The "Corsican geology" observation field

https://www.inaturalist.org/observation_fields/16686

In a nutshell: these are the broad types of bedrock geology found in Corsica, affecting the development and properties of soils and vegetation.

Definition and extents in descending order of total area:

• granite - granitoids and related magmatic rocks, locally metamorphosed (orthogneiss);
  dominant in two-thirds of the island west of a Saint-Florent–Corte–Solenzara line / small zones of the Cap Corse, around Santa-Lucia-di-Mercurio, near Linguizzetta, etc.

• alluvium - surficial loose deposits masking the bedrock e.g. sand dunes, river gravel, peat, rubble, etc.;
  eastern coastal plain from Bastia to Solenzara / coastal valleys near Calvi, Ajaccio, Porto-Vecchio etc. / large inland alluvial fans and floodplains / thick peatlands / landfill sites...

• siliciclastics - sandstones, conglomerates, shales, flysch, and other carbonate-poor sedimentary rocks, sometimes metamorphosed (slate, paragneiss);
  Saint-Florent and Bonifacio plateaus / many parts of the Cap Corse, Castagniccia and Fium'Orbo areas / smaller zones from Balagna to Corte and Vizzavona, in the Falasorma–Porto area, around the Chiappa peninsula...

• ophiolite - magmatic rocks of oceanic-mantellic origin such as peridotite, gabbros, basalts, commonly metamorphosed to serpentinites, metagabbros, blueschists, etc.;
  large zones of the northeastern part of the island from Cap Corse to Solenzara through Castagniccia and Fium'Orbu / eastern Balagna between Île-Rousse and Ponte-Leccia / small zones around Corte...

• rhyolite - silica-rich volcanic rocks, usually associated with pyroclastic deposits such as ignimbrites;
  most of the Monte Cinto range / Scandola peninsula and Falasorma valley / tiny areas around Morosaglia, Ghisoni, Vizzavona...

• carbonate - limestones, dolostones, calcschists, and other carbonate-rich sedimentary rocks, locally metamorphosed (marble);
  Caporalino–Omessa–Sant'Angelo–Pedani ridges / Punta di Calcina and Punta di u Furnellu summits / small areas scattered from Belgodère to Venaco, from Cap Corse to Castagniccia, in Fium'Orbo...

N.B. Geological formations of very limited extent are ignored — inasmuch as they have little or no effect on soils.

Posted on 30 December, 2023 15:07 by sqfp