page_title: Geology of the Iberian Peninsula
section_title: Cantabrian Zone
hierarchical_section_title: Geology of the Iberian Peninsula / Iberian Massif / Cantabrian Zone
caption_attribution_description: English: Karst topography in the Cantabrian Mountains. The port city of Santander in the distant right. Alto de Brenas (579 m.). Riotuerto. Cantabria. España Español: Relieve kárstico en la Cordillera Cantábrica. Al fondo a la derecha se aprecia la ciudad portuaria de Santander. Alto de Brenas (579 m.). Riotuerto. Cantabria. Spain Français&#160;: Relief karstique dans la Cordillère cantabrique. On aperçoit la ville portuaire de Santander au loin à droite. Alto de Brenas (579 m.). Riotuerto. Cantabrie. Espagne
context_page_description: The geology of the Iberian Peninsula consists of the study of the rock formations on the Iberian Peninsula, which includes Spain, Portugal, Andorra, and Gibraltar. The peninsula contains rocks from every geological period from the Ediacaran to the Quaternary, and many types of rock are represented. World-class mineral deposits are also found there.
  The core of the Iberian Peninsula consists of a Hercynian cratonic block known as the Iberian Massif. On the northeast this is bounded by The Pyrenean fold belt, and on the southeast it is bounded by the Betic Fold mountain chain. These two fold chains are part of the Alpine belt. To the west, the peninsula is delimited by the continental boundary formed by the opening of the Atlantic Ocean. The Hercynian Fold belt is mostly buried by Mesozoic and Cenozoic cover rocks to the east, but nevertheless outcrops through the Iberian Chain and the Catalan Coastal Ranges.
context_section_description: The Cantabrian Zone consists of Carboniferous and older Paleozoic unmetamorphosed rocks.
  It is bounded on the west and south-west sides by a concave arc of Precambrian rocks called the Narcea window, and the Villabandin window in the Narcea antiform.
  The Herreria Formation from the Lower Cambrian consists of shale and feldspathic sandstone alternating, with some conglomerate.  These have a thickness of 1 to 1.5 km.
  The Lancara Formation consists of a couple of hundred metres of limestone.  The lower part was formed in peritidal zones in the Lower Cambrian, and the upper member from the Middle Cambrian contains fossils and is red or green glauconictic and nodular limestone.
  The Oville Formation from Middle to Upper Cambrian contains alternating shale and sandstone.  Trilobite fossils are common in the shale.
  The Barrios Formation is Arenigian and up to 500 metres (1,600 ft) thick.  It consists of a white massive quartzite.
  The Penas and Vidrias area, close to the western boundary of the Cantabrian zone has a complete succession of Ordovician deposits.  Black shales from Llanvirnian times  are found in the Central Coal Basin eastern side.  But mostly in the Ordovician Period, this zone was above water and eroding.
  The Formigoso Formation dates from Middle Llandovery time in the Silurian.  It consists of Monograptus black shales and is up to 150 m thick.
  The San Pedro and Furada Formations are up to 300 metres thick and consists of  shale and iron bearing sandstone interbedded,  These are from Wenlock Ludlow and Lower Gedinian times.
  In the Devonian Period deposition occurred on the western side, with dolomite, argillaceous limestone, marl and shale from the Raneces Complex or La Vid Formation.  It is 600 metres (2,000 ft) thick and Gedinian to Emsian in age.
  The Santa Lucia Formation is of limestone. It contains coral near the Narcea Antiform in the west and has peritidal facies in the east near the Central Coal Basin.  The Huergas Formation alternates between red sandstone and shale and is of Couvinian to Givetian age.  The Portilla formation is of coralline limestone of Givetian to Frasnian age.  This is topped off by sandstone layers up to 500 m thick from the Frasnian to Fammenian age.  Devonian sediments are not found to the east of the central coal basin, and are thickest in the west.
  A pelagic facies comes from the Pisuerga-Carrion province.
  In Carboniferous times deposition started with black shales and cherts from the Tournaisian age, and then red limestone, red shale and radiolarites were formed in the Visean age.  Mountain Limestone is a thick black lifeless limestone of Serpukhovian age.  Turbidites with olistoliths also appear in the Serpukhovian, indicating the first sign of the Hercynian (Variscan) tectonic events.  These first events happened in the Pisuerga-Carrion province.
  Variscan compression lifted the west side, turning a sedimentary basin into a mountain range.  Over time the compressed zone moved towards the east.  In the Namurian A stage,  the Olleros formation was byukt from turbidites in a trough in front of the orgen, and the Barcallente formation was a carbonate platform further off shore.  In the Namurian B stage the trough was forming San Emillano Formation, and the Valdeteja Formation was offshore, but in deeper marine conditions. During Westphalian A time the trough was filled and deposits of terrestrial material formed the San Emiliano Formation and Sama Group and the Lena group being thickest in the Central Coal Basin Unit.  Further east in the Picos de Europa it remained covered in shallow water with continuous formation of a carbonate platform.
  The Westphalian age is represented by 5000 m of the Central Coal Basin, which as the name suggests contains coal.  To the east this grades into the marine carbonates of the Picos de Europa. In the Pisuerga-Carrion province, there are conglomerates composed of quartzite, turbidites with slump deposits from deeper sea water.  There are also some limestone layers with fossils.
  The source of the Westphalian sediments was from the west and south.  The
caption: The Cantabrian Mountains. The peak Alto de Brenas in Riotuerto has a height of 579 metres (1,900 ft).
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