I do not yet know what to make of this. Is it a riddle? Maurice and I are eager to know what you think.
Yours ever,
James Dillen
They read the translation several times in silence. Costas was the first to speak, his mind as ever seeking practicality where others saw only mystery.
“This is no riddle. It’s a treasure map.”
CHAPTER 8
Jack! Welcome aboard!”
The voice was raised above the din of the Rolls-Royce Gem turboshafts as they powered down. Jack had just stepped out onto the inflatable skid landing gear, a modification of the usual fixed-wheel naval configuration that allowed the IMU helicopters to land on water. He hurried over to shake Malcolm Macleod’s outstretched hand, his tall frame stooped low as the rotor shuddered to a halt. Costas and Katya followed close behind. As they made their way below, several of the crew scurried round the Lynx, securing it to the deck, and began offloading gearbags from the cargo bay.
Sea Venture differed from Seaquest only in the range of equipment suited to her role as IMU’s chief deep-sea research vessel. She had recently conducted the first manned submersible survey of the Mariana Trench in the western Pacific. Her present role in the Black Sea had begun as a routine sedimentological analysis but had now taken on a startling new dimension.
“Follow me to the bridge console.”
Malcolm Macleod led them below the same dome-shaped screen they had viewed on Seaquest. Macleod was Jack’s counterpart in the department of oceanography, a man whose expertise Jack had come greatly to respect through their many collaborative projects around the world.
The burly, red-haired Scotsman sat down in the operator’s chair beside the console.
“Welcome to Sea Venture. I trust your inspection can wait until I show you what we’ve found.”
Jack nodded. “Go on.”
“Do you know about the Messinian salinity crisis?”
Jack and Costas nodded but Katya looked perplexed.
“OK. For the benefit of our new colleague.” Macleod smiled at Katya. “Named after deposits found near the Strait of Messina in Sicily. In the early 1970s the deep-sea drilling ship Glomar Challenger took core samples across the Mediterranean. Beneath the sea floor they found a huge layer of compacted evaporates, in places three kilometres thick. It formed during the late Miocene, the most recent geological era before our own, around five and a half million years ago.”
“Evaporates?” Katya asked.
“Mainly halite, common rock salt, the stuff left when seawater evaporates. Above and below it are marls, normal marine sediments of clay and calcium carbonate. The salt layer formed at the same time across the Mediterranean.”
“What does this mean?”
“It means the Mediterranean evaporated.”
Katya looked incredulous. “The Mediterranean evaporated? All of it?”
Macleod nodded. “The trigger was a huge drop in atmospheric temperature, a far colder spell than our recent Ice Age. The polar ice trapped a vast amount of the world’s oceans, causing the sea level to fall as much as five hundred metres. The Mediterranean was sealed off and began to dry up, eventually leaving only brackish mire in the deepest basins.”
“Like the Dead Sea,” Katya suggested.
“Even more saline, in fact barely liquid at all. Too salty for most life, hence the paucity of fossils. Large areas became desert.”
“When did it fill up again?”
“About two hundred thousand years later. It would have been a dramatic process, a result of massive melt at the Poles. The first trickles from the Atlantic would have become a torrent, the biggest waterfall ever, a hundred times bigger than Niagara, carving the Strait of Gibraltar down to its present depth.”
“How is this relevant to the Black Sea?” Katya asked.
“The Messinian salinity crisis is an established scientific fact.” Macleod looked across keenly at Jack. “It will help you believe the unbelievable, which is what I’m going to tell you next.”
They gathered behind Sea Venture’s remote operated vehicle station on the far side of the console. Macleod invited Katya to sit behind the screen and showed her how to use the joystick.
“Think of it as a flight simulator. Use the joystick to fly it any way you want, up or down, sideways or backwards. Speed control is the dial on the left-hand side.”
Macleod put his hand on Katya’s and executed a full clockwise circle, pulling it round at maximum depression. The wide-format video screen remained pitch-black but the direction indicator spun through 360 degrees. The depth gauge read 135 metres, and a set of GPS coordinates showed the ROV’s position with an accuracy deviation of less than half a metre.
Macleod pulled the stick back to its default alignment.
“A freefall spin followed by a perfect recovery.” He grinned at Jack, who well remembered their ROV dogfights when they had trained together at the IMU deep-sea equipment facility off Bermuda.
“ROVs have been used extensively by scientific teams for a couple of decades now,” Macleod explained. “But over the last few years the technology has become increasingly refined. For exploratory survey we use AUVs, autonomous operated vehicles, which have multitask sensor packages including video and side-scan sonar. Once a target is identified we deploy direct-control ROVs. The IMU Mark 7 we’re operating here is not much larger than a briefcase, small enough to penetrate a sub-sea vent.”
“You can turn one of these babies on a dime,” Costas added. “And the Doppler radio-pulse control means it can go fifteen nautical miles horizontally or straight down to the deepest abyss.”
“Nearly there,” Macleod interrupted. “Activating floodlights.”
He depressed the joystick, flipping several switches on the console panel as he did so. Suddenly the screen came to life, the inky blackness replaced by a brilliant shimmer of speckles.
“Silt,” Macleod explained. “Our lights reflecting off particles disturbed in the water.”
They began to make out something more substantial, a shadowy background which gradually came into clearer view. It was the sea floor, a bleak, featureless expanse of grey. Macleod switched on the ROV’s terrain-contour radar which showed the seabed sloping down on a 30-degree gradient from the south.
“Depth 148 metres.”
A strange tower-like structure suddenly hove into view and Macleod halted the ROV a few metres away.
“Another of Costas’ ingenious contraptions. A remote-operated excavator, capable of drilling cores a hundred metres below the seabed or airlifting huge volumes of sediment.” With his free hand Macleod reached into a box beside his seat. “And this is what we found just below the sea floor.”
He passed Katya a shiny black object the size of his fist. She weighed it in her hand and cast a quizzical look.
“A beach pebble?”
“Worn smooth on the seashore. All along this gradient we’ve found evidence of an ancient coastline, one hundred and fifty metres deep and ten nautical miles from shore. Even more astonishing is its date. It’s one of the most remarkable discoveries we’ve ever made.”
Macleod punched in a set of GPS co-ordinates and the image on the screen began to move, the floodlit sea floor showing little change as the ROV kept to the same depth contour.
“I’ve put it on autopilot. Fifteen minutes to target.”
Katya handed back the blackened beach pebble. “Could this be associated with the Messinian salinity crisis?”
“We certainly would have put it before the arrival of humans — or rather, hominids — in this region two million years ago.”
“But?”
“But we would have been wrong. Wildly wrong. Submerged shorelines are hardly unusual in our line of work but this one’s big news. Follow me and I’ll show you.”