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Stratigraphy around the Jurassic-Cretaceous boundary in the Bosso Valley Section (Umbria-Marche Apennines, Central Italy): Geological setting, historical review and current situation
Marco Chiari, Angela Bertinelli, Xin Li, Atsushi Matsuoka

Building: Muséum d'Histoire Naturelle de Genève
Room: Amphithéâtre
Date: 2018-12-07 11:20 AM – 11:40 AM
Last modified: 2019-02-06

Abstract


The Umbria-Marche Apennines, located in the southern part of the Northern Apennines, resulted from the movement between Africa and the European plate. The Umbria Marche stratigraphic successions include Triassic-Messinian units deposited in the southern margin of Western Tethys. This basin was implicated in three different tectonic phases: extensional in the Mesozoic, compressional in the Neogene and extensional again starting in late Miocene (Menichetti and Pialli, 1986; Menichetti, 2016).

In this work we present a historical review and the current situation of the Bosso section (Umbria-Marche Apennines), which is located near the town of Pianello along the Bosso valley. This section is particularly important because it is one of the candidates for the GGSP for the J/K boundary and it was studied for calpionellid biostratigraphy and magnetostratigraphy by Housa et al. (2004).

The J/K boundary was recorded in the lower part of the Maiolica Formation, which started in the Tithonian and is characterized by whitish, beige and gray pelagic limestones with black and gray cherts. The contact with the underlying Calcari ad Aptici Formation is transitional and represents an important environmental change.

In particular, we present a historical review of the radiolarian biostratigraphy of the Bosso Valley section published in the last 37 years. The first paper describing radiolarians was published by Kocher (1981) and the data were re-examined by Baumgartner (1984). Successively, Jud (1994) sampled the Tithonian-Barremian interval in the Bosso valley. These data were included in the database utilized for the radiolarian zonation proposed by Baumgartner et al. (1995). Recently a detailed radiolarian biostratigraphic study was carried out by Li et al. (2018).