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

Above: Looking down on the stromatolites, here forming linear features due the movement of tidal water. Unfortunately we were there at high tide, and were thus not able to see the stromatolites from the side. The high salinity of the water in the bay is thought to exclude most grazers, protecting the stromatolites from destruction.
Above: A peaceful morning on the beach at the Hamelin Pool area of Shark Bay on the coast of Western Australia. Lithified microbialites were at the beach where we visited the stromatolite site.
Below: I am holding a tear up clast of microbialite that was on the beach. These microbialites are made up of small clasts (clay to sand sized) that are held together by the EPS (extra polymeric substance) made by the microbial community.

Turee Creek Group, ~2.35 Ga

Right: A stromatolite from near the base of the formation, with red chert (SiO2) weathering out from the blue-grey carbonate.
Left: A 'before' (bottom) and 'after' (top) image of tightly packed stromatolites where the top has all of the carbonate minerals dissolved, leaving the more resistant chert.
Right: The group dispursing to explore the basal Turee Creek Gp. outcrop after Erica Barlow gave a short description of the exciting suite of microfossils that she has discovered in the black cherts found interbedded in the carbonate rocks. Her paper is now out, and you should check it out!
​https://doi.org/10.1111/gbi.12304

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

Left: A large rhyolitic dropstone weathering out of the Meteorite Bore Member shale. This cobble was dropped by a glacier that formed right after the GOE. The shale deformation from the cobble settling into it left a cupped depression. There were several small layers of diamictite deposited by a glacier that likely was extended over a shallow ocean much like the shelfs of Antarctica today.
Right: The transition from a reducing atmosphere recorded in the Boolegeeda Iron Formation (bottom) to an oxic atmosphere recorded in the Meterorite Bore Member shale (middle and upper units) exposed in the Boundary Ridge outcrop. The lower units are magnetic, indicating the presence of reduced iron, while the upper iron-rich shales are not magnetic, indicating the presence of Fe(III).
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!
Above: The 2.49 Ga Brockman Iron Formation of the Dale's Gorge BIFs of the Hamersley Gp.
Above: A pool in the bottom of Dale Gorge where spring water continues to cut down through the BIFs.

McRae Shale (~2.5 Ga): a 'whiff' of O2

Left: A massive road cut exposes the same units that were studied in Anbar et al. (2007), the first paper to suggest geochemical evidence for a 'whiff' of oxygen in the atmosphere prior to the GOE.
Right: I am touching the equivalent portion of the section where the start of the 'whiff' occurred. The shale here had pyrite bearing shales with interbedded cherts. As the pyrites weather they generate iron oxides (staining the rock red) and sulfate minerals (precipitated as gypsum, staining the rocks white).

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.
Above: Grand Tour participants looking at the outcrop where the impact horizon is exposed.
Left: Professor Martin Van Kranendonk pointing to the impact horizon. Lenses and layers of impact spherules were located throughout the deposit.

Tumbiana Formation of the Fortesque Group (~2.72 Ga)

Above: Large domal stromatolites weathering out of the surface of the Tumbiana Fm. The Tumbiana Fm. in the Fortesque Group (lowest portion of the Mount Bruce Supergroup) is thought to have been deposited in a massive freshwater lake that formed in a rifting zone, with abundant subaerial volcanism producing lava flows as well as accretionary lapilli tuffs (Below).
Above: Exposure of a microbial mat texture.
Below: Tara Djokic of the UNSW showing the right amount of excitement and enthusiasm for the stromatolites.

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.
Above: What is likely a fault separation (cutting through the middle center, top to bottom) defined whether the conical stromatolite unit was preserved as a carbonate (left) or as silica (right).
Right: Closeup of a conical stromatolite preserved as silica. This site has been the source of controversy, with competing hypotheses suggesting an abiotic mode of formation for the conical stromatolite features.

Apex Basalt (with Apex Chert) ~3.46 Ga

Above: A large pile of pillow basalts (deposited subaqueously). The extreme quality to which these pillow basalts were preserved after almost 3.5 billion years of tectonics and burial was mind boggling for me.
Above: Bubble tracks are preserved next to the quench zone of these pillows.
Below: A heart shape weathering out of a basalt pillow. Apex Basalt sending you some love from 3.46 billion years ago.
Above: The setting for the Schopf microfossils from the Apex Chert. The dike to the right is the hydrothermal source, with feeder dykes between it and the up-column chert unit where Schopf collected his samples. Up strat column is from right to left. The cherts are all intruding basalt flows.
Right: Brecciated cherts from the Apex Chert. The brecciation attests to the explosive eruptive forces present at the time of emplacement. Controversy from the Schopf work (Schopf and Packer, 1987) comes from inconsistencies in the reported versus actual collection sites, such that the Schopf sites were actually of brecciated cherts, indicating the collection site was not the actual source site for the preserved putative microfossils.

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.
Left: Microbialites preserved in the Dresser Fm. Buick Locale. The microbialites form the Black unit that has been stained red from iron oxides.
Right: Ripple marks preserved in the Buick Locale provide direct evidence that this was a higher energy 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.
Left: Tara Djokic (far right in image) describing the geological setting of the site that was the source of her paper reinterpreting previously described marine Dresser Fm. units as actually subaerial hot spring deposits. Check out her cool work: 
https://www.nature.com/articles/ncomms15263
Left: Putative microbialites from the edge of a hot spring. Pool edge boundary seemed to be along the bottom of this image, with microbialites/stromatolite growing from the edge and into what would have been the hot spring pool.