Geologic dating activity Kiki chatham x x x
Sometimes the land uplifted only to be worn down again and be pushed back into the sea. The Tuhua Orogeny, late Devonian to Carboniferous period (about 370 to 330 million years ago) The long period of sedimentation ended with a period of pressure and uplift.
Sea floor sediments were pushed up, folded and melted together to form mountains.
The orogeny deformed the sediments deposited during the earlier sedimentation period differently: the western rocks in open simple folds, whereas the eastern block was much more severely deformed, commonly in a stack of folds with complex faulting. The break-up, Cretacous to Oligocene period (99 to 24 million years ago) This period is characterised by a long period of weathering and erosion of the mountains that were formed during the preceding orogeny, so much so that some places were reduced to so called , that is areas of low relief.
About 85 million years ago a rift valley formed to separate the New Zealand region from the rest of Gondwana, resulting in the formation of a new ocean floor by means of and by the Oligocene period (about 35 million years ago) most of the country was submerged.
To the south of the South Island, the situation is reversed.
This has resulted in about 450 km of displacement along the Alpine Fault.