Doctors Rocks trip, November 2016

PMAT had its last field trip to the year to Doctors Rocks, Wynyard, on the 20th November.

The group assembled outside the entrance to the Seabrook Golf Club, on the Old Bass Highway, and traveled to Doctors Rocks. The main fossicking area is approximately 300 m along the Old Bass Highway after the turn-off from the Bass Highway, with plenty of parking on the seaward side of the road. Rock platforms with holes and crevices are exposed at low tide between the mouth of Seabrook Creek and Doctors Rocks proper. Digging the wash out of the cracks and holes, and along the bottom just above solid bedrock, produces fine gold with occasional pieces of a few mm.

Low tide was forecast for about 11:30, so we dug down the beach as the rock shelves were exposed.

A good turn-out!

The trick is to dig just along the solid bedrock.

Panning off.

All in all about thirty people turned up, and most of us found at least a little bit of gold. Several people, including one young fellow, were out for their first gold panning trip!

The origin of the gold at Doctors Rocks is still a bit of a mystery. The main theories are that it was brought down relatively recently (during the Tertiary) by Seabrook Creek, which also carries gold and comes out just around the corner, or that it’s coming out of the Permian conglomerate bedrock that the cobbles sit on. Gold is known from Permian conglomerates in other places, such as Mangana. It’s possible that the action of the waves that constantly pound the bedrock and break it up is slowly releasing the gold.

While some people dug and panned, others tried their hand at metal detecting:

John detecting along the cracks and crevices.

Wait, is that gold?

The gold is under a layer of boulders and cobbles.

It should be possible to detect around this area, and the gold is present in pieces large enough to detect, but the sheer amount of rubbish means you’d need a lot of patience. There are a myriad rusty hooks, sinkers, and other metallic rubbish, and plenty of EMI (electromagnetic interference) from nearby powerlines, wifi, etc.

The tide is almost out.

Right at low tide.

Some of the gold is in crevices well out of the water.

By about 3:00 pm the tide was coming right up and we started to head home.

Thanks again to all those who turned up. See you next at our AGM!