Julian & Ali Travels


Pilbara - Punda Petroglyphs and Hickman Crater		May 1 - 2 2018

		With a little regret we left our first real rest stop. The first time in a month we've stopped for more than a day. Some camps are simply stops along the way. Some camps are destinations. Kalgan Pool suited our idea of a destination. But all part of a journey.

		Mobile internet was excellent at Olympia Dam. Good for a planned phone call. Pelicans, swans, coots, bee-eaters, etc.

		So then we headed back north. Taking the same track across the railway line, but then heading north alongside it. As we approached the crossing so did a train. Trains are bigger than trucks, so we stopped and waited. We saw the train before the red lights started flashing but it took us a few moments before we realised it was probably more than a km long. Two locos at the front, and two more in the middle. This train is empty, on its way to the mine to be filled. About 2.7 km long with 268 ore cars. Each car carries 130-138 tonnes of ore. Which means about 33,000 tonnes when full. About a 24 hour cycle. Someone else can work out how many trains there are.

		After what seemed an age it was past. These are not high speed trains. We carried on our way.

		30km north there's a sign to a track heading west to the hills. The sign has been doctored. We decided we weren't just one 4wd, we were the one.

		A wonderful sand track. Devoid of corrugations. We guessed the pimple to left of centre was where we were headed.

		As we approached the valley to the left of the pimple became obvious.

		Heading into the valley the track was less used. We stopped when the trees impeded our progress. Just before an old, well collapsed, corrugated iron tank.

		We have no idea what we are looking at, its age, or its significance. This looks like a couple of goannas.

		And a flightless bird.

		We found only one image like this. Somewhat abstract to us.

		We are again unsure. The technique for creating the petroglyphs is common. Tap the rock surface with a stone and the surface is removed. Sometimes an outline of something, sometimes "coloured in" like in the first pic.

		We've seen reference to concentric circles such as this but cannot recall the significance. Particularly on its own, as this one is, for us there is no reference point to convey map information.

		Sometimes a rock is so attractive as a surface newer images are created over older images. Is that an image of a person we see? Possibly dingoes. A couple of abstract "eggs". And there are lots of the striped long thin things in the area.

		As we climbed up the hillside we looked back at the entrance to the valley. And the trees that stopped our progress.

		Its quite likely that rocks have moved since the glyphs were originally crafted as erosion took its toll.

		A person? We think this a bit unusual, but are not sufficiently educated to know. Our impression is that images of people are not particularly common. Like the other image of a person we saw its been drawn over other images.

		A last look at circles, a couple of bird feet (we think), and another "stripey thing". We think the darker brown background colour is "desert varnish". A high manganese dust deposit which has oxidised producing the hard shiny surface that allows and preserves the petroglyphs.

		We are headed towards the Hickman Crater. We have to follow the foot of the hills to the south east then head roughly west into the hills to the crater.

		As we drive up hills we can look back at the plain. Formed by the Fortescue River.

		As mentioned in the Info Centre mud map the track becomes steeper and rockier. We have much dispute in the cab about when stony becomes rocky. Progress is relatively easy, but slow.

		There's a few junctions to negotiate. There are prospecting tracks in the area. The track to Punda is on our maps. However, beyond that tracks to the crater aren't. Our maps also differ in which other tracks are shown. In theory, putting all the maps together, its possible to drive to Kalgan Pool across the mountains via Eagle Falls. To meet the track we walked up from the pool. Its only 16 km. In our collection of maps the crater is shown on the Hema Regional Map of Pilbara, but none of the others (probably age) But, there is a point at which we become cautious. Our aim is to visit the crater, the 4wd bit is the means to that end.

		At last, the crater. We are stood beside the letter box. A tour operator's novel contribution to nature. It helped as we knew the letter box was there, and saw it before we realised we were next to the crater. The visitors' book suggests about one party a week. We are this week's.

		A wider view. Discovered in 2007 by Arthur Hickman while looking at satellite images. Looking for channel iron deposits for mining. Confirmed as a meteorite (impact) crater around 2015 after some serious geological analysis and drilling. The original floor of the crater is about 50m below the current floor. The impact occurred more than 50,000 years ago.

		Without the tracks, this is something like how it looked to Arthur when discovered.

		We chose to drive anti-clockwise around the crater. We chose poorly. In some places there are metre high bushes in the centre of the track.

		But, after a slow, slightly nervous, drive, we found ourselves in the middle of the crater. "Because we can". We don't know why, but spending the night in the middle of a meteorite crater had a strange attraction. There's lots to see. We'll start by climbing up the side to the letter box (its visible to the right of the tree on the rim). Lots of rocks, and lots of birds.

		Next morning we tried the direct approach. Scrambled up the side of the crater to the letter box. Walked back down the short vehicle track (clockwise round the crater).

		Rock that's a little bit different. Colours a bit diffused. Without knowing if its significant we are simply having fun.

		The best I could do to see the rim is raised relative to the surrounding hills and ridges.

		The letter box put to good use as a stand for the mobile internet modem. The letter box is at a high point in the surrounding country. A couple of bars of 4G. Newman is about 35 km south. More height, better signal. There's a "tower" marked on maps, and visible, to the west. We wonder if the signal is coming from the tower. But yesterday we had to be nearly at Olympia Dam to get a very good signal, so we think Newman. The letter box trick failed later during a phone call (voip). The wind blew the modem off the top. The backup plan was to put the modem under my hat. The extra height yielded an extra bar!

		Having never seen it, we haven't a clue what pseudotachylite looks like, apart from black and glassy. Sounds a bit like furnace slag to me. Ali spotted it while I was pressing keys. Subsequent internetting suggests it is what we think it is. It provides evidence of heating, which was part of confirming the site really is an impact crater. We didn't see the fracturing that has been described as present.

		Definitely "glassy". But not exactly "black". Keep looking?

		A panorama from the letter box. Truck in the centre. Counter intuitively (to me) the meteorite arrived from the north east, from the right of the pic, from over my right shoulder. We'll have a look to the south west later. Further to the west, beyond our walking range, is Opthalmia Mine. Just a dot on a map, with no tracks shown. But just guessing that there are tracks and they all join up, at least at some time in the past.

		There's some clouds and a nice breeze blowing - we've had cooler weather since the desert. The bread maker is doing its thing, and we happen to have parked next to a dead bush on the zebra finches route around the crater. Spotted a kangaroo (or big wallaby) but not quick enough with the camera. Its surprising how easily birds and animals hide. The crater floor is only a couple of hundred meters across. When we think about it, this is Australia, we've driven more than 5,000 km over a month, and that is the first kangaroo we've seen. The same goes for the dingo we saw yesterday. A very big country hiding lots of things.

		Similarly the first budgerigar we've seen.

		Though the gecko you'll recognise. Its following us.

		A quick walk to the west and a look back. A panorama. I really am a geological dunce. I probably didn't walk far enough to find the stuff that was ejected from the crater. Perhaps its the thought of being somewhere where something from another planet hit Earth thats sparked our imaginations.

Pilbara - Mt Whaleback Mine and Wanna Munna		May 3 - 4 2018

Gateway

Comments		Home

Laurie	Wed, 02 May 18 14:28:29 +1000
Loved the petroglyphs. You know that cute lizard at Kalgan Pool ? I have a pic of his/her cousin on the verandah here in Phoenix AZ. Will email it to you.

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