Editing Guadeloupe (section)

=== Geology ===
Basse-Terre is a [[volcanic island]].<ref>{{Cite journal |last1=Mathieu |first1=Lucie |last2=van Wyk de Vries |first2=Benjamin |last3=Mannessiez |first3=Claire |last4=Mazzoni |first4=Nelly |last5=Savry |first5=Cécile |last6=Troll |first6=Valentin R. |date=5 March 2013 |title=The structure and morphology of the Basse Terre Island, Lesser Antilles volcanic arc |url=https://doi.org/10.1007/s00445-013-0700-y |journal=Bulletin of Volcanology |language=en |volume=75 |issue=3 |pages=700 |doi=10.1007/s00445-013-0700-y |bibcode=2013BVol...75..700M |s2cid=129467145 |issn=1432-0819 |access-date=8 November 2020 |archive-date=13 December 2023 |archive-url=https://web.archive.org/web/20231213042707/https://link.springer.com/article/10.1007/s00445-013-0700-y |url-status=live}}</ref> The Lesser Antilles are at the outer edge of the [[Caribbean Plate]], and Guadeloupe is part of the outer arc of the [[Lesser Antilles Volcanic Arc]]. Many of the islands were formed as a result of the [[subduction]] of [[oceanic crust]] of the [[Atlantic Plate]] under the [[Caribbean Plate]] in the [[Lesser Antilles subduction zone]]. This process is ongoing and is responsible for volcanic and earthquake activity in the region. Guadeloupe was formed from multiple volcanoes, of which only La Grande Soufrière is not extinct.<ref name="jussieu">{{cite web |title=Guadeloupe |url=http://www.ipgp.jussieu.fr/~beaudu/download/2004_Komorowski_VHA.pdf |archive-url=https://web.archive.org/web/20061120120412/http://www.ipgp.jussieu.fr/~beaudu/download/2004_Komorowski_VHA.pdf |archive-date=20 November 2006 |url-status=live |website=Institut de physique du globe de Paris |publisher=Universite de Paris |access-date=17 April 2019}}</ref> Its last eruption was in 1976, and led to the evacuation of the southern part of Basse-Terre. 73,600 people were displaced throughout three and a half months following the eruption.

[[K–Ar dating]] indicates that the three northern [[massif]]s on [[Basse-Terre Island]] are 2.79&nbsp;million years old. Sections of volcanoes collapsed and eroded within the last 650,000 years, after which the Sans Toucher volcano grew in the collapsed area. Volcanoes in the north of Basse-Terre Island mainly produced [[andesite]] and [[basaltic andesite]].<ref>{{cite journal |doi=10.1016/j.epsl.2007.03.030 |title=Timing of effusive volcanism and collapse events within an oceanic arc island: Basse-Terre, Guadeloupe archipelago (Lesser Antilles Arc) |journal=Earth and Planetary Science Letters |volume=258 |pages=175–191 |year=2007 |last1=Samper |first1=A. |last2=Quidelleur |first2=X. |last3=Lahitte |first3=P. |last4=Mollex |first4=D. |issue=1–2 |bibcode=2007E&PSL.258..175S}}</ref> There are several beaches of dark or "black" sand.<ref name="gag">{{cite web |title=Geography and geology |url=https://www.leguideguadeloupe.com/en/geography-and-geology/ |website=Le Guide Guadeloupe |access-date=17 April 2019 |archive-date=18 April 2019 |archive-url=https://web.archive.org/web/20190418022256/https://www.leguideguadeloupe.com/en/geography-and-geology/ |url-status=dead}}</ref>

[[La Désirade (commune)|La Désirade]], east of the main islands, has a [[Basement (geology)|basement]] from the [[Mesozoic]], overlaid with thick [[limestones]] from the [[Pliocene]] to [[Quaternary]] periods.<ref name="brgm">{{cite web |last1=Bourdon |first1=E |last2=Bouchot |first2=V |last3=Gadalia |first3=A |last4=Sanjuan |first4=B |title=Geology and geothermal activity of the Bouillante Volcanic Chain |url=http://calamar.univ-ag.fr/cgc2011/images/stories/ft-bouillante.pdf |access-date=18 April 2019 |archive-url=https://web.archive.org/web/20190419001006/http://calamar.univ-ag.fr/cgc2011/images/stories/ft-bouillante.pdf |archive-date=19 April 2019 |url-status=dead}}</ref>

Grande-Terre and Marie-Galante have basements probably composed of volcanic units of [[Eocene]] to [[Oligocene]], but there are no visible outcrops. On Grande-Terre, the overlying [[carbonate platform]] is 120 metres thick.<ref name="brgm" />