The Rocks Don't Lie: A Geologist Investigates Noah's Flood (6 page)

All people, geologists included, tell stories to explain the world around them and thereby understand our place in it. Different ways to see the Grand Canyon led to very different interpretations of the canyon and what it means. It might seem reasonable to think that a global flood carved the canyon if all you have to explain earth history is what you read in the Bible. But if you let the rocks speak for themselves they tell another story, just as grand: about the unimaginable depths of geologic time instead of the devastating power of a single flood.

How did it come to be that today what one sees along the Bright Angel Trail contradicts what many consider a Christian view of the canyon? To answer this question, we need to explore a two-thousand-year-old running argument about how to interpret nature and the story of Noah’s Flood. Perhaps the best place to start is at the top—of the world.

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Bones in the Mountains

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. The world’s highest mountain consists of three geological formations separated by two faults, shattered zones across which rock formations slid into place. Much as the layer-cake rock sequence exposed in the Grand Canyon captures the scope of geologic time, the shuffled geology of Mount Everest reveals the power of unimaginably slow deformation to transform the bottom of the sea into three different kinds of rocks and stack them back up to crown the world. This would have been unimaginable to early Christians. Climb up the mountain and you can see it for yourself.

After leaving Katmandu and trekking more than a week through the glacier-carved valley of the Dodh Kosi river, you’d arrive at Everest base camp, 17,590 feet above sea level. From there it is another eleven and a half thousand feet up to the top. The bottom half of the mountain, the part below about 23,000 feet, consists of the Rongbuk Formation, metamorphic rock with a composition similar to granite. Like the Vishnu Schist at the bottom of the Grand Canyon, the Rongbuk Formation formed when marine sediments were buried miles below ground.

The suite of minerals in the Rongbuk indicates it formed at temperatures of 1000–1250°F and at 8,000–10,000 times atmospheric pressure, more than fifteen miles down in Earth’s crust. Radiometric ages of unaltered mineral inclusions in the Rongbuk reveal that the original marine sediment was deposited some 490 million years ago. Once the rocks were stacked up into enough of a pile to heat up, deform, and start melting its own base, numerous granitic dikes rose like crystallized tendrils climbing their way up toward the surface.

Continuing up through shattered rock to cross the Lhotse Detachment, the lower of two fault zones, you’d reach the North Col Formation, which extends up to about 28,200 feet. This formation consists of 490-million-year-old marble, schist, and phyllite—limestone, sand, and mud buried deep enough to be pressure-cooked into harder rocks, but not so deep as to start melting. The mineral assemblage in the North Col Formation shows it underwent metamorphism just two to four miles below ground, at temperatures of 850–950°F and pressures of 1,000–2,000 times atmospheric. It was never buried anywhere near as deep as the rock right below it. Missing are the miles of rock that must have once lain between the now neighboring rock formations.

At the top of the North Col Formation, a distinctive stripe of yellowish marble (metamorphosed limestone) called the Yellow Band cuts across the mountain. At the top of the Yellow Band, a zone of completely shattered rock defines the second fault zone, the Qomolangma Fault, which separates the marble below from unmodified limestone of the overlying Qomolangma (or Everest) Formation. These uppermost rocks also date from about 490 million years ago, and extend to the summit 29,035 feet above sea level.
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The three rocks of Everest were born in the same sea, but they had radically different histories before being spliced together to form the world’s highest mountain.

Standing on the frigid summit of Everest, if you could pick up a piece of the limestone and view it under a microscope you would find that the top of the world consists of fragmented trilobites and tiny fecal pellets that settled to a tropical seabed. Beneath your boots you’d see the essential truth of the world’s highest mountain—the rock at its top once lay at the bottom of the sea.

How could a scrap of seafloor come to cap the world? Based on the cooling history of minerals they contain, these rocks started rising from the sea about fifty million years ago, when India began smashing into Asia. As India moved north, Asia stayed put, crumpling, folding, and faulting the incoming rock that had been deposited in a shallow sea. Crushed in a geological vise, the old seafloor was squeezed up and up, rising centimeters a year to eventually stand more than five miles above the coast. Faults formed as the incoming rock compressed, fractured, and pushed aside the rock that was already there. The southern edge of the Tibetan Plateau began to slide down toward India in much the same way that material starts sloughing off the top and sides of a pile of sand if a bulldozer keeps advancing into it.

But if you didn’t know about plate tectonics, how could you explain finding an old ocean floor on top of the planet’s highest peak? People around the world faced a similar question when they saw marine fossils entombed in high mountains. One way to resolve such puzzles is to assume that mountains don’t rise and that an incredibly deep sea once covered the peak, and thus the whole world. Another way is to assume that the rocks now exposed in the mountain somehow rose miles up out of the sea. Imagining that Noah’s Flood submerged the Himalaya is no less intuitive than the modern scientific idea that India is slamming into Asia and bulldozing up the world’s highest mountains in a process so slow one could not observe its progress over many lifetimes.

If you think the world is static, the idea of deforming and deconstructing rocks into whole new formations would never cross your mind. Before the concept of geologic time entered into people’s thinking, it was crazy to imagine that India was pushing up an old seabed to form the Himalaya. Faced with the choice between a catastrophic flood or mysteriously rising mountains, early natural philosophers considered a mammoth flood less preposterous.

Naturally, arguments erupted about how to interpret and reconcile religious beliefs with discoveries about nature, and vice versa. How could they not? Humanity’s essential curiosity and propensity to talk promote debate. Was Genesis intended as a concise history of the Jewish people, a literal and comprehensive history of the world, or as metaphorical parables for ages to come? The modern creationist concept of fundamental conflict between faith and reason would have shocked early Christians who believed that discoveries about the world revealed natural truths that could only support biblical truths.

Noah’s Flood was a powerful narrative that greatly affected the early development of geology because natural philosophers initially looked to the biblical flood to explain rocks, topography, and whole landscapes. How could the shells of sea creatures come to rest inside mountains? Discoveries of marine fossils found far above the sea bolstered the view of Noah’s Flood as a global catastrophe. The idea that the world had been reshaped by a great flood doubled as biblical truth and the first geological theory for much of postclassical antiquity.

In ancient Greece, however, there was a wide range of strikingly modern ideas about why mountains contained marine fossils. Some of the earliest known philosophers recognized the organic nature of fossils as creatures that lived in a remote time long before people walked the Earth. Fossil seashells told of oceans that covered the land. Giant vertebrae and enormous teeth that were occasionally unearthed were widely recognized as ancient bones. Fossils discovered near sites of legendary battles were displayed in temples as the remains of epic heroes or mythical monsters. The Greek idea that modern animals and people were but puny shadows of bygone days reinforced the widespread belief that the world was running down, wearing out, and growing old.

One might even be tempted to consider the great philosopher Aristotle a protogeologist for recognizing that landscapes evolved over unimaginably long time spans. In his view, land and sea constantly swapped places, and marine fossils in the rocks of mountains testified to how sea could become land. Rivers carried silt and sand to the sea, gradually filling it in, causing the sea level to rise and submerge coastal areas. This endless cycle in which land became sea and then land again so slowly as to escape observation paralleled Aristotle’s belief in a world without beginning or end. Civilizations rose and fell before they could record even a single round of this grand cycle. The world was eternal and always changing.

Philo offered one of the earliest surviving commentaries on Noah’s Flood in his
Questions and Answers on Genesis
, published in the first century
AD.
Born into an aristocratic Jewish family in Greek-ruled Alexandria, Philo didn’t question the historical veracity of the biblical flood. He was primarily interested in revealing the true meaning of scriptural passages. To him, this meant exploring deeper, allegorical meanings. He considered literal interpretations superficial. Philo singlehandedly initiated both sides of a long history of novel and conflicting interpretations of Noah’s Flood. He characterized the biblical flood as both limitless, having drowned the whole earth, and as having flowed almost beyond Gibraltar, implying that its influence was restricted to the Mediterranean.

Whether he meant to or not, Philo articulated both sides of what would become a grand debate among generations of theologians and natural philosophers. Did the biblical flood inundate the entire planet or just the world known to Noah? Christians debated this question long before science entered the fray. At stake was how to evaluate the truth about the world. Do you have faith in what you already think you know, or do you adapt your thinking to new information? Ever since, this question has been at the heart of an ongoing conversation between faith and reason. And the story of Noah’s Flood has put these different styles of belief into direct conflict perhaps more than any scientific issue other than evolution.

Among those arguing about how to read Noah’s story was Celsus, a second-century Greek philosopher. An opponent of Christianity, he charged the Jews with borrowing Noah’s story from pagan sources. Biblical critics like Celsus questioned the ability of the ark to hold pairs of all the world’s animals. How could one build such a boat? The preposterous story of a farmer building a lifeboat for all of creation seemed like a Jewish fairy tale.

In response, the second-century church father Origen countered that Genesis should be understood figuratively.

Now what man of intelligence will believe that the first and second and the third day, and the evening and the morning existed without sun and moon and stars… . I do not think anyone will doubt that these are figurative expressions which indicate certain mysteries through a semblance of history and not through actual events.
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Origen invoked Greek culture in promoting a figurative reading of the story of Noah. Why did his contemporaries allow Greek myths allegorical meanings but insist on literal meanings for the biblical story? To him, the symbolic meaning of Noah’s Flood was as important as its historicity. Noah foreshadowed Christ, the animals stood for the kingdom of Christ, and the ark represented the church—the ark’s three decks symbolized heaven, Earth, and the underworld. In his mind, a literal reading did not do Noah’s story justice.

Origen’s insistence on allegorical readings was not unique. Christians in his era tended to interpret biblical stories allegorically to encourage moral behavior. Sensitive to pagan critiques like those of Celsus, Christian philosophers advocated using knowledge of the natural world to better understand the Bible. Clement, Origen’s teacher and head of the Catechetical School in Alexandria, chided those who did not wish to use logic and reason in interpreting the holy book. He embraced both faith and reason. Understanding the truth expressed in God’s creation could only lead to a better understanding of God. Clement held that Christians should bring
all knowledge to bear on the truth because the world could not contradict its creator. To him the bond between faith and reason was as close as that between God and Christ.

Saint Augustine stands out among early Christians who wrestled with such questions. Born in Roman Africa in 354
AD
to a pagan father and a Christian mother, Augustine was educated in Carthage, where he became familiar with classical knowledge, Latin literature, and pagan beliefs. A brilliant intellect who lived a hedonistic lifestyle as a youth, he rose to become professor of rhetoric at the imperial court in Milan, the most visible academic post of his day. His worldly experiences before converting to Christianity in his early thirties helped frame an attitude of belief in what one could see firsthand. In his view, nature didn’t lie. He interpreted fossil shells and bones entombed in the fabric of the land as natural evidence that verified the story of Noah’s Flood.