record of deposition from diverse sediment gravity flow types. The magnetostratigraphic profile of the Costa Grande Mb was correlated to the Geomagnetic Polarity Timescale using a well-established statistical method devised to be applied to sedimentary successions with steady accumulation rate. The results of the correlation exercise, validated with the available biostratigraphy, indicate an early Miocene age (from Chron C6AAr.3r to C6Bn.2n) between 21.7 and 22.3 Ma. The obtained age model was then used to calculate accumulation rates and frequencies of small volume and low-density vs. large volume and high-density gravity flows over an estimated 650 kyr time span. Results show that low-density flows contributed at a constant pace of 545 m Myr−1 to sediment accumulation, depositing relatively thin-bedded turbidites with a minimum recurrence time of 1.7 kyr, whereas the high-density flows, which are at least four times less frequent, are clustered in the stratigraphy, and become more abundant up-section. We also show that the minimum sediment volumes discharged by high-density flows suggest triggering by submarine failures whose recurrence and magnitude were probably not random. Lastly, we propose that the statistical method used in this study to correlate the Costa Grande Mb magnetostratigraphy to the GPTS provides best results when the products of episodic but voluminous depositional events are carefully identified and removed.

Abstract The latest Triassic was an interval of prolonged biotic extinction culminating in the end-Triassic Extinction (ETE). The ETE is now associated with a perturbation of the global carbon cycle just before the end of the Triassic that has been attributed to the extensive volcanism of the Circum-Atlantic Magmatic Province (CAMP). However, we attribute the onset of declining latest Triassic diversity to an older perturbation of the carbon cycle (δ13Corg) of global extent at or very close to the Norian/Rhaetian boundary (NRB). The NRB appears to be the culmination of stepwise biotic turnovers that characterize the latest Triassic and includes global extinctions of significant marine and terrestrial fossil groups. These biotic events across the NRB have been largely under-appreciated, yet together with a coeval disturbance of the carbon cycle were pivotal in the history of the Late Triassic. Here, we present new and published δ13Corg data from widespread sections (Italy, Greece, ODP, Australia, New Zealand, USA, Canada). These sections document a previously unknown perturbation in the carbon cycle of global extent that spanned the NRB. The disturbance extended across the Panthalassa Ocean to both sides of the Pangaean supercontinent and is recorded in both the Northern and Southern Hemispheres. The onset of stepwise Late Triassic extinctions coincides with carbon perturbation (δ13Corg) at the NRB, indicating that a combination of climatic and environmental changes impacted the biota at a global scale. The NRB event may have been triggered either by gas emissions from the eruption of a large igneous province pre-dating the NRB, by a bolide impact of significant size or by some alternative source of greenhouse gas emissions. As yet, it has not been possible to clearly determine which of these trigger scenarios was responsible; the evidence is insufficient to decisively identify the causal mechanism and merits further study.

Abstract The Kimmeridgian (Late Jurassic) stage has proven difficult to define in modern timescales essentially because the land sections used to describe it are typically condensed and discontinuous. For example, no single land section has been able to replicate the full record of magnetic polarity reversals recorded on the ocean floor as marine magnetic anomalies. Here, we report the magnetostratigraphy of the S'Adde carbonate succession from the Tethyan realm of Sardinia (Italy) that was previously studied for nannofossil biostratigraphy. We applied a statistical approach to correlate this magneto-biostratigraphic record to a recent global stack of M-sequence magnetic anomalies. We found that the base of the Tethyan Kimmeridgian, as approximated by the first occurrence (FO) of nannofossil Faviconus multicolumnatus, falls within M25Ar1n at a nominal age of ~152.8 Ma, while the base of the Tethyan Tithonian (top Kimmeridgian) as approximated by the FO of Conusphaera mexicana minor falls in the lower part of M22n at a nominal age of ~146.5 Ma. A discussion of the relationship between our Tethyan Kimmeridgian and the Sub-Boreal Kimmeridgian as defined in the Flodigarry GSSP candidate section is also provided. By virtue of its continuity, the S'Adde section is a valuable reference section for defining the Tethyan Kimmeridgian in modern Jurassic timescales.

We provide an updated and detailed magnetostratigraphy across the C34n/C33r polarity reversal boundary at the Bottaccione section (Gubbio, Italy) that represents a candidate GSSP for the base of the Campanian Stage (Late Cretaceous). The position of the C34n/C33r boundary is stratigraphically located at 221.525 ± 0.075 m in agreement with previous estimates from the literature. Following a critical review of data from the literature, we assign a nominal age of 83.06 ± 0.18 Ma to the observed C34n/C33r polarity reversal boundary and an average rate of deposition of the Santonian/Campanian boundary Scaglia Rossa Formation of 1.09 ± 0.25 cm/kyr (~11 m/Myr). We also assess the paleolatitude of deposition of the Scaglia Rossa at Bottaccione by correcting the characteristic remanent magnetization component directions for sedimentary inclination flattening, obtaining a value of 21.1° N (± 1.6°).

In an effort to improve the calibration of the Late Triassic time scale, two stratigraphic successions in Italy were investigated for magnetostratigraphy: the Pignola-2 (Southern Apennines) and the Dibona (Dolomites) sections. These sections reveal a sequence of biostratigraphically calibrated (conodonts and palynomorphs) magnetic polarity zones encompassing the Julian/Tuvalian boundary (Carnian). A total of 63 samples have been collected from the Pignola-2 section that helped defining 3 magnetozones. These data are constrained by a published radiometric U/Pb age of 230.91 0.33 Ma from the Aglianico ash-bed (Furin et al. 2006). From the Dibona section, 81 samples have been collected, revealing 2 magnetozones in the Heiligkreuz Fm. (lower part of the succession) and 2 magnetozones in the Travenanzes Fm. (upper part). The Dibona section provided only few high-quality paleomagnetic data in spite of the sampling effort, so we considered only the Pignola-2 section as suitable for the correlation with other Carnian sections from the literature , in order to define the magnetostratigraphy around the Julian/Tuvalian boundary in the Tethys realm. The correlation between the Pignola-2 and the Newark Astrochronological Polarity Time Scale (APTS) provides independent insights on the age of the base of the Newark basin APTS. We found that the U-Pb zircon-dated Pignola-2 level, magnetostratigraphically projected on the Newark APTS, falls within Chrons E5-E4 at around 231 Ma, in agreement with the (extrapolated) astrochronological ages of the Newark APTS.

A detailed magnetostratigraphic investigation of the Pignola-Abriola section of Norian to Rhaetian age permits the identification of 22 magnetic polarity reversals grouped in 10 magnetozones. We correlate the magneto-stratigraphy of the Pignola-Abriola section with the Newark astrochronological polarity time scale (APTS). In total, 19 correlation options were tested, and only one (option 7) yielded a statistically significant correlation that was consistent with the available information on the stratigraphic age of the Newark APTS. After some adjustments to minimize erratic variations in sediment accumulation rates, a final correlation (option 7.1) was used to generate an age model of sedimentation for the Pignola-Abriola section. The Pignola-Abriola section has been correlated with Rhaetian sections from the literature, notably the current global boundary stratotype section and point candidate for the base of the Rhaetian at Steinbergkogel, Austria, where the Norian-Rhaetian boundary is proposed to be placed at a stratigraphic level containing the first appearance datum (FAD) of conodont Misikella post hern steini, traced on the Newark APTS to ca. 209-210 Ma. Issues regarding the taxonomy of M. post hern steini, a species characterized by transitional forms with its ancestor Misikella hernsteini, lead us to propose the alternative option of placing the Norian-Rhaetian boundary at a prominent negative δ 13 C org spike observed in the Pignola-Abriola section at meter 44.5, 50 cm below the level containing the FAD of M. post hern steini sensu stricto and close to the base of radio-larian Proparvicingula moniliformis zone. This level has been magnetostratigraphically correlated to Newark magnetozone E20r.2r at ca. 205.7 Ma. Assuming an age of ca. 201.3 Ma for the Triassic-Jurassic boundary, the Rhaetian Stage would have a duration of ~4.4 m.y.