It's before dawn and we are thundering along the Arnhem Highway east from Darwin with Donna, a Kiwi, at the wheel, average speed 130km/h. The inky southern sky is ablaze with stars, matching the blinding lights of the snaking road trains that she swings past. As the short-lived sunrise turns the horizon from pink to yellow, clouds of smoke from the seasonal burn-off drift across the road. Then we cross the crocodile-infested Cahill Creek and after over three hours on the road, we enter Arnhem Land.
Declared a Aboriginal reserve in 1931, this land is where outsiders need permits to enter, where tribal law holds sway for 16,000 Aborigines and where exquisite animal drawings are created. Few tour groups are allowed in, so even a day-trip feels like gold-dust (or uranium, given the mine we passed on the way) – though less so when I learn that Boris Johnson and his family preceded me by days.
Over the years, I have seen the art of the world's oldest living culture in the Red Centre, in Kakadu National Park, in the Tiwi Islands and out in Western Australia's Kimberley region. Now, as the Royal Academy launches an exhibition of Australian art that covers the period from 1800 to the present day, I'm curious to see the rather more ancient rock art of this "stone country", protected for aeons by its natural barriers of escarpment, rivers and crocs, as well as the transition of these same images to portable, saleable form. In a nutshell, the intimate indigenous connection between art and landscape.
Extreme is not the word for the entire Top End (the north of the Northern Territory) that regularly sees cyclones and experiences the greatest number of lightning strikes in the world. These happen during five months of Australia's heaviest rainfall – the infamous "wet" – extending the country's largest floodplain to a vast 10,000sq km (half the size of Wales). Dubiously brought to world fame by Crocodile Dundee in 1989, this untamed region was also the subject of an infinitely more subtle movie, Ten Canoes (2006), depicting aboriginal story-telling and hunting with humour and insight.
Rapidly the scenery morphs from monotonous stringybark and woollybutt trees into patches of lush green and savannah dotted with the odd car wreck and wild horses. Towering above us comes a sculptural outcrop where eagles swoop and, in one elevated cleft of rock, projecting spears remain from target practise long ago.
As the dirt road winds past uninspired government-financed bungalows into Gunbalanya (also called Oenpelli), Donna warns us, "We're on Arnhem time now," meaning no time, as Aborigines use no system of measurement, either for time or distance.
Our local Kunwinjku guide is Eleziah, long-limbed, baseball-hatted and softly-spoken. Soon, 16 of us are struggling behind him up Injalak Hill, clambering between, over and under huge sandstone boulders. Eventually we stop at an immense overhang that turns out to be a massive art gallery covered in countless overlapping images of crocs, spiny anteaters, turtles, fish, goannas, wallabies and snakes, all visual records of nearby food sources or prompts for local legends. Like Kakadu, the more graphic ones show inner organs and bone structures, but all are in natural pigments of ochres, white and black.
Haltingly, Eleziah explains some of the symbolism in convoluted moral tales going back to the Dreaming, the aboriginal creation of the world. "If people don't paint on rocks we have no stories," he says. Then he is off at a tangent describing the two-month male initiation ceremony at nearby Goose Egg Dreaming Hill, their intricate body-paint, dancing and how a totem is chosen for each boy. "My clan totem is the eagle, but I like emus," he adds earnestly.
As we climb further, almost every turn reveals more drawings, some more elaborate than others. At one point we're lead to a shadowy burial site. When Eleziah points out a skull and bones tucked between boulders, some of us express surprise at the lack of taboo, yet his response is simple: "Spirits gone long time ago." At last, from a magnificent viewpoint near the summit, we look down over the plain below where a billabong, or waterhole ("Good turtle hunt," smiles Eleziah, who is slowly warming up) fronts Gunbalanya's art centre. During the wet, Eleziah tells us, the entire area floods and the only access is by plane.
Seated on a ledge away from the group, I get a strong sense of the spiritual significance and age of this landmark, feel the breeze, hear the whistling kites, watch drifting leaves and imagine how, until only about 60 years ago, Eleziah's grandparents were still nomadic, living in temporary paperbark huts as they roamed, hunted and gathered.
Later, at the professionally run Injalak art centre, where screenprints and works on paper and bark are produced and displayed, I watch male artists carefully trace those same X-ray style animals that we have seen on the hill, while women sit in the shade splitting lengths of pandanus to dry, dye then weave into gorgeous baskets. Externally, Kunwinjku lives may be transformed, but it seems their language, beliefs and rituals are perfectly intact.
Sunsets are another sublime feature of landscapes here. That night I revel in the gaudy yellows, vermilions, purples and scarlets painted above the horizon at Wildman Wilderness Lodge, in Mary River National Park. Early next morning I wake to see wallabies bouncing past my deck. One balances on his back legs, raises his paws, stops and watches me inquisitively, then hops off across the overgrown air-strip, making a close shave with a termite mound. Then I too am off, this time across the alluvial plain.
Soft light filters through paperbark trees as Scottie, our guide, steers us through this fast-shrinking billabong, the chug of the motor shattering the idyll by sending cockatoos screeching into the branches and flocks of whistling ducks and magpie geese flapping skywards from the bank. "Watch out for the big arse – he's about five metres along. Should be out sunning himself to raise his body temperature. We've got more crocs here than anywhere else in the world," Scottie says, then announces with some pride. "Hermès buys skins directly from the farms here!"
The day before I arrived in the Northern Territory, a local man had met his maker in the jaws of a croc as he recklessly went for a dip in Mary River. "Stupid drunk," was the typical comment from his countrymen, showing zero sympathy. Speech gets truncated up here, maybe due to the heat, a style you soon adopt, yep, learning about the wet, the dry and distinguishing pretty fast between the aggressive "saltie" and less harmful "freshie", also grasping the elliptical meaning of "handbag": croc (as in Hermès).
Around us the water is carpeted in water-lilies, their petals unfolding to greet the sun. "I love this place – beauty above with evil lurking below," says Scottie. Suddenly a huge bird takes off and wings gracefully past us – a Jabiru, native to these parts. Pandanus and ficus alternate with mangroves, then comes a glorious spread of pink lotuses, favourite bush tucker from stalk to seed, which we sample. Beyond, wading through the water, is a family of buffalo, surreal reminders of early British settlers who brought them from Asia to serve as fodder for passing ships.
Back on the road, I head for Nitmiluk National Park, about 340km south-east of Darwin. Colossal termite mounds, ancient cycads and outback pit-stops end at the town of Katherine where a turnoff leads to the rugged plateau and park. Here, deep in Jawoyn country, the Katherine River has slashed 13 deep gorges through the fissured sandstone, creating another of Australia's geological wonders: raw, elemental and extending about 16km.
In 2006, a phenomenally rich cache of paintings was discovered in a far-flung "rock cathedral", proving that Jawoyn culture has existed for 45,000 years. Although the site is still being researched, by next year exclusive helicopter access will be organised by the newly opened Cicada Lodge. Planted lightly on stilts beside the gorge, the slick hotel is Aborigine-owned, like the entire park, and allows me to stay in incongruous comfort and style.
Although the Jawoyn people still hunt and fish inside the park, named Nitmiluk after the "nit nit" sound of cicadas, today they live in communities on the perimeter, so I feel privileged to meet a group of them for an informal introduction to their customs, food and art. Skinning a roasted kangaroo tail (fatty and sinewy), Terence tells us: "One day you guys can have a go". I'm not so sure about that. Speaking fluent English and kitted out in park uniforms, superficially they seem far more Westernised than the Kunwinjku of Arnhem Land, yet they are still imbued with art, traditions and Dreamtime stories as well as being primed on hunting and gathering.
For three days I am mesmerised by the scale and diverse vegetation of the gorges: seen from a trail high above; from higher up on a helicopter tour that reveals the geological forms; from a dinner cruise when the setting sun sets jagged crevices and strata aglow; and, best of all, from an early morning canoe trip.
After gliding tranquilly up the deserted first gorge full of bird chatter and aromas of the bush, I stop at a bank to slide into the water. Salties? Not here apparently, though I am wary. As I float, I think of Bolung, the rainbow serpent believed to inhabit the second gorge, of the Jawoyn's five seasons, far more precise than mere wet and dry, and of the 1,650 million years that these rocks have existed – older even than vertebrates, so no fossils exist. Above all, I think of the indigenous artists who, millennia after millennia, mixed their paints and drew animals on stone – the original landscape art.
Fiona Dunlop travelled as a guest of Tourism Northern Territory and WEXAS Travel (020-7838 5892; wexas.com).
The tour operator has an eight-day Top End package from £2,560pp, including flights with Malaysia Airlines (0871 423 9090; malaysiaairlines.com) to Darwin, car hire, some meals, excrusions and accommodation at the Mantra Esplanade in Darwin, the Wildman Wilderness Lodge and Cicada Lodge.
Tourism Northern Territory: australiasoutback.co.uk
The Australia exhibition at the Royal Academy, Burlington House Piccadilly, London W1J 0BD runs from 21 September to 8 December (020-7300 8027; royalacademy.org.uk; admission £14 )
"Australia: Shifting Sands", a festival of Australian indigenous cinema at London's BFI Southbank, will screen Ten Canoes on 29 September and 6 October (020-7928 3232; bfi.org.uk).