by Lauren Fuge
I’m hiking down a tributary of Arkaroola Creek, right in the middle of Cryogenian Period. Above me the winter sun glares down, and beneath me lies 700-million-year-old glacial tillite: a jumbled mix of lavender, reddish purple and pastel grey rock, studded with ice-scoured pebbles and boulders dropped by glaciers during the first Snowball Earth.
I’m just outside Vulkathunha-Gammon Ranges National Park, 200 km north of Enorama Creek but along the same spine of mountains. The landscape tells the same story of deep time. Some kilometres back I passed a hilltop capped with buff-coloured rock that was once an ancient reef, home to unusual sponge-like structures that emerged after the great melt 650 million years ago and may, as a small sign quietly notes, be among the earliest signs of multicellular life on Earth. Now, I’m walking on tillite that appears to flow down the creek in a series of frozen cascades. The region is once again transformed today – both ice and shallow sea have vanished, replaced by drought-gripped rock and red dirt. I slip between the precious shade of shrivelled red gums; the black eyes of Sturt’s desert peas blink at me; algae clings to the surface of shrunken waterholes.
I climb out of the creek and enter a moonscape of volcanic basalt, formed 830 million years ago when the continents tore apart. As I pick my way over crumbled chunks of rock mottled with green and orange, I’m travelling backwards through time, towards the beginning of the Neoproterzoic Era. The millennia speed up in my head and the planet reveals its restlessness: rocks move as though they have tides; mountains rise and fall like breaths. Reading the landscape through time reveals not just its age, but the threads that make up the vast story of its history.
“I don’t think any of us really understand what a billion years means,” Marcia Bjornerud tells me later, in a video call across time and space, oceans and seasons. “But little by little, you start filling in geologic time with stories, and I think that’s where we will understand.”
Bjornerud is a professor of geosciences at Lawrence University in Wisconsin, in the US, where she studies rock formation and mountain building. She’s also the author of a slim, powerful book called Timefulness: How thinking like a geologist can help save the world. In our conversation, she mentions two distinct Greek words for time: chronos, which is the straightforward measurement of seconds, minutes and hours, and kairos, which is “time within a narrative”.
“That’s what really makes geological thinking different,” Bjornerud says. “We do want to quantify time, but the power of geology has been to recreate these narratives of earlier ecosystems and tectonic events on Earth. That’s where you start developing a sense of how long a billion years is.”
Reading the land in four dimensions can give us a consciousness of what she calls timefulness: a “clear-eyed view of our place in time, both the past that came long before us and the future that will elapse without us”.
It’s important to understand because we too live in geologic time: “We’re part of this continuum – we have deep roots evolutionarily in the tree of life.”
As I walk the remnants of vanished worlds in Arkaroola Creek, where the ebbs and flows of the landscape are visible, I’m keenly aware of my own deep roots in the Earth – as an organism not separate from or above the rest of nature but inextricably linked to the ancient, almost alien animals that teemed in the shallow seas of the Flinders.
Geology confirms how deeply we are bound to the planet itself. As writer Robert Macfarlane describes in his epic work of literary non-fiction Underland: A deep time journey, humans are in fact part mineral beings: “Our teeth are reefs, our bones are stones – and there is a geology of the body as well as of the land. It is mineralisation – the ability to convert calcium into bone – that allows us to walk upright, to be vertebrate, to fashion the skulls that shield our brains.”
With this knowledge in my minerally fortified mind, the boundaries between living and non-living begin to blur; the illusion of separation breaks down.
“Dazzled by our own creations,” Bjornerud writes, “we have forgotten that we are wholly embedded in a much older, more powerful world whose constancy we take for granted.”
Standing on the rocks and gazing back down into the Earth’s history, I wonder what the enormity of time can teach us about the planet’s future.
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Originally published by Cosmos as Time travel and tipping points
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