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Sand Cycles

This series of works reflect my time travel around Australia and my fascination with our ancient geological history, stripped of vegetation and exposed for all to see in our arid lands. These landscapes started with my desire to depict the arid landscapes I had explored as a kid while my father painted. As I travelled I realised that I was travelling through time, planning one trip to visit the major stages in the evolution of this ancient continent.

Australia is an ancient continent, many of its mountains eroded away by rain and ground down by glaciers over the eons into sand and pebbles that are moved around by water and wind. These sediments may then be buried again and converted by pressure and heat back into rock – siltstones, sandstones and conglomerates – before once again being liberated by water to wander across the landscape. It is a cyclic process taking place over billions of years.
Much of the arid landscape is now covered by loose sediments with a sparse cover of vegetation, interrupted by ranges, plateaus and gorges where sediments have been recast into rock and once again are eroding. In them you can see the history of the land.
I have attempted to accurately depict some of the most intriguing landscapes I have come across in my time travels. I am more liberal with my depicting the process of weathering and the colours and patterns it leaves behind.

My time travel started near Marble Bar, one of Australia’s hottest and most ancient places. Here I saw fossilised stromatolites laid down by cyanobacteria (blue-green algae) 3.45 billion years ago. Though it was not until 2.5 billion years ago that I started painting the consequences of the stromatalites in the Pilbara. It was once a large shallow sea, stained reddish-brown with suspended iron and surrounded by bare lifeless hills. The cyanobacteria flourished in the warm seas, generating vast quantities of oxygen which rusted the iron – precipitating the beds of iron-oxide which form the Banded Iron Formations revealed at Joffre Falls. Once the iron was used up the seas cleared, allowing the oxygen to escape to the atmosphere, turn the sky blue and enable life to move on to the land. This was the great oxygenation event.
My next visit was to the sandstones and conglomerates formed from sediments eroded 1,700 million years ago from some long lost place and deposited by meandering rivers in deep layers across the northern territory, remaining as the plateaus, escarpments and waterfalls characterising Kakadu (Nourlangie Rock) and Litchfield (Tjaynera Falls) National Parks.
Leaping forward to around 600 million years ago are sand and rocks washed from the then snow capped Petermann Mountains into an inland sea in the Amadeus Basin. The mountains are now mostly levelled. The sediments were compressed and buckled into sandstone and conglomerate, before being eroded once again, leaving two of Australia’s most iconic features behind – Uluru (Ayers Rock) and Kata Tjuta (The Olgas). On one face, Uluru has a wide grin – Ikari (smile cave – Uluru Laughing).
It is not far in space, but some 240 million years in time, to another part of the Amadeus Basin where remnants of 360 million year old sandstone plateaus are manifest as Chamber’s Pillar and Rainbow Valley (in part the Tafoni series). Perhaps, in part, formed by sediments eroded from Uluru, before being reformed into stone. Here laterisation (a process whereby underground iron oxide is dissolved by water and then drawn towards the surface by capillary action) has concentrated iron oxide into surface layers, giving a distinctive graduation from soft, bleached-white sandstone at the bottom of the cliffs to hard rusty, deep-red, iron-rich layers at the top. In places the weathering of sandstone rockfaces by water and osmosis has formed intricate three-dimensional patterns by mineral differentiation and erosion of softened rock – known as tafoni.

Close in time, but far in distance, erosion of the mountainous northern Kimberley has resulted in some of the most spectacular arid landscapes in Australia. Purnululu (Bungle Bungles) is a remnant from blankets of sand and gravel washed from the Kimberleys that filled the Ord Basin around 360 million years ago. Over 60 million years they were overlaid by sediments kilometers thick that compacted the sand into sandstone and the gravels into conglomerate. The overburden has long since been eroded away. To the south-east the sandstone has been weathered into domed “beehives”, with grey bands formed by cyanobacteria growing on the clay-bearing layers of sediments (Piccaninny Creek, Purululu View). To the west it is dominated by conglomerate which is more resistant to erosion and characterised by sheer cliffs and gorges up to 200m high (Purnululu Gorge 3).
As erosion liberates the pebbles and rocks (once again) from the conglomerate, they resume their journey downstream, carving intricate flowforms into the sandstone stream beds as they go (Purnululu Flowforms series).

As the Kimberleys eroded 360 million years ago, in the shallow seas around them on the margin of the Ord Basin a 1000km barrier reef formed, built up of limestone from the skeletons of corals, algae, cyanobacteria and sponges, interspersed with clams and the bodies of a variety of ancient bony-plated fish called placoderms. These were formed on the cusp of one of the world’s mass extinction episodes, which the placoderms did not survive, except for those bodies I clamber over. I wonder if we will survive the current mass extinction. .
The Lennard River has cut across this ancient reef and formed a deep gorge with permanent pools now inhabited by Freshwater Crocodiles and visited by Brolgas (Windjana Gorge). I am fascinated by the fantastic limestone forms, topped by razor sharp ridges (Geike Gorge).
130 million years ago I stop near near Broome where tidal currents deposited sands from some distant land in a shallow sea (Gantheaume Point), with the ripples frozen in time. This was the age of the dinosaurs who roamed these shores- I search for their footprints which are meant to be there though don’t find them. I find intricately carved rocks and deep caves instead. I am captivated by their rich colours, hollowed out cliffs and honeycombed crests.
I now step forward in time to 115 million years ago on another coast near Darwin in the Northern Territory, another place where sediments were deposited on the seabed to form sandstones. I wonder what sort of creatures inhabited this area. 110 million years ago the sea retreated, but now it is back eating away at the rock once formed in its depths.
The differential leaching of the iron oxides, combined with the layers of deposition, has resulted in a myriad of hues from yellows, through oranges, reds and browns to rich purples. Chemical leaching along fracture lines and around roots has bleached the rock pure white. Where frequently inundated the rock is honeycombed by worm holes. The addition of sea salts to this mix has resulted in an astounding variety of patterns and designs, it is the most beautifully patterned sandstone I have encountered (Sandstone and Salts series).

A lot of time was spent exploring these sandstone foreshores, washing sand off the rocky substrate as the tide receded to reveal astounding abstract patterns. To do them justice I would have liked to have had an exhibition by placing empty frames on the rocks.
I return to the reality of the present at Mission Beach on the east coast. This is a new beach, golden sands are enriched by basalt and patterned by erosion rivulets and coils of beachworms’ refuse (Mission Beach Sand-worms series). Though I don’t know how old the sand grains are, how many reincarnations as mountains they have already undergone, or what they will be in a few million years. While I have travelled back in time 3.45 billion years and seen the beginnings of life on earth I cannot see into the future,