Giannutri Island, Isola del Giglio, Grosseto Province, Tuscany, Italyi

Regional Level Types
Giannutri Island	Island
Isola del Giglio	Commune
Grosseto Province	Province
Tuscany	Region
Italy	- not defined -

Giannutri (2.6 km2) is the southernmost island of the Tuscan Archipelago.

The island is made of sedimentary rocks and has rocky and rugged coasts with inlets and caves, mainly in its southern part, interrupted only by two coves called Cala dello Spalmatoio (on the north-east) and Cala Maestra (on the north-west) where are the docking points. The island landscape is characterised by three hills: Poggio del Cannone (83 m) and Monte Mario (78 m) in the northern part, and Poggio Capel Rosso (93 m), the highest, in the southern part.

Simonelli (1889), beside the widespread presence of calcite (as small crystals and concretions) inside the limestone fractures, noticed also the presence of pelagosite as black varnish-like concretions on littoral rocks; veins of manganese oxides (that he called "manganite") in the limestone forming the cape between Cala dello Spalmatore and Cala dello Schiavo and in boulders along the path connecting Cala dello Spalmatore to Cala Maestra; outcrops of gypsum layers with minor veinlets of sulphur in the walls of a cave along Costa dei Grottoni, not far from the lighthouse; small limonite layers in the areas of Cala dello Splalmatore and Punta Secca.

Furheremore, Simonelli described also some allochthonous minerals. In particular, he noticed that the hard breccia layer outcropping along the coasts and in some points of the inland area, consisting of limestone fragments cemented by a mixture of clay and iron oxides, contains microscopic particles of volcanic ashes (tephra) produced by the explosive eruption of an unidentified Italian volcano, composed of biotite, magnetite, pyroxene (augite), and a vitreous substance interpretable as sanidine or volcanic glass.

In Simonelli's opinion the blocks of specular hematite flakes, which Giuli (1843) described from the harbour of Cala dello Spalmatore, come from Giglio or Elba Island and are dumped-on-the-shore boat ballast. The same extraneous origin is attributable to a block of hematite recently found in the cove by a scuba diver (see http://forum.amiminerals.it/viewtopic.php?t=10300).

Fossils

This region is too big to display the fossil list, try looking at smaller subregions.

References

External Links