#fossicking

I've discovered a metamorphic contact aureole in my local area. The image of the most rocks/pebbles is the full collection of samples.

Pretties include agates, Carnelian, fossilised wood, Hornfels, Quartzite and other beauties.

While we were staying at Gemtree we went fossicking for zircon - talk about sore back and legs etc!

It was hard work! The natural color of zircon varies between colorless, yellow-golden, red, brown, blue and green so try finding them in a bunch of stones was a challenge. I kept anything remotely possible from our diggings to inspect later. They are not as hard as diamonds but are ancient and precious. Those found in WA from the Yilgan Crator (one of the chunks of original earth crust like the Pilbara) using uranium dating (for they have an element of radioactivity) are dated 4.4 billion years old which they say was the age of crystallisation. This makes them the oldest minerals so far dated on Earth. Not sure about the ones from the Harts Range but they are a wonderful piece of earth’s geological history. They’ve really only come onto my radar recently but evidently Australia leads the world in zircon mining producing about 40% of the worlds total ‘yield’.

Beside the fossicking area was an old mica mine. Now water filled but this was one of the world’s most productive mica areas.

Each time we have visited Central Australia we have spent time in the East MacDonnell Ranges mainly because there are fewer tourist buses, people etc than the West MacDonnells and there is so much to see. This visit was no different. On our second day at Gemtree we took off to explore a little more of that eastern aspect of the massive mountain ranges which cut central Australia in half. The idea was to get to Ruby Gap. Ha! fat chance the way we travel – we stop too often to look at birds, flowers etc.

We headed out on part of the Binns Track and took a detour to the zircon fossicking fields along the way. We didn’t stop and get out there but every detour etc etc – time passes. This is the mud map we were given – whoa! Fortunately I have a Hemma Maps app on my phone and that was proved very valuable (even if there are errors in the mapping!) We drove off the track to see the Mad Russian’s copper mine campsite (more on that later). As I said we were heading for Ruby Gap via The Gardens Road which runs from the Stuart Hwy to Arltunga, passing through a number of huge old pretty-wealthy, mostly cattle, stations - The Garden, Hale River, Ambalindum, Alcoota. Once an interesting drive the road to us has been upgraded and while still a dirt road it is pretty much flat and straight.

It was from this road that 10 years ago we bravely set off on the Cattlewater Pass through the Harts Ranges and got comprehensively bogged for 5 hours! (Top pic) That ‘road’ is now permanently closed because people were constantly getting stranded and a few people died. Of course we had to drive a wee way in this particular day! We saw no closure signs but decided to be sensible and turned back after a couple 100 m. Some days later we found its northern exit on the Plenty Hwy (in fact there are two exits). Again there were no closure signs so we explored 4 or 5 Kms just for a look see. The road was pretty shabby so we ‘parked’ and walked a little way further. I found a new species of Eremophila for me and lots of other pretties.

The other branch ends after 11 km at a large bore and dam. That’s as much exploring of this ‘adventure’ track as we were going to do – except we did go back there some days later looking for the promised fossicking grounds. We came to a dead end in terms of how far we would drive and parked for a bit.

It was near here that I had found a couple of pieces of moonstone a few days earlier so I suggested that we poke around a bit and, lo and behold, we found a huge handful of garnet chips just lying on the surface, sort of.