Nuovi risultati sul comportamento idrodinamico dei gusci fossili di Nummulites da due banchi a nummuliti del Bartoniano e Priaboniano dell’Italia settentrionale

Autor(en)
Mona Seddighi, Antonino Briguglio, Johann Hohenegger, Cesare Andrea Papazzoni
Abstrakt

Settling velocities of 58 well-preserved tests of fossil Nummulites were experimentally determined using a settling tube. The tests were collected from the nummulite banks of Pederiva di Grancona (A forms of N. lyelli and N. striatus, Middle Eocene) and San Germano dei Berici (A and B forms of N. fabianii, Late Eocene), both in the Berici Mts. (Veneto, northern Italy). The data were compared with estimated settling velocities that the same specimens might have had in life conditions. This was done by reconstructing their densities simulating water-filled condition and, to simulate post-diagenetic effects, under calcite-filled condition. These simulations show that A and B forms, even if they greatly diverge in shape, volume and size, still possess comparable settling velocities, and that each nummulite bank is characterized by specific hydrodynamic parameters. The use of settling velocity as a parameter to quantify the hydrodynamic behaviour of particles in seawater enables estimation of palaeoenvironmental conditions such as depth, substrate and the energy scenario. Such information is useful in obtaining further insights into the genesis of nummulite banks, the autochthony or allochthony of which is still being debated. Our results point to an autochthonous interpretation.

Organisation(en)
Institut für Paläontologie, Dekanat der Fakultät für Lebenswissenschaften
Externe Organisation(en)
Università degli Studi di Modena e Reggio Emilia, Universiti Brunei Darussalam (UBD)
Journal
Bollettino della Societa Paleontologica Italiana
Band
54
Seiten
103-116
Anzahl der Seiten
14
ISSN
0375-7633
DOI
https://doi.org/10.4435/BSPI.2015.06
Publikationsdatum
09-2015
Peer-reviewed
Ja
ÖFOS 2012
105118 Paläontologie
Schlagwörter
ASJC Scopus Sachgebiete
Palaeontology
Link zum Portal
https://ucrisportal.univie.ac.at/de/publications/nuovi-risultati-sul-comportamento-idrodinamico-dei-gusci-fossili-di-nummulites-da-due-banchi-a-nummuliti-del-bartoniano-e-priaboniano-dellitalia-settentrionale(762d7b9a-894a-41e2-80d4-43421ae9aefc).html