I depositi fluviali pleistocenici di Monticello (Valdarno Superiore, Toscana)

The following thesis is focused on gravelly fluvial deposits exposed in a quarry near the locality of Monticello, in the Terranuova Bracciolini surroundings, along the SE margin of the Upper Valdarno Basin (Tuscany). The thesis aims to analyze in detail the gravelly fluvial succession deposited by the Arno river during the Middle Pleistocene. The present work, which was carried out on the bases of modern facies analysis, is based on the previous model developed by Billi et al. (1987), who concluded that the study deposits were deposited by a coarse-grained low-sinuosity river. The study outcrops (about 150 m long) has been divided into five sections. Each section has been described and analyzed using methods such as sedimentological logs, linedrawing and paleocurrent measurements. At the outcrop scale, the study deposits are organized into form a large scale inclined set (up to 5-6 m thick) of gravelly beds dipping transverse to the main transport direction, and covered by a wedge-shaped sandy unit (2-3 m thick). Both sandy and gravelly beds were deposited under tractional conditions, as attested by the well-developed imbrications and sedimentary structures (e.g. plane-parallel stratification, cross-stratification). These gravelly and sandy deposits have been interpreted as a lateral bar and channel-fill deposits respectively. According to their stratal architecture and palaeocurrent distribution they developed in a relatively sinuous channel, confirming the model proposed by Billi et al. (1987)