Tiber Valley

The Tiber Valley is the largest geographical part of the Tiber basin of the Tiber river included in the Emilia-Romagna, Tuscany, Umbria, and the Lazio regions; it is characterized by river terraces and floodplain areas that extend from the Apennine belt up to the delta of the Tiber river in the Lazio coast of the Tyrrhenian Sea.

Geology
The Tiber basin is made up of four main morpho-structural environments:


 * the upper Tiber basin, composed mainly of terrigenous sediment in flysch facies of Tuscan origin (on the right bank north of Lake Trasimeno) and Umbria-Marche (on the left bank)
 * the Apennine carbonate ridge, which occupies the eastern and southern sector, made up of carbonate reliefs;
 * the Tiber graben with its marine to continental facies deposits, the intermountain basins;
 * the volcanic systems of the Volsini Mountains, Cimini, Sabatini and Alban Hills, which occupy the southwestern sector.


 * Graben:


 * Paleotevere Graben
 * Paglia-Tevere Graben
 * Tiber Graben (Chiana Valley)