A tour of deep time brings comfort in hard times


Canada’s Northwest Territories contain some of the world’s oldest known rocks.Credit: Sherry Galey/Getty

Notes from Deep Time: A Journey Through Our Past and Future Worlds Helen Gordon Profile (2021)

If there were ever a good time to think about deep time, it’s now. The COVID‑19 pandemic has unmoored us from the rhythms of the Before Times and left us scrambling for temporal perspective as the days blur. In such a situation, geology offers a mental anchor — the knowledge that rocks represent untold eons during which animals, plants and even viruses arose, evolved and died.

From my COVID-19-confined home in Colorado, I can see mineshafts puncturing the mountainsides, tapping into deposits of gold and other minerals that began to form around 75 million years ago. Their story began when one great plate of Earth’s crust shoved beneath another in what is now western North America, melting rocks into magma that ferried elements towards the surface. The trials of these rocks — heat, pressure, violence — put the events of the past year into broad context.

So do many other locations venerated for their contributions to geological knowledge. Take Siccar Point, a cliff in southeastern Scotland where eighteenth-century geologist James Hutton saw two rock types jammed against one another — and recognized that they represented enormously different time periods, and that long, uniform processes must have shaped Earth. Or consider the fossil-rich cliffs of Lyme Regis, on England’s south coast, where the mineralized bodies of ammonites and other long-vanished creatures collected by fossil hunters such as Mary Anning in the nineteenth century forced us to take the long view.

In Notes from Deep Time, writer Helen Gordon explores many of these celebrated spots. Facing big changes in her personal life, she sets out to ground herself in the story of landscapes across Europe and North America. The result is a whirlwind tour of our planet’s deep past and far future.

Geology, she shows, offers an odyssey through unfathomable amounts of time. Touch a fragment of an ancient meteorite, and you’re feeling metal that coalesced around the newborn Sun more than 4.5 billion years ago. Visit Canada’s Northwest Territories, and you can hike on a chunk of Earth’s ancient crust dating back four billion years.

Siccar Point in Berwickshire, Scotland

‘Hutton’s Unconformity’, where two rocks of different ages meet at Siccar Point, Scotland.Credit: Mark Godden/Shutterstock

Time capsules

That’s the deep-time perspective Gordon craves. And she crams a lot in. In Copenhagen, she visits a repository of ice cores, precious frozen columns that have been carefully drilled from ice sheets in Greenland and elsewhere. They are time capsules containing bubbles of prehistoric air and layers of pollutants such as lead — from which scientists can deduce the amounts of carbon dioxide in the atmosphere in the past, and unravel the history of metal-smelting going back to the ancient Greeks.

Elsewhere, Gordon explores the urban geology of London and Naples, Italy, where the marbles, limestones and granites that make up major buildings are a portal to many past worlds. (As well as to other parts of our current one: the bust of former South African president Nelson Mandela on London’s South Bank sits on a two-billion-year-old piece of igneous rock, a shimmering black stone originally found near Pretoria.)

Gordon wraps in the fan favourites: eruptions, dinosaurs and earthquakes. A visit to the volcano Campi Flegrei, near Naples, is less a meditation on deep time and more an analysis of how scientists monitor active volcanoes and work with local officials to try to keep the fire-mountains from killing anyone. A trip to Utah lumps a visit to a famed bone bed with ruminations on the sale of fossils, and dinosaurs’ enduring appeal to children. And a drive around southern California with seismologists explores questions of just how long we need to study a geological fault, such as the San Andreas, before we can forecast its behaviour.

It’s hard not to compare this collage of jaunts with accounts such as Marcia Bjornerud’s 2018 book Timefulness, which synthesizes ideas of deep time in a more holistic way. And Gordon does not explore insights from non-Western cultures, such as Aboriginal Australians’ perspectives on deep time and — apart from one or two nods — the many palaeontological and geological discoveries coming out of China, India and other places across Asia.

Ultimately, however, she succeeds in grounding our existence firmly in the context of geological time. This is especially apparent in the ongoing debate about whether humanity has entered a new geological epoch, the Anthropocene.

Clearly, Homo sapiens has altered the planet. But how and when did this become blindingly obvious? Was it the slow adoption of agriculture some 10,000 years ago? The rise of industrialism in the late eighteenth century? The past century’s acceleration of fossil-fuel burning? The imprint of nuclear-bomb fallout in the world’s sediments, starting with the terrible dawn of the Trinity test in 1945? Scientists debate this in extraordinary detail, as if the particulars of how we affect the planet are less important than the fact that we do.

Looking to the future, Gordon skips past the planet’s imminent climate reckoning, and instead visits the planned nuclear-waste repository in Olkiluoto, Finland. It is meant to hold radioactive debris from nuclear-power plants safely for 100,000 years — the ultimate geological disposal. Deep-time rocks can at least help to isolate humanity’s biggest messes.

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