ARCTIC DREAMS : <i> by Barry Lopez (Scribner’s: $22.95; 464 pp.)</i>

It is as if the Earth’s crust had worn paper-thin up there, and living Nature were the most precarious of sparks and liable to go out at any sudden gust. For Barry Lopez, the ring of arctic territories around the frozen Polar Ocean--the Yukon, Alaska, Siberia, Novaya Zemlya, Svalbard, Greenland--are an enchanted land in a fearful morality tale.

“Arctic Dreams,” a record of four years of travel and reflections above the Arctic Circle, is a number of things. It is a lyrical geography and natural history, an account of Eskimo life, and a history of northern explorations.

But mainly, it is a poetic, though sometimes awkward, reflection about the meaning of mankind’s encounter with the planet, taken at its extreme. Its question, starting as ecology and working into metaphysics, is whether civilization can find a way of adapting itself to the natural world, before its predilection for adapting the natural world to itself destroys self and world, both.

The Arctic has always drawn prospectors: first for furs, then for gold, now for oil and, as always, for scientific knowledge. In his four years, Lopez traveled with oilmen, construction crews, meteorologists, zoologists and Eskimos. What he was prospecting for was beauty and a sense of wonder. Finding them, his message is not “come and get rich,” but “come and abstain,” or “stay away altogether, and preserve another kind of wealth.”

The book begins and ends with a bow. Lopez is walking in the tundra among the ground nests of plovers, longspurs and snowy owls; and their beauty forces a gesture of homage. And in the last pages, after accompanying an Eskimo party on a walrus kill, he tries to reconcile his hosts’ reverence for Nature with their joyful bloodletting. The need to revere the world while praying upon it tightens inside him into a paradox that only a bow can relieve. Between these bows, one lyrical and one tormented, “Arctic Dreams” unfolds.

The author ranges from phytoplankton to musk oxen, from a consideration of northern light to the American school of Luminist painters, from the reason explorers died from eating polar-bear heart--excess vitamin A--to the suitability of the Hopi language for discussing the theory of relativity.

There is a wealth of striking and suggestive detail. The Greeks named the region “Arktikos” or land of the bear, not because they had been there or knew about polar bears, but because the Great Bear constellation shone over it. It was, appropriately, a place named by the stars.

Lopez is intoxicated with the landscape. Dry as the Mojave desert, its apparent barrenness in the summer disguises the detail and nuance that rewards those who walk and observe. It has a slow beauty, and Lopez is at his best in talking about this slowness. Of the Ellsmere Island tundra, he writes, “The winter face of a musk ox its unperturbed eye glistening in a halo of snow-crusted hair, looks at you over a cataract of time, an image that has endured through all the pulsations of ice.

“You can sit for a long time with a history of man like a stone in your hand. The stillness, the pure light, encourage it.”

He does not so much describe the landscapes as conduct a dialogue with them, and often this dialogue is more evocative than any simple description could be. One of his themes is the vulnerability of life where life is only just possible. Seventy-five thousand musk oxen perish when an October rain freezes, covering their forage-grounds. He sees a loon paddling vainly to keep a stretch of water clear from ice so her mate, bringing food, can land. If anything, this is more vivid than his dramatic account of a narrow escape when ice closed in on a launch he was traveling in.

“Animals are always testing the landscape,” he writes, “experimenting, pushing at the borders of their familiar areas in response to changes in their environment.”

This awareness of nature, this ability to hear its signals and adapt to them is, for Lopez, a kind of model for humans, as well. Our civilization, he argues, has become so accustomed to imposing itself on its surroundings that it has lost the will or ability to learn from them. And in losing this attentiveness, we have lost a part of our humanity that so-called primitives, such as the Eskimos, have preserved.

The book’s main weakness lies in the author’s struggle with his own lyricism. Sometimes, he succeeds quite strikingly. At other times, he brings on herds of highly colored language without marshaling the discipline needed to make them work. Many of his more highly charged sentences are irregularly packed, and their cargoes shift and bump. There are several misspellings, and a wandering battalion of misplaced commas makes the book’s hazier bits of syntax even more difficult to follow.

Lopez’s vision is an exalted one. Even the contradictions he falls into are illuminating. He is striving to re-create the reverence for the land that we have so largely lost. He delights in the Arctic because it seems to be “almost not touched . . . by human schemes.” But he is only a visitor; if he lived there, he would have his own schemes. The Eskimos have them, as he recognizes in his final thoughts about reconciling our divergent needs to belong to Nature and to prevail over it; and in his final bow.