Lithological expression of Milankovitch cyclicity in carbonate-domimated, pelagic, Barremian deposits in central Italy

Authors
Citation
N. Fiet et G. Gorin, Lithological expression of Milankovitch cyclicity in carbonate-domimated, pelagic, Barremian deposits in central Italy, CRETAC RES, 21(4), 2000, pp. 457-467
Citations number
31
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
CRETACEOUS RESEARCH
ISSN journal
0195-6671 → ACNP
Volume
21
Issue
4
Year of publication
2000
Pages
457 - 467
Database
ISI
SICI code
0195-6671(200008)21:4<457:LEOMCI>2.0.ZU;2-6
Abstract
In continuous sedimentary sequences, cyclostratigraphy can provide good tim e control on the duration of stratigraphic stages and palaeomagnetic chrons . This approach has been applied to the Barremian pelagic mart-limestone al ternations of the Umbria-Marche Basin. Two criteria have been used: variati ons in the thickness and carbonate content of limestones and the vertical d istribution of intercalated black marls. Mart-limestone alternations are or ganized in bundles of generally four or five couplers. The cyclicity expres sed by the vertical stacking of couplers and bundles has been interpreted a s the sedimentary expression of the Earth's orbital parameters, specificall y the precession of the equinoxes and the eccentricity. This breakdown of the Barremian Stage into astroclimatic cycles allows the calibration of the duration of the stage and of the magnetic chrons M-3 to M-0. The lower and upper stratigraphic boundaries of the Barremian Stage ar e picked at the base of the M-3 and M-0 chrons, respectively. The duration of the Barremian Stage is estimated at 5.13 +/- 0.34 Myr by adding up conta ined cycles. The duration of related magnetic chrons varies considerably fr om 0.43 to 2.3 Myr. (C) 2000 Academic Press.