Sarrabus, Sardinia, Italyi

Regional Level Types
Sarrabus	- not defined -
Sardinia	Autonomous Region
Italy	Country

This page is currently not sponsored. Click here to sponsor this page.

PhotosSearchMineralogy

Sarrabus is a geographical area in the south-east of Sardinia, part of the Sarrabus-Gerrei subregion and corresponding to the ancient "curadorias" of Sarrabus and Colostrai, which is now comprised mainly in the municipalities of Burcei, Castiadas, Muravera, San Vito, Villaputzu, and Villasimius. The westernmost part of Sarrabus belongs to the municipality of Sinnai (Cagliari metropolitan city) and only to a minor extent to the municipalities of Soleminis and Dolianova (South Sardinia province). Sarrabus is bounded to the north by Gerrei and Salto di Quirra (or Quirra), although the geographical boundaries among these regions are sometimes unclear and not unequivocally defined.

Here, as northern boundary of Sarrabus the Villasalto overthrust, previously known as "Villasalto fault", is considered. The Villasalto overthrust, one of the most important Variscan tectonic feature in south-east Sardinia, crops out for 40 km, running roughly E-W, from the Tyrrhenian coast in the east, near capo San Lorenzo, to the eastern border of the Miocene rift near Monte Grighini in the west. Along its surface the Sarrabus Unit is thrust over the Gerrei Unit and a foliated cataclasites, up to 300 m thick, made up mainly by Silurian shale fragments, developed.

The Cambrian to Lower Carboniferous succession forming the Sarrabus Unit starts with thick (>500 m) siliciclastic turbidite deposits, mostly sandstones and shales, of the San Vito formation (?Middle Cambrian-Arenig). Up section follow Middle Ordovician acidic to intermediate volcanic rocks ("Porfidi Bianchi" and "Porfidi Grigi" formations). The contact between the San Vito formation and the overlying Porfidi Bianchi and Porfidi Grigi formations is marked by an angular unconformity (the so-called "Fase Sarrabese" of Calvino, 1959), well exposed along the Rio Ollastu and north-east of Genn’Argiolas. Along the contact conglomerates (Rio Ceraxa conglomerates) outcrop, the overlying sandstone and shale-rich sequence can be divided into three formations: the lowermost Punta Serpeddì formation (Caradoc-Ashgill), the Tuviois formation (Ashgill), with limestone intercalations in the upper part, and uppermost graptolite-bearing shales (Silurian black shales and limestones). The youngest sediments exposed are conglomerates, sandstones and shales of the Pala Manna formation (Lower Carboniferous). This formation, which frequently includes blocks of younger rocks, is interpreted as a thick succession of elastic material accumulated in foredeeps during synorogenic deposition (Conti & Patta, 1997). All these rocks were deformed during the Hercynian orogeny. The Cambrian-lower Carboniferous low-grade metamorphic basement of Sarrabus was intruded, at the end of Hercynian orogeny, by calcalkaline magmas forming the Sarrabus igneous massif outcropping widely in the southernmost part of the region. Minor Plio-Quaternary volcanics are present in the Capo Ferrato area and at Riu Gironi.

Sarrabus is an important fluorite-baryte district, characterised by a wide variety and number of mineralised areas, including the so-called "Argentiferous vein of Sarrabus" ("Filone argentifero del Sarrabus"), a complex of silver veins hosted in Silurian-Devonian metasediments extended for more than 30 km, with the old silver mines located in the lower valley of River Flumendosa to the south of Muravera and San Vito (Bacu Arroddas, Giovanni Bonu, Monte Narba, and Masaloni mines) and in the valleys of Riu Su Predi-Rio Brabaisu with its parent stream Rio Ollastu, which forms the left branch of Sa Picocca stream (Tuviois, Serra s'Ilixi, Nicola Secci, Tacconis, and S'Arcilloni mines). The paragenesis of this group of deposits is constituted of quartz, calcite, fluorite, and baryte as gangue minerals, associated with main Pb-Zn-Ag sulphides and native Ag.

Mineral List

Mineral list contains entries from the region specified including sub-localities

150 valid minerals.

Rock Types Recorded

Rock list contains entries from the region specified including sub-localities