Monday, July 6, 2009
The Second Week in the Pilbara
25th June – The rain continued intermittently through the night. I woke up around 3 am and saw faint stars. I hoped the weather was changing. The blue plastic tarp that I was using to cover my swag was definitely waterproof. No rain got in, but none of my respiration or perspiration got out. My bivy and sleeping bags were wet. Oh well, I was still warm enough.
At 5:30 I was ready to worm my way out into the cool morning. The sky was clear. My damp gear would dry. I walked down a track from camp. I hadn’t seen Pilbara bush that was this wet before. The desert pavement was almost black. The puddles of mud were bright orange-red. The flora glistened; there were droplets on many branches, twigs and leaves. It was strange to see so much water in this semiarid place. As the sun rose, ground fog began to fill the lows. Mt. Nameless turned orange as first sunlight struck it. I hoped that the outcrops would be dry.
We drove to Tom Price and met Jim Gordon, who’s one of the chief exploration geologists for the Rio Tinto TP operation. We’d been in email contact about accessing a section that was technically on the mine site. We met Jim at the TP Shell station near town. Accessing the mine site required acquisition of visitor IDs, a safety induction session, and an escort. It was no dramas. Jim seemed happy to be our minder. The section was on Mt. Reeder-Nichols (whoever this was). I’ve worked there before. We drove up a muddy track, parked by the mine water tanks, and parked.
Jim was immediately curious about the rocks. The climb up the usual steep rubbly spinifex-covered slope was slow, as we talked the whole way about stratigraphy, Hamersley Basin geology, mining geology, life in Tom Price, and all the other facets of conversation with geological kin. It was a blast. I rarely meet anyone who knows the rocks and is interested in the stories they tell. He’d been a lot of places I haven’t and vice versa. I got to be a geologist with another geologist.
The measurements were quick. The spherule layer was simple here; ripples (maybe tsunamigenic) and some overlying argillite and carbonate. Samples taken, we headed to the mess hall for lunch. I’d been promising Louis an endless feast. He got it. I ate lots of vegetables. Jim and I talked and shared info for another couple hours. A nice break and intellectual airing from the norm of field work.
The mess hall closed. Time to head back into the field. I secured a pass to drive on the Pilbara Rail access road: a time saving shortcut and a nicer drive, in terms of scenery. We drove to north to Hamersley Station. This is one of the earliest cattle stations in the Pilbara. It’s still a working station: however, helicopters, utes, and quad bikes have replaced horses when it’s mustering time. Permission to work on station land secured, I drove the Cruiser across the station airstrip, in search of the track heading west through the Serpentine Creek drainage.
It was easy to find. Rio Tinto is doing a lot of iron ore drilling in the area. The road had been refurbished. The speed limit sign read 60 kph. I thought to myself: this is too easy. The track kept going. It wasn’t even muddy. 50 kilometers rolled by. The sun began to set; hard to drive directly into it. Dangerous on dirt too. 80 kilometers. We wanted to camp early; tonight was Chernobyl potato night. We needed a lot of coals in the fire.
95 kilometers. A track turned off to the south. I took it. It ended in a turnaround about a kilometer off the road, just north of the Serpentine Creek drainage. There were palm trees beyond the turnaround and – a large pool. Wow. That explained the palm trees. I figured it must be a spring from the cave system that likely underlies the valley. A sampling pipe at the edge of the pool was labeled “Palm Spring”.
There was a lot of dead wood from past bush fires and floods. Coals achieved, we roasted potatoes, onions, apples, and carrots. Bruce labeled this the Chernobyl process years ago as the one potato that gets lost ends up as a carbon ball with a core of baked potato. Haw. A clear night.
June 26th – A dew-rich morning near the spring, well worth it for the light on the cliffs to the north. It’s such a joy to wake up in the Pilbara. The light is always red and beautiful someplace.
I had two research targets for the day. We’d camped near the first: Mt. Farquhar. A short drive, then a long walk across minor drainages and spinifex, followed. The usual climb up steep slopes and stumbles on loose rubble. The commute was made more anxious by an abundance of large spider webs hosting very big spiders. Hard to see them; I jumped spastically when intersecting one, usually face first. I’ve never liked the feeling of spider webs. In addition, almost every spider here is toxic in some way. No need to find out if these bugs were on the list. After the climb and much searching, the spherule layer appeared. It was thin, and poorly exposed. I had forgotten my hammer. Crap. I sent Louis back to get it and fetch some lunch. I found some decent outcrops. The now familiar process commenced: measure, sample, photograph, and scoot.
Target number two was Mt. Delphine. This isolated peak at the western end of the Serpentine Creek drainage has intrigued me since I first sorted it out on the geologic map in 1992. The section looked promising. My Google Earth reconnaissance was enticing.
Bruce has always been dubious about Mt. Delphine; he rightly pointed out that it’s a long drive to a site of unknown quality; we know the spherule layer does thin to the west. I wanted to go look at it, driven by both curiosity and hope. This was the time. Ninety minutes of driving on progressively degrading roads brought us to the base of Delphine. Park, assemble gear, climb. Hmm, the Paraburdoo Member was pretty deformed. Not a good sign. We climbed. The rocks showed more folding than usual. They were also cleaved, showing a regular fracture pattern caused by deformation. Another troubling sign. It also made smaller pieces of rubble underfoot: more slippery. A place to fall on spinifex for sure.
We scoured the available outcrop. Louis and I both picked the same bed as the impact layer, but could not find any spherules in it. Damn. We climbed most of the way up Delphine as compensation, and watched a wedge-tailed eagle soar.
Driving back east in search of a swag out spot, I thought that Bruce and I were both right about Mt. Delphine. He was right; the spherule layer exposure was cryptic at best, and probably not worth the time and effort to get there. But I was happy to have looked. My inquisitiveness - scientific and personal - was satisfied. My sense of place was expanded; another hill visited. New vistas seen. Now I want to go west and south from Delphine. It would be a cool loop down to the Paraburdoo access road through some neat rocks and the spherule layer might be there...
June 27th – Time for a break. Jim had told us about a tiger eye locality near Hamersley Station. This semiprecious gemstone forms when quartz and a couple minor minerals replace some of the asbestos minerals in iron formation. Toxic, like at Wittenoom. We fond the locality. There were asbestos warning signs on the entry road. Clearly, a lot of geologists and rockhounds had been here already. The informal parking area was well defined. The original mine, more of an odd little quarry, had been picked over pretty well. Many of the large pieces of waste rock had been bashed on. I gave Louis my hammer (his remains somewhere on Mt. Reeder-Nichols). He had a good go at the rocks and found some decent tiger-eye.
The real break was Karijini National Park. I’ve written about this in previous years. In a nutshell, a number of streams have cut very narrow and deep gorges through the iron formation. In the local Aboriginal mythology, the gorges are the trails left through the rock by large snakes. There are streams and pools in most gorges. Good hiking, swimming and photography. I’d been here enough times that I had sites in mind where I thought I could compose good images.
Two hundred and forty kilometers later, we reached the Park boundary. I was done in. A long way on dirt. After a stop at Hamersley Gorge, we checked into the Eco Retreat campground on the west side of the park. This used to be a Park campground; it’s now run by an Aboriginal corporation. I’ll review the campground in another post. For now, it gets 8 out of 15. The abrupt change from being with one other person out to the west, with no one else around to a campground was awful. I hated the noise of generators, music, and just the sight of so many people. It took me out of the sacred of the Pilbara and back into a human reality. I did not need this yet. I slept, somehow.
June 28th – At least the sick baby across the track did not keep me up. Time to play. I made my first descent into Hancock Gorge: steep, narrow, and wet. I took multiple exposures of the same scene: definitely a place to see if the HDR function in Photoshop really works. Louis did what seemed like a lot of risky bouldering. I was worried, and then he told me he teaches rock climbing. I worried less. Hancock is a place to come back to: the full trek requires warmer weather, a wet suit, ropes, and inner tubes. Sign me up.
More gorges. A tragedy; my Nikon lens committed suicide, via the truck hood, a slamming door, and my right shin. I almost caught it, I swear, but it’s nonrepairable. Crap. After a minute of agony, I realized that it was a done deal. Attachment wouldn’t change the scenario. I felt relieved. Not due to detachment, but because suddenly the burden of taking pictures was lifted. I’d shot a lot in the morning and been trying too hard. This was holiday, right? Now I could fool around with just my ultrawide zoom. Joffre Gorge, Knox Gorge, and then time to head east to the Visitors Centre.
June 29th – see my earlier post, Pools, A Roo, Spherules
Morning Chores List:
1. Drive to Newman
2. Fill Cruiser with diesel
3. Go on BHP Billiton Mine Tour (Louis)
4. Scott, while Louis is on tour:
a. buy boxes and packing material for mailing rocks
b. get back door of truck fixed
c. chat up CoreFleet (truck rental agency)
d. finally have a good cup of coffee (Macchiato)
e. pack rocks
f. mail rocks
g. resupply with food and ice
h. fuss with gear
i. pick up Louis
Afternoon Chores List:
1. drive back to the new spherule layer site
2. find more exposures
3. sample the limestone above and below the layer
4. drive back to the east of Newman
5. camp someplace near the Jimbelbar mine; a second post-twilight camp
July 1st – A final night in bush. I’d hoped it would be someplace scenic if not special. However, the run back the new layer forced a camp after dark off the Newman-Port Hedland road. At least it was warm and dry – no dew in. After the moon set, the Milky Way was fantastic. I said farewell to the Magellanic Clouds and the Southern Cross for another year or two. I watched the sunrise on my morning walk. It was especially good. The full spectrum of visible light crossed the sky. High and low altitude cloud layers added to the drama.
On this last field day, I wanted to look at the easternmost exposure of the Wittenoom spherule layer. It’s on a BHP leasehold. I’d arranged another round of induction with a mine supervisor in order to get site access. After some pitching around, I read my notes correctly and arrived at the right remote gate: Orebody 18. I rang the buzzer as instructed. My contact had gone on long service leave. He didn’t tell anyone about my visit. They were all in meetings. They wanted me to refax my site access request form. Hello, the nearest fax was in Newman 40 kilometers away. Stonewalled. My cell phone had service. I left my number. We sat by the gate for 2 hours. A grader, a new Haulpak, and a water truck drove by. No response. I took it as a sign.
We went to Newman, checked into hotel, and started the clean up process. This took much of the day. In the evening. Fish and chips rarely tasted better.
July 2nd – Up at 5 am. Hard to see the sunrise over the houses of Newman. To the airport. South to Perth. A successful field season.