Geology, Geosites and Geodiversity

The Parco delle Colline Metallifere – Tuscan Mining Geoapark narrates the geological history of 300 million years in over 100 thousand hectares of its territory. Its existence and morphology are linked to complex geological events that affected southern Tuscany during the formation of the Northern Apennines. Starting from the oldest rocks of the carboniferous age in the Val di Farma and Val di Merse, crossing the Mesozoic in the rocks of the Val di Bai, Roccatederighi, Gavorrano, Cornate di Gerfalco and La Pietra, we arrive in more recent times at the rocky outcrops of Massa Marittima and Sassoforte: this is how the geological history of the Park in this part of the Colline Metallifere can be told.

The marked geodiversity of this area, the result of its long and complex geological evolution, tells of sedimentary basins and intrusive magmatic “plutons”, of relief inversions and geothermal reservoirs, of important tectonics and of mineralised strands of mixed sulphides that have made the Metalliferous Hills one of the most important mining districts in Europe, exploited for the metals of copper, iron, lead and silver since ancient times (Copper Age, about 3000 years before Christ) and in recent times for the extraction of pyrite (until the end of the 1900s), used to produce sulphuric acid.

The work of nature has been followed by the frenetic activity of man, which has left indelible traces in the landscape and splendid examples of industrial archaeology. In this landscape, which ranges from coastal to mountainous, in which more than 250 different minerals and rocks have been surveyed, 41 geosites have been identified, which cover a wide range of geological themes and aspects with their scientific, didactic and educational relevance. Some of them have been incorporated into geologically themed visitor itineraries, thus becoming geo-hiking trails.

I canaloni del fiume Farma

Geosites are the key to understanding a Geopark.
They are places that bear clear and exemplary witness to the evolution of the earth’s crust or the influence it has had on the development of life and mankind. This is why they are elements of the Geological Heritage. They include rock outcrops, soils, fluids, minerals, fossils and also particular landscape forms.

Il Parco delle Biancane

The geopaths are:In the Metalliferous Hills Park 41 geosites have been identified, divided into 5 categories:
– geosites of prevalent STRATIGRAPHIC character;
– geosites of prevalent GEOTHERMIC character;
– geosites of prevalent MINERAL character;
– geosites of prevalent GEOMORPHOLOGICAL character;
– geosites of prevalent HYDROGEOLOGICAL character.

Geosites are:

(years are indicated in M.a. = million years and K.a. = thousands of years):

1. The Canaloni and the Poggio al Carpino Formation (Lower Permian-Triassic 255-250 M.a.)
2. The bend at elevation 190 of the Farma Stream (Upper Permian 260-253 M.a.)
3. Phyllites and quartzites of the Mersino Stream (Permian-Triassic 255-250 M.a.)
4. The Bai Stream Valley (Triassic ~ 230 million years)
5. The Gavorrano Mining Park and the Theatre of Rocks (Lower Triassic-Jurassic 228-200 M.a.)
6. The red “marble” quarries of Caldana (Lower Jurassic ~ 195 M.a.)
7. The ammonite red quarries of Gerfalco (Lower Jurassic ~ 190 M.a.)
8. The Bartolina ophiolites (Upper Jurassic ~ 150 M.a.)
9. The rocky spur of La Pietra (Upper Jurassic ~ 148 M.a.)
10. The Boccheggiano fault and cupriferous quartz seam (Lower Pliocene ~ 4.5 M.a.)
11. The “Biancane” of Monterotondo Marittimo (Lower Pliocene ~ 4,5 M.a.)
12. The Gavorrano granite (Lower Pliocene ~ 4,5 M.a.)
13. Sassoforte (Upper Pliocene 2.6-2.0 M.a.)
14. The lava dome of Roccatederighi (Upper Pliocene 2.6-2.0 M.a.)
15. The travertines of Poggio al Montone (Upper Pleistocene ~ 179 ± 17 K.a.)
16. The travertines of Massa Marittima (Upper Pleistocene ~ 130 K.a.)
17. The travertines of Pianizzoli (Upper Pleistocene ~ 47 ± 6 K.a.)
18. The limestone sands and travertines of the Pecora River (Upper Pleistocene ~ 126 K.a.)
19. The Campo alle Rose quarry (Upper Pleistocene ~ 126 K.a.)
20. The Accesa Lake (Upper Pleistocene ~ 126 K.a.)
21. The Pecora River waterfall (Upper Pleistocene ~ 126 K.a.)
22. The fumaroles of San Federigo (Upper Pleistocene ~ 126 K.a.)
23. The Furnace Hole of Accesa (Upper Pleistocene ~ 126 K.a.)
24. Cala Violina (Holocene ~ 11.7 K.a.)
25. The Aronna spring (Holocene ~ 11.7 K.a.)
26. Serrabottini (Etruscan, medieval, 16th century)
27. Castel di Pietra (Middle Ages)
28. The caves and mines of Poggio Mutti (Middle Ages)
29. The silver mines of Montieri (Middle Ages)
30. The Buca delle Fate (Fairy Hole) (Middle Ages)
31. Rocchette Pannocchieschi and Cugnano (Middle Ages)
32. Lo Stregaio, Monte Gai (Middle Ages)
33. Poggio Mozzeto (Middle Ages)
34. The Monte Leo quarry (Middle Ages to 18th century)
35. The Cavone (15th century)
36. The alunite quarries of poggio Speranzona (Montioni) (16th-19th century)
37. La Castellaccia (19th century)
38. The Camilletta dens (from prehistory to the 20th century)
39. The “Roste” of Boccheggiano (late 19th-early 20th century)
40. The Monte Calvo sinkhole (first half of the 20th century)
41. The route of the trenches of the Cornate di Gerfalco (Lower Jurassic – Palaeogene ~ 195-23 M.a.)

Geosites can be found described in the following volumes:

The geopaths are:
1 The silver paths of Montieri (Montieri)
2 The travertines of Massa Marittima (Massa Marittima)
3 The red “marble” of Caldana (Gavorrano)
4 The Sassoforte (Roccastrada)
5 The alunite of Poggio Speranzona (Follonica)
6 The Castellaccia (Massa Marittima)
7 The “roste” of Boccheggiano (Montieri)
8 The mines of Poggio Mutti (Montieri)
9 The dens of Camilletta (Massa Marittima)
10 The trenches of Cornate di Gerfalco (Montieri)
11 Pian delle Gore (Massa Marittima)
12 Above and under the Accesa Furnaces (Massa Marittima)