Editing Alpine Fault (section)

== Geological origin and evolution ==
[[File:30_ma_New_Zealand_Zealandia.png|thumb|New Zealand before the activation of the Alpine Fault (30 Ma).]]
[[File:Alpine Fault Outcrop Hare Waikukupa River New Zealand 02.jpg|thumb|Outcrop showing hydrothermally altered [[cataclasite]] in green, within the Alpine Fault zone, Waikukupa River.|alt=]] 
[[File:Alpine Fault Outcrop Hare Waikukupa River New Zealand 01.jpg|thumb|Alpine Fault outcrop showing banded [[cataclasite]] and [[breccia]], Waikukupa River.|alt=]]Between 25 and 12 million years ago the movement on the proto-Alpine Fault was exclusively strike-slip. The Southern Alps had not yet formed and most of New Zealand was covered in water.<ref name="Graham2008" /> Then uplift slowly began as the plate motion became slightly oblique to the [[Strike and dip|strike]] of the Alpine Fault. In the last 12 million years, the Southern Alps have been uplifted approximately {{convert|20|km|abbr=on}}, however, as this has occurred more rain has been trapped by the mountains leading to more erosion.<ref name="gnsHome" /> This, along with [[isostasy|isostatic]] constraints, has kept the Southern Alps less than {{convert|4000|m|abbr=on}} high.

Uplift on the Alpine Fault has led to the exposure of deep metamorphic rocks near the fault within the Southern Alps. This includes [[mylonite]]s and the [[Haast Schist|Alpine Schist]], which increases in [[metamorphic grade]] towards the fault. The eroded material has formed the [[Canterbury Plains]].<ref name="Graham2008" /> The Alpine Fault is not a single structure but often splits into pure [[Fault (geology)|strike-slip]] and dip-slip components.<ref name="Norris2001"/><ref>{{Cite journal|last1=Cooper|first1=Alan F.|last2=Norris|first2=Richard J.|date=1995-02-01|title=Origin of small-scale segmentation and transpressional thrusting along the Alpine fault, New Zealand|journal=GSA Bulletin|volume=107|issue=2|pages=231–240|doi=10.1130/0016-7606(1995)107<0231:OOSSSA>2.3.CO;2|issn=0016-7606|bibcode=1995GSAB..107..231N}}</ref> Near the surface, the fault can have multiple rupture zones.{{sfn|Graham|2015|p=|pp=120}}