THE ARTIC National Wildlife Range is a part of Alaska well north of the Arctic Circle, about one and a half times the size of Maryland. It is inhabited mainly by the last great herd of healthy and undisturbed caribou in the world, although the wilderness is shared by many other members of the wild kingdom. Unfortunately for the caribou and other animals, the geologic formations under part of the wild-life range may contain huge amounts of oil and gas. Therein lies a conflict that has become the major symbolic issue in this year's congressional debate on the future of Alaska's back country.

The arguments are obvious. A major oil strike in the Arctic Wildlife Range now could do wonders for this nation's domestic oil supply and its international balanece of payments. It could also do horrors to the caribou. The key world is "could," because no one really knows how unhappily the caribou would react to sharing their turf with oil and gas wells, and no one really knows how oil and gas from the wildlife range would be transported to market in the near future.

Even if Congress gave them the go-ahead, the oil and gas people would not begin drilling and pumping immediately. But they do want to begin exploring. Their logic is that sooner or later the country will need the oil and gas that is thought to be under the wildlife range and rational planning requires knowing in advance how much is there. That's an appealing argument given our energy troubles.

Conservation groups and the Carter administration, particularly Secretary of Interior Cecil Andrus, vehemently oppose letting exploration begin in the wildlife range. They contend that even minor human intrusions into the calving grounds of the caribou will do immeasurable harm to the herd. They also argue that other areas on Alaska's north slope contain enough oil and gas to keep the Alaskan pipeline - the obvious way to bring oil south from the wildlife range - busy for the next two or more decades.

The argument might be a close one except for one fact. Once industrialization and the caribou collide, whatever damage is done to the caribou and the fragile but beautiful land on which they live will not be reversible. So why tamper with their habitat until the day is nearer when what lies under it is needed and can be wisely used? There is a chance - may be only a faint one, but still a chance - that some dramatic breakthrough in fusion or solar research will solve the energy problem before the rest of Alaska's oil is exhausted. If that should happen, the caribou and their associates in this part of the Arctic could go on living free from human interference for centuries to come.

The same fact hangs over the entire congressional debate on what to do with the federal lands in Alaska. A virgin forest once cut or a hillside once mined is never the same. In considering the three versions of an Alaskan bill now pending before them, members of the House of Representatives must recognize that it is better to err on the side of preserving too much than of preserving too little. A mistake that keeps development out of parts of Alaska's great resources and beauty can be undone by later Congresses. A mistake that lets development in cannot.