Stop work on the geological feature (6)
I believe the answer is:
strike
'stop' is the definition.
(thesaurus)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for strike that I've seen before include "Hit out in industrial dispute" , "Hit; withdraw labour" , "Make a sudden large financial gain" , "Attack - industrial action" , "Industrial dispute - it's a blow" .)