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Early diagenetic bedded cherts of the Tuscan sequence (Miocene) near Città di Castello, Italy

Published online by Cambridge University Press:  01 May 2009

N. Molenaar
Affiliation:
Institute of Earth Sciences, Budapestlaan 4, 3508 TA, Utrecht, The Netherlands
A. J. De Feyter
Affiliation:
Institute of Earth Sciences, Budapestlaan 4, 3508 TA, Utrecht, The Netherlands

Abstract

Summary. A distinctive level of bedded, internally laminated, deep-sea cherts in the area west of Città di Castello, central Apennins, has been studied. These cherts form part of the Lower Miocene Monte Santa Maria Tiberina Formation, and belong to the Tuscan sequence, consisting of pelagic and turbidic sediments. The sediment is enriched in diatoms and Radiolaria. The diatoms provided silica as well as barium, now present as submicroscopical baryte concretions. Synsedimentary volcanism could have provided silica as well, through calcitization of volcanic fragments within the sediment. Since the laminations display early diagenetic microdeformations,. it can be concluded that the cherts themselves are an early diagenetic feature.

Type
Articles
Copyright
Copyright © Cambridge University Press 1983

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