The paleo-lacustrine diatomaceous deposits of Monte Amiata volcano (Tuscany, Italy) and the Ezio Tongiorgi paleontological collection in the Museum of Natural History of the University of Pisa

Abstract

At the foothillof Monte Amiata volcano (southern Tuscany, Italy), small extinct lake basins of late

Pleistocene age are documented. These lake basins were characterized by the deposition of two

very different types of sediment: a) derived from the authigenic precipitation of iron oxides

(goethite) and exploited as earth pigments; b) biogenic siliceous sediment composed of fossil

diatoms and named diatomaceous earth or diatomite. The lacustrine sediments of Mount Amiata

volcano were widely exploited for various applications since ancient times. Literary documents

begin in the 16th century, with the descriptions of Cesalpino, Gesner, Agricola, and Imperato.

Specific references to the diatomites of Monte Amiata are quoted in the 17th century by Boccone

and Bonanno. The quarrying activity was described by Micheli in 1733. During the 18th and 19th

centuries, the diatomaceous earths of Monte Amiata are part of the important geological

collections of Micheli, Targioni Tozzetti, Baldassarri, Campani, and Tommi. A particular

significance has the collection of botanic and ichthyologic fossils collected by Ezio Tongiorgi,

and now preserved in the Museum of Natural History of the University of Pisa sited at the

Charterhouse of Pisa in the Calci village. These paleontological samples preserve the biological

and physical testimonies of the environmental and climatic changes of the late Pleistocene and

are now particularly valuable because they are the only remaining evidence of the diatomaceous

lacustrine deposits of the paleo-lakes of Monte Amiata. For these reasons, they represent

geological materials with a fundamental cultural value.