The surface of the glacier proved to be extremely broken, as the literature had suggested— mixed with regolith during the flooding, and shot through with trapped carbonation bubbles. Rocks and boulders caught on the surface had melted the ice underneath them, and then it had refrozen around them, in a daily cycle that had left them all about two-thirds submerged. All the seracs, standing above the jumbled surface of the glacier like titanic dolmens, were on close inspection found to be deeply pitted. The ice was brittle because of the extreme cold, and slow to flow downhill because of the reduced gravity; nevertheless it was moving downstream, like a river in slow motion, and because its source was emptied, the whole mass would eventually end up on Vastitas Borealis. And signs of this movement could be found in the newly broken ice seen every day— new crevasses, fallen seracs, cracked bergs. These fresh surfaces were quickly covered by crystalline ice flowers, whose saltiness only added to the speed of crystallization.
Fascinated by this environment, Sax got in the habit of going out by himself every day at dawn, following flagged trails the station crew had set out. In the first hour of the day all the ice glowed in vibrant pink and rose tones, reflecting tints of the sky. As direct sunlight struck the glacier’s smashed surfaces, steam would begin to rise out of the cracks and iced-over pools, and the ice flowers glittered like gaudy jewelry. On windless mornings a small inversion layer trapped the mist some twenty meters overhead, forming a thin orange cloud. Clearly the glacier’s water was diffusing fairly quickly out into the world.
As he hiked through the frigid air he spotted many different species of snow algae and lichen. The glacier-facing slopes of the two lateral ridges were especially well populated, flecked by small patches of green, gold, olive, black, rust, and many other colors— perhaps thirty or forty all told. Sax strolled over these pseudo-moraines carefully, as unwilling to step on the plant life as he would be to step on any experiment in the lab. Although truthfully it looked as though most of the lichens would not notice. They were tough; bare rock and water were all they required, plus light— though not much of that appeared necessary— they grew under ice, inside ice, and even inside porous chunks of translucent rock. In something as hospitable as a crack in the moraine, they positively flourished. Every crack Sax looked in sported knobs of Iceland lichen, yellow and bronze, which under the glass revealed tiny forking stalks, fringed by spines. On flat rocks he found the crustose lichens: button lichen, stud lichen, shield lichen, candellaria, apple-green map lichen, and the red-orange jewel lichen that indicated a concentration of sodium nitrate in the regolith. Clumped under the ice flowers were growths of pale gray-green snow lichen, which under magnification proved to have stalks like the Iceland lichen, great masses of them looking delicate as lace. Worm lichen was dark gray, and under magnification revealed weathered antlers that appeared extremely delicate. And yet if pieces broke off, the algal cells enclosed in their fungal threads would simply keep growing, and develop into more lichen, attaching wherever they came to rest. Reproduction by fragmentation; useful indeed in such an environment.
So the lichen were prospering, and along with the species that Sax could identify, with the help of photos on his wristpad’s little display screen, were many more that seemed not to correspond to any listed species. He was curious enough about these nondescripts to pluck a few samples, to take back and show to Claire and Jessica.
But lichen was only the beginning. On Earth, regions of broken rock newly exposed by retreating ice, or by the growth of young mountains, were called boulder fields, or talus. On Mars the equivalent zone was the regolith— thus effectively the greater part of the surface of the planet. Talus world. On Earth these regions were first colonized by microbacteria and lichen, which, along with chemical weathering, began to break the rock down into a thin immature soil; slowly filling the cracks between rocks. In time there was enough organic material in this matrix to support other kinds of flora, and areas at this stage were called fellfields, fell being Gaelic for stone. It was an accurate name, for stone fields they were, the ground surface studded with rocks, the soil between and under them less than three centimeters thick, supporting a community of small ground-hugging plants.
And now there were fellfields on Mars. Claire and Jessica suggested to Sax that he cross the glacier, and hike downstream along the lateral moraine, and so one morning (slipping away from Phyllis) he did so, and after half an hour’s hiking, stopped on a knee-high boulder. Below him, sloping into the rocky trough next to the glacier, was a wet patch of flat ground, twinkling in the late-morning light. Clearly meltwater ran over it most days— already in the utter stillness of the morning he could hear the drips of little streams under the glacier’s edge, sounding like a choir of tiny wooden chimes. And on this miniature watershed, among the threads of running water, were spots of color, everywhere, leaping out at the eye— flowers. A patch of fellfield, then, with its characteristic millefleur effect, the gray waste peppered with dots of red, blue, yellow, pink, white. . . .