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Middle triassic ammonoid fauna from the recoaro and tretto areas (NE Italy) and its stratigraphic and paleobiogeographic evidence
No full textBetween the mid 19th and the beginning of the 20th centuries, several Austrian and German geologists such as Beyrich, Mojsisovics and Tornquist, studied the geology of the Recoaro area (NE Italy). They described important ammonoid faunas, the majority being collected from a stratigraphic unit known as the Nodosus Formation.
Among these faunas are problematic species that have been the focus of long discussion both from a biostratigraphic and taxonomic point of view. Unfortunately, most of the historical material has been either destroyed or lost, and recent studies in the field provided only a few scarce specimens thus making taxonomic revision difficult. One of the unresolved issues is related to the possible occurrence of the ceratitids peculiar to the Upper Muschelkalk of the Central Europa (Germanic) Basin and the Sephardic Triassic province among the Alpine ammonoids. An unexpected discovery of an old ammonoid collection stored at the Museo Geologico e Paleontologico of Padova University (MGP-PD) permitted confirmation of the presence of a distinctive ammonoid species Alloceratites tornquisti (Philippi) within the Triassic Recoaro domain. Two other species of Alloceratites have also been found in the Val Gola section near Trento. These occurrences are significant taxonomically, biostratigraphically and in relation to Middle Triassic sequence stratigraphy
Application of the graphic correlation method to compare the bio-and litho-stratigraphic record at the Anisian/Ladinian boundary in the type area
No full textMiddle Triassic ammonoid biostratigraphic scales: hints on correlations, climatic changes and global events.
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NEW BIO AND CHRONOSTRATIGRAPHIC CONSTRAINTS TO THE UPPERMOST LADINIAN EVOLUTION OF CARBONATE PLATFORMS FROM THE WESTERN DOLOMITES (SOUTHERN ALPS, ITALY)
No full textDinosaur footprints from the top of Mt. Pelmo: New data for early jurassic palaeogeography of the dolomites (NE Italy)
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Stratigraphic, volcanologic, and geochronologic constraints of a unique accretionary lapilli layer in the Livinallongo/Buchenstein Formation (Middle Triassic, Southern Alps, Italy)
No full textCorrelation potential of Middle Triassic hemipelagic carbonate successions using carbon isotopes
No full textStable isotope studies of the marine Triassic have previously focused on two intervals, the Permian/Triassic and Triassic/Jurassic boundaries. The potential of stable carbon
and oxygen isotopes as chemostratigraphic correlation tools, however, is largely untapped for Triassic carbonate successions. The present study was launched to explore the usefulness of carbon isotope data in correlating Middle Triassic deep-water,
hemipelagic carbonate sediments of the Livinallongo Formation of the Dolomites (Southern Alps, Northern Italy).
The samples come mostly from the Knollenkalke Member consisting of greenishgrey, bioturbated, nodular limestones. We analyzed the micritic calcite within individual nodules and compared its composition to that of matrix calcite as well as late
diagenetic calcite veins.
Thin-section examination aided by cathodoluminescence petrography and scanning electron microscopy suggest that the fine grained calcite cement in the nodules formed near the sediment-water interface and has not been diagenetically altered since then.
Its carbon isotopic composition therefore most likely reflects the initial seawater isotopic composition.
The carbon isotope data from the Knollenkalke Member show a secular trend of increasing values upsection which coincides with a similar trend in biostratigraphically correlated sections in eastern Romania (Atudorei et al., 1997) and Oman (Hauser et al., 2001). These preliminary results suggests the presence of a possibly Tethys-wide chemostratigraphic marker in the Middle Triassic.
Hauser M. et al., 2001, Eclogae geol. Helv., 94, 29-62
Atudorei V. et al., 1997, Extended scientific report of the project 95-32 “The Triassic of north-Dobrogea”, Geological Museum, Lausanne, Switzerland
The ammonoid succession in the Bagolino section (NE Italy)
No full textOn the basis of data from an interval of the Bagolino section, which was ill-checked by the Swiss Authors, the writers found some layers in which, among a diversified ammonoid fauna, Aplococeras avisianum occurs. This and other taxa from the investigated horizons are new for the Bagolino section, despite the several researches (cf. Brack and Rieber, 1986; 1993a; 1993b) carried out there so far
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