6/24: Woke up feeling strangely normal in Kununurra. Maybe it was my meal of barramundi the previous night, plus just enough travel to be on some semblance of a normal sleep cycle. A wait at the airport produced our 4WD: a Mitsubishi Pajero. Downtown Kununurra provided food, ice, drinks, and other random supplies, and we were off south on Rt. 95 towards Purnululu National Park.
This is the first time I’ve driven a Pajero. It’s not a field vehicle like the Land Cruisers that I idolize, but a good, practical SUV with a big diesel, a gear ratio decent for highway and unsealed roads, and carpet. Not sure about the carpet, but we’re making do: glad I don’t have to clean it.
As I wrote earlier, Purnululu is the official name for the Bungle Bungle Range, or the Bungle Bungle. This is broad plateau of Paleozoic sandstone, shaped like a very fat “U”. It’s a national park, and a World Heritage site, for its remarkable erosional patterns. More on that later. No one seems to know where the name “Bungle Bungle” came from. There are several competing whimsical hypotheses, involving ranchers, aboriginals, and a variety of miscommunications. None of them are that compelling. I just like being someplace called the Bungle Bungle.
My guidebook stated a five hour drive from Kununurra: east on Rt. 1, the Victoria Highway, and south on Rt 95. The Pajero seemed happy, stable and safe at 120 kph. I enjoyed this initial run through new territory. The landscape of the East Kimberley seemed is a series of fault controlled linear hills and mountains, separated by valleys of various widths and lengths. A lot of the bedrock looked like highly deformed sediments, with occasional interruptions of granite or other crystalline rock. This terrain was covered by a variety of bush grasses, sprinkled with low density of somewhat familiar acacias and other trees that I don’t know. A startling addition to this biota were frequent boab trees. These are the same as the baobabs of Africa; my plant books states that the first boabs arrived from shipwrecks on the Kimberley coast. Boabs have fat grey elephantine trunks, all out of proportion to “normal trees”. This barrel is topped by an often symmetrical fan of branches. Some of the boabs we passed were leafy, some just bare branches, while a few had what looked like fruit. I haven’t a clue what this variety was about. The boabs made me smile; they were a sure sign of being in a new place.
As we drove along, I kept thinking, something looks different here. After enough gazing, I think this is due to the absence of bush-sized plants. A wide variety of bushes are a part of my Australian desert biota model from my time in the Pilbara and the Red Centre. Here, it’s the trees and grasses. This gives the landscape a park-like feel, especially in areas of recent burn.
After 245 kilometers, we reached the eastward turn-off to the Bungle Bungles. Bitumen ended; the washboard dirt road began. This fifty-three kilometers was supposed to take us two hours. It was 3:45 pm; ninety minutes to sunset. The track wound across hills and through many watercourses. The Pajero was no longer white. I drove rapidly well within safe limits; I was glad the sunset was behind us. We reached the park visitor center in eighty five minutes. It was closed. We went to the nearest campground, and groped around in the dark for enough space to camp. I was asleep by 8:15.
6/25: I was awake before dawn, at 5 am. The Bungle Bungle is at about 17oS; definitely subtropical. In spite of this, I’d read that since it was winter, it should be cold a night. I guess cold is a relative thing; according to the Pajero’s digital thermometer, the low was 15oC – around 60oF. No worries, I was happy to be up before the sun wearing only shorts and a shirt. I wandered away from camp, eventually climbing a nearby limestone ridge: smeared and discontinuous beds; clearly a fault zone. The Bungle Bungle massif was beginning to glow red in the morning light. On this, its west side, the Range is a steep north-south trending cliff, pierced by a number of narrow gorges or chasms, as they call them up here. I stood and watched this brighten in the increasing light. The Bungle Bungles is largely flat-laying sedimentary rocks; the coarsest scale of this bedding gave the range a striped appearance. I knew we’d be heading there to hike soon.
I wandered back to the campground. It’s appeal was limited to being the only legal place to stay on the west side of the park. Other than that, it was dusty and crowded with 4WDs and campers. A little too promiscuous, not the kind of camping that Paul and I prefer. As I walked back into camp, Paul stuck his head out of this tent, and shared his first brainwave of the day – let’s get out of here and eat breakfast at the trailhead. We were on the road by 6:15.
Fourteen kilometers of dirt road was followed by a quiet breakfast at Mini Palm Gorge and a pair of hikes: Mini Palm Gorge and Echidna Chasm. These walks, maybe a total of eight kilometers, wandered into a couple of the narrow canyons that knife into the west side of the range. These chasms follow major structural joints – vertical planes of weakness – in the bedrock.
As we headed out on the first hike, I felt strangely disoriented; how did I suddenly come to be walking along this hot sandy track in Western Australia? It was a particularly fast evolution this time; maybe being tired in advance contributed to this.
Well, I was here, healthy and awake, so I walked to see what the Bungle Bungle was really like. The hike into Mini Palm Gorge gently ascended into a blind canyon full of Livionsia palm trees; a species endemic to this area. It wasn’t clear which palms were dwarfs; there was enough evidence of flash floods that I wondered if the smaller ones weren’t just younger. Although it was 8 am, it was already hot and I was sweating. We turned a corner into the gorge per se; deep shadows and a breeze greeted us. The hike immediately seemed more tolerable. The trail climbed over and under large boulders of conglomerate, eventually ending above a grove of the maybe mini palms, in a blind canyon. It was totally quiet, except for the sound of birds and my heartbeat. The vertical walls of the gorge glowed red a the top. I thought, this is a good start.
Echidna Chasm proved this to be the case. This canyon, while an easy walk, pinched down until it was little more than hip wide, albeit 600 feet high. We passed under several large chockstones; boulders that had been trapped in their fall by the narrowing chasm. I hoped they were stable, at least for the rest of our hike. Like Mini Palm, the trail ended in a blind canyon; in this case defined by a waterfall chute fifty feet above the trail’s end. This would not be a good place to be in the wet. The chasm widened out a bit here, and many of our fellow hikers gathered here for a rest in the relatively cool shade. Most of the people were encountered were pensioners who were exploring the remoter parts of AustraliaThey were inevitably fun to talk to; for some reason most of them thought we were Canadian. . However, I was particularly struck by one family on holiday from Perth. They had three young boys, under ten at the oldest. Not only had they got them this far and up Echidna Chasm, but the eldest son was clearly mentally challenged. The father carried him the whole way, while patiently answering the middle son’s questions about spiders.
A quick stroll down the trail, and time for lunch. Geez, it was hotter. Riding in the truck with the AC on full seemed a good idea, so we went to the visitors centre for, in order: cold drinks, an excellent guide to Bungle Bungle geology, and reservations for a helicopter ride on Sunday. After sunset (talking to more pensioners, seeing the family again) it was time for dinner and sleep.
Sunday, June 27, 2010
Wednesday, June 23, 2010
The Run to Kununurra
Off in the early evening for SFO, a hot East Bay night. This departure felt substantially more complex and random than in 2009. This was largely attributable to house chores. Last year, preparation consisted of arranging my plants on my table, setting timers and stopping my mail. This year, with my increase in property and space, there were many new tasks, more moving parts: ranging from installation of drip irrigation to killing my weeds I mean lawn to covering all of my windows to keep the interior cool. The randomness was more a function of being over capacity emotionally and mentally – I did not feel as organized and prepared for this trip, as empty and ready as it were. I already have a list of things forgotten, albeit short so far.
But the departure: an emotional leaving from my sweetheart, lugging my bags onto BART, and then feeling the leading edge of this adventure stop looming and finally assert itself. This was the BART ride of the cyclists. After a couple stops, a Cyclist #1 boarded; he looked like a student based on his street clothes. He had a fairly new street bike, red with yellow tires, modern brakes and derailleur, plus the inevitable Crumpler messenger bag. A stop later he was joined by Cyclist #2 in full cycling mufti (bright yellow), with a very high end lime green bike: disk brakes, direct drive gears; and a fancier Timbuktu messenger bag. I could see cyclist # 1 eyeing him. Both bikes were aluminum-framed; watching them was like seeing a mismatched stereo photograph. I enjoyed this dichotomy for a couple stops, and then Cyclist #3 got on. Another aluminum frame, but there the parallel ended. This was the punk model. #3 was easily the oldest, wearing much worn jeans and a torn t-shirt, with a ratty Timbuktu messenger bag, all smelling strongly of cannabis. His one-speed, drum brake bike was scratched, dented, and plastered with decals. Parts of the frame were covered in plastic bags. Much of this had been spray-painted silver at some point. Multiple strata were evident. The bike’s handlebars were severely cut to at most 10 inches width, and covered with ratty silver duct tape. Cyclists #1 and #2 studied him, as did everyone else in olfactory range. The train filled up; all three bikes became jammed together. We vibrated together as a mass under the Bay into San Francisco. They untangled and pedaled their individual ways at the first stop; I can only imagine to three separate destinations.
Into the SFO International Terminal. The Qantas gates were at the far end: not a problem. Even less of a problem was check in; I’d done this online, so I literally walked up to the agent and handed in my bags. This left me feeling oddly anticlimactic; the anticipated stress of seating, luggage weight, and carry on density (mine is easily 200% of max) was removed. I waited for Paul, and we had a bite and decompressed before flight time.
Another Qantas 747-400, somewhat tired and worn on the inside. I was happy to have gotten an aisle seat, but when I got to it, I discovered that there was a metal box filling almost half of the space under the seat in front of me –where my feet were supposed to go. Bugger. I kicked it in frustration, but it was clearly part of the plane, so desisting seemed indicated. Some centered observation showed that I could fit myself pretty well, but I was annoyed. A bad travel omen? Too soon to tell.
A long take off roll, and all 438 of us headed out over the Pacific. I settled in, hoping for a cycle of naps and movies. I don’t sleep well on planes; they are such an orthopedic nightmare if one is two meters in length. These ridiculous long haul flights are worse, as blood pools in my legs and my contact points – heels, butt, and shins – are squeezed. Oh well, I suppose it beats three weeks on a boat to get to the other side of the Earth. I also carry background excitement and anxiety about travel logistics. This is a holdover from my early trips, when I was naïve to the process and had a thick sheaf of paper tickets. More unknown and more to loose. Plus now I have semifashionable travel shirts that have seven pockets (I just inventoried), so I can keep all the stuff I’m worried about literally on my chest.
Wide-body jets have a unique suite of noises; the murmur of passengers, the muted roar of the engines, the rush of air turbulence over the fuselage, and a bunch of transient sounds: the toilets flush, a burst of audio, and the creak of seats. These sounds are a psychic cue: when I hear them I immediately enter the vibe going somewhere far away. Having conjured this historical pattern, I have to confess that this flight added a new sound: the baby alarm. The family seated to my right included an infant boy in a bassinet. He was on a three hour sleep and wake up and scream cycle. This was quite clear, even through my noise-cancelling headphones and earplugs. A different kind of time stamp, but it did prove to me that I got at least seven hours of sleep. Not bad at all.
Landing at Kingsford Smith Airport, Sydney in cloudy dawn light. Customs had been rearranged from last year, with a clever minimum of signage. More annoyance. I was eventually waved through, and officially entered Australia. A wait in the domestic terminal, which also provided fruit and coffee, and we were off to Darwin.
More of Australia from the air, cryptic beneath scattered clouds and haze. Over the channel country of inner New South Wales and Queensland; tan-brown earth and occasional saline lakes. I dozed. On my next look we had entered the subtropics; a greener landscape, with more clearing and farming than I had expected. A dozen bushfires added smoke to the sky. Descent into Darwin, a hairpin over the Tasman Sea, and the second of three flights was over.
Darwin Airport is at most six gates in size, but you can fly from here to Kununurra, not to mention Singapore and Denpasar (Bali). Another place to sit for a few hours. I left Paul sipping his Diet Coke and wandered the length of the terminal. All of five minutes journey. I went outside. Hot, but less muggy than Maryland. This didn’t seem proper, especially in the brighter than normal sunlight of the tropics. The sun is just a tad closer, it seems. The airport entries were decorated with recent Aboriginal art – a series of funeral poles, and murals on the undersides of the awnings. I smiled; back in Australia for sure, if I wasn’t already convinced by the weight of the money, the long broad Aussie accent, or the abundance of ginger beer.
Finally, Kununurra. A night landing, abrupt in the dark tropical night. A five minute ride to our hotel, a quick dinner, a rinse, and blessedly horizontal for ten hours. In summary, a few numbers from this leg:
3 flights
~17,100 miles
4 meals, plus 30% of a Krispy Kreme doughnut
15 time zones
41 hours between beds; 29 hours involving airplanes
But the departure: an emotional leaving from my sweetheart, lugging my bags onto BART, and then feeling the leading edge of this adventure stop looming and finally assert itself. This was the BART ride of the cyclists. After a couple stops, a Cyclist #1 boarded; he looked like a student based on his street clothes. He had a fairly new street bike, red with yellow tires, modern brakes and derailleur, plus the inevitable Crumpler messenger bag. A stop later he was joined by Cyclist #2 in full cycling mufti (bright yellow), with a very high end lime green bike: disk brakes, direct drive gears; and a fancier Timbuktu messenger bag. I could see cyclist # 1 eyeing him. Both bikes were aluminum-framed; watching them was like seeing a mismatched stereo photograph. I enjoyed this dichotomy for a couple stops, and then Cyclist #3 got on. Another aluminum frame, but there the parallel ended. This was the punk model. #3 was easily the oldest, wearing much worn jeans and a torn t-shirt, with a ratty Timbuktu messenger bag, all smelling strongly of cannabis. His one-speed, drum brake bike was scratched, dented, and plastered with decals. Parts of the frame were covered in plastic bags. Much of this had been spray-painted silver at some point. Multiple strata were evident. The bike’s handlebars were severely cut to at most 10 inches width, and covered with ratty silver duct tape. Cyclists #1 and #2 studied him, as did everyone else in olfactory range. The train filled up; all three bikes became jammed together. We vibrated together as a mass under the Bay into San Francisco. They untangled and pedaled their individual ways at the first stop; I can only imagine to three separate destinations.
Into the SFO International Terminal. The Qantas gates were at the far end: not a problem. Even less of a problem was check in; I’d done this online, so I literally walked up to the agent and handed in my bags. This left me feeling oddly anticlimactic; the anticipated stress of seating, luggage weight, and carry on density (mine is easily 200% of max) was removed. I waited for Paul, and we had a bite and decompressed before flight time.
Another Qantas 747-400, somewhat tired and worn on the inside. I was happy to have gotten an aisle seat, but when I got to it, I discovered that there was a metal box filling almost half of the space under the seat in front of me –where my feet were supposed to go. Bugger. I kicked it in frustration, but it was clearly part of the plane, so desisting seemed indicated. Some centered observation showed that I could fit myself pretty well, but I was annoyed. A bad travel omen? Too soon to tell.
A long take off roll, and all 438 of us headed out over the Pacific. I settled in, hoping for a cycle of naps and movies. I don’t sleep well on planes; they are such an orthopedic nightmare if one is two meters in length. These ridiculous long haul flights are worse, as blood pools in my legs and my contact points – heels, butt, and shins – are squeezed. Oh well, I suppose it beats three weeks on a boat to get to the other side of the Earth. I also carry background excitement and anxiety about travel logistics. This is a holdover from my early trips, when I was naïve to the process and had a thick sheaf of paper tickets. More unknown and more to loose. Plus now I have semifashionable travel shirts that have seven pockets (I just inventoried), so I can keep all the stuff I’m worried about literally on my chest.
Wide-body jets have a unique suite of noises; the murmur of passengers, the muted roar of the engines, the rush of air turbulence over the fuselage, and a bunch of transient sounds: the toilets flush, a burst of audio, and the creak of seats. These sounds are a psychic cue: when I hear them I immediately enter the vibe going somewhere far away. Having conjured this historical pattern, I have to confess that this flight added a new sound: the baby alarm. The family seated to my right included an infant boy in a bassinet. He was on a three hour sleep and wake up and scream cycle. This was quite clear, even through my noise-cancelling headphones and earplugs. A different kind of time stamp, but it did prove to me that I got at least seven hours of sleep. Not bad at all.
Landing at Kingsford Smith Airport, Sydney in cloudy dawn light. Customs had been rearranged from last year, with a clever minimum of signage. More annoyance. I was eventually waved through, and officially entered Australia. A wait in the domestic terminal, which also provided fruit and coffee, and we were off to Darwin.
More of Australia from the air, cryptic beneath scattered clouds and haze. Over the channel country of inner New South Wales and Queensland; tan-brown earth and occasional saline lakes. I dozed. On my next look we had entered the subtropics; a greener landscape, with more clearing and farming than I had expected. A dozen bushfires added smoke to the sky. Descent into Darwin, a hairpin over the Tasman Sea, and the second of three flights was over.
Darwin Airport is at most six gates in size, but you can fly from here to Kununurra, not to mention Singapore and Denpasar (Bali). Another place to sit for a few hours. I left Paul sipping his Diet Coke and wandered the length of the terminal. All of five minutes journey. I went outside. Hot, but less muggy than Maryland. This didn’t seem proper, especially in the brighter than normal sunlight of the tropics. The sun is just a tad closer, it seems. The airport entries were decorated with recent Aboriginal art – a series of funeral poles, and murals on the undersides of the awnings. I smiled; back in Australia for sure, if I wasn’t already convinced by the weight of the money, the long broad Aussie accent, or the abundance of ginger beer.
Finally, Kununurra. A night landing, abrupt in the dark tropical night. A five minute ride to our hotel, a quick dinner, a rinse, and blessedly horizontal for ten hours. In summary, a few numbers from this leg:
3 flights
~17,100 miles
4 meals, plus 30% of a Krispy Kreme doughnut
15 time zones
41 hours between beds; 29 hours involving airplanes
Thursday, June 17, 2010
Aus 15: The New Places
My last entry talked about the work of Australia Fifteen: the part that the grant covers. What about the fun? On Fifteen, a week of new places exploration happens first. I’m being joined for this leg by my frequent travel buddy Paul. He’s in the throes of getting a job in Perth (if I weren’t happy for him, strangulation would be in order). Last summer’s pleasure excursion, with both Paul and Louis, was in the central deserts of Australia: Uluru, Kata Tjuta, Kings Canyon, and Alice Springs. This year, we’ll be further north, in the subtropics. After a lot of investigation, we’ve settled on a bipartite itinerary: splitting our time between the Kimberley Region of Western Australia and Kakadu National Park in the Northern Territory. My initial urge was to just visit the Kimberley. Lots of desert and rocks – my kind of place. Then I realized that more than half of our waking time would be driving in order to glimpse the area’s highlights. This is normal in Outback Australia, but since this year’s field season will have a lot of driving, we’ve decided to focus on one spot: the Bungle Bungles Range, more recently named Purnululu National Park. The Bungle Bungles are my desert fix. It is one of those places that is strikingly and uniquely scenic, hard to get to, and largely unheard of outside of Australia. A rough analogy would be Grand Staircase-Escalante National Monument in the US. I’ve wanted to go there since first hearing its name in 1985. It features lots of exposed sedimentary rock, which has weathered into a variety of gorges and “beehive” structures. It just looks like a fun place to hike, poke around, and photography.
Getting the Bungle Bungles will be the usual multi-tube adventure. After flying from San Francisco to Sydney, we take a domestic jet to Darwin, the capital of the Northern Territory. After a couple hours to feel jet lag, we fly on a puddle jumper to Kununurra, in the East Kimberley. With a night of recovery, we rent a 4WD vehicle and make the five hour drive to the Bungle Bungles, and start camping.
Eventually we’ll fly back to Darwin, rent another vehicle, and head east to Kakadu National Park. Kakadu was Paul’s idea. It’s not arid, so it was off my radar screens. Like the Bungle Bungles, Kakadu is another gem largely unknown outside of Aus. It’s a huge expanse combining river plains that drain north to the Gulf of Carpentaria (lots of birds and crocodiles) and a southern sandstone escarpment that’s cut into dramatic canyons. It looks beautiful and lush – even in the dry season, when we’ll be there. In addition to these natural charms, Kakadu has been home to Aboriginal groups for at least 40,000 years. The park has several significant rock art sites. These are stylistically more elaborate and complex than the petroglyphs I’ve see in WA and the NT. As I wrote last summer, I’ve gradually become more attuned to Aboriginal Australia; the art, the places, and the people. Kakadu is an opportunity to further this osmotic process. When I read the park literature, I sense that visiting Kakadu is not going to a park; it’s visiting part of cultural homeland. The Aboriginal culture persistent has persisted enough that I sense it through the overprint of colonization. Or so it feels from pictures and words. We will see what ground truth is like.
Getting the Bungle Bungles will be the usual multi-tube adventure. After flying from San Francisco to Sydney, we take a domestic jet to Darwin, the capital of the Northern Territory. After a couple hours to feel jet lag, we fly on a puddle jumper to Kununurra, in the East Kimberley. With a night of recovery, we rent a 4WD vehicle and make the five hour drive to the Bungle Bungles, and start camping.
Eventually we’ll fly back to Darwin, rent another vehicle, and head east to Kakadu National Park. Kakadu was Paul’s idea. It’s not arid, so it was off my radar screens. Like the Bungle Bungles, Kakadu is another gem largely unknown outside of Aus. It’s a huge expanse combining river plains that drain north to the Gulf of Carpentaria (lots of birds and crocodiles) and a southern sandstone escarpment that’s cut into dramatic canyons. It looks beautiful and lush – even in the dry season, when we’ll be there. In addition to these natural charms, Kakadu has been home to Aboriginal groups for at least 40,000 years. The park has several significant rock art sites. These are stylistically more elaborate and complex than the petroglyphs I’ve see in WA and the NT. As I wrote last summer, I’ve gradually become more attuned to Aboriginal Australia; the art, the places, and the people. Kakadu is an opportunity to further this osmotic process. When I read the park literature, I sense that visiting Kakadu is not going to a park; it’s visiting part of cultural homeland. The Aboriginal culture persistent has persisted enough that I sense it through the overprint of colonization. Or so it feels from pictures and words. We will see what ground truth is like.
Saturday, June 12, 2010
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.
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.
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