The Rocks Don't Lie: A Geologist Investigates Noah's Flood Read Online Free PDF Page B

pile. And that’s when it’s dry. Saturated sand can hold a slope only about half that steep—nowhere near a vertical wall. In contrast, wet clay is cohesive enough to support short vertical cliffs. If the creationist view held water—that the canyon’s slopes formed when the sediment was still saturated—then the slopes today would have shale cliffs and sandstone benches, the opposite of what’s visible along the trail.
    How long does it take for the finest sediment to settle out? Even in a bucket of still water it can take weeks for fine clay to drop to the bottom. The distinctive microrhythm of coarse to fine, coarse to fine, coarse to fine in the walls of the canyon proves how the now rock-solid sediment settled out from a series of flows. The hundreds of thousands, if not millions, of layers of silt could not have settled out and separated from the intervening layers of sand during the passage of a single violent current because turbulence would have resuspended the fine sediment. Individual layers of clay, silt, and sand take a long time to segregate out—and far longer to do so over and over again to build up a pile it takes hours to hike up through.
    Every step brought me closer to the canyon rim, and I passed into the soft, easily eroded Hermit Shale, where the slope relaxes and piñon pines and juniper trees manage to hold down a thin soil. Within the rust-colored shale below the soil, fossil ferns, conifers, and the tracks of reptiles and amphibians revealed the former nature of the region. I had climbed out of an ancient ocean and into the remains of a temperate coastal jungle.
    Passing out of the Hermit Shale, I started up more switchbacks and crossed onto a massive, strikingly white sandstone. Composed of pure quartz sand, the Coconino Sandstone exhibits cross-beds that define the faces of fossilized sand dunes rising diagonally through cliffs along the trail. Invertebrate tracks and burrows are preserved in these fossil dunes. One outcrop near the trail preserves reptilian footprints that displaced the sand, sending it slumping back down the face of a dune. Such fine-scale features would have been obliterated if they had formed underwater, the way waves running up a beach erase footprints in the sand. These dunes were made by wind.
    Continuing my trudge, I passed through the yellow-gray Toroweap Formation, evidence that a sea submerged the desert sands of the underlying Coconino Sandstone. Then a final, grueling climb up the nearly vertical white wall of Kaibab Limestone. Plodding past day hikers heading down the trail, I could see 270-million-year-old fossil coral and mollusks that reminded me of the complexity and diversity of life I’d seen learning to scuba dive on Australia’s Great Barrier Reef. Finally, I reached the top.
    Standing on the rim, I reviewed the story I read hiking up through ancient worlds—missing mountains, shallow and deepwater seas, coastal jungles, windswept sand dunes, and coral reefs. The few simple organisms in the lowest layers offered an obvious contrast to the complex reef community at the top. I had completed a grand tour through geologic time telling of the rise and fall of ancient mountains and seas, with the rocks at the bottom reaching back to the dawn of life and those at the top predating the dinosaurs. That the cliffs were solid rock right up to the canyon rim testified to erosion of all the formerly overlying rock that provided enough pressure to solidify a pile of sand and mud in the first place. Whole worlds came and went before the one we know today.
    One doesn’t need to hike up through thousands of feet of rock outcrops to refute the notion that the Grand Canyon formed during a flood that somehow managed to lay down all those rocks right before carving through them to create the canyon. A simple experiment you can conduct at home will prove the point. Get a glass-walled box (a fish tank will do nicely), fill it with water, and pour in a mix of clay