Search results for " Tethys"

Sr isotope variations in the Upper Triassic succession at Pizzo Mondello, Sicily: Constraints on the timing of the Cimmerian Orogeny

2018

Abstract The Late Triassic Cimmerian Orogeny was a result of the final closure of the Palaeotethys Ocean and the accretion of Gondwana-derived (Cimmerian) continents to southern Eurasia. Determining the timing of the Cimmerian Orogeny is crucial to our understanding of the large-scale climate changes driven by the uplift of the Cimmerian Mountains. Here we present stratigraphic variations in 87Sr/86Sr values of Upper Triassic pelagic limestone from the Pizzo Mondello section, Sicily, Italy, that constrain the timing of uplift of the Cimmerian Mountains. The 87Sr/86Sr values remain relatively constant in the lower part of the section, decreasing slightly in the Tuvalian (upper Carnian) and L…

Pseudoskirroceras, a remarkable but poorly known Early Pliensbachian Tethyan ammonite genus: New data from the High Atlas (Morocco).

2007

13 pages; International audience; The discovery of new Early Pliensbachian ammonite faunas in Central High Atlas (Morocco) allows the re-examination of the taxonomic, stratigraphical and palaeogeographical framework of the genus Pseudoskirroceras, an intriguing but until now poorly known Tethyan taxon. For the first time, several specimens of Pseudoskirroceras mastodon (Fucini, 1935) the type species of the genus, have been collected in a well-known stratigraphical context. This material allows the evaluation of intra-specific variability and consequently the assessment of the taxonomical relevance of various geometrical and ornamental features. The best diagnostic features are the clearly …

The end-Triassic mass extinction: A new correlation between extinction events and δ13C fluctuations from a Triassic-Jurassic peritidal succession in …

2018

Abstract A new δ13Ccarb curve was obtained from an expanded peritidal succession in western Sicily and was used to investigate the relationships between isotopic signatures and biological events on carbonate platforms across the Triassic-Jurassic boundary (TJB). The resulting curve shows two main negative carbon isotopic excursions (CIEs) that fit well with the “Initial” and “Main” CIEs that are recognized worldwide and linked to the End-Triassic Extinction (ETE). In the studied section, the first negative CIE marks the disappearance of the large megalodontids, which were replaced by small and thin-shelled specimens, while the “Main” CIE corresponds to the last occurrence (LO) of the megalo…

The genus Palaeolituonella (Foraminifer) and description of Palaeolituonella angulata nov. sp. from Upper Triassic reef limestones of the Tethys

2009

Shallow ocean oxygen decline during the end-Triassic mass extinction

2022

The end-Triassic mass extinction (ETME) was associated with intensified deep-water anoxia in epicontinental seas and mid-depth waters, yet the absolute oxygenation state in the shallow ocean is uncharacterized. Here we report carbonate-associated iodine data from the peritidal Mount Sparagio section (Southern Italy) that documents the ETME (~ 200 Ma) in the western Tethys. We find a sharp drop in carbonate I/(Ca + Mg) ratios across the extinction horizon and persisting into the Early Jurassic. This records local dissolved oxygen and iodate decline in the near-surface ocean of low-latitude Tethys due to the development of depleted oxygen concentrations. Consequently, during the ETME even sha…

Ammonite diversity and its palaeobiogeographical structure during the early Pliensbachian (Jurassic) in the western Tethys and adjacent areas.

2009

14 pages; International audience; The early Pliensbachian (Early Jurassic) is known as a time of marked provincialism in the marine realm, notably between the Mediterranean Tethys and North–West Europe. In order to test this observation quantitatively, we compiled 104 locality-level species lists from those areas based on a comprehensive revision of early Pliensbachian ammonites. With this dataset, we also explore the relationship between ammonite richness and biogeography at the scale of the sub-chronozone during the early Pliensbachian. Using various multivariate statistics and rarefaction techniques, we show that: (i) there is a sharp contrast between the NW European (NWE) and the Medite…

An anomalous case in the evolution of the Mesozoic sedimentary basins between Alpine and Ionian Tethys: the Panormide Carbonate Platform (Sicily).

2007

Quantifying OAE2 marine oxygen levels from coupled Mo and U isotopes: A Tethyan perspective.

2016

U and Mo isotopes are promising geochemical proxies for globally averaged ocean redox conditions in deep time. Because the Mo and U isotope compositions of seawater are controlled primarily by variation in ocean redox conditions, coupled Mo and U isotope records can be used to reconstruct variation in the relative sizes of oxic/suboxic, anoxic and euxinic sinks over geological time. The different sensitivities of Mo and U to anoxic and euxinic conditions creates a situation in which joint evaluation of the Mo and U isotope records provide greater constraints on variation in ocean redox conditions than either proxy can in isolation. Here we report new and published Mo- and U-isotope data fro…

Macroecological properties of ammonites : spatial distribution, phylogeny, and faunal similarity

2016

The present work, which lies between macroecology and macroevolution, focuses on the spatio-temporal dynamics of early Pliensbachian ammonites of the western Tethys. Two main questions are addressed: how does inter-assemblage compositional similarity decrease with geographical distance? What is the relationship between species range size and phylogeny, species duration and latitudinal position?Ammonite dispersal dynamics are studied through a multi-scale Similarity Distance Decay analysis. We show that their long-distance dispersal is facilitated when the environment is more homogeneous and that it is not related to their morphology. This suggests that their long-distance dispersal occurred…

A possible bridge between Adria and Africa: New palaeobiogeographic and stratigraphic constraints on the Mesozoic palaeogeography of the Central Medi…

2010

Abstract Dinosaur records in central and southern Italy testify to the occurrence of a diverse dinosaur fauna on the Apennine and Apulian carbonate platforms at least from the Tithonian to the Santonian. Most of the palaeogeographic reconstructions show these domains as topographically isolated areas, separated by deep pelagic basins and far from emerged continental areas. Thus, they hardly justify the long-lasting occurrence of these terrestrial vertebrates. Recent studies on the Mesozoic Panormide Carbonate Platform (western Sicily) yielded important stratigraphical and palaeontological data, which provide evidence for a convincing explanation of this unresolved problem. The recent discov…