Golden Sea: the most efficient concentrator
Powerful storm waves erode river gravels and moraines along the West Coast, and gold ends up in the beach sands. These beach sands also contain other heavy minerals from the Southern Alps, such as garnets (red semiprecious minerals), magnetite (black iron oxide) and ilmenite (black iron titanium oxide).
Gold becomes concentrated with these heavy minerals in red or black layers called "beach leads". Some of these leads are spectacularly rich, especially after westerly storms erode the beaches.
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Haast Beach
A sample of gold concentrated from beach sands south of Hokitika. |
