Answer:
Chuska and San Mateo mountains.
Step-by-step explanation:
The strontium isotopes indicate that timbers and logs used to build houses and infrastructures at Chaco Canyon came from Chuska and San Mateo mountains.
These mountains are about 100 kilometres away from the canyon and Strontium ratio from the Chaco canon's dust, water and bedrock reveals that these construction beams were from the Chuska and San Mateo mountains.