The battle over oil and gas development across the high desert that surrounds Chaco Culture National Historical Park has been brewing for years.
The campaign to curb drilling in one of the nation's oldest basins has spanned at least three presidential administrations, with concerns expanding beyond environmental impacts to the preservation of cultural landmarks in what historians say was once an economic and ceremonial hub.
Native American tribes joined environmentalists and archaeologists in calling for a reset in the San Juan Basin. And now, New Mexico's all-Democratic congressional delegation has reintroduced legislation aimed at protecting the area.
Here's a look at Chaco and what the bill would and wouldn't do:
A WORLD HERITAGE SITE
A UNESCO World Heritage site, Chaco park includes what's left of an ancient civilization whose monumental architecture and cultural influences have long been a mystery. While the park represents the heart of the area, numerous archaeological sites lie well outside its boundaries.
Aside from archaeological sites containing stone structures and pottery shards, researchers say the landscape helps explain what drew people to Chaco centuries ago. They've noted less tangible features, such as unobstructed views to distant buttes or mountain peaks.
Scientists agree the location offered something of a religious or ritualistic experience for the ancestors of today's Native American pueblos. Many of the structures align with celestial events, such as the summer solstice.
The San Juan Basin covers portions of northwestern New Mexico and southwestern Colorado. Production there began nearly a century ago, with the basin hitting its stride in the early 1990s and 2000s as thousands of new wells were drilled.
The area since has taken a distant backseat to the Permian Basin on the other end of New Mexico where the oil boom has reached unprecedented levels.
Still, environmentalists and tribes are concerned that as technology advances, development could pick up and put more pressure on Chaco's boundaries and other culturally significant areas within the region.
WHAT WOULD BE PROTECTED?
Supporters say passage of the latest federal bill would help permanently protect the area's archaeological resources and sensitive landscape.
Federal land managers in recent years have denied the leasing of parcels within a 10-mile (16-kilometer) radius of the park, but the measure would formalize that practice for future development on federal inholdings within the area.
The proposed protection zone stretches across 1,420 square miles (3,680 square kilometers) of federal, state, private and tribal land.
Congressional staffers say the bill would withdraw nearly 500 square miles (1,280 square kilometers) of minerals owned by the federal government.
The New Mexico State Land Office also plans to withdraw state trust land within the buffer from future mineral development.
Critics have argued that the buffer is arbitrary. And, the bill will be a tough sell in the Republican-led U.S. Senate.
WHAT'S STILL ON THE TABLE?
Most of the area within the protection zone is Navajo land and individual Navajo allotments. The legislation would not affect mineral rights on these lands, meaning development would still be possible there.
The 328 square miles (850 square kilometers) of allotted land alone has 628 oil and gas leases, according to the U.S. Bureau of Indian Affairs. In the last fiscal year, the agency said it paid out $32 million to those who have rights to the land.
The All Pueblo Council of Governors, which represents a coalition of New Mexico tribes, has called for a moratorium on drilling around Chaco park.
Navajo Nation President Jonathan Nez has said his people cannot afford the risk of water contamination from drilling. However, the tribe hasn't banned it and a resolution to oppose hydraulic fracking expired this year without a final vote by tribal lawmakers.
The legislation also would not halt existing development. According to the Bureau of Land Management, there are 133 active wells within the proposed buffer zone.
Some Navajos are pressing for limits beyond what's in the federal bill.
"Where industry is really pushing is places off the buffer zone," said Mario Atencio, an assistant to Navajo Nation lawmaker Daniel Tso. "We're still trying to fight for protection of those communities."
A VISIT FROM CONGRESS
Members of Congress are touring Chaco this weekend and holding a field hearing Monday in Santa Fe on the impact of oil and gas drilling on air quality and sacred sites.
The House Subcommittee on Energy and Mineral Resources, led by Arizona Rep. Raul Grijalva and New Mexico Rep. Deb Haaland, is expected to hear from tribal leaders, top state officials, archaeologists and other advocates.
None of the panels include representatives of the oil and gas industry or the Bureau of Land Management.
The hearing comes as the federal agency continues to work with the Bureau of Indian Affairs on revamping the basin's resource management plan. A draft is expected in a few months.
Fonseca reported from Flagstaff, Arizona.