UPPER TRIASSIC AMBER FROM THE DOLOMITES (NORTHERN ITALY).A PALEOCLIMATIC INDICATOR?

Amber in Triassic deposits in the Dolomites is demonstrated for the first time. The amber-bearing deposits belong to the middle part of the Dürrenstein Formation, referred to uppermost Julian (Lower Carnian, about 225 My). Chemico-physical features of amber, which occurs as small yellow to reddish droplets, have been determined. Infrared (IR) spectroscopy shows typical bands of fossil resins; the "fingerprint" region of the spectrum presents a unique pattern that cannot be referred to any other known fossil resin. Palynological investigation of amber-bearing layers shows a large prevalence of bisaccates and circumpolles. Particularly, the taeniate bisaccates are frequent (41%) and suggest a correlation with the amber-producing species. Amber production and preservation is possibly related to a humid climatic event.&nbsp

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

A MONOTYPIC STAND OF NEOCALAMITES IRANENSIS N. SP. FROM THE CARNIAN PLUVIAL EPISODE (LATE TRIASSIC) OF THE AGHDARBAND AREA, NE IRAN (TURAN PLATE)

The Aghdarband Basin in the Kopeh-Dagh Range (NE Iran) is one of the most important areas for unraveling the evolution of the Turan plate (southern margin of Eurasia) during the last phase of the closure of the Paleotethys and to reconstruct the history of the Cimmerian blocks just before their collision with Eurasia during the early Late Triassic. The youngest sediments affected by the Early Cimmerian orogeny are those of the Upper Triassic Miankuhi Formation, which covers unconformably the Upper Triassic (lower Carnian) marine beds of the Sina Formation by an interval of continental facies including local conglomerates, cross-bedded sandstones, mudstone layers, silty shales, an up to one-meter thick coal layer with plant remains, and shales. The plant assemblages represent a relatively wide variety of different forms (sphenophytes, ginkgophytes, conifers, and incertis sedis), documenting wetlands with lush vegetation typical of warm and humid environments. In this study, we describe a plant fossil assemblage from the base of the Miankuhi Fm., dominated by roots and vegetative organs of Neocalamites iranensis n. sp., with few plant fossils of uncertain botanical affinity. Palynological investigations of the basal part of the Miankuhi Formation confirm a latest early Carnian to late Carnian age for this interval and reveal, for the first time, a clear link between this plant-bearing bed, and a time of global environmental changes, the Carnian Pluvial Episode. This is the first report of the Carnian Pluvial Episode in the Turan plate (southern margin of Eurasia) and Iran

Dinosaur diversification linked with the Carnian Pluvial Episode

Dinosaurs diversified in two steps during the Triassic. They originated about 245 Ma, during the recovery from the Permian-Triassic mass extinction, and then remained insignificant until they exploded in diversity and ecological importance during the Late Triassic. Hitherto, this Late Triassic explosion was poorly constrained and poorly dated. Here we provide evidence that it followed the Carnian Pluvial Episode (CPE), dated to 234–232 Ma, a time when climates switched from arid to humid and back to arid again. Our evidence comes from a combined analysis of skeletal evidence and footprint occurrences, and especially from the exquisitely dated ichnofaunas of the Italian Dolomites. These provide evidence of tetrapod faunal compositions through the Carnian and Norian, and show that dinosaur footprints appear exactly at the time of the CPE. We argue then that dinosaurs diversified explosively in the mid Carnian, at a time of major climate and floral change and the extinction of key herbivores, which the dinosaurs opportunistically replaced

Update of ichnofaunal units and link with footprint biochrons in the late Palaeozoic to early Mesozoic of the Southern Alps: towards a better correlation with the marine realm

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THE PRATI DI STUORES/STUORES WIESEN SECTION (DOLOMITES, ITALY): A CANDIDATE GLOBAL STRATOTYPE SECTION AND POINT FOR THE BASE OF THE CARNIAN STAGE

The Prati di Stuores/Stuores Wiesen section (Dolomites, Italy) is proposed as a candidate Global Stratotype Section and Point for the base of the Carnian Stage. In addition to being a famous, richly fossiliferous locality, it includes the type-section of the Cordevolian substage. The section is located near Pralongià, along the southern slope of the crest separating the Badia/Abtei and Cordevole valleys. Below the levels with Trachyceras aon, the section contains a rich ammonoid fauna that chacterizes the lower part of the Regoledanus Subzone and subsequently records the first appearances of the mid-high latitude genus Daxatina (Daxatina sp., D. cf. canadensis) and of traditional Trachyceras with species different from T. aon. Moreover, the Daxatina cf. canadensis Subzone is recognised above the Regoledanus Subzone. Very rare conodonts of the Budurovignatus group and species of Gladigondolella from the diebeli Assemblage Zone occur. Gondolella polygnatyformis, already known from the Aon Subzone, is absent. Palynomorphs, foraminifers, gastropods, bivalves, brachiopods, microcrinoids and holothurian sclerites were studied. Variations in frequency and taxonomic diversity of these faunas suggest anaerobic-disaerobic bottom conditions for the lower-middle part of the section (0-105 m), followed by a more stable oxygen content in the upper portion. Magnetostratigraphy showed four intervals with normal polarity and three intervals with reversed polarity. The Daxatina cf. canadensis Subzone falls close to the normal polarity interval S2n. The present study proposes the FAD of the cosmopolitan genus Daxatina as a marker of the base of the Carnian Stage, placing it at a lower stratigraphic level than previously indicated in the Stuores area. The Prati di Stuores section is proposed as GSSP of the Ladinian-Carnian boundary.&nbsp

Updated Italian Tetrapod Ichnology Reference List

We provide a list of contribution by Italian scientists to tetrapod ichnology with papers on both material from Italy and abroad. Foreign author’s contributions on tetrapod ichnology based on material from Italy are also considered. The list updates the previous one published by D’Orazi Porchetti et al. (2008) and, as a result, includes works from 1869 up to now. Following the previous reference list, papers of non-Italian researchers on foreign material are reported when the material was found on Italian territory at the time of publication