In Chaco Canyon, New Mexico, it is still possible to wander the maze of rooms of an ancestral Puebloan village erected roughly 1,000 years ago.

Visitors use the same staircases and duck through the same T-shaped doorways as residents did at the time. A jigsaw puzzle of rocks form walls that stand several feet thick and multiple stories tall. Where rooftops are gone, windows now let in glimpses of sky. It’s a simultaneous experience of vast space and marvelous connection.

Hundreds of such dwellings sprawl over the south-west, from New Mexico to Colorado, Utah and Arizona. Each is a testament to the determined faith of their inhabitants, who aligned the walls of structures with the axis of the rising sun on an equinox, and etched petroglyphs the sunlight bisects only on solstices.

Chaco Culture national historical park, created in 1907, contains a concentration of these ancestral Puebloan structures abandoned around 1200 AD. Unesco recognized it as a world heritage site in 1987 for its “monumental public and ceremonial buildings and its distinctive architecture – it has an ancient urban ceremonial centre that is unlike anything constructed before or since”.

It’s as close as the US gets to Egypt’s pyramids and Peru’s Machu Picchu, but recent years have seen drilling pressing closer to the park’s boundaries, now aided by the Trump administration’s work to accelerate oil and gas development.

If not stopped, those developments could spell the end of a myriad of clues archaeologists and anthropologists are still unraveling about Chacoans’ way of life.

A ‘great house’ in Chaco Culture national historical park. Photograph: VW Pics/UIG via Getty Images

Anthropologist Ruth Van Dyke is trying to unveil what visitors would have seen and heard on their way into the canyon and the epicenter of their civilization. But while she made a visit last fall, a dozen oilwell pump jacks interrupted her view of landmarks that still figure in Native American stories. The nearest one, less than a mile away, could be heard working.

“It very much feels like an industrial park,” Van Dyke says. “They haven’t put any of these pump jacks on an archaeological site, and yet the overall effect is really horrific.”

For Native Americans descended from these ancestral Puebloans, the ability to pray in places their ancestors prayed is not just significant; it’s sacred.

“If you speak to any other pueblo cultural leader, they will likely tell you that none of these places were abandoned, that these places were always meant to be places that we simply refer to as ‘home’, and that we continue to have a responsibility as stewards of these places to maintain a connection to them,” says Theresa Pasqual, former historic preservation director for the Acoma Pueblo and a consultant to the All Pueblo Council of Governors, an alliance of 20 pueblos in New Mexico and Texas.

Recent years have seen the landscape around Chaco changing in ways that worry natives and archaeologists.

The San Juan Basin seeped natural gas for decades, a sleepy little play that drew modest interest. Then in 2013, energy companies took new technology to a nearby shale formation, and a previously unyielding layer began to spout oil. The ability to drill wells a mile deep and a mile and a half long and to hydraulically fracture those rock formations spurred development, and has drawn it toward Chaco.

The local field office for the Bureau of Land Management (BLM), responsible for leasing many of those mineral rights, has conceded the pace of drilling exceeds anything their planning documents foresaw. They’re at work on updates.

Meanwhile, lease sales continue.

While the park itself may be protected, it’s only a portion of what remains of ancient Chacoans. Many outlier sites or ceremonial roads may not even yet be identified.

“If we destroy our ability to study these outlier communities and we destroy our ability to study these connections, particularly these connections in terms of these roads and visibility, we’re never going to understand Chaco,” says Van Dyke. “We need to take care of all of the pieces of that system and the connections among those pieces, not just the center of it.”

A guide talks to visitors beside an excavated kiva in the ruins of a massive stone complex (Pueblo Bonito) at Chaco Culture national historical park. Photograph: Robert Alexander/Getty Images

The BLM checks a state-run database of cultural resource records before leases are issued, and if those records show possible artifacts, will send a boots-on-the-ground survey. The trouble is, that database may not include information held by other agencies, including universities, the park service and tribal governments.

“It is abundantly clear that the archaeologists that are going out to do work prior to oil and gas development are not identifying all of the sensitive resources and phenomena on this landscape and if we continue, we’re going to have significant losses to undocumented cultural resources and overall to this landscape,” says Paul F Reed, preservation archaeologist and Chaco scholar with Archaeology Southwest.

Already, he says, he’s seen losses to drilling.

“All of our pueblo communities maintain our history and our language orally – it’s not a written language, so we don’t have the ability to reach out to a library and pull out an encyclopedia or a history book that tells us what the history of that place is. Our history book is the physical landscape,” says Pasqual, with the Acoma Pueblo.

“Every time development continues on that landscape, it is much like losing pages and chapters of that history book,” she adds. “You cannot repair the landscape and put it back to what it once was. Once the roads and the drill pads are placed there, you cannot put the landscape back to that historical context any more.”

There’s concern for more than just artifacts in the area, which has been home to Navajo, or Diné, for centuries. It’s Diné tradition to bury an infant’s umbilical cord in the middle of a sheep corral. “That’s your connection to Mother Earth, and the homestead is a spiritual place,” says Daniel Tso, a Navajo allottee and former Navajo councilor.

He’s among those working to curtail oil and gas development to prevent adverse effects to the place itself and people who live there, the latest effort for which is a health impacts assessment.

“We’ve got to the point of, ‘Hey, the archaeologists and anthropologists say it’s a site, sorry,’” says Tso. “I think that’s the wrong way of designating it. It’s not a site. It’s the whole space, the landscape, that’s sacred.”

There’s concern for more than just artifacts in the area, but also for the park’s culture. Photograph: VW Pics/UIG via Getty Images

A Navajo chapter house protested against oil and gas leases issued in January over concerns with the noise, traffic and air quality that development could bring close to homes. The BLM dismissed the protest because their rules require submitting such documents by mail or fax, and the correspondence was emailed.

In response to the pressure to expedite drilling and to leases listed this fall that came within 10 miles of the park, the National Congress of American Indians called for a moratorium on drilling throughout the greater Chaco Canyon region.

Hope had rested with a master leasing plan that could guide a more nuanced approach to development in this region and steer it from sensitive areas and viewsheds. However, those plans were listed among the “burdensome” regulations to target for rescinding, repealing or suspending in a 24 October report from the interior department.

Chaco is not the only national park facing pressure from oil and gas development, and recent actions from the Trump administration suggest those threats are likely to increase in the name of domestic energy production.

The interior secretary, Ryan Zinke, who oversees the BLM, has called for expediting reviews and other processes to speed drilling. For the BLM staff near Chaco, that means moving up the timeline on revising the planning documents locals and native groups have sought to help draft. (Regional BLM staff members were allowed to provide basic information for this story, but the Washington DC office disallowed them from making specific comments.)

Existing regulations offer scant protections to scenic vistas, quiet and night skies filled with an abundance of stars. Based on current land and mineral ownership, more than 40 parks could be opened to oil and gas wells. Icons such as Grand Teton, Everglades, and Mammoth Cave national parks are on that list. More than 12 already have active wells.

Development also moves in on parks from the edges. Leases are proposed for near Theodore Roosevelt national park that could punctuate the prairie the namesake president retreated to while grieving the deaths of his mother and wife. Drilling near Dinosaur national monument, conservationists caution, could be seen from the Carnegie Fossil Quarry. Zion and Capitol Reef national parks, Hovenweep national monument, and Fort Laramie national historic site are also targeted.

In August, the Coalition to Protect America’s National Parks, an organization of former National Park Service employees, sent Zinke a letter expressing their alarm.

“As former land managers, we understand the need to balance competing priorities,” they wrote. “But we fear the pendulum is swinging too far to the side of development.”

The regulatory rollback may only go so far with oil selling for around $50 a barrel. At current oil prices, Kelly Swan, spokesperson for WPX Energy, one of the leading companies working the San Juan Basin, says their pace will be reduced in the area for the remainder of 2017 and into 2018, with their current rig in the area finishing in December.

The archaeological workarounds are, he says, “just a cost of doing business, and our eyes are very open to that.”

“The argument for and against development is exactly the same, and it’s about history,” he says. On one side, people want to preserve their past, and on the other, families now have a tradition of working with oil and gas companies.

Leases give rights to drill any time in the next 10 years and to maintain the well for as long as it produces.