Valdarno (Val d'Arno), Florence & Arezzo Provinces, Tuscany, Italy

This is a general report of an area that extends over three Provinces: mainly Arezzo and Florence and a little bit in Siena Province (see the map). Valdarno Area is an internal depression due to distensive fault movements (graben) after Apenine uprising. In theses depressions there were in Pliocene great lakes, filled with sediments, now eroded by Arno river, which gives the name to this valley and in which there are many lignite deposits. These deposits were once mined, but presently are all abandoned.