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Monday, 21 October 2013

South Coast trip, part 4

Bingie Bingie Point is south of Moruya: turn off at Bergalia.  It offers two interesting dykes.  The first one is basalt cutting through granite, though curiously, there seems to be a granite dyke running down the centre of the basalt: I assume that what has happened is that the basalt came up both sides of a sliver of granite. That was on the southern side.

 After scrambling over boulders, we got onto the point and headed out to where we found what Chris found in one of the pamphlets was said to be an aplite dyke: that's the pink rock.
 A close view of the margin, showing the granite as well.

 And here is what appears to be a later basalt dyke, running through the aplite. Can anybody comment helpfully on this and set me straight?

 If you look carefully, the basalt is cutting across the aplite!

Cuttagee is south of Bermagui. We only stopped off there because there was a lagoon that I wanted to photograph, but we found these (tested for hardness) quartz veins in a sort of sandstone, and above, some interesting honeycomb weathering in the headland at the northern end of the beach: we could access it at high tide.

Next time: The Pinnacles, and Myrtle Beach, which has an unconformity, as it lies at the base of the Sydney Basin.

Links to the other four parts:

Part 1
Part 2
Part 3
Part 5

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