"Moonscape" could be the term used to describe the Central Otago scenery of natural rocky outcrops that dominate the smaller hills while on the bigger mountains, the lower slopes and mountain tops. But these features would not be seen on the moon. The forces that moulded them just do not exist there. These rocky outcrops "tors", are of schist rock and the remains of an earlier land. Like bones laid bare by decay, they are the hard parts left behind after the ancient soil has been eroded, blown away.
The moon has no water and air and thus no erosion. On earth, weathering or "rock rotting", that softens the original rock and erosion goes on all the time, though here in Central Otago with its climate of dry air and low humidity, has slowed down the rock erosion weathering influence which makes for these impressive tors that can been seen today.
However, many millions of years ago it was so much different. For a period, New Zealands climate was tropical in the north and sub-tropical in the south. The land was then a cover of a rain forest and the rocks weathered deeply. Some parts of the rock weathered more quickly than others. The best example of this weathering is of the very brightly coloured ancient soils of some 20-25 million years old soils - paleosols, seen today exposed by the early miners on the terrace slopes at Butchers Dam, just a short distance south of Alexandra.
Then 4-2 million years ago was the great upheaval of the mountain-building period followed by a series of ice ages. In the south, first the protecting forests disappeared from the mountain tops, followed later in the drier regions with the a result of wide-scale erosion bought about by climatic changes and fire. The deeply weathered soil ("loess"), was washed or blown away, slowly exposing the solid rock tors.
In a time-lapsed movie covering this period of time would be seen the grotesque shapes of the tors gradually appearing from their earthly tombs. The only creatures watching would have been the many strange birds of this land. Today very few species of these birds remain, but the tors have survived. The rate of erosion has now slowed, leaving in the dry Central Otago air only the sand blasting of the strong winds and the on going frost splitting on cold nights, as the main cause of erosion.
Today, the most impressive tors are to be seen in the driest parts - especially around Alexandra. Some of the easiest to be seen landscape tor scenery, is that coming into Alexandra from Butchers Dam, Little Valley Road up past the Alexandra lookout, the Hawksburn Road up past the Clyde Dam lookout as well as the roads to Fraser Dam and Poolburn Reservoir.
On the wetter fringes of Central Otago, the process of rock decay is faster and the tors have been worn down to stumps. However, for the traveller coming to Central Otago via Middlemarch to Kyeburn, the drive would be most impressive alongside the foothills of Rock and Pillar Range, SH 87.
Some of the lower altitude hills close to Alexandra - the appropriate named Raggedy Range and Rough Ridge can be travelled over, further to the west the Nevis Road over the Carrick Range, while that of Knobby Range and Flat Top Hill can only be visited. The north end of Flat Top Hill, is a now a DOC Reserve which not only has its tor landscape but ancient soils and a large variety of wild flowers - native and introduced, that have now been left untouched by grazing.
Once the snow clears from mountains, then it becomes possible to visit most of the Central Otago Mountains. The Old Man Range has some very distinctive rocks while the tors at the south end of the Dunstan Mountains would have the best example of a tor landscape to match that anywhere in the world. Closer to Dunedin is the Rock and Pillar Range - no more need to be said.
Landscape tours, heritage trails, general/scenic tours and wild flower walks can be arranged with John Douglas of Safari Excursions
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