So we rose at 05:30 and wended our way out of the crater when there was sufficient light from the sunrise.

We felt a bit uncertain about our navigation, even something simple like retracing steps can be a nightmare if one wasn't concentrating.

Note to self .... next time driving on tracks that aren't on maps record the gps track!

Seeing our tyre marks from the journey in helped. Basically find way to base of hills then turn left towards Punda.

The Mt Whaleback Mine is the largest open cut iron ore mine in the world.

A nice complement to our tour of the Kiruna underground iron ore mine in Sweden.

This mine is hematite. Kiruna is magnetite.

The average iron content of finished product (fines or lump) is above 60%. Very high grade.

Most of the action is in the distance, at the west end of the mine. Below the water table. This end is being back filled. Surprisingly (to me) anything less than about 60% iron is discarded. And some of the ore has a higher than acceptable sulphur content. So far about 1,000,000,000 tonnes of product has been shipped, since 1967.

The explosive is ammonium nitrate and diesel. A very controlled blast to fracture the ore rather than send up a big cloud of dust. A couple of times each week as required.

And a water truck with 100,000 litres to keep the dust down.

"Drive this truck around for 3 hours until its empty then fill it up and start again!"

The conveyor in the back left is providing finished product for loading - there's a tunnel under the ore pile through which trains travel, moving continuously, for loading.

Mt Newman in front of us.

We are cruising at 80 km/hr. Horribly fast! The road is smooth and wide. We are not used to this.

We stopped at Wanna Munna, about 70 km from Newman, for some more petroglyphs and camping.

Next morning we were not so tired and spent a couple of hours exploring the rocks and the creek.

We couldn't avoid making comparisons to Pandu. Here it seems the petroglyphs are a bit less distinct. Less obvious to us, we had to work a bit harder to find them.

On the other hand, this is obviously a kangaroo. Its tail hidden in the shadow.

We aren't trying to document the site. Just remind ourselves of what we have seen. And possibly to help settle future discussion about what we saw.

I wonder if its a result of how much energy the artist had, or whether its different artists at different times.

We are in a branch of Weeli Wolli Creek. There are many branches that form and combine on the south side of the Hamersley Range. Its one of a few creeks that flow all the way through to exit the range to the north. And disappear into the sands before reaching the Fortescue River.

There are vehicle tracks marked alongside it. With a small gap in the middle.

There was another, almost dried up, that cattle frequent.

Which probably means that while it may be metamorphosed it wasn't because of the impact.

It may just be polished by rain or wind. To our unpractised eyes it doesn't have the roundedness of river stones.

At least the most exposed is shiny, otherwise remnants of mud from pools as they dried hide it.

I looked hard to find the boundary between the rock in the floor of the creek and the rock in the sides.

I have no doubt there is one, but I couldn't find it. The bedding planes are continuous between floor and sides. Just that beneath our feet its this polished grey and yellow stuff while the sides are crumbly reddish stuff (to put it in technical language).

Reminiscent of sawn through tree trunks but on examination perhaps just the way its been eroded and broken. But it looks like "tree". About 450mm diameter.

When we looked at "the ends" we could imagine rounded, river worn, stones that were part of the sediment.

Ever more beautiful.

We think we are looking at jasper. We've only ever seen small river worn stones of jasper. This is a big seam.

Rocks and minerals are harder for us to identify than birds. Birds have distinctive shapes and colours while all have feet, wings, and beaks. Rocks and minerals have much more variety. More species .... with different origins and no common ancestor.

But we think "jasper" is a feasible conclusion. Jasper is a form of chert. As is agate. Jasper is silica, with impurities to give it colour and opaqueness. Formed through hydrothermal activity - silica crystallising (micro crystals) from sea water. Agate is transluscent.

We can well imagine our "tree" getting in the way of the process, being in the wrong place and time. There are places in the world where petrified trees appear in jasper, but of course we can't be certain here. We also know that agates form in geodes (nodules or spheres with agate inside), as does jasper. Perhaps that is our stones, though we'd prefer they were more spherical.

It also occurs to us that Marble Bar (the town some long way to the north east of us) actually has a Jasper Bar. When we visit there we will have a reference.

Reasonably consistent with Banded Iron Formations that are most of the Hamersley Range, also crystallised from sea water.

Of course one would have to ask the obvious and inevitable question of how the tree arrived and was petrified. Our understanding of the banded iron formations is they were formed in an era when cyanobacteria were the dominant life form. If there is a petrified tree it must have been petrified at a later date. Many millions of years later.

So far we are moderately comfortable with our mental meanderings. And continue to wonder at the world around us. A wonder that is somehow independent of "how" or "why".

Looks like there's a second kangaroo, drawn at the same time, part of the same story.

The rock looks to us almost as if its been drawn on several times.

If someone were to ask should they visit Wanna Munna or Punda we would probably say both. They are sort of "the same but different". Just that one is more accessible than the other.