The mysterious pictographs in Horseshoe Canyon have long been admired as some of the best examples of prehistoric art in the United States.Now they have a new distinction: This style of painting has just been dated, and it's apparently 3,000 years old.

"Assuming the association between the charcoal stained soil and the rock art is a good one, it would make (this Utah's) oldest dated rock art," said Gary M. Brown, an archaeologist who worked on the excavation last year.

It was dated by determining the age of charcoal in soil next to a panel of the same type in Canyonlands National Park's Needles District.

Brown, who recently moved from Salt Lake City to Farmington, N.M., worked last year with a company called P-3 Associates, South Salt Lake. This contract archaeology company carried out excavations for the National Park Service in Canyonlands; a report is planned.

"We were testing a site in the Needles District, and it had a real simple pictograph panel. It was a little boulder overhang," Brown said. "It was not in mint condition or anything; it was an anthropomorph, a human-like figure, triangular with vertical stripes."

It was in the Barrier Canyon pictograph style.

Beneath it, researchers found a scattering of stone tools, flakes chipped from spear points or hide scrapers, and soil stained by charcoal from the camp fires of the ancients.

There was enough charcoal in the soil to allow dating by Carbon-14 analysis.

"They did get a date of 1300 B.C. out of there," said Polly Schaafsma, a researcher with the Museum of New Mexico, Santa Fe, and one of the world's most famous experts on Utah pictographs. "It seemed like a very good association."

Brown cautions that nobody can prove yet that the charcoal and the panel were produced by the same people but says the likelihood is high. It can be confirmed if excavations at other sites yield similar dates.

Horseshoe Canyon-- earlier known as Barrier Canyon - is a separate section of Canyonlands about seven miles west of the main park area. It was established to protect the world-famous pictograph panels.

Perhaps the new name derived from one panel in which a man's figure has a decoration at the midriff that looks like a horseshoe with the ends down.

Most of Horseshoe Canyon's ancient Indian paintings are in the Barrier Canyon style, which is also the most common of the pictograph types in the nearby San Rafael Swell.

Horseshoe Canyon's best panel is called the Great Gallery, paintings in a cliff alcove of dozens of human-like figures, gods and animals.

Great, spooky basket-headed figures, decorated with zigzags, lines and streaks, loom along the wall. The most imposing is seven feet tall.

To visit this shrine, turn east from Utah-24 a short distance south of the Goblin Valley turnoff. Then it's about 30 miles on a good dirt road to a parking area at the rim of the canyon.

Along the dirt road is a field of crescent-shaped salmon sand dunes. At times the wind blows a fine haze of sand from the crests. To reach the dunes you need to walk back a short way from the road.

Horseshoe Canyon is a long intermittantly wet tributary that eventually reaches the Green River, about 20 miles down-canyon from the Great Gallery. From the rim above you see tall Navajo sandstone hills and a deep crease in the earth, but you can't get much of an idea of the canyon's depth.

The hike down into the canyon is easy, along a winding path marked by cairns. It offers spectacular overlooks to the canyon floor hundreds of feet below.

At the bottom, walking up-canyon another two or three miles to the Great Gallery is delightful.

Groves of cottonwood break out here and therebeside the tawny walls. On both of my trips there - in August 1985 and this past May - we found long shallow pools of water at the canyon's sides. Tall, vividly green grass grew from some of the pools, and tadpoles wriggled in them.

Another pool in the sandy floor reflected an unwavering vista of upside-down cliffs, Navajo sandstone turrets, and the intense sky.

Pictograph panels seemed to show up only where there were trees - wet areas now, and probably wet thousands of years ago. As we hiked, we kept wondering when the Great Gallery would appear.

A fine cliff face would unroll as we rounded a bend, we'd eagerly scan it for the famous panel, and then we'd realize it was yet farther.

When we finally came upon the panel, it was a stunning surprise.

The pictures are on the flat surface of an alcove, created when the sandstone cliff spalled away in a huge break. We scrambled up onto a ledge to reach them.

Mainly an ocher color on the beige sandstone, they're clear but some are faint. After all, they've been weathered by 3,000 winters and baked by a million noonday suns.

A tall popeyed ghost stands off to the left, surrounded by seven retainers. One of them looks like a Byzantine saint with a halo.

To the right is a sweep of more than a score of figures: men, their bodies covered with streaks and crosshatching, frills lining the sides. A circle of animals. Hunters with spears.

There are two large broad-shouldered figures with designs like piano keyboards on their chests. Each is accompanied by another big figure who has zigzags running down the side of his body.

You get the feeling these are two representations of the same personages. One of the zigzag figures has two animal designs on his chest.

Close up, looking up with the sun glancing off the pictographs above, some of the paint is glossy and purplish. You can see the designs aren't simply painted on the rock, they're carved in, too, lines scratched into the cliff, eyes that are round holes.

Hiking back out the canyon is rough for anyone out of shape, as it's steep. Rest up beneath the cottonwood near where the trail starts up.

Never hike without plenty of water, suntan lotion and a wide-brimmed hat. And take breaks at the slightest excuse.