Editing Mount Warning (section)

==Shield volcano==
{{main|Tweed Volcano}}
Wollumbin is the central [[volcanic plug|volcanic remnant]] of an ancient [[shield volcano]], the [[Tweed Volcano]], which would have been about {{convert|1900|m|ft|abbr=on}} above sea level or just under twice the height of the current mountain.<ref name="iviea">{{cite book |title=Intraplate Volcanism in Eastern Australia and New Zealand |chapter=Eastern Australia Volcanic Geology |last=Johnson |first=R. Wally |author2=Jan Knutson|author3=Stuart Ross Taylor|author4= Australian Academy of Science |year=1989 |publisher=Cambridge University Press |isbn=0521380839 |page=114 |url=https://books.google.com/books?id=4NBOn7ecZeAC |access-date=2 June 2012}}</ref><ref name="cald">The Caldera of the Mount Warning Shield Volcano. [brochure] New South Wales National Parks and Wildlife Service. 1990.</ref>  This volcano last erupted around 23&nbsp;million years ago.<ref>{{Cite journal|last1=Knesel|first1=Kurt M.|last2=Cohen|first2=Benjamin E.|last3=Vasconcelos|first3=Paulo M.|last4=Thiede|first4=David S.|title=Rapid change in drift of the Australian plate records collision with Ontong Java plateau|journal=Nature|volume=454|issue=7205|pages=754–757|doi=10.1038/nature07138|pmid=18685705|year=2008|bibcode=2008Natur.454..754K |s2cid=4427792 }}</ref> As the mountain's central vent cooled it shrank, forming a depression at the top that has greatly eroded.<ref name="cald"/>
[[File:Mount Warning.jpg|thumb|left|Wollumbin and surrounds]]
[[File:AU Mt Warning from Tweed.jpg|thumb|left|Wollumbin seen from Point Danger, [[Coolangatta, Queensland|Coolangatta]]]]
[[File:Mt Warning 011.jpg|thumb|left|View of [[Byron Bay, New South Wales|Byron Bay]] and surrounding areas from the summit]]

Today the vast areas that were part of the volcano include many mountains and ranges at some distance from Mount Warning, and include the [[Border Ranges (Australia)|Border Ranges]], [[Tamborine Mountain]], the [[McPherson Range]] and both the [[Lamington Plateau]] and [[Springbrook Plateau]]s. The erosion [[caldera]] formed since this eruption is easily visible around the summit and forms the rim of the [[Tweed River, New South Wales|Tweed Valley]].

During the last stages of eruption, different and more resistant forms of [[lava]] that were cooler than those flows that created the shield volcano remained to form the current peak. The whole central Mount Warning [[massif]] was also pushed up by forces that remained active after lava eruptions had stopped.<ref name="cald"/>