Above: Chert and barite veins stand out as positive relief features in the 3.5 billion year old Dresser Formation in Western Australia. These veins represent fossilized remains of the hydrothermal feaders for the when active hydrothermal vents were driving hot spring activity in an Archean caldera.
Exploring ancient rocks in Western Australia
Above: Red kangaroo tracks in the sand of the Shaw River, Western Australia.
Below: Emu tracks in the sand of the Shaw River, Western Australia.
Above: Camel tracks in the sand of the Shaw River, Western Australia. These are wild camels that were released by the British Army after their experiment in using them in Western Australia.
Below: A controlled burn on one of the massive stations that we traveled through. These burns are done to knock down the native spinifex grass and allow grasses that are more favorable for cattle grazing to grow.
Above: A billabong (water hole) on the Shaw River.
Below: Accouterments in the Marble Bar, part of the Iron Clad Hotel, located in Mable Bar, Western Australia.
Above: When driving through Western Australia, a lot of the countryside passes by as one looks out the window.
Below: While not necessary, having gators while hiking through the back country makes dealing with the spinifex grass much more tolerable. The truly tough in the group (read: Tara Djokic) didn't bother with gators. For some, though, allergic reactions to the stabs from spinifex grass necessitated protection.
Above: They really should have done something about that hobo riding in the back of the 'Ute...
Above: One of the locals watches us as our caravan passes. (Red Kangaroo)
Below: Though not all of the places we stayed were as scenic, we had several beautiful places to camp on our trip. Here we were in a Eucalypt grove at the base of an outcrop packed with stromatolites.
Above: Looking down from the top of an outcrop onto one of our campsites. A ring of chairs is set up in anticipation of a camp fire and dinner served from the mess wagon at the back of the bus.
Below: The last standing 'sugar scoop' antenna. This is located at what was Satellite Earth Station Carnarvon, now part of the Carnarvon Space and Technology Museum. This station served as one of the means for communicating with Apollo astronauts.
Above: Massive 'road trains' involving up to four trailers being towed by one tractor. In this case it is an ore train, carrying iron ore to harbor. These truck and trailer combos were no joke.
Below: Termite mount whizzing by as we travel to the next location. These massive constructs were easily 2 meters high (~6 ft).
Above: Looking across the Shaw River. No water now, but clearly a massive amount of water moves through here when typhoons strike.
Above: "Traveling in a fried-out combie
On a hippie trail, head full of zombie"
Below: A new outback proverb - If you can't beat the spinifex grass, WEAR the spinifex grass.
Above: 'Stray animals...'
Below: The sun sets over the Indian Ocean at Port Hedland, Western Australia.
MAD EGG Lab was given the opportunity to join the Astrobiology Grand Tour, put on in July of 2018 by Professor Martin Van Kranendonk and organized by (soon to be Dr.) Erica Barlow with help from (soon to be Dr.) Tara Djokic, all of the University of New South Wales, Sydney, Australia.
This was a once-in-a-lifetime experience and amazing opportunity to visit so many sites that have outcrops that are significant for the study of the development of life on Earth from 3.5 Ga to 2.3 Ga and later, preserving rocks that bracket some of the earliest undisputed evidence for life on Earth to after the Great Oxidation Event of 2.45 Ga.
The Grand Tour started at the far southwestern tip of Australia in Perth, where we all loaded into a bus with a trailer that would serve as the mobile kitchen for the nearly 50 people participating, and joined by a truck hauling a trailer for all of our camping gear and suitcases. For us (Dr. Jeff Havig of the MAD EGG Lab and Dr. Trinity Hamilton of the Forge Lab) and several others this was a continuation of the Australasia Astrobiology meeting we attended at Rotorua on the north island of New Zealand and associated hot spring tour led by Professor Kathy Campbell of the University of Auckland. One benefit of this is that we had been able to adjust to the time shift from Minnesota to New Zealand (and crossing the international dateline) before tacking another four hour shift from NZ to Western Australia.
Here I will touch on some of the highlights of the trip, starting from modern and moving back in time.
Shark Bay: Modern living stromatolites
Turee Creek Group, ~2.35 Ga
Boundary Ridge: Great Oxidation Event - contact between the pre-GOE Boolegeeda Iron Formation (Hamersley Gp.) and the post-GOE Meteorite Bore Member (Turee Creek Gp.) - 2.45 Ga
Below: Professor Hamilton points to the very last layer of the Boolegeeda Iron Formation, with the geologic 'moment' of the GOE at 2.45 Ga captured just above.
Dale Gorge: Brockman Iron Formation (Hamersley Gp.) ~2.49 Ga
Above: Fine scale features are likely products of dewatering. Prof. Clark Johnson gave a short talk summarizing his recent iron isotope work on these units, and the conclusions of that work suggest that the banded Iron Formation (BIFs) that we see today are likely the products of deposition followed by a loss of water (dewatering) from compaction that resulted in a reduction of anywhere from 10:1 to 20:1 of original stratigraphic depth!
McRae Shale (~2.5 Ga): a 'whiff' of O2
Bee Gorge Member, Wittenoon Formation, ~2.56 Ga
Above: Bee Gorge Member impact horizon, exhibiting turbidite features resulting from tsunamis generated from an impactor striking the Earth. I am pointing at crossbedding generated from the initial tsunami. The Bee Gorge Member is a carbonate-siltstone unit deposited in a shallow ocean.
Tumbiana Formation of the Fortesque Group (~2.72 Ga)
Strelley Pool Formation, Trendall Locality Stromatolites (~3.35 Ga)
Above: Coniform stromatolites preserved in what was likely either an evaporitic basin or a shallow marine setting. These conical stromatolites were likely originally deposited as carbonate minerals and have been completely replaced with silica.
Apex Basalt (with Apex Chert) ~3.46 Ga
Dresser Formation: Buick locality stromatolites (~3.48 Ga)
Above: The black layer is made up of silicified microbial mats and stromatolites. The next layer up is a grey chert preserving domal stromatolites (see above my notebook). This unit represents some of the most convincing early evidence for life preserved in the rock record. The setting was likely a shallow marine environment.
Dresser Formation: Putative hot spring deposits in a caldera setting (~3.48 Ga)
Above: Feeder veins mark out the tracks of hydrothermal fluid supplying the hot spring activity in a volcanic caldera. The veins go from lower right to upper left in the image, with the main hydrothermal deposit the cliff forming unit cutting across the middle of the image at the top of the prominent ridge.