Petrified Forest National Park

Ancient solar calendars still mark the summer solstice in Petrified Forest National Park. For thousands of years, people of this area used rock surfaces as drawing boards. Recent research suggests that some of these petroglyphs are more than drawings, they are in fact solar calendars that still keep time.

Solar calendars are usually single petroglyphs, most commonly circles or spirals, that interact with sunlight or shadows to mark the passing of the seasons. As the sun's position changes through the year, shadows or beams of sunlight are projected onto some petroglyphs. The projections mark solstices, equinoxes and other dates.A small circular petroglyph etched on a boulder behind Puerco Pueblo marks the summer solstice on June 21.

During the sun's morning trek across the sky, a shaft of light is projected onto the boulder, travels across the top and down the side to hit the center of a small petroglyph circle at approximately 9:00 a.m.

Join rangers at Puerco Pueblo to experience this solar calendar event as it marks this year's summer solstice. Puerco Pueblo is located on the main park road almost midway between the north and south entrance. Rangers will be at the Pueblo each day during the Solstice.

For more information, interested persons may telephone the park at (928) 524-6228 between 8:00 a.m. and 4:00 p.m. MST or write Chief of Interpretation, Petrified Forest National Park, P.O. Box 2217, Petrified Forest AZ 86028.

Printed by permission of Tessy Shirakawa, Chief of Interpretation, Petrified Forest National Park.