A Sense of Place
Roosters woke me. They began at dawn, echoing each other’s cries from across the town. My sleeping mind seemed to unravel, pulled little by little back into the world. Occasionally there were lulls and I dozed off, but then the crowing started up again.
It took me a moment to remember where I was. When I’d first moved to a city in my early twenties, to downtown Montréal, I lived in an apartment whose windows faced an inner courtyard. I sometimes awoke at night, disoriented, and had to go out to the street, to stand on the sidewalk in my socks, just to find my bearings, to see which direction was north. I wasn’t sure what startled me awake those nights, at two or three o’clock—if I was used to freedom and big spaces, to sensing my place on the earth.
I often had a similar experience during my travels, a desire to look at a map and see how the landscape made sense, where the rivers originated, whether the mountains I was seeing were the beginning of a higher, more dramatic range, or just ragged, stony outcroppings stripped of earth by millennia of wind. The rises and curves on the map, and the winding human paths that conformed to them, remind me of something I once read, that the ancient Greeks perceived knowledge as a means of expanding the self, of feeling connected to existence. I couldn’t name the African trees, the ferns and flowers and reeds, or say how they interacted, which roles they played within the ecosystem, but I was sure that if I could, my world would have seemed larger and more open.
Now, as roosters crowed and I woke up in a room the length of my too-short bed, I tried to connect this landscape with all I’d learned about it, to make sense of this spot on the map—Djolu, mud huts and dusty footpaths, a town harder to reach than the vast majority of places on earth. It lay at the heart of the Congo River basin, an immense territory covering more than 1.4 million square miles, its tributaries draining from Gabon, Angola, Rwanda, Burundi, Cameroon, Equatorial Guinea, Central African Republic, Congo-Kinshasa, and Congo-Brazzaville. Half of the basin’s territory is rainforest, nourished by the tributaries on their way to the Congo, the fifth-longest river on earth carrying the third-largest volume of water. Djolu lies to the south of the Congo’s arc, just north of the equator, near the Maringa River, in the middle of a landscape that has been forested almost continuously for millions of years.
Long before my first trips to Africa, from numerous photographs, I’d sensed something different about the continent, so visually unlike anywhere else: its high, rolling plains, its undulating landscapes and gradual, expansive basins, all unmistakable.
It hasn’t been shaped in the same way as the other continents. Though it separated from South America about 126 million years ago, Africa remained largely unchanged for 100 million years, with virtually no rifting or volcanism. By 65 million years ago, erosion and the lack of volcanic activity had turned it, as geologist Kevin Burke writes, into “a low-lying continent with widespread deep weathering.” I liked this image and found it easy to picture the endless, worn-out ranges of ochre dust, the landscape wind-scarped and cut with rivers.
This erosion continued until thirty million years ago, when Africa collided with Europe. The African plate ceased to drift, pinned possibly by its collision in the Mediterranean, or by the giant volcanic plumes that rose through the earth’s mantle to create the Cape Verde and Afar archipelagoes. Only once Africa became static did the continent we know begin to take its shape. This large, flat expanse of deeply weathered land rested above a hot area, a convection circulation in the underlying mantle. Like a sheet of metal slowly warping above a flame, the continent changed its shape over millions of years. Plumes of less dense material rose from the hot mantle, pressing against the crust, at once thinning it by partial melting and pushing it up, warping its surface, initiating volcanic activity, and reactivating ancient faults.
The old Africa of low, eroded plains lifted into the landscape that geographers and historians have remarked on since Herodotus’s time, a continent of long swells and basins. Whereas most continents have areas of extremely high elevation and others almost at sea level, very little of Africa is extremely high or low. The continent bulges from ocean to ocean, rising and falling in successive sweeps 125 to 1,250 miles in length. On the resulting tablelands are peaks, ridges, and escarpments created by millions of years of wind and water erosion. The elevation drops to both the north and west, marking the paths of the Nile and the Congo, the continent’s two largest, though dramatically different, rivers.
The Congo is unlike other rivers in Africa. The gradual slope of the landscape usually results in slow drainage and immense deltas, as with the Nile, Niger, Zambezi, and Limpopo, all of which carried large quantities of sediment down from areas of the continent that were lifted. But Africa’s basins and swells also cause internal drainage. As the continent was reshaped, water that was unable to reach the ocean formed immense lakes, then spilled out into a new river, to another set of lakes, slowly working closer to the coast.
At first glance, the Congo basin fits this description, draining internally. For millions of years, it most likely formed a massive inland lake as the result of a geologic swell along the coast that blocked access to the ocean. But at some point in the last thirty million years, the Congo River cut through the highlands beyond the Pool Malebo and created an outlet, a 220-mile descent of narrow, violent rapids that possess, Adam Hoschchild writes, “as much hydroelectric potential as all the lakes and rivers of the United States combined.” Over millions of years, the water rushing out from the land created the world’s largest submarine river canyon, 497 miles long and 3,900 feet deep on the floor of the Atlantic, as well as an abyssal fan, a river delta composed of millennia of sediment, hidden beneath the ocean.
But the landscape where I found myself listening to roosters crow across Djolu’s clustered homesteads is more ancient than much of the rest of Africa. The Congo basin is a craton, an ancient continental core dating back 2 to 3.6 billion years. Whereas much of the earth’s crust is composed of relatively new material from plumes and rifting, cratons are typically thicker and deeply rooted, resistant to volcanism, which will occur at their edges but not their centers. While the lands of Africa swelled and broke open around it, the Congo craton held its place. East Africa lifted, drying out and losing its forests as it gained altitude, but the Congo remained lush. The waters drained from the newly raised lands, pouring into the low, immovable basin and making it one of the wettest places in Africa. Today, most of the DRC lies within what Alden Almquist, in Zaire, describes as a “vast hollow . . . the shape of an amphitheater, open to the north and northwest and closed in the south and east by high plateaus and mountains.”
When the glacial cycle started in the Northern Hemisphere, a brief 2.6 million years ago, trapping vast quantities of the planet’s moisture in polar ice, many African rivers, the Nile among them, ceased to reach the ocean, and the tropics withered. The Congo basin was one of the few areas to retain some of its rainforest. Though great apes likely died off elsewhere on the continent, small groups of them could have survived here.
As early as six million years ago, in the long cooling period leading up to our current ice age, our earliest ancestors became increasingly bipedal, spending more time on the ground. However, the severe changes caused by glaciation coincided with a rapid spurt in evolution that may have given rise to modern humans. The situation could have been similar to that of the earlier apes, only more extreme: the drying eliminated trees and created a hostile environment with few resources. Paleontologist and anatomist Kevin Hunt argues that as trees became much smaller and branches thinner, early hominids found that foraging by climbing was increasingly difficult; instead, they often stood on the ground and reached up for the fruit. Supporting this theory is the observation that today, among chimpanzees, tool use, carrying food, confrontational display, and looking over obstacles account for only 1 to 2 percent of bipedal behavior, whereas feeding, most often from the low branches of small trees, accounts for 85 percent of it. Again, if the environmental conditions were harsh, a bottleneck might have occurred, many of the early hominids dying off, leaving only those who were adapted to the new circumstances and capable
