But the Wheel is not merely the upraised edge of one tectonic plate or another. It is not a wrinkle. It is itself an entire plate, upended.
A tiny plate, albeit. Most tectonic plates are much, much bigger. There are seven so-called major plates—the Pacific Plate, the Indo–Australia Plate, the Antarctic Plate, and so on—and each of them is thousands of kilometres wide or long. Then there are about ten minor plates scattered between the larger ones, and finally a dozen or so micro plates squeezed between yet again. But even those plates labelled as micro are usually still pretty big, at least several hundred kilometres from side to side.
But the Wheel plate—in its original horizontal form—is thought to have been only about sixty kilometres across. Just sixty. It was the merest flake of a thing, floating light as a leaf upon the hot magma underbelly that is the world’s innards.
This was about two hundred million years ago. At the time, the Wheel plate formed part of the ocean floor somewhere to the south of modern-day Australia. And, of course, it was anything but a leaf. Sixty kilometres wide and roughly circular in shape, it was also about sixteen kilometres thick (average for tectonic plates) and, made of the most common stone in the world, a tough, dense basalt, it would have weighed billions of tonnes.
But the Wheel was also positioned between two much vaster plates, the mighty Indo-Australian Plate, and the equally mighty Antarctic Plate, each of them about sixty million square kilometres in size, dwarfing the Wheel by a factor of tens of thousands. Nor were these two great plates standing still; both were in motion, which made for a complicated life for the Wheel, caught in the middle.
At least the two bigger plates were not butting heads directly, which would have simply crushed the Wheel to nothing in between. Instead, the Antarctic Plate was marching eastwards across the bottom of the Indo-Australian Plate, while the Indo-Australian was in fact pulling away from the Antarctic to head north. This made for relative calm along most of the boundary, but the Wheel was trapped in an odd north–south kink between the plates, and there the forces involved were much more abrasive, as unimaginable weights of rock jammed and contorted awkwardly against other unimaginable weights of rock.
For many millions of years, the Wheel was simply bruised and spun about by all this shifting and straining. But about seventy million years ago (in fact, at the same time that the Himalayas were starting to rise, caused by the Indo-Australian Plate, far away at its northern rim, beginning to crash violently into the Eurasian Plate), by outlandish chance something different happened, something that has never happened anywhere else on Earth.
The Wheel caught on underlying and overlaying corners of the Indo-Australian and Antarctic plates, and, as the bigger formations kept pushing by one another, the tiny flake began to rotate on its vertical, rather than horizontal, axis. Its western edge dipped down, its eastern edge reared up.
It was not an instantaneous process, of course. It took millions of years, but gradually the entire Wheel plate was tipped onto its side, to become in essence an upright disk, a giant coin standing on its rim, sixty kilometres in diameter and sixteen kilometres thick.
Or, as it could be called, a wheel. (Though of course the mountain was given its strange name for entirely different historical reasons.)
But sixty kilometres? Was the newly raised Wheel really ever that high?
No. Nowhere near that. For a start, the lower edge of the plate had sunk into the underlying mantle even as the upper edge rose, so that only one side of the disk was reared upwards—reaching at best thirty kilometres high. But that was thirty kilometres above the ocean floor, not above sea level. As the Southern Ocean was then and still is now about four thousand metres deep, that leaves an ancient height for the Wheel of twenty-six kilometres at the utmost, before time and erosion began their work.
Nor did the great disc rise cleanly and in one piece; the stresses involved were literally Earth-shattering, and great fragments of the Wheel broke away, or sheared off in cataclysmic avalanches, as the inexorable rotation continued. This fact would be more obvious if the ocean around the Wheel did not hide the vast litter of rock debris that lies about the great mountain’s feet, as well as drowning the great chasms that the rotation tore open here and there.
(The only such piece of debris visible above sea level today is, of course, Theodolite Isle. It is thought to be a particularly large fragment of the plate that broke off quite early in the rotation process, then itself bizarrely upthrust.)
In the end, of the ancient plate that began its life sixty kilometres across and sixteen thick, all that remains today is an upraised rim that lofts twenty-five kilometres above sea level, and which extends forty-five kilometres north to south, and twelve kilometres east to west. And the plate is not ‘flat’ anymore. The torsion acted upon it by the Indo-Australian and Antarctic giants bent the north and south ends of the Wheel in a westward direction, resulting in the familiar arc the mountain describes today.
Nor did the plate ever become entirely upright. It was left with a lean to the east at an angle of about seven degrees. Hence the inward- and outward-tilting slabs of the West and East faces.
So that’s one puzzle solved.
This entire process is thought to have taken about twenty million years, after which … well, nothing much. After so much upheaval, the Wheel was finally released by the grip that had upended it, and in the fifty million years since has been left in relative peace. The two bigger plates continue their movements, but the Wheel, now lubricated by the ring of its own debris, has slid smoothly between them. Which is not to say that the region is utterly stable. There is evidence of periodic earthquake activity through the millennia. But in the modern era there have been amazingly few tremors detected, and those only minor.
But still, how do those towering cliffs of basalt endure? Even without earthquakes, they should, as mentioned, be crumbling under their own weight. While basalt is indeed considered a hard, enduring rock, other rocks like granite are stronger, and yet no granite monolith has ever risen beyond a few thousand metres in height without eventually collapsing. How does the Wheel manage it?
Well, it’s all about the type of basalt. Basalt, an igneous rock, is typically made up largely of minerals like quartz and feldspar, combined with a smaller mix of other minerals such as iron and titanium. Its actual hardness will rely much on the precise ratios of these various minerals within the rock.
Geologists have thus studied the basalt of the Wheel with interest. Intriguingly, they have discovered unusually high ratios of titanium there, but more importantly they have detected the trace presence of a very rare mineral that is normally only found deep within the Earth, called eclogite.
Eclogite, a supremely dense and tough mineral, not unlike diamond, is a metamorphic variant of basalt that forms under the immense pressures of the inner mantle, say fifty kilometres deep and more. It is rarely brought to the surface, and when it is, freed of the underworld pressures, it usually reverts to other basaltic forms. Yet minute flecks of the mineral pervade the basalt of the Wheel.
How this can be is not quite known, but somehow, in the torturous process by which the Wheel was created, a profuse and stable form of eclogite managed to suffuse the plate. It’s thought that this is part of the explanation as to how the Wheel remains so sheer. In short, the very immensity of the mountain’s own weight has helped to create a high-pressure mineral within the stone that in return is tough enough to bear the weight that created it.
A bizarrely circular process.
Or, a wheel within the Wheel.
And a final note. Eclogite in its pure form is crimson or pink in colour. While its presence in the Wheel basalt is minimal, for those seeking the secret behind the unusual red hue of the mountain’s stone, here too perhaps—in the unprecedented fury of the Wheel’s formation—lies the answer.
12
THE RED WHEEL
The vibration came with a rush of rumbling and buzzing and shaking underfoot all at once. Rita
’s first thought was that some vast piece of machinery—maybe one of the lift winch mechanisms—was running amok somewhere within the Mount.
But then Clara was up out of her chair and shouting, ‘Earthquake!’
She dragged Rita away, both of them reeling across a solid floor that, impossibly, was leaping and shuddering and making their knees buckle. Their destination turned out to be the airlock doors leading out to the Terrace—the major-domo threw the inner door open, and then crouched under the metal lintel, pulling Rita down beside her as the quake clattered on, a steam engine tearing itself apart.
Then it was done. The mad concussions ceased abruptly and the floor became fixed stone once more. Silence fell, aside from a few final tinkles and clangs from the bar. The teapot and the cups had all fallen off and smashed on the floor.
Rita and Clara huddled a moment longer, then straightened slowly, staring around.
‘Just a tremor, I think,’ said Clara, a little shakily. They were cautiously venturing out from the doorway. ‘I don’t see any major damage.’
Nor could Rita. In the bar, several glasses and bottles of wine had fallen from the shelves and smashed, but throughout the rest of the Conservatory all the tables and chairs remained upright, and none of the hundreds of glass panels that made up the walls and the ceiling had fallen or shattered, or even cracked. Also, the lights were still on.
‘Even so,’ said the major-domo, ‘I think we should get out from under this roof for the next few minutes, in case there are bigger aftershocks.’
Rita nodded. They passed back through the airlock, along the way seizing two of the coats that hung on the adjacent rack.
Outside the cold was like a tonic, the slap of it on Rita’s face settling her jangled nerves. But she already felt better than she had all day—exhilarated, relieved, the hangover banished at a stroke, and with it the nagging toothache of foreboding that had bothered her since waking. Was that what it had been all along? Had she merely been sensing, subconsciously, the build-up of the stresses within the earth?
‘Do you get quakes often here?’ she asked. They had walked out to the centre of the Terrace, staring about in search of any damage, but other than some strange ripples still washing back and forth on the surface of the swimming pool, there was no visible evidence of the tremor at all.
‘No,’ said the major-domo. ‘In fact, there’s a seismic monitoring station down at Base—there has been since the military days—and its records show that this whole zone is actually remarkably stable, given that it’s a plate boundary. I know because Mr Richman had structural engineers look into it before construction began. Of course, the Observatory was still built to the highest quake-proof standards. You’d be safe here even against a big tremor.’
Rita supposed it was true. Certainly, the stone beneath her feet felt secure once more, although the memory of the floor leaping under her like a skittish living thing was difficult to shake.
Clara had pulled her phone from her pocket. ‘It really all looks fine up here. But it might have been worse down at Base. I’ll check with Eugene, seeing as he just went down there.’
Rita gazed away to the Wheel while Clara dialled. The mountain loomed amazingly vivid and close out here in the cold air, gigantic beyond conception as it rose away to the edge of space. But for once she found nothing oppressive in its size, nothing ominous. Her mood was too buoyant. Yes, she had been full of dread before the quake struck, convinced of all sorts of perils. But now she felt only light and energised, as if she had just escaped an unpleasant duty, or avoided some deeper danger, with no more than a minor shake and scare.
Or had she? A faint voice of warning sounded somewhere inside her. Was her sense of relief a little madcap, foolhardy even, the oblivious joy of some small creature that eludes the swooping hawk, and yet does not see the plunging eagle?
There was a mist on the Wheel.
She blinked, stared again. No, she wasn’t imagining it. All across the snowy regions of the great mountain a diaphanous veil sparkled, blurring the icy cliffs and the hanging glaciers. Rita understood suddenly. It must be a great flurry of snow and ice shaken loose from the mountainside by the earthquake, like glittering dust.
It was beautiful.
‘And no one is hurt or anything?’ the major-domo was saying into the phone, presumably to Eugene down at the bottom of the Mount. ‘Good, good. Well, I’d say we dodged a—’
A great rippling, crackling sound suddenly washed across the Terrace. It was like a rapid series of detonations, loud, but coming from faraway and softened by the distance. For a moment Rita could only think that there must have been fireworks left unexploded from last night, and in some weird delayed effect, they had been set off by the quake.
But there were no fireworks. The sounds—the crackling was going on and on—was coming across ten kilometres of air, from the Wheel.
‘Jesus,’ exclaimed the major-domo, both into the phone and to Rita. ‘What is that?’
Rita was staring. Something was happening on the mountain, high up on the centre of the face, near the top of the snowpack. The mist there appeared to be in motion, a more coherent mass now, more solid, creeping slowly down the sheer slope. And the faraway crackling had merged into a dull roar.
Except—
It wasn’t mist that was falling.
‘Shit,’ breathed the major-domo, her right hand, holding the phone, dropping to her side.
It wasn’t mist, it was the mountainside itself. All across a huge section of the central face—Rita couldn’t begin to guess how big a section, but it must be kilometres wide—the very bedrock of the Wheel seemed to be slumping, sliding and falling, churning up great dirty-white clouds of debris. From this distance the immense mass seemed to inch its way downwards, but the roaring that filled the air ever more loudly gave lie to that apparent slowness.
‘Avalanche,’ said Clara softly.
Rita understood at last. It was not the mountain itself that was falling, it was ice and snow. An avalanche. A big one. And of course, part of her reasoned, it should be no surprise. The earthquake had struck the Wheel as well as the Mount, and on any steep, snow-covered mountain the result of such a shaking would be all but inevitable.
And yet the scale of it!
Rita had never seen an avalanche before, but she suspected that in most mountain ranges even the largest avalanche would scarcely be visible from a vantage point ten kilometres distant.
But this … this was like watching the sky itself fall. It wasn’t just a single slab of snow that was moving, or a single chute that was unloading, or a single overhanging ice ridge that was tumbling; it was everything on the central face. On the open slopes entire snowfields were in motion; in the ravines where glaciers lurked, snouts of ice were toppling forwards, shattering as they went, the broken chunks slamming into the frozen cliffs below and setting them loose as well. It was everything, slumping, plunging downwards, leaping and jagging from slope to slope, jostling in a mad rush to reach the distant sea.
The roar was all pervading now, like a gale blowing in Rita’s face, and yet still the titanic collapse was growing. On both the left and right its edges were racing outwards, great slabs of white breaking away and dragging their neighbours with them. Nothing could stop it; nothing could block its dreadful spread; no crevice or couloir was wide enough. Even the Plateau, the long, wide ledge that ran across most of the West Face at five thousand metres, was no hindrance. As Rita stared, the leading edge of the avalanche reached the great shelf and overflowed it, not even slowing.
And still it grew. The avalanche now stretched across the entire central face, from far out on the southern shoulder to the middle of the north ridge, an expanse that must be thirty kilometres wide.
She spared a glance to Clara. The major-domo, wide-eyed, was mouthing something. Rita couldn’t hear the words but she thought it might be Oh shit, oh shit, oh shit, over and over like a mantra. Clara was afraid? But why? As a mountain climber, she must have se
en avalanches before, and though the collapse was a cataclysm, yes, it was also safely ten kilometres away across the ocean.
Rita swung her gaze back to the grand spectacle, and forgot about everything else. Lord, how many millions upon millions of tonnes of ice and snow were falling now? How many billions of tonnes? Avalanche? No, she decided, it wasn’t just an avalanche; avalanche was far too small a word. Yet she had no word for what it truly was.
But now—had it been sixty seconds since the vast movement began?—there was a new and stupendous aspect to behold. At the centreline of the Wheel, the leading edge of the collapsing mass was ravaging down the last thousand or so metres of the face—burying the scant trees there in an instant—to slam into the ocean. In immediate response, great towers of water began rising up, the creep of their ascent and then fall betraying the tremendous size and weight and violence of the process.
The thunder grew even louder as the impact upon the sea spread left and right, falling ice piling upon falling ice, until a vast arc of the Wheel’s shoreline was lost behind fountain walls of spray. And this was from only the leading edge of the collapse—above it a whole mountainside of ice was still in mid cascade, runaway and unstoppable.
Rita became aware that Clara was poking feverishly at her phone.
She stared, amazed that the major-domo could think of texting—yes, she was texting—at a moment like this. Clara caught her eye and explained at a shout over the thunder. ‘All that ice—all that volume—hitting the sea; it’ll send a wave this way! A tsunami! It could hit down at Base! I tried to ring Eugene, warn him, but he doesn’t answer! So I’m trying this instead!’
Rita was taken aback. A tsunami? A tsunami. But they were things that happened in other places—in Asia, in Japan, she had seen videos. It couldn’t be happening here, right now, right in front of her.
She returned her disbelieving gaze to the Wheel. The thunder was eternal, but in fact the collapsing face was mostly hidden now behind a cloud of ice and snow that had been thrown up by the tumult, climbing like a cumulonimbus. The impact upon the ocean was all too visible. All along a thirty-kilometre curve of shoreline the sea was swelling and withdrawing, as if in horror, from the land, shoved aside by the countless tonnes of ice crashing from above. The fact that the displacement of water was visible at all from this distance only proved how vast it was—and already a white line could be seen forming at the forefront of the bulge, forging outwards from the Wheel.
The Rich Man’s House Page 30
