Lawmakers from the country’s largest American Indian reservation may have thrown a wrinkle into efforts aimed at establishing a permanent buffer around Chaco Culture National Historical Park, as New Mexico’s congressional delegation, environmentalists and other tribes try to keep oil and gas development from getting closer to the World Heritage site.Lawmakers from the country’s largest American Indian reservation may have thrown a wrinkle into efforts aimed at establishing a permanent buffer around Chaco Culture National Historical Park, as New Mexico’s congressional delegation, environmentalists and other tribes try to keep oil and gas development from getting closer to the World Heritage site.