STRATIGRAPHY, PALEOGEOGRAPHY AND GENETIC MODEL OF LATE CARNIAN CARBONATE BRECCIAS (CASTRO FORMATION, LOMBARDY, ITALY)

Autor: F. JADOUL, F. BERRA, S. FRISIA, T. RICCHIUTO, P. RONCHI
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Rivista Italiana di Paleontologia e Stratigrafia, Vol 97, Iss 3-4 (2017)
Druh dokumentu: article
ISSN: 0035-6883
2039-4942
DOI: 10.13130/2039-4942/8955
Popis: The stratigraphic and paleogeographic analysis of the Carnian-Norian boundary succession in central Lombardy allows the recognition of a new unit, the Castro Formation. This unit, 100-250 m thick, is represented by carbonatic intraformational breccias and associated limestones. Two lithozones have been recognized in the Castro Fm.: the lower one, heteropic with the S.Giovanni Bianco Fm., with dark dolomitic limestones and breccias intercalations, and the upper lithozone, massive, with amalgamated calcareous breccias. Microfacies, recrystallized and often tectonized, consist of mudstones, wackestones and fine packstones, locally rich in ostracods. Geochemical analyses show differences between the Castro Fm. and the overlying and underlying units, possibly because of early diagenetic meteoric imprint. The Castro Fm. depositional setting is represented by coastal ephemeral lakes with periodic emersions and erosional, tectonically controlled phenomena in a monsoonal regime.
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