Archaeologists who explored the remote mesas of Northern Arizona have identified a previously undocumented group of petroglyphs, one of which confirms the presence of a prehistoric solar calendar.

According to Western Digs , the solar calendar has been marking the seasons for more than 700 years with a shadow dagger that travels across the sandstone face. This feature is made by a natural outcropping of rock above a panel of petroglyphs. Western Digs reports that the “shadow dagger” bisects a spiral carved onto the cliff wall, while another shadow interacts with a set of eight circles pecked into the panel’s left side.”

The researchers discovered the petroglyphs in the back country of the Wupatki National Monument site northeast of Flagstaff, in Arizona, USA. The area includes the ruins of dozens of sites built by Ancestral Puebloans, also known as the Kayenta or the Sinagua.

A panorama of the Wupatki ruins. ( CC BY SA 2.5 )

The research had been led by experts affiliated with the Museum of Northern Arizona , with the support of the National Park Service. The supervisor of the study was David Purcell. Work began in 2014. The main goal of the project was to document the full extent of the rock art and other features of the site, many of which haven't been studied for decades or have never been seen before.

Some petroglyphs at Crack in Rock at Wupatki. ( CC BY NC 2.0 )

The result of their research is a complete library of photographic images of every panel, feature, and element of the area. The group of scientists were able to expand the scope of the project and conduct some pilot analysis as well. The works were focused on looking at how the rock art of the area is oriented to the horizon.

After nearly two years, they combed areas known as Horseshoe Mesa, Middle Mesa, and Little Mesa. The researchers watched the interplay of the sunlight at certain spots in different moments of the year. In the meantime, the documentation grew to 122 panels of petroglyphs at the Horseshoe Mesa and 107 at Middle Mesa. Altogether 138 new panels of petroglyphs were found, whilst others were rediscovered. But many of the panels contained dozens of individual petroglyphs. This sums up to the impressive number of more than 1,500 separate glyphs being recorded for the first time.

The first information about petroglyphs in northern Arizona comes from the late 1800s. The study of them proved the human occupation of this area back as much as 4,000 years. Many of the pictures seem to be the work of the Ancestral Puebloans .

The Puebloans were an ancient Native American culture, who lived in southeastern Utah, northeastern Arizona, northwestern New Mexico, and southwestern Colorado. Researchers says that they developed as a part of the Oshara Tradition (circa 5,440 BC - 460 AD), which grew from the Paleo-Indian Picosa culture. Ancestral Puebloans lived in a range of structures from small family pit houses to larger buildings like grand pueblos - cliff side dwellings for defense and house clans. They especially dominated the Colorado Plateau and connected hundreds of communities around them.

Cliff Palace, at Mesa Verde. Montezuma County, Colorado, USA. ( CC BY SA 3.0 )

Among the petroglyphs, the most eye-catching is the one located on the southern face of a sandstone ledge at Horseshoe Mesa’s northern end. It is known as Panel 50, and was recorded for the first time in 1931. Purcell confirmed that it is an imaging calendar, which means a time-tracking feature that uses the play of light and shadow. The panel is a set of eight circles, each 7 to 9 centimeters (3 to 4 inches) across, arranged in rows of two, three, two, and one.

An example of a Cave painting at Palatki Heritage Site near Sedona, Arizona, USA depicting the position of the sun with respect to the facing rock formations at the various solstices. ( CC BY SA 3.0 )

In 2006, archaeologists discovered another extraordinary petroglyph in Arizona. It was a rock carving which depicted an ancient star explosion seen by the Native Americans. It is believed to be the only known recording of a supernova in 1006 AD. That carving was found in the White Tanks Regional Park, Phoenix.

Featured Image: Wupatki National Monument Arizona - First Light. Source: CC BY NC 2.0

By Natalia Klimczak