Presentation on theme: "Google images. The Boulder Bank is composed of granodiorite. The source of this rock is Mackay Bluff. It is still debated what process or processes."— Presentation transcript:
The Boulder Bank is composed of granodiorite. The source of this rock is Mackay Bluff. It is still debated what process or processes have resulted in this odd structure. Long shore drift (see next slide) however is the most accepted hypothesis for creation. The main objection for long shore drift is that Tasman bay does not receive enough wave action to move the large boulders in a south west direction. Studies have been conducted since 1892 to determine speed of boulder movement. Rates of the top course gravel movement have been estimated at 7.5 metres a year Wikipedia
Long shore drift: The waves have pushed the boulders along from Mackays bluff Thanks Keiri
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