Punta Polveraia Lighthouse
Punta Polveraia lighthouse is located on the rocks of the cliff of the same name, 52 metres above sea level, near the village of Patresi.
It is a simple construction, resting on the bare rock, comprising an early 20th-century building with essential architecture, above which a small octagonal tower rises, topped with a lantern equipped with a fixed lens with a 500 ml focal length, emitting a set of three white flashes every 15 seconds, with a nominal range of 16 miles. The lighthouse, also identified as number 2060, is shielded for 36° to the south. The building is managed by the Italian Navy Lighthouse Service.
Since light signalling began in the building, lighthouse keepers and their families have lived here. Navy lighthouse keepers were entrusted with maintaining the building and lighting the lantern. Initially, the light was powered using acetylene, which was then replaced with petroleum gas, methane and, finally, electricity. With the advent of electrical power, the Punta Polveraia lighthouse keepers were reduced from three to two. In the early 1970s, when his father, Aristodemo, retired, Muzio Berti remained, until 2001, the last 'commander' of this lighthouse, swept by the southwesterly, westerly and northwesterly winds, scanning and lighting up the sea between Elba and Corsica. Battaglini, Retali, Bolano, Quintavalle and Brignetti are names of some of the other lighthouse keepers who worked here. A very young Raffaello Brignetti, the Elba-born writer, also once lived here with his father, Angelo, who was then the lighthouse keeper, and spent his first year of primary education at a local village school in 1927.
Polveraia marks the beginning of the Island's western side which then ends further south at Punta Nera, the westernmost tip of the Island. The area around the building features the shapes, aromas and colours of Mediterranean flora, with Aleppo pines, Phoenician junipers, rosemary, rockrose and lentisk. These are plants that love the serpentine soils constituting the promontory.
(Antonello Marchese, translation from Italian)
Ophiolites
On this section of the Via dell'Essenza, the terrain on which we are treading is made up of serpentine rocks, also known as ophiolites, one of the lithological varieties that form the diverse mosaic of the Island's geology. The term 'ophiolite', indeed, derives from the Greek ofios, meaning 'snake', due to the stone's typical green colouring, reminiscent of the skin of these reptiles. From a geological perspective, ophiolites are a type of rock crucial to understanding part of our planet, namely the oceanic crust and the Earth's underlying mantle.
When encountering these rocks on the surface, we should consider that this material originated in an extremely deep marine and crustal environment (tens, if not hundreds, of kilometres below the surface) which, due to tectonic activity, rose up to us, so much so that the presence of ophiolites is synonymous with an ocean that disappeared millions of years ago due to subduction. Studying these rocks has enabled us to understand the dynamics of plate tectonics. the term 'ophiolitic sequence' refers to the layered series of rocks that formed in these extremely ancient oceans, from the base, comprising the lower part of the oceanic crust (mantle), upwards.
This sequence includes peridotite and serpentine rocks originating in the mantle, gabbros (intrusive rocks), basalts or 'pillow lava' created by magma flowing out of mid-ocean ridges and quickly cooling on contact with the very cold water of the ocean floor, and clayey and siliceous sedimentary rocks (jaspers, Palombini clays and Calpionelle limestones). The colours of serpentine rocks, created by weathering of rocks rich in magnesium and iron, range from pale green to darker, earthier shades, featuring fibrous, solid and crystalline structures. The deformation processes that have affected the ophiolitic rocks on Elba took place essentially during the formation of the Western Tethys Ocean (in the Jurassic period) and contributed to forming the metamorphic structures visible today in the Punta di Fetovaia area, in Colle d'Orano, near Punta Le Tombe, on the Golfo Stella coastline and in the Mount Strega area.
(Antonello Marchese, translation from Italian)
