Editing Pyrenees (section)

== Geology ==
{{See also|Geology of the Pyrenees}}

The Pyrenees are older than the [[Alps]]: their [[sediment]]s were first deposited in coastal basins during the [[Paleozoic]] and [[Mesozoic]] eras. During [[Ediacaran]] to [[Ordovician]] times, Pyrenees were located at the Northwest margin of [[Gondwana]], where they formed a lateral continuity of neighbouring areas, such as the [[Montagne Noire]] and the [[Mouthoumet]] massifs and Southwestern territory of [[Sardinia]].<ref name=maxime2022>{{cite journal |author1=Padel Maxime |author2=Sébastien Clausen |author3=Marc Poujol |author4=José-Javier Alvaro |year=2022 |url=https://www.researchgate.net/publication/364935999 |title=Shifts in the Ediacaran to Lower Ordovician sedimentary zircon provenances of Northwest Gondwana: the Pyrenean files |journal=Geologica Acta |volume=20 |issue=14 |page=2 |doi=10.1344/GeologicaActa2022.20.14 |bibcode=2022GeolA..20...14P |language=en |hdl=20.500.12210/78094 |hdl-access=free }}</ref> Between 100 and 150&nbsp;million years ago, during the Early [[Cretaceous]] Period, the [[Bay of Biscay]] [[Seafloor spreading|fanned out]], pushing present-day Spain against France and applying intense [[Compression (geology)|compressional pressure]] to large layers of [[sedimentary rock]]. The intense pressure and uplifting of the Earth's crust first affected the eastern part and moved progressively to the entire chain, culminating in the [[Eocene]] Epoch.

The eastern part of the Pyrenees consists largely of [[granite]] and [[gneiss]]ose rocks, while in the western part the granite peaks are flanked by layers of [[limestone]]. The massive and unworn character of the chain comes from its abundance of granite, which is particularly resistant to [[erosion]], as well as weak [[glacial]] development.

The upper parts of the Pyrenees contain low-relief surfaces forming a [[peneplain]]. This peneplain originated no earlier than in [[Miocene|Late Miocene]] times. Presumably it formed at height as extensive sedimentation raised the local [[base level]] considerably.<ref>{{cite journal |last1=Babault |first1=Julien |last2=Van Den Driessche |first2=Jean |last3=Bonnet |first3=Stephanie |last4=Castelltort |first4=Sébastien |last5=Crave |first5=Alain |date=2005 |title=Origin of the highly elevated Pyrenean peneplain |url=https://archive-ouverte.unige.ch/unige:20401/ATTACHMENT01 |journal=Tectonics |volume=24 |issue=2 |pages=n/a |doi=10.1029/2004TC001697 |bibcode=2005Tecto..24.2010B |doi-access=free }}</ref>