Saturday, July 24, 2010

Pilbara: The Second, Final Week

7/11: Woke up with the dull rumble of iron ore trains accompanying the usual bird song. Our swag out site was at most four kilometers west of the railway. It was somewhat eerie to hear engines in the night. Moreover, the rails would sing for quite a time before the train per se rolled by.

It was a good morning for a bush walk in search of spherule layers. There was a promising outcrop to the south. Only a couple kilometers of spinifex, desert pavement, gum trees, mulga, and wattles separated it from camp. I led a weaving path through the bush. It was clear, and warmed up quickly. I’m kind of glad it’s been dry; the density of spider webs has been quite low. No post-walk into the web spaz dance moves.

The outcrop disappointed. This is certainly the way of field work. From a distance, the rocks beckon. I am made hopeful of finding a spherule layer or whatever is my goal. But sometimes, no, commonly, the far view proves unreliable. Maybe there is too much talus; the outcrop is buried. Rarely, there is too much vegetation; it’s usually possible to move laterally and find an exposure. Most uncommonly, the layer I’m after simply isn’t there. Not in the sense that I can’t find it, but that it was not deposited in the first place. This is one of the fun challenges of sedimentary geology. Layers change from place to place, due to such causes depositional variations, topography, and chemistry. Understanding changes means making sense of the history, and that’s what I like to do.

The truck was out of site in the bush. A normal situation. Luckily the GPS knew where it was, at least in a straight line sense. While I don’t mind the adventure of finding my ride, I wanted to be on the road. With a dog leg to avoid some thick spinifex, we were in the Patrol and headed back up the power line road by late morning.

Food was low. Fuel was below 20%. We had less than 25 litres of water. A visit to Tom Price was in order. I drove down the railway access road. Bumpy, dusty, but by mid-afternoon we were back in my favorite Pilbara town. It was Sunday, but the Coles grocery was unexpectedly open. Wow, fresh veggies, fruit and ice.

7/12: I’ve probably written before that Tom Price is the “top town” in WA in the altitudinal sense, at 745 metres. This means potentially cold winter nights. I don’t mind chilly nights, but I dislike cold mornings, especially when the needs of nature force emergence from my swag. For this and other reasons I drove us south to Paraburdoo, in search of a lower, warmer swag out site. We found a nice site on Fortescue lavas west of town.

I’d made arrangements to look for the Paraburdoo Layer near the Paraburdoo iron mine, which is near (wait for it) Paraburdoo. Bruce and I had looked at the target section in the late 1980s. Jim Gordon, our contact at Rio Tinto, suggested that I just go look at it. But where was it, i.e., the access road to Radio Hill? I’d forgotten. I asked at the store where we bought supplies. The woman there said, ask Kerrie at the post office. I went to the post office. I didn’t see anyone named Kerrie. I asked the clerk who sold me stamps. She said, I’ll ask Kerrie. Kerrie appeared: she was the postmaster, an apparent fount of local knowledge. She said, no love, some bloke fell off the top of Radio Hill a couple years ago so now the track has a locked gate.

OK. I tried to call Jim: no answer. Did Para have internet? According to Kerrie, you bet, at the library. So at 9am Louis and I traded time online, sharing the library with a dozen Para mothers and their children. I felt large, smelly, and oddly out of place. Rio Tinto had come through for me. I had contacts at the Paraburdoo mine. I reached them on the phone. We arranged a rendezvous on Tuesday morning.

It was thus time for geotourism. With 3/4ths of a day remaining, there was adequate time to visit a pair of interesting sites west of Para. So back on the road. It’s a bitumen track all the way to Nanutarra. Relaxing to drive at 110 kph and not vibrate and bounce excessively.

I can’t resist writing the full geologic name of the first stop: the Meteorite Bore Member of the Kungarra Formation. The Meteorite Bore part has nothing to do with impacts; it’s the name of a nearby windmill; a groundwater pump. What’s cool about the Meteorite Bore is that it’s a glacial deposit. It’s composed of lithified mud and dropstones – pebbles, cobbles, and boulders – deposited on the seafloor by melting icebergs. At the time of accumulation this results a pile of mud with rocks in it. The technical name for this is diamictite. I like the way this term sounds.

Meteorite Bore Member

Since the glaciation that froze the water to make the culprit icebergs took place over 2.3 billion years ago, the Meteorite Bore Member rocks are not in the best shape. They’ve been metamorphosed. This compression squeezed the mud into low grade metamorphic rock. Since the forces involved were largely horizontal, the Member has a pronounced vertical fabric. The outcrops look like giant decks of poorly shuffled red-orange cards: big piles of rocks staked up end on. The dropstones are harder than the surrounding muds; they don’t deform, so they stick out of the rocks, similar to nuts in bread dough. Even neater, fins of metamorphosed mud have fused to each dropstone. When I picked one up, the hard rock – a piece of iron formation – was surrounded by a halo of compressed mud. I’ve never seen anything like this.

After contemplating the Meteorite Bore rocks for a bit, it was time to proceed to Woongara Pool. While only about eight kilometers from Meteorite Bore, it’s a thirty kilometer drive. Time was a bit short. I did not want to be on the road too late and up the odds of a road kill encounter with a roo or a cow. But hey, we were there. The track looked good. I didn’t see the sign at the gate that said “Cheela Springs Station – No Entry”.

Woongara Pool sits along the south edge of the Hamersley Basin, where deformation is greatest. The sedimentary rocks of the Hamersley Group at Woongara have thus been folded to vertical orientations. This makes a dramatic landscape. Woongara Pool sits in the fairly narrow Woongara Gorge. I hoped Louis would like it. The Patrol rounded the corner into the dramatic opening of the Gorge. The pool was mostly dry. Damn. There were dead and dying cows around it. Ugh. Well, the Gorge was still pretty in the afternoon light.

Woongara Pool, no dead cows in sight

7/13: I was sore after swagging out on a rubbly surface of Fortescue Group lavas. I’d sort of hollowed out a rock-free spot for my swag, but something poky still had conversation with by back during the night. Nonetheless, the rocks were interesting; very different from the usual Hamersley Group debris. Sandstone, lava, and white quartz – some sort of vein fill I suspect – instead of the usual chert, iron formation, and carbonate.

By the time we got to the security gate at the Paraburdoo Iron Mine, at 9 am sharp, I was alert. Time to chat up new geos and go look for the Paraburdoo Layer at a site I had not visited for twenty-three years. No worries. I called the geology office, and Jacqui arrived in about five minutes. She led us through Rio Tinto’s safety induction: a straightforward quiz this time. We both passed.

We waited while Jacqui fetched a truck. She returned with a graduate geo – a student – in the shotgun seat. Denzyl was on a break from Curtin Institute of Technology in Perth. This uni produces a lot of mining geos. Like Phil at Orebody 18, he was curious and avid to learn what we were about. We followed their Rio Tinto Landcruiser to the locked gate. I was pleased and touched at the preparations made for our visit. I’d anticipated searching for the drainage where I’d worked in the past, hoping that my vague memories would be triggered by the landscape. Bruce had sent me a couple of aerial photographs of our old sites, which I’d forwarded to Paraburdoo. The Rio Tinto geos had already reconnoitered the area; they knew just where to go. How nice.

As we left the track to Radio Hill and turned up an old route, the landscape did begin to look familiar. I recognized the hill I’d been on in 1986 when I’d watched a man and a woman load a trailer with slabs of rock. That was a weekend day; I presume the rocks ended up in a wall or patio in Para. The track degraded. We parked. I gave a brief spiel about what we were looking for. Both Denzyl and Jacqui looked shocked when I said that the Paraburdoo Layer was two centimeters thick. Sure, it was hard to imagine finding such a thin bed amidst the steep ridges of dolomite, spinifex, spider webs, and loose rock where I planned to look. There was to be a blast in the mine at 12:30. For safety, we had to exit this area by noon. I looked forward to a long day of up and down scrambles.

We started climbing. The dolomite exposures were pretty good, though badly folded and faulted. This was becoming normal. We climbed a ridge. The outcrop died. The next ridge to the east looked good. I led a short march over there. The dolomite bedding matched where we’d been, but I could tell that there was more continuous exposure here. I went up the drainage. I sent Louis over the ridge top. Denzyl and Jacqui followed me. I’d made Louis go the hard way. We chatted about life in Para, geology work in North America, and the Rio Tinto work culture. The drainage got steeper. I wondered how long we could all stand to look for the Paraburdoo Layer.

Then, like at the Governor last year, I just looked down. There was the layer. I said something to the effect of, I hate to make this look easy, but here it is. We’d been working for seventy-five minutes. I called Louis over, and we got to work, quickly measuring a section and taking samples. We were able to exit the area well in advance of the blast. That was easy.

Denzyl invited us back to the Geology office, where we met the rest of the geo team. Like Denzyl, they were curious and avid to hear about the project. I’d prepared a short talk for just this situation, so I gave it to them. Such a pleasure to have an intelligent and interested audience. I think they also appreciated a break from the routine of mine work. We said our goodbyes and left by early afternoon.

Back to Tom Price. We needed more supplies. It was time to ship rocks to the States. I dealt with rocks and gave Louis a shopping list. He came back quickly; unbelievably, the store was out of produce. Bugger, so much for Chernobyl potatoes! We eventually found enough palatable food for finish out the trip, and sent 12 kilos of rocks to the Northern Hemisphere.

My next goal was to get a shower. The closest hot water was in Karijini National Park. The sun was setting; no way to get there before dark. We ended up swagging out along the same track as last year’s rainy camp. Louis was pleased to see that the remnants of his rain shelter were still in place. This night, it was clear, the usual lovely shifting panorama of the planets and the Milky Way, punctuated by meteors.

7/14: I was dangerously close to having dreadlocks and flies were avoiding me, in spite of clothing changes and spit baths. I suggested that we camp at the Eco Lodge in Karijini. It had solar showers. Last year the Eco Lodge was the least appealing place I slept; the campsite was dirty, the neighbors noisy, the staff surly, and the showers cool. As we turned into the Lodge access road, I thought, how can they improve this year? This question was quickly addressed; the campground had burned. As learned later, a bush fire threatened the complex, so the staff preemptively ignited the grounds. The recent burn made the camping loops absurdly stark: a loose arrangement of caravans, tents, and vans on the brown and black earth. I thought, ugh, but maybe the water is hot.

In the spirit of being curious or optimistic, I booked a campsite. The young Aussie woman behind the counter gave me a site near the upscale part of the Lodge (canvas tents with raised floors and other amenities). This area had not burned off. OK, plus one. I checked out the showers. They were decently warm. Plus two.
It was late morning. After setting up camp, there was abundant day light left for exploring Karijini again. I’ve been here so many times in winter, what to do? I looked at the Park map, and found a few hikes I did not remember taking. Louis was amenable, so we headed first to Knox Gorge.

I’ve written extensively about the Hamersley Range gorges: deep clefts cut into the iron formation, up to several hundred feet deep. Each gorge differs, depending on the rocks making up its floor. If the base is iron formation, the gorge trends narrow and deep; if it’s a softer rock such as shale, it can be a broader valley. Knox was one of the broad ones. I think that the softer substrate also encourages plants; Knox was choked with gum trees, rock figs, bunch grasses, and wattles. The hike was a gentle walk among the vegetation, gradually opening out into pools with small waterfalls. Eventually I felt the urge to sit and take pictures, leaving Louis to continue through a large pool that required wading. He had been looking forward to this.

Knox Gorge

After lunch, we tackled Weano Gorge. I don’t know why it’s called Weano. This was a wholly different place than Knox. A steep descent and scramble down a talus pile led to the narrow gorge floor. There was no chance of getting lost here; the gorge was narrow, and all of its short side drainages quickly ended in chutes or cliffs.
Down and further down. Weano eventually reached a point where it was a couple meters wide, with an extreme drop off. This point was blocked by a whole gum tree trunk, which was jammed in the declivity. The flood that brought these remains here – stripped of small branches and bark- must have been epic. This was as far as we could go without technical equipment. The sun shone on the cliffs through the cleft; this produced a vertical ribbon of orange light framed by the horizontal layering of iron formation. It was good that I had carried my tripod.

Weano Gorge

A shower, finally. I enjoyed removing a layer of grime from my skin, and was surprised to discover a bit of tan underneath it, in spite of all of the sunscreen and dust I was also wearing.

A good dinner led to a short hike, an epic search for the camper’s dishwashing station. Harder to find in the burned off area in the dark: no paths. The relative abundance of civilization suggested that it was a good night to indulge a tad. I went to the lodge to buy a couple drinks. The guy helping me was the only other American I met on the trip. He was easily the rudest person I met. Maybe this was in contrast to the average gregarious and helpful Aussie, or maybe it was his personality. I hope people thought he was Canadian.

7/15: My morning walk was through the burned bush. It was barren but moving. All of the burned trees, shrubs, and grasses were resprouting. The way of an ecology of fire.

One gorge left: Kalamina. An early start guaranteed some quiet time in the gorge. This was rare. It’s school holiday time in Australia. The Eco Lodge had been rich in families as well as the usual travelers: twentysomethings, adventurers, pensioners, and the odd geologist or two. Interacting with Australian families is interesting. In every instance I can remember, only the father/husband talked to us. The women would smile, but rarely converse. Was this because we were guys, or does it reflect some Aussie family dynamic? Most families also consisted of two parents and three children. This grew to be uncanny. I could consistently predict whether a family was Australian or foreign (mostly Europeans) based on the number of kids. This pattern was consistent in the NT and Kimberley. Kalamina Gorge attracted lots of families. I talked to fathers from Port Hedland, Perth, Drobbo, Tom Price, and Brisbane. It takes valor to drive across Aus in a campervan with three small children, that’s for sure.

Kalamina Gorge

 More Kalamina Gorge

7/16: Time to go back to work. I’d spent the afternoon at Fortescue Falls in Dales Gorge, writing this blog. Louis went walkabout. I generated many surprised stares as I sat typing, with my feet dangling over the big pool. Cognitive dissonance, my pleasure.

Australia Fifteen had taken me to the western, eastern, and northern margins of the Hamersley Basin. Only one direction was left. Luckily, there were mapped outcrops of Wittenoom Formation available in the far south. Another remote area of the Basin, which I’d never penetrated. The rocks at the southern margin have crumpled into tight folds, courtesy of the same mountain building event, the Capricorn Orogeny, that I’ve mentioned before. The peaks are higher here, well over one thousand meters. I needed no more rationales to go for a look see.

The most promising area was southeast of Mt. Hilditch, named for Len Hilditch, the prospector who discovered the ore deposit at Newman. An adjacent peak is Mt. Ella, named for his wife. Why not Mt. Len? The Hilditch’s old prospecting vehicle is displayed at the Newman Visitor Centre. It’s a 1950s 4WD; a raw piece of machinery. I admire the courage, individual and relationship stamina, and hope it must have taken to poke around the Hamersley Basin in the fifty years ago. This was before quality maps existed. Bad tracks, hard living, and unknown territory. Running up hills to see their rocks. Hmmm, that actually has a certain appeal.

Anyway, the direct route to Mt. Hilditch was blocked by the West Angelas iron mine. I outlined a dog leg route around this via Giles Point – named for Ernest Giles, the first European explorer to travel the Pilbara. I fully trusted Louis to navigate us in while I focused on the road. The Giles Point track is another old route like the Pannawonica-Millstream road. It was in surprisingly good shape, courtesy of many recent exploration tracks that slashed off it across the bush.

We cut across Wanna Munna Flats. The bull dust was thick in places, making the Patrol fishtail a tad and leaving a suspended cloud of fine red dust in our wake. After an hour, Mt. Ella came into view. The track remained good. We took a short pass to the north, and turned west towards Mt. Hilditch, only to see the tailings pile from the West Angelas mine. Tailings had been spread further south beyond any reasonable expectation. I wanted to avoid active mine areas at all costs. What to do. Well, the Patrol looked official, so I turned on the beacon light, lit the headlights, and drove on.

The track turned south, and abruptly climbed. I was able to downshift rapidly, avoiding any traumatic need to use the low range gears, or roll off the hill. The track wound into the valley I’d targeted. I could see promising outcrops to the north. After some prospecting, we found an old track that wandered the right direction. Lunch and a hike. I set off quickly. The landscape was pretty rugged and spinifex-laden. This was no place to swag out, so a mid-afternoon departure was indicated.

I came to the first outcrop. Crap. It was a blue-black, fractured, and badly ferruginized chert. Not a good sign. This lithology often indicates poor exposures and bad preservation of the sort of information I am interested in. Pressing on, the next exposure was no better. It was a thick accumulation of surface weathering deposits. From the truck, it had looked tantalizingly like a dolomite outcrop. No Paraburdoo Layer here. Well, the cliffs still looked promising for the Bee Gorge Layer. The hills were a challenging climb, even for the Hamersley Basin. Steep and treacherously covered with loose rock, just enough to make balancing difficult. The outcrop improved. I began to hope. I passed through the last good marker bed below the Bee Gorge Layer. The outcrop died. Bugger. We poked around for a couple hours. No joy.

Redemption occurred during egress. I’d spotted another promising exposure right by the track, within distant sight of the mine tailings pile. A five minute hike and we were on the Bee Gorge Layer. A good continuous exposure. Easy. This simplicity raises a question of geologic philosophy. I had driven past this outcrop en route to the futile site at Mt. Hilditch. Was it necessary to struggle first before this easy find? There are many answers to this, take your choice from karma to the Protestant worldview to my own stubbornness.

A final swag out in the Pilbara. Where to have it? Not near Mt. Hilditch. In addition to the spinifex issue, there was certain to be the constant rumble of the West Angelas mine. We returned to the east, eventually finding a good clear spot on the flats. I regret last nights in the Pilbara. A good camp, a decent meal, the standard fantastic sunset, and a night of stars help, but also make the ache worse.

7/17: The last field day dawned as normal. Incipient light in the east. The stillness of bush night giving way to bird song and the rush of a slight breeze. The first sunlight touching tops of hills and trees, golden and brightening. Spotty clouds drifting down from the northwest. It was decently warm. I wiggled out of my swag to enjoy this beginning.

Australia Fifteen had successfully reached all of my target areas. My planning had included leeway for the unexpected. This day looked like one of these times, only the unanticipated part was – what to do rather than go to Newman and begin the civilization reinsertion process? Eagle Rock Falls sounded interesting and photogenic, and it was on the way.

We packed, buried the fire pit, found the track, and headed east past Giles Point. When I’m driving in the Pilbara I always track the stratigraphy in the hills around me. It’s become second nature. The mountain east of Giles Point looked very intriguing. Louis sensed it too. I took another glance through the trees. Whoa, there might even be dolomite over there. Eagle Rock Falls suddenly seemed much less interesting.

Park, gear up, boot up, hike out. There was certainly lots of dolomite exposed. I began to hope that we might find the Paraburdoo Layer. I found a drainage that seemed to have the thickest dolomite exposure, i.e., the most rocks visible, and started looking. Typical scratchy deeply weathered cryptically layered stuff. I examined every bed. Louis did the same. Moving upwards, I recognized some of the marker beds I’d found in the Paraburdoo. The Layer should be below them. I worked back downhill. The outcrop remained tantalizingly promising. We couldn’t find the bloody thing. Time to move uphill, searching for the Bee Gorge Layer. That should certainly be exposed… But a repeat of Mt. Hilditch ensued. The outcrop died, inconveniently. We searched until exhaustion, hunger, and the need for a shower overruled the hope of success.

It was interesting to examine such a promising site and not find either of the spherule layers. There are plenty of good reasons for such non-success:
  1. The layers may have been buried.
  2. They might have been locally removed or rendered unrecognizable by deformation.
  3. They might have been visible but simply different in appearance.
  4. Louis and I might have been too tired and just missed them.
  5. They might not have been deposited here.
I’ve listed these hypotheses in order of decreasing likelihood. So was the time at Mt. Giles failure? I usually feel tense at a new site until I find what I’m after. Did I pick a bad place to search? Am I wasting my time and resources? Am I not good at what I’m doing? I felt these anxieties and others many times during the work of Australia Fifteen. I’ve had similar and stronger feelings during my past field seasons. This year, they mattered less. Oh well, I didn’t find the damn layers, but I could not have looked any harder for them. Wherever I went, I learned more about the Paraburdoo Member of the Wittenoom Formation; building this mental map was both fun and satisfying. It was just fun to be out there trying.

I haven’t answered the failure question. It’s not a binary choice. I’m sure on some grant report the work at Giles Point will reduce to a dot on a map indicating no spherule layers were found: non-success. But on the larger scale, I’ve have the satisfaction of poking into a new place and examining it with my best effort. The process is a sufficient result.

I didn’t worry this too much on the drive back to Newman.

7/18: Goodbye to the Pilbara via an early afternoon flight. Hello to Perth: chilly, strikingly humid, and suddenly full of the diverse rush of human activity.

Sunday, July 18, 2010

Pilbara Road Encounters

It’s been as strange year for driving in the Pilbara. Here is my evidence. As preamble I should say that outside of a town it’s extremely unusual to see anyone on a road without a motor vehicle nearby.

1) En route from Range Gorge to Pannawonica, I’d driven for two hours across the Chichester Ranges and seen exactly three vehicles. We came over a rise. There were two women jogging on the road. They were clean, wore nice track suits, and looked quite happy. They waved as we drove past. I tried not to cover them in dust.

2) We were sitting on the Jimmy Creek road eating lunch; out of the spinifex. Louis said, there’s some one on the road. I looked up to see a woman walking towards us. She came closer. We waved. She waved. She was Aboriginal, but dressed in safety clothes. After greetings, she wanted us to understand that much of the land behind us was an Aboriginal religious site. There were certain areas we could not go. No problem there. She thanked us and walked away. I later sighted a power shovel and truck working to the east about a kilometer. Maybe she walked over from that operation.

3) Earlier the same day on the same track, we drove past a Thrifty rental truck parked on the verge of the road. As I slowed to pass it, a helicopter suddenly took off from nearby. It headed to the top of a nearby mesa and landed. It eventually flew on to the east. I assume some one got picked up near the truck. We stayed in the area the rest of the day. The helicopter never returned.

4) We drove in Paraburdoo. The main street was blocked by cows. It was a clear sign to leave town and camp. When we returned the next day for phone, groceries, internet, and lunch, I inquired about this at the AusPost. The cows were in town because that’s the only place in the area where there’s forage. Paradurdoo’s common areas and many lawns are keep green using groundwater, unlike the surrounding parched regions. The cows were simply trying to survive. Apparently there had been many more around until the previous week, when Rocklea station mustered them out. Paraburdoo would have been quite an exciting place if this involved the usual helicopter and station hands in trucks.

5) On the way into the Mt. Hilditch section, my target was putative dolomite outcrop about ten kilometers southwest of the West Angelas iron mine. I wanted to avoid the mine site; easier for everyone. The track ran through a gap in the hills and turned west. Directly ahead as a massive tailings pile from the mine. It had expanded beyond all expectation. Luckily the Patrol looks like a mine vehicle.

6) I held my breath wondering how to end this post. What would the land provide? I cringed at the idea of having to manufacture something that fit this narrative. Provision occurred. After a final swagout, we drove west on the Giles Point track towards Newman. It’s one of the old Pilbara roads, now used for mine exploration and station work. It’s in good shape, but has serious patches of bull dust. I drove the Patrol through one of these soft patches at a sharp curve in the road. I looked to my right, checking the berm height, and saw a flash of purple.

The turn in the road: the bush just left of center

I stopped. It was a Common Fire Bush in flower. Wow; it’s early in the season and it’s been really dry, so flowers have been very rare. One of my loves of the Pilbara has been its flowers; so diverse, so fecund. The Fire Bush was lovely. It was covered with blooms and about-to-be blooms. It was a stark and welcome contrast to the harsh dryness of the Pilbara this season.

Common Fire Bush, close up

Saturday, July 17, 2010

On to the Pilbara: A First Week

7/3:  quick flight to Perth, adios to Paul, hola to Louis. 

7/4: Eighteen hours in town, chilly in the morning, close to zero.  A late morning flight to Newman.  I chatted with a gent who worked as a safety trainer for a bunch of the mining contractors.  He was also in the Australian Navy Reserve, and Commander of the Sea Cadets.  He had many interesting stories. 

Newman and suddenly the weather was temperate again.  I found the truck – vehicle number four of this trip – in the car park.  It is a Nissan Patrol, which I had expected with some regret.  It’s Landcruiser Lite –a powerful engine and plenty of truckness, it’s not as taut in the gearbox or suspension as the Toyotas.  No worries – this will keep me from getting too far off road.  It was Sunday.  All of the town businesses save for the pub were closed.  We sorted gear and packed the truck.

7/5: A return to the end of last year’s field season: the gate at Orebody 18.  Last year, they pretended I had not been in contact.  This year, Phil, a BHP geo, was there to meet us within fifteen minutes of contact.  He was a young bloke, a mine geologist.  He and a couple other geos had been intrigued by the project.  Too bad only he was available on Monday. 

Our first stop was to gather safety gear and read a safety briefing.  All of the companies have gotten very serious about this, which is a good thing I suppose.  It’s a bit strange to see the uniformity of all staff in safety gear all the time, even the receptionists. 

I read the briefing materials after rolling my shirt sleeves down, as requested, to comply with the safety code.  I signed on the appropriate line.  I handed it to the safety officer.  She said, you didn’t fill it out.  I said – huh?  It was a quiz.  Oh.  This wasn’t apparent, but now I’ll never forget that I should call for help on Channel 84.  We put on our safety vests, hard hats, safety glasses, and stowed our gloves and ear plugs, and headed out in Phil’s truck. 

I had not been to this research site for nine years; on that visit I was jet lagged so it was a haze anyway.  Nonetheless, the scenery began to look familiar.  We parked, and within thirty minutes I’d found the spherule layer. 

It’s remarkable to me that my long term memory retains the visual map of this spot in the Pilbara, much less that I can so unerringly look at the rocks anywhere out here and find what I am after.  If it were possible to quantify the last twenty-five years, I’ve spent relatively little time in the Pilbara, and even less looking at its rocks.  Yet this place is ingrained in me.  I don’t think I’ll ever loose the capacity and knowledge of here.  I suppose this is true of places that are significant in one’s life.  My time here has consistently been a catalyst in my maturation through the various stages of life.  That has to help.

Anyway, Phil was delighted to see the impact layer and hear about how we think it formed. He waited patiently while Louis and I did our work.  We were off-site – free of safety gear and able to take risks again – by early afternoon. 

The shops in Newman were open.  $450 later, we had enough chairs, ice, gas, food, water, and other random gear to last a week or two.  There was still time to drive west on Rt. 95, shoot the gap north through Cathedral Gorge, and swag out off of the track to Weeli Wolli. 

7/6:  Oh, the pleasure of a first night under the Southern Cross, with the only noise the very distant murmur of road trains.  A partially cloudy sky; the weather seemed unsettled.  Louis was still asleep.  I got up and stared at the back of the truck.  Well, I opened it first.  I’d quickly sorted and packed all of the food, water and gear the previous evening.  With each new vehicle, it’s a geometric challenge to fit everything in ways that don’t rattle, abrade the truck, or cause self destruction.  It’s was made a bit more challenging by the second spare tyre, which hogged a large inconvenient section of storage space.  However, the current set up of the Patrol looked pretty good, although the chairs, shovel, and stove seemed ready to fall out.

After breakfast, I drove us on to Weeli Wolli.  This was another return to the scene of the crime from last year, only this time I was in search of the new spherule layer.  With minimal effort, we found the track we took to the research site last year.  It was a rubbly and rough drive, but at least there was a track.  We eventually came to a reasonable outcrop of dolomite; the main type of limestone that makes up the lower Wittenoom Formation, where the Paraburdoo Layer is located.  I don’t know these rocks as well. They are poorly exposed, and when you do see them, they comprise thin layers of brown laminated rock.  Yawn.  Nonetheless, it was time to learn them, in order to find the Paraburdoo Layer. 

Weeli Wolli is a fairly large drainage, typical of the southern Hamersley Basin.  It occurs in the soft rocks – the Wittenoom – and takes advantage of the abundant folds and faults in the area.  To us, this meant that the dolomite exposures we looked at were isolated hill-sized blobs.  Well, time to work with what nature provided.  We worked uphill.  The dolomite began to show a consistent stratigraphy that we could trace from outcrop to outcrop.  This was a relief.  However, we couldn’t find the spherule layer. 

I could tell that the dolomite continued downhill and across the creek from where the truck sat.  Near the northern edge of the drainage, there was a nice ravine with good outcrop on both sides.  This seemed like a good target.  After lunch we set out.

Back to walking on rubbly stumbly outcrops, through and around spinifex, and scrambling down cliffs.  My route hit the main Weeli Wolli drainage.  It showed evidence of recent flooding; large gum trees lay horizontal in the channels, their roots and branches packed with debris.  The bare dolomite outcrops were polished and scoured.  Large bars of gravel and cobbles partially covered them, and made walking tricky. 

We made it across, and got to my target ravine.  I left Louis there to look for the spherule layer, while I walked uphill to tie us into the stratigraphy we’d looked at earlier in the day.  Of course, I went slowly so I could look for the spherule layer.  This means staring at every visible bed, a slow process. 

I performed my once-a-field season fall into the spinifex.  A couple dozen punctures in the left hand and arm, oh well.  I’d climbed high enough, it was time to turn around and find Louis.  I figured, we’d looked hard, but no layer, no regrets.

When I got back to the ravine, he waved something at me and mumbled indistinctly (a trend).  Eventually I understood that he’d found the layer!  A few very minimal outcrops at the top of the cliff on the south side of the ravine.  I was suddenly happy, and forgot the allergy-induced fatigue I had been suffering.  We had a look.  Definitely spherules.  I was bemused to have a new spherule section.  I’d essentially assumed we would not find it at Weeli Wolli.  I was happy to be surprised.  It reinforced my faith in serendipity.  If I had not gone on walkabout, and Louis weren’t so thorough and inclined to scramble up cliffs, we would have never found the one centimeter of spherules at Weeli Wolli.

7/7: The morning entertainment was a several hour drive from Weeli Wolli to my next site, Range Gorge.  More time north on Rt. 95, then west towards Wittenoom from Auski.  Range Gorge is one of the series of steep valleys that cuts the north side of the Hamersley Range.  There are no tracks into it, nor does it have access from Karijini National Park.  However, an exploration company drilled a research core here in the late 1980s.  I’ll look at that in Perth next week.  I wanted to come here to look at the above ground part of the section, in the hopes of finding the Paraburdoo Layer. 

The first challenge was to find the twenty four year old track to the drill site.  A new berm on the site of the road made this tricky, but with some high torque from the Patrol, we succeeded.  I was pleased to see that the drill site, the outcrops of dolomite behind it, and several hundred acres of the surrounding bush had recently burned.  Bare rock, burnt bushes and trees, and the ashes of spinifex – what’s not to like?  It was dramatic.  The bare rock of the plain ended right at the first cliff of dolomite; a xeriscape without the plants (currently). 

More dolomite, only this time a straightforward bottom to top section to see and learn.  I again put Louis to work at bed by bed examination, and went climbing to get perspective on the overall stratigraphy.  My coordination was a bit dicey from my allergies, but I looked, climbed, and eventually got oriented.  I’d managed to climb an isolated knob.  In the 180 degree view in front of me the Hamersley Range continued to rise.  There were a series of intriguing rock overhangs in the cliffs right below me.  I immediately thought: Aboriginal sites?  To the right (west), Range Gorge cut into the cliffs, its incision making a broad alluvium- and gum tree-filled valley.  It was a big drainage.  I wanted to walk up it and see what was there.  Maybe very long day hike In the future?  The Fortescue River plain filled the scene behind me.  Broad, flat, and mostly burned off from my vantage.  The Chichester Ranges were barely visible on the horizon.  I loved this view. 
Louis had not found the layer.  We worked it over together.  It wasn’t there, or was hiding really well.  Actually, there were a number of thick landside beds in the dolomite, which is unusual.  Their presence meant that the Paraburdoo Layer had to be deeper underground.  I hope we can find it in the core when we get back to Perth.

Our work done, I suggested a walk to look at the overhangs I’d seen.  We scrambled up the burned over drainage.  There was still plenty of loose rock.  The overhangs were all at the top of steep talus piles.  They turned out to be kangaroo hostels, based on the tracks and droppings covering the area.  If the Aboriginals used these sites, they did not leave any evidence. 

Time to explore was good.  This is one beneficial aspect of this research project.  The rock unit we are looking for is so specific that I can definitely say we’ve looked hard for it, time to cease.  Projects covering a broader areas require more self-control.  It’s thus a luxury to have energy and time for a post-work stroll in the bush.

7/8: A cloudy morning, especially in the west.  That was our direction of travel.  I thought, a good day for driving; my plan was to commute to the west edge of the Hamersley Basin, where there was a potential Paraburdoo Layer exposure.  Escaping from Range Gorge, I pointed the truck west on the Wittenoom-Pannawonica road.  Time to sit and drive, racing over the Fortescue River floodplain at maximum safe speed.  A landscape covered with mulga and gum trees; frequent cattle sightings too.  We passed the Mt. Florance Station turnoff.  Coolawanyah Station was next.  Coolawanyah had done a particularly nice job marking their turnoff, using a pair of nicely painted tractor tyres. 

A pause at the Rio Tinto railway to watch an ore train roll by, headed north.  A bit more than a kilometer long.  I lost count of the number of ore cars.  All that rock, going to China, Japan, Taiwan, and Korea.  I wonder how many of my home appliances are made with Pilbara iron ore? 

The sky was darker.  I could see rain bands in the west.  Oh crap.  Nothing to do but drive onwards.  A light sprinkle began at lunch time.  Good, the Patrol windshield wipers were in decent shape.  The rain got heavier.  I was relieved we were on a main track.  It was unsealed, but the surface was well-compacted so it wasn’t immediately going to turn into a sea of red mud. 

I had to put the wipers on high and slow down.  Water began to puddle on the road.  About forty kilometers from Pannawonica, the sky lightened.  The rain stopped.  The wet track was doing just fine.  I slowed for the numerous muddy patches.  Splash!  Oops, that big puddle was more of a pool.  The white Patrol was now largely red, up to about mid-window height.  No worries, we did not loose traction.

Stopping in Pannawonica seemed like a good idea.  I wanted a tarp for weather security.  Panna is another mining town.  It was founded in the early 1960s like Tom Price and Newman.  Its independent operation was absorbed by Rio Tinto in the 1990s.  It’s a small place.  Luckily the store had a tarp, bread, and the other few things that we needed.

OK, the clouds seemed to have dissipated, but where to go?  I saw a sign that said Bungaroo Project, pointing south down a wide track.  Hmm, Bungaroo Creek was pretty close to where I wanted to look the Paraburdoo Layer.  The track was good, built by Rio Tinto.  Definitely for exploration; roads cut off from it at intervals to drill sites.  We eventually found a old, unused side track and swagged out. 

The clouds gradually returned.  We were at a relatively low elevation at 360 meters.  It was warm and after the rain, strangely humid with a strong smell of damp rocks.  We swagged close to the Patrol, and prepared for a quick evacuation.  I fell asleep right away.

Only to wake up with rain falling on my face at 12:30 am.  Time to bolt.  We threw our stuff in the Patrol and headed back to the main road, stopping just at the berm.  Slow, somewhat anxious driving through a heavy downpour.  Parked, we sat in the truck.  The downpour stopped.  Louis bravely set up his tent.  I went to sleep again, in the driver’s seat.  No worse that economy class on a Qantas 747.

7/9: I woke up at 4 am.  The stars were out.  I spread out my swag and got a bit more rest.  Dawn and the weather looked a bit more settled.  Still partially cloudy: numerous blue patches.  The brief storms had soaked the ground to a depth of six centimeters at most.

We went in search of the old Pannawonica to Millstream road.  When I came to the Pilbara in 1985, this was the main route from Wittenoom to Panna and beyond to the coast road.  The Bungaroo Project road had bisected it somewhere.  I’d missed it the night before in haste to make a wet swag out. 

This trip has been much more about hunt and find than Australia Fourteen.  We’ve done all the easy sites.  The project has pushed into the peripheries of the Hamersley Basin: more remote, old, and less traveled tracks.  Finding the old Millstream Road is a good example.  It was on my Pilbara Tourist map (1:1000000 scale) and on my topographic map (1:100000 scale).  My GPS, which includes the topo database, showed us where we were: not on the Millstream Road.  However, this was useless.  We could tell the geographic direction to go, but which route to take to get to it?  All of the new mining tracks weren’t on any map or the GPS.  Finally, I decided, let’s just try this one: a straight track, probably a mining survey line, plowed through the bush.  It cut the Millstream Road in about 2 kilometers.  The GPS confirmed our location.  Easy continued.

I’d wanted to find the Millstream Road in order to get to the Jimmawurranda Creek area.  I’d been there in 1985 with Bruce, and subsequently for some of my Ph. D work.  It had dolomite.  Thirty kilometers of damp dirt track, and a couple road encounters (see a future post) later, wee found a good site.  It was mid-morning.  The sky was clear enough to seriously boost my morale.

This project requires optimism.  As I wrote in the introduction, the Paraburdoo Layer is at most a couple of centimeters thick: fingernail-scale.  Imagine trying to find this amidst discontinuous outcrops, talus, spinifex, faults, fold, streams, and other complexifiers and the need for hope should be clear.  One helpful bit is that the spherule layer weathers to a grey-green color, which is unlike the usual brown dolomite, black to grey to ochre to red cherts, tan shales, and green volcanic rocks.  Unless of course, any or all of the above are covered by an orange-red iron stain, whitish caliche, or purple-black desert varnish. 

Does this mean I’m an optimist?  Well, at minimum I’m persistent.  I like the feeling of success.  There is also the hope of finding something new, unusual, and exciting.  This is also a great excuse to be outdoors, in Aus, and looking at rocks.

We went south of the road.  Lots of dolomite exposures, along with abundant folds and faults.  Déjà vu for the Weeli Wolli sections.  However, just like that site, my observations began to crystallize quickly into stratigraphic patterns.  Ok, these two black chert/golden carbonate sequences are here, above the think dolomite beds…  Intensely creative and useful as long as I wrote it down. 

Lunch and time to work to the north.  It seemed a good idea to pick a campsite first.  The bush was thick and unburned throughout the area.  I think it always has been.  This meant that best bet for swag out was a stream drainage.  Drainages always have plenty of wood stacked up from past floods, a reasonable sky view for star patrol, and the stream sediments are often softer than typical Pilbara soils.  So how do you find a good place to swag out in a stream?  Bruce and I evolved the following technique in the late 1980s:

1)      Aim the truck along a fairly wide drainage: one that’s pretty open, where there’s potential to get far of the road.
2)      If tyre tracks exist, follow them.  They usually mean some one has successfully followed the drainage, and returned (hopefully).
3)      Bounce along as far as you can stand, trying to control the truck as it groans in 4WD over bars of sand, gravel and small boulders.
4)      Back up frequently to avoid drop offs that would bog the truck.
5)      Get tired.
6)      See the right place to stop: room for swags, a fire pit, a kitchen, and the truck.
7)      Park, fall out of the truck and recover.

Louis and I did this.  He’s initiated now. 

The rocks to the north called.  We walked several kilometers and looked at a dozen outcrops.  The rocks showed the same sequence as south of the road.  Interesting but disappointing; we were not getting any deeper in the stratigraphic section, meaning that the Paraburdoo Layer was buried.  Just like Range Gorge

7/10: I’d driven at least 760 kilometers since July 4th, mostly on unsealed roads.  A good night’s sleep in the Jimmawurranda Creek drainage had helped, but I was still tired after the rainy night.  Louis was developing a cold.  My allergies were fading but still taxing.  Another long drive was next on the agenda.  It seemed like a good time for a break.  We followed the Millstream Road to Millstream.

Millstream is a part of national park.  It’s historical; Millstream Station opened in the late 19th century as a cattle station and sheep station.  The sheep didn’t last, at minimum because dingoes find lambs to be delectable.  The cattle station persisted into the 1980s, when the government took over the lease, i.e., no more cows.  Well, this is the colonial history of Millstream.  The station site was a in a logical site because it is where a major aquifer breaches to the Earth’s surface.  This has formed fairly permanent spring-fed pools.  Of course, the Aboriginals knew this was an important place a good 20,000 years ago.  New signs at the station indicated that Millstream has been an important gathering site for a number of different groups for at least that long. 

I was happy to be someplace that was verdant and wet.  We had enough energy for a couple of short walks among the pools.  It was quite strange to hear and see running water: well, water running on the ground, not falling from clouds.  Millstream had a real feeling of oasis.  This was most poignant at the lily pond; a pool full of flowers, seeded there by one of the station women over one hundred years ago.  I’ve never seen wild water lilies before. 

Most of the large Millstream pools follow old channels of the Fortescue River, creating long curved water bodies.  A swim in one of these was indicated as a pre-lunch activity.  I jumped in, and happily floated in the cloud of dust, sweat, and grime dissolved from my skin as I paddled about. 

Back to work.  More dolomite called to the south, along the Hamersley Front.  Back to hunt and find.  Ok, Millstream was on the maps, so we knew where we were starting from.  How about this track?  Damn, a “Pastoral Lease – No Passage” sign, hand lettered in green paint on a sheet of corrugated iron.  It didn’t say which station this was: no one to call about access.  OK, let’s go seventeen kilometers and try this one.  A locked gate, another hand lettered sign.  This trend continued monotonically.  I was annoyed and somewhat frustrated; the day was passing, it was time to find a swag out spot. 

The road intersected the Pilbara Iron railway line (Karratha-Tom Price-Paraburdoo).  I’d gotten an access permit, so we headed south along the tracks.  More locked gates.  Finally, the power line road, following the same trend as the railway, but here cutting across the bush – pretty close to a dolomite exposure.  We took it.  We swagged out close to the Front, in hopeful site a good outcrop for the next morning’s work.

Magnetic Termite Mounds?

A typical Pilbara termite mound

Termite mounds are ubiquitous in arid Australia.  I’ve looked at them with variations of awe and boredom for twenty five years – mostly from trucks.  For some reason, they are not very abundant in the areas I’ve studied the geology.  So most of my observations below are passing, literally.  Termite mounds aren’t anthills; I’ve seen one over four meters – seventeen feet - high and with a volume of at least three couple cubic meters.  They’re commonly at least a meter high.  Whatever the size, mounds are truly edifices.  They have vaguely columnar shapes with rounded tops, and rise abruptly from the surrounding landscape, whether it’s a grassy plain or a rocky slope.  They seem anomalous and clearly organic.  Texturally, the surfaces of the mounds are composed of several thousand oval blobs the size of a finger accreted together to form a single mass.  Imagine making a sculpture out of toothpaste squeezed from tubes, and you’ll get the idea.  Internally, they are a honeycomb of passageways, based on the abandoned and decayed mounds I’ve come across. 

Close up of a Pilbara termite mound

Termite mounds seem to vary geographically in two ways: color and shape.  Color certainly reflects the underlying soil.  In the Pilbara they’re most frequently deep red-brown.  In the Red Centre, they are a lighter orange-red.  In the East Kimberley and NT, they are tan to brown.  Mounds seem to be biggest in the NT and smallest in the Red Centre.  In terms of shape, Pilbara mounds are massive, and often seem to have a point on top.  Red Centre mounds are more truly columnar in shape.  NT mounds are particularly elaborate; many feature multiple columns amalgamated into a single mass.  I wonder if this more complex structure reflects erosion caused by higher annual rainfall.

I should also say that in all three areas, termite mounds are either loners or joiners.  The joiners occur in fields of up to several dozen mounds, each a unique shape and size.  I plead etymological ignorance: I don’t know how connected they are underground, nor how mounds propagate within a field.  On the other hand, in the Pilbara at least, the really big mounds are isolated.  It’s possible that these variations reflect different termite species.

Pilbara - a field of termite mounds

So what about the so called Magnetic Termite Mounds?  When I read that these things existed in Litchfield National Park in the NT, I filed them away as something to go see if time allowed.  The MTMs, as I’ll call them, sounded like a variation on my categories of termite moundness.  I figured that the termites either incorporated magnetic minerals into their mounds, or that they were magnetically oriented in some way.  Intriguing, but seeing them was a back burner plan: termite mounds are interesting, but hey, they are not rocks.  Time allowed, so as I wrote in an earlier post, Paul and I headed to Litchfield in hope of a final night outdoors in the NT.  We were thwarted by the heat and crowds, but not before seeing the MTMs.
The access road into Litchfield wound through outcrops of red sandstone and conglomerate.  Our progress was slowed by any number of slug-like vehicles; cars towing trailers, locals in old cars, and distracted tourists.  I passed them when I could.  Eventually the MTM pullout appeared.  It was large and full of vehicles.  There is not much else to do on the way into Litchfield except this stop, other than sweat and pass slow vehicles.  Or maybe drive one. 

We got out and geared up.  A short stroll along a boardwalk ended at the edge a flood plain.  The large, crescent-shaped area looked like it got pretty damp in the Wet.  It was full of termite mounds.  I was dumbfounded.  They had huge sheet-like shapes, like giant cooling fins.  I had brought my GPS unit along to see about the magnetic business.  Using its compass app, it was soon clear that the MTMs weren’t oriented with any relation to the Earth’s magnetic field.  This had been my assumption.  Instead, they formed a long arc that followed the broad curve of the stream drainage where they occurred.  What to make of this? 
I thought the MTMs were brilliant.  What whimsical shapes to see, what a mystery on a hot winter day.  As with much of my experience in the NT, they challenged my mental model of termite mound-ness.  They were worth the drive to Litchfield. 


More MTMs, note "normal" termite mound in rear.

The park signage offered an explanation for the MTMs.  Their environment is unusual; most mounds form in dry settings, while the MTMs have been built in a stream channel.  There was direct evidence of this at the MTM site.  A “normal” termite sat just off the stream drainage.  Anyway, the wet setting means that when it gets hot, the termites can’t go underground, as they apparently do in normal environments.  To avoid sauna like conditions the MTMers built these giant platy mounds, which have more surface area and thus stay cooler.  This seems plausible to me; if not it’s a good hypothesis.

One final comment: termite mounds of any shape and origin are hard.  I kicked one, and my foot hurt for several days afterward.  I doubt I could knock one over with a truck.

Sunday, July 4, 2010

The Rest of the Top End: Art, Marsupials, Cycads, and Beyond

6/30: Kakadu seemed to be giving me a migraine headache. Maybe this was the driving, the dust, the brushfires, Mozzie Night Dreaming, or the radioactive rocks. Seriously, there are a number of uranium ore bodies and a mine or two within the park; luckily most of the former will remain undisturbed. None of the tourist areas are really dangerous. Interestingly, most of the areas identified by geologists as radioactive have long been known as dangerous to the local Aboriginal bands.

Since my head was hurting, I took a pass on a morning walk and doped up with pain medications. Doing a headstand in the campground seemed too challenging. We bolted early for the Nourlangie rock art area. Paul drove, thankfully. It was fun to ride and see him quickly sort out the perceptions and mechanics of “driving on the left”.

Nourlangie is south of Ubirr by several tens of kilometers, but is also located along the escarpment. Geez, the rocks here were reddish sandstones with interbedded conglomerates, just like Ubirr, just like Keep River, just like the Bungle Bungle. Whatever.

The rocks in Ubirr and Nourlangie do not show much evidence of folding or other deformation. However, at Nourlangie, the overhangs seemed bigger. The escarpment per se was higher, and in several places large masses of rock had detached and slid downhill; this produced a number of large cavities. The trails wound through several of these openings. They were clearly areas of past occupation. Portions of the walls were stained with soot. The upper surfaces of several large rocks were pocked with concave depressions; the result of many years of grinding seeds and other foods. The walls were of course covered with stunning paintings. Similar themes to Ubirr; mythology, food, people. Here, the paintings seemed more vibrant and more colorful. The X-ray style was more prominent as well.

These sites were all isolated from us visitors by fences, or in the case of several of the cavities, raised walkway. This was fine except when a high school group wandered through clogged up the walkway. Several of the sites looked fresh to me. I wonder if they are still in use. The tradition in the art, as explained by signage, is to paint over preexisting art as necessary for religious purposes. In some sites there are clearly many layers of painting – no way to say how many.

This was another site where I felt: this would be a nice place to be a hunter-gatherer. Abundant food on the flats and in the hills, probably year round - no need to migrate very far. Given the cavities, also cool places to rest in the heat of the day.

Keep River and Kakadu have expanded my sense of Aboriginal history, as it were. My previous experiences were in more arid regions: the Pilbara, the Gascoyne, and the Red Centre. These areas can’t be as rich in potential food as the Top End. It makes sense that art in the latter is more elaborate than in the dry regions. There may be other explanations of course, such as the people involved, the length of human occupation (longer in the Top End) or the availability of “art supplies”. As I ponder this, I’ve seen more petroglyphs in arid regions, and more pictographs – painting – in wetter, more abundant zones.

Nourlangie occupied the morning. Post lunch, Paul drove us further south to Gunlom, our final Kakadu destination. Nearly 40 kms of dirt track took us to the campground. It was refreshing to be off bitumen; I felt like I was back in Australia, migraine or no migraine.

Gunlom attracted us because it featured many bushwalks. It also featured what had become common on the trip: a campground filled “chock-a-block”, lots of campers, lots of kids, lots of noise. We found a site on the edge of the area. Paul sat in his chair, facing out into the grasslands. I slept, hoping my head would clear.

7/1: A morning hike up the escarpment, along Gunlom Falls. Geez, more red sandstone and conglomerate! Here the rocks were tilted almost vertically, and were much coarser grained; lots of bouldery layers. A short and steep scramble brought us to the pool above the falls. This was the only place in the Top End that I visited where swimming was permitted. Every billabong and stream we had passed had featured a crocodile warning sign. This is also the NT rule of thumb; don’t swim if a sign says not to and don’t swim if there is no sign (the crocs may have removed it). Well, this pool at the top of a 200 meter ridge of sandstone is safe if anywhere is. I’ve not heard of a croc climbing that kind of a cliff before. We didn’t swim. The far views over the lowlands and the close-ups of the pool and rocks were sufficient pleasure.

Back at the truck, we agreed that two nights was enough for a first visit to Kakadu. We weren’t heat adapted for long hikes. There was more to potentially see before heading back to Darwin. I drove the RAV 4 south out of the park towards Katherine, NT. Nitmiluk, formerly Katherine Gorge, National Park, east of Katherine, sounded appealing. A good hour further south on the Stuart Highway, a brief pause in Katherine (the third largest town in the NT – supermarkets, aboriginal art stores, internet, the works), and off to Nitmiluk…

… to another crowded campground. There are two ways to see Katherine Gorge; by tour boat or by walking. Of course we walked. Of course, this meant climbing up a steep trail in the afternoon sun. Of course, the rock was red sandstone and conglomerate. The view from the top, once reached, was not particularly photogenic, so we hiked back to the campground to relax.

Nitmiluk seemed a bust. More people, more sandstone, more heat. Well, at least it had marsupials. At dusk, as Paul prepared dinner, a pair of Agile Wallabies appeared. They hovered around the margins of the campground. I suspect they were used to handouts. Their lack of fear was an opportunity to study them from just a couple meters distance. Wallaby and kangaroo locomotion has two main modes. First is the hopping we all associate with Down Under animals, it’s for covering ground quickly. To me, it’s also a marvel of animal mechanics. The animal hops on the toes/balls of its feet, which essentially form one balance point. Massive amounts of energy are stored with each hop in the animal’s leg, tail, and back tendons. It’s such a graceful, effortless motion, so efficient and beautiful. It’s also bloody uncanny when an animal looks at you and hops away. My brain expects it to walk; such is my Northern Hemisphere bias. Anyway, these wallabies were not hopping. They moved along the ground in a humped over position, alternating contact between their strong, clawed arms and legs. A slower movement, ideal for feeding. Equally amazing and pleasing as the hop. And did I write that they’re really cute?

I fell asleep using my mask and earplugs as normal. When nature called around 2 am, I stumbled over to the open air ablutions block. There were a good dozen wallabies and a couple kangaroos on the lawn outside the building. They ignored me. I went in to use the urinal. The trash can in the block was stridently signed “Keep Closed So The Wildlife Can’t Get In”. I heard a small noise. I turned around, and there was a wallaby sitting next to the trashcan looking at me. Then it looked at the trash can, back at me, back at the trash can, etc. I think it would have pointed if possible. I did not take the hint.

7/2: Escape from Nitmiluk commenced early. On the way back to Katherine, we could not resist a stop at the Jurassic Cycad Gardens. This is a private park – self-admittedly in its literature, “a hobby gone amok”. It featured several acres of cycads and other primitive plants. These veggies were around long before the dinosaurs; they pioneered the land in the early Paleozoic Era, and are ancestral to all of the plants we know today. Even spinifex (nothing is perfect).

It was a pleasure to see such a proliferation of uncommon plants, well arranged and well explained. Many of these are native to Gondawana – the southern continents

I drove us back north through Katherine, and eventually west towards Litchfield National Park. As we neared the park, the tourist density increased. Again. It was hot. Again. I could tell that the rocks would be red sandstone and conglomerate. Again. We made it as far as the Magnetic Termite Mounds (stay tuned) and turned around.

Where to camp? My Lonely Planet guide recommended the Tumbling Waters Holiday Park, somewhere on the very distal fringes of outermost Darwin. We found it. It was shady. The owner was delighted to give us a tent site, by the tumbling creek (mostly dry). The whole park had wireless internet. There was to be a crocodile feeding that evening. So a final NT evening of reading and rest commenced.

Saturday, July 3, 2010

Mozzie Sleep Dreaming

6/29-6/30: Last night in Muirella Park, Kakadu proved to be the night of the mozzies. After escaping Ubirr, and with dinner and ablutions complete, I crawled into my bivy sack. I knew it would be hot, so I was sleeping only within my cotton bag liner. I’d hoped to leave my bivy open; the sky was fairly clear in spite of the brush fires, and the moon was just past full. There was enough time to fall asleep before the lights came on, as it were. I listened to music for a while; it’s more relaxing than hearing to the other campers (the campground host was also laughing noisily to whatever was on TV). Sleepiness loomed. I turned my player off. Its sounds were replaced immediately by a chorus of little whines around my head. Mosquitoes. Bugger. I zipped up my bivy. Stuffy but tolerable. OK, the bugs could not get in and bite me, but the netting on the sack scratched my face. Bugger. OK, turn on my side. Hmmm, now my ear was up against the netting. There were at least five different pitches of mozzie whine. Different types? Different sizes? Bloody bugger all. I put in my earplugs.

The moon came up.  It was light enough to read.  Bugger bugger bugger.  I put my sleep mask on.

And went to sleep, eventually.

The Top End

6/28: We arrived back in Darwin in the evening. In advance; it had seemed a good idea to make a hotel rezo for a night. I was curious about downtown Darwin; it’s an old town, has some interesting history (much communication with Asia, the Japanese Navy bombed it repeatedly during World War II, etc.), and hey, it was a new place. However, I did not realize that 1) I’d booked a hotel on Mitchell Street, the main area of nightlife, 2) the USS Peleliu, with several thousand sailors and Marines on board, would be in town, and 3) our room, while having two beds, was approximately 8’ x14’ in size. Paul was a good sport about all of this.

Well, what to do. The room had AC; the World Cup was on cable. We found a decent pizza joint. The waterfront provided a nice stroll in the humid dark tropical air. We saw a number of plaques dedicated to the servicemen and their units from WWII.

I stopped at the backpacker hostel associated with our hotel to do some internet prior to sleep. This became a bit strange when I realized that much of the room trade happening around me was just that: military personnel and their “dates”. The older looking enlisted men seemed to be doing better, as it were, than the ones who looked sixteen or so. I’ve not been around such an overt scene since I was in Indonesia, a long time ago. It was both saddening and distracting to see these events go on around me.

6/29: Leaving Darwin was not a problem. Some casting about and the related traumas of driving on the left in the new unknown city provided food, gas, and other supplies. A short stretch south on Rt 1, the Stuart Highway, and I turned our current vehicle, a Toyota RAV 4, east towards Kakadu National Park on the Victoria Highway. More subtropical landscape rolled by. Fruit plantations near Darwin gave way to tropical woodland; acacias and grasses (for a change) and a variety of broadleaf trees – myrtles, kapoks, and others. It was 34oC; I’ll guess humidity was in the 70% range. The air grew smoky; lots of spot fires in the bush. I assume that these were deliberately set for land management purposes. The Aboriginals have been doing this for up to 60,000 years, so it’s become kinda ecologically necessary. Mid-winter, i.e., the dry season – now – is the time to burn. It began to seem unlikely that Kakadu would provide much in the way of dramatic vistas.

The National Park boundary came and went. The Victoria Highway continues past the park further east into Arnhemland; this area is largely Aboriginal preserve; one needs a permit to stop there. Maybe on a future visit.

A stop at the Jabiru Visitor Centre gave us permission to stay in Kakadu, however. We found a campsite near Muirella Park, on Djarradjin Billabong. It was still 34oC. Being in the air conditioned RAV 4 seemed a good idea, so we drove to Ubirr, in the northeastern corner of the park, to see the sunset. Ubirr composes part of the sandstone escarpment of Kakadu; a series of ridges and jump ups that more or less divide the park into two parts. The lower, northern bits of the park – mudflats, mangroves, and monsoon forest - run up to the Gulf of Carpentaria. This part is largely swampy and inaccessible to Americans without boats, and who aren’t that into fishing or wildlife, especially birds or large carnivorous reptiles.

The escarpment at Ubirr also has lots of sandstone overhangs. Like Keep River, many of these cavities featured Aboriginal paintings. They were extraordinary, truly world class art. The paintings, in shades of red, ochre, and white, focused on Aboriginal mythology, such as the Rainbow Serpent, and X-ray style depictions of many of the important local and huntable things to eat – barramundi and other fish, turtles, wallabies. There was also a spectrum of humanoid figures; clearly male or female, but I was not clear on their importance.

Between these overhangs and the upcoming sunset, Ubirr was swarmed with people. It was difficult to get a decent look at many of the art sites; ranger talks and other tourists filled the spaces behind the fences (the art is all quite delicate, so is off limits, like in any good museum).

As sunset approached, I followed Paul up the escarpment trail to the primary viewing area. Unfortunately, this was to be a repeat of last year’s sundown experience at Uluru; we shared the vista with a good six hundred to one thousand of our tourist colleagues. The multitude included at least two tours comprised of high school students; their hormonal fizz added to the distraction of the people around us.

These human interferences were unfortunate. The 360 degree view from the escarpment was breaktaking – really. A wide open vista over green grasslands to the west was balanced by the stony cliffs of the escarpment punctuated by high gum trees in the east. It would have been lovely to sit on the edge in a comfy spot and watch the light change, the birds emerge, and swat the occasional mosquito. This was not possible. In addition, smoke from bushfires in the park gave the scene a slightly apocalyptic feel. We left early, and avoided the mass exodus of trucks, cars, buses, and other conveyances once it got dark.