Sedimentation in shallow to deep water carbonate environments across a sequence boundary: effects of a fall in sea-level on the evolution of a carbonate system (Ladinian-Carnian, eastern Lombardy, Italy)
Articolo
Data di Pubblicazione:
2007
Citazione:
Sedimentation in shallow to deep water carbonate environments
across a sequence boundary: effects of a fall in sea-level on the
evolution of a carbonate system (Ladinian-Carnian, eastern
Lombardy, Italy) / F. Berra. - In: SEDIMENTOLOGY. - ISSN 0037-0746. - 54:4(2007), pp. 721-735.
Abstract:
In the Concarena-Pizzo Camino Massif (Lombardy Basin, Southern Alps, Italy)
the lateral transition from Ladinian-Carnian carbonate platforms to coeval
intraplatform basins is preserved. The succession records the sedimentological
evidence of a sea-level fall on a flat-topped platform with a narrow marginal
reef rim and its effects in the adjacent deeper-water basin. Repeated highfrequency
exposures of the platform top are recorded by a peritidal–supratidal
succession that overlies subtidal inner platform facies of the former highstand
system tract (HST). On the slope and in the basin, the sea-level fall is recorded
by a few metre thick succession of bioclastic packstones. These facies directly
lie on coarse clinostratified breccia bodies (slope facies of the former HST) or
on resedimented, well-bedded, dark laminated limestones (basinal facies of
the HST). This facies distribution indicates that during the sea-level fall
carbonate production on the platform top decreased rapidly and that
sedimentation in the basin was mainly represented by condensed facies.
Microfacies record an enrichment, during low stand, in pelagic biota
(packstones with radiolarians and spiculae), whereas the occurrence of
platform-derived, shallow-water materials is limited to thin lenses of
reworked and micritized Fe-rich oolites and bioclasts (mainly pelecypods
and echinoderms). The facies association in the Concarena-Pizzo Camino
Massif demonstrates that a highly-productive carbonate factory was almost
completely turned off during the emergence of the platform top at a sequence
boundary, leading to low-stand starvation in the basin. The reconstruction of
the stratigraphic evolution of the Concarena-Pizzo Camino carbonate platform
therefore represents a significant case history for the study of the behaviour of
ancient carbonate systems during a fall in sea-level, independent of its origin
(eustatic or tectonic).
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Carbonate platform, intraplatform basin, sequence boundary,
Southern Alps, Triassic.
Elenco autori:
F. Berra
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