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.

Australia Fifteen: Preamble

A year proceeds quickly. My last entry was a series of reflections on Australia Fourteen. Suddenly it’s time for my fifteenth trip to what Bill Bryson calls “A Sunburned Land”. The upcoming trip follows a similar arc to last year. First, a week of poking around in new areas, i.e., vacation. “New areas” on this trip means the Kimberley Region of Western Australia, particularly the Bungle Bungles, and Kakadu National Park in the Northern Territory. Assuming I survive crocodile assaults in the Kakadu, this holiday will be followed by a few weeks of field research in the Pilbara.

Recap and Plans

In case you did not read my blog last year, check out this entry for explanation of how I’ve come to be a recidivist geologist/visitor in Australia. The short version is that I’m currently on a grant through my work with Oberlin College to study meteorite impact deposits. These strata are really old; the four layers we’ve recognized so far accumulated on the sea floor around 2.5 billion years or go, plus or minus 70 million years. The rocks we look at have been uplifted and very well preserved; they comprise the rocks of the Hamersley Basin. They outcrop in the Pilbara Region of Western Australia: the Outback with lots of iron mines. We’ve done a lot of work demonstrating that these layers formed after very large extraterrestrial impacts, and sorting out their environmental effects – massive tsunami and underwater landslides. On a personal level, in the twenty-five years I’ve been going down under, I’ve become extremely fond of the continent and its rocks, plants, animals and people. I always look forward to return and further exploration. I also relish the time away from the normal for reflection and restoration.

Australia Fifteen has two major scientific goals. The first is to finish up the main work of the grant project, which is to make detailed lateral measurements of the best exposed and preserved impact layer in the Hamersley Basin: the Bee Gorge Spherule Layer. I have a couple final sites to visit, including the mine property we were thwarted from reaching last year. We call the impact layers “spherule layers” because their most distinctive component is lots and lots of BB-sized spherical particles. These spherules formed from the cloud of vaporized rock blown out of the impact crater. They subsequently settled to the surface, forming a fairly unique sedimentary layer.

The second goal is more exploratory. The 2009 field season ended dramatically with discovery of a new Hamersley Basin spherule layer. We named this the Paraburdoo Spherule Layer, which I’ll call the PSL to save you all from trying to pronounce Par-a-bur-doo in your heads. By the way, Paraburdoo is one of the local mining towns, and its name comes from a presumably local Aboriginal dialect; “paraburdoo” means “meat feathers”. I can only hope this refers to emus or bustards, and not corellas or galahs, the local, nasty cockatoos. I’d describe them as gaudy crows, but that would be insulting crows. As I wrote last year, I literally stumbled upon the PSL, a 2 centimeter thick layer of impact debris, at my personal nadir point for Australia Fourteen. I was tired, cranky, sore and possibly flatulent (Louis – my field assistant - had cooked the night before). I climbed a rubbly hill, looked down, and there was the PSL.

This was particularly exciting because it was new. It’s the fourth spherule layer we’ve found in the Hamersley Basin. Based on looking at similar rocks in South Africa, I knew very roughly where it should be in the Hamersley rock sequence, but it was dead awesome to find it. However, since the PSL revealed itself almost at the end of last year’s field season, it remains a single point on a map. This is very unsatisfactory; we have no sense of the PSL’s distribution, or how its internal characteristics change from place to place. So I have put together a list of about a dozen exploratory sites that might have PSL outcrops. This will mean driving to the far reaches of the Hamersley Basin; seeing new areas and places I have not been for upwards of seventeen years. I expect this to be frustrating; the PSL interval is generally poorly exposed, the layer is damn thin, and it outcrops amidst nasty rubbly limestone. As some compensation for this, we’ll also spend a couple of days looking at drill core that might contain the PSL in the Geological Survey of Western Australia Core Library in Perth. Looking a core has its own challenges; rocks can look completely different when they are extracted from the ground than they do “normally” in a weathered outcrop.

Louis will again be my assistant and companion on this part of the journey. He’s an Oberlin student, a double major in geology and jazz trumpet. His help was outstanding last year. Not only is he bright and observant, but he can cook and put up with how inner-directed I get in the field. He’s one of the best student assistants we’ve had. I’m looking forward to more time with him. He’s going walkabout prior to meeting me in Perth, spending a couple weeks in New Zealand. I’m trusting that he’ll appear in Perth on the right day.