The little animal had been acting unsettled since late yesterday, browsing little and stopping for long moments to listen and sniff the air, its bright black eyes darting to every motion in the dim under story below the high canopy of what other animals many years later would call sequoia, redcedar and Douglas-fir.
Despite having lived beneath the same huge tree for all the little years since the animal was littered in a burrow under a dawn redwood near the edge of what was now a clearing and small pond, the familiar forest lent it no confidence now. In fact, if it could have comprehended the notion of emotions, it would have felt frightened since waking late in the long afternoon. The epigaulus dimly comprehended that the wind and the heat and the smells in the air were not…right…but knew intimately the movements and rhythms of the forest. And for a day these had been strange, too; disjunctive, unusual stillness broken by the frantic rushing passage of animals, many of which stank of fear and hurt, many of which were unfamiliar to the little rodent that knew every bird and animal, predator and competitor and insignificant, that lived and passed within its circumscribed world.
The epigaulus bolted a fennel top and sat up on its haunches, cocking its odd-looking horned muzzle to try and catch a hint more of the strange, metallic smell. The odd smoky haze seemed denser, the summer heat more intense, and now it could hear a vaguely familiar sound; a faint hissing and snapping.From the shallow depths of its rodent brain the epigaulus dredged a memory connected with that sound: heat, smoke, sudden flame as the forest burned. Last summer – in fact, every summer – part of the animal’s forest had burned. The fire was common and dangerous but not devastating; a connection the little animal had no way of understanding. In the epigaulus’ first summer this very stand had burned over, the rodent huddled safely with its littermates in their burrow. Still nervous but now less panicked the epigaulus retreated towards its burrow, stopping to browse a less-withered plant in its slow progress. Its deep hole under the big redcedar would be cool and dim in even the biggest fire it had ever known. It scuttled down below the ground as the hissing grew to a crackling, and then a roar.
Huddled in its burrow the little rodent didn’t see the first immense wave of fire rush overhead, driven by the shrieking wind and explosive heat.
It felt the air go from cool to warm to tinder hot. But deep in the darkness it had no way to understand the horrifying rolling hill of smoking black and flowing crimson lava that pushed through the forest from the east. The front of the flow shed black gravel and small boulders as the living wall of rock moved down the low slope toward the pond. Small trees and brush were just buried; larger trees engulfed ten feet or more above the ground. The monstrous creeping, burning thing stretched from horizon to horizon, moving hungrily to the west.
The little pond and marsh exploded into steam as hot lava chilled and shattered in the waters. Within the flow steam blasts continued from the entombed water; columns of bubbled and shattered rock were tooled into the cooling flow. From either side new lobes of magma burst from the clinkery lava front, racing up the short slope to the redcedar, enveloping it with thousand-degree heat. The trunk charred instantly; the crown candling violently as the little animal below thrashed and died a quick and violent death.
The tree itself, however, did not. The crown burnt down to ash within minutes. But within the flow the lack of oxygen slowed combustion to a gradual charring that itself slowed as the colder ground drew heat down from the lava.
More than a foot burned away around the outside of the cedar; but the old tree was large enough to absorb the loss and remain in place. Slowly the rock cooled around the immense stump, as water hissed and steamed out of the rock and the wood baked hard and dry within the dark basalt.The tree, the epigaulus, the forest and the pond and every living thing died in one day in August fifteen million years ago, where now in four minutes drivers can zip past the sign that reads: “Exit 10, West Linn”.
The sleek black Columbia River Basalt is perhaps the best known rock type in Oregon and southern Washington. It forms the walls of the monumental Columbia Gorge and underlies the Portland West Hills and the high desert plateau of north central Oregon. Erupted from a swarm of linear fissures along the modern Oregon-Idaho-Washington border in Miocene and Pliocene time, more than 170,000 cubic kilometers of basalt flowed out over central and western Oregon and southeastern Washington.
No human eye ever saw these flows, but they and the others like them – called “large igneous provinces” – are the most massive volcanic events in Earth history. They must have been terrifying to the Miocene animals; a wall of liquid rock hundreds of miles wide, burning and burying everything before it. Hundred of times. Every flow leaving a smoking, glassy desert across the Northwest, pocked by the stubs of trees and islands of vegetation
(what Hawaiians call “kipukas”) left in the weird hollows between strands of the flow or on the highest ground.
There are several mysteries that still cling to the immense igneous provinces. We're not sure exactly how they form; some geologists associate them with "hot spots" or "mantle plumes"; immense jets of hot magma emerging from deep within the Earth's mantle. Several people have noted the coincidence of these immense eruptions and mass extinctions: the "Siberian Traps" and the immense dying at the end of the Paleozoic; the "Deccan Traps" with the smaller but better known "KT Extinction" (i.e. "what killed the dinosaurs")
Little remains of the world destroyed in these eruptions. But along the I-205 roadcut just southwest of West Linn, half of the old redcedar stump remains in the wall of rock ripped open for the highway.
Amazingly enough, the wood is not petrified but remains only partly silicified. It's still wood. Light a match to it, it will burn a smoke that filled the Oregon sky many billions of lifetimes before.
The old stump is deserted now, just an unnoticed bit of rock wall along a busy highway. The roadside is littered; empty Cheetos bags and fast food wrappers whirl up in the hot diesel wind against the black rock of the Miocene. The ancient forest, the quiet of that ancient landscape, is hard to imagine standing along the edge of the traffic's hiss and rumble.
And yet...scramble up the weedy slope, duck into the low aperture, and you can recognise the vestige of that fading flame, hold in your hands wood that grew living in the warm soil of an Oregon that vanished fifteen million years ago.
