Editing Castile and León (section)

===Geology===
The Northern Plateau (Meseta Norte) is constituted by Paleozoic sockets. At the beginning of the [[Mesozoic|Mesozoic Era]], once the [[Variscan orogeny|Hercynian folding]] that raised the current [[Central Europe]] and the Gallaeci zone of [[Spain]], the deposited materials were dragged by the erosive action of the rivers.

During the [[alpine orogeny]], the materials that formed the plateau broke through multiple points. From this fracture rose the [[Montes de León|mountains of León]], with mountains of not much height and, constituting the spine of the Plateau (Meseta), the Cantabrian Mountains and the Sistema Central, formed by materials such as granite or metamorphic slates.

The [[Karst|karst complex]] of [[Ojo Guareña]], consisting of 110&nbsp;km of galleries<ref name="length">{{cite web |url=http://grupoedelweiss.com/web/index.php/principales-karst-mainmenu-49/ojo-guareainmenu-55 |title=Grupo Espeleologico Edelweiss 2010 |website=GrupoEdelweiss.com |access-date=21 January 2018|archive-url=https://web.archive.org/web/20161226054940/http://grupoedelweiss.com/web/index.php/principales-karst-mainmenu-49/ojo-guareainmenu-55|archive-date=26 December 2016 |url-status=dead}}</ref> and its caves formed in [[Carbonate|carbonatic]] materials of [[Coniacian]] which are situated on a level of impermeable [[marl]]s, is the second largest of the peninsula.

This geological configuration has allowed upwellings of mineral-medicinal or thermal water, used now or in the past, in [[Almeida de Sayago]], [[Boñar]], [[Calabor]], [[Caldas de Luna]], [[Castromonte]], [[Cucho]], [[Gejuelo del Barro]], [[Morales de Campos]], [[Trescasas|Tresacasas]], [[Valdelateja]] and [[Villarijo]], among other places.<ref>{{Cite book |url=https://www.worldcat.org/oclc/1026278787 |title=Castilla y León : las aguas minerales y termales : panorámica actual y perspectivas de futuro |date=2010 |publisher=Instituto Geológico y Minero de España |author=Castilla y León Junta |isbn=978-84-7840-851-1 |location=Madrid |oclc=1026278787}}</ref>