About 30 million years ago, the land was in volcanic turmoil as a series of violent
eruptions changed the landscape dramatically.
The term "supervolcanoes" is used to describe the type that
created the landscapes you will see as you drive
along the Byway. Supervolcanoes are the largest
volcanic eruptions known to occur on earth. They
produce great quantities of ash and usually result
in a large crater (caldera) rather than a cone.
The Bursum and Gila Cliff Dwellings calderas are the remnants of two supervolcanoes. These eruptions produced catastrophic amounts of ash and pumice with a force estimated at 1000 times the power of the 1980 eruption of Mount Saint Helens. A supervolcano eruption is so explosive that magma withdrawal causes the overlying mass to collapse and fill the empty magma chamber, leaving a large caldera.
The Bursam caldera is 25 miles in diameter and extends from Hells Hole on the West Fork of the Gila River to the vicinity of Glenwood, New Mexico. Gila Cliff Dwellings National Monument sits on the southeastern edge of the slightly older and smaller (15 miles in diameter) of the two calderas.
The Bursum and Gila Cliff Dwellings calderas are the remnants of two supervolcanoes. These eruptions produced catastrophic amounts of ash and pumice with a force estimated at 1000 times the power of the 1980 eruption of Mount Saint Helens. A supervolcano eruption is so explosive that magma withdrawal causes the overlying mass to collapse and fill the empty magma chamber, leaving a large caldera.
The Bursam caldera is 25 miles in diameter and extends from Hells Hole on the West Fork of the Gila River to the vicinity of Glenwood, New Mexico. Gila Cliff Dwellings National Monument sits on the southeastern edge of the slightly older and smaller (15 miles in diameter) of the two calderas.
The relationship between geologic riches and the
economic development of this area is visible in
many places along the Byway. You can see
mining in progress at the Santa Rita Mine
overlook today. Many old shaft-mining locations
can also be seen from the road. Weathered head
frames mark their entrances and remind us of
mining activity in the past.
Early geologists accompanied military explora- tions of the western territories after the Civil War. Eastern entrepreneurs began to take an interest in Grant County in the 1870s and 1880s after word spread of the Pinos Altos gold strike and the abundance of copper at the Santa Rita Mine.
Mining companies sent geologists, mining engineers and smelter specialists to determine where mining could be done profitably. Workers settled in the area. Local Apache resisted these changes as they were being forced from their homelands.
Ft. Bayard was created as an army base to protect the mining industry. Prospectors, who were here before and after the big mining companies, continued to seek gold and silver independently.
Early geologists accompanied military explora- tions of the western territories after the Civil War. Eastern entrepreneurs began to take an interest in Grant County in the 1870s and 1880s after word spread of the Pinos Altos gold strike and the abundance of copper at the Santa Rita Mine.
Mining companies sent geologists, mining engineers and smelter specialists to determine where mining could be done profitably. Workers settled in the area. Local Apache resisted these changes as they were being forced from their homelands.
Ft. Bayard was created as an army base to protect the mining industry. Prospectors, who were here before and after the big mining companies, continued to seek gold and silver independently.
There are two main sources for geothermal water:
a magma body below the surface or an increase
in temperature due to the deep circulation of
rainwater.
Within the wilderness, the water chemistry of the hot springs shows no evidence of a magma body. It is most likely that the water has seeped deep into the earth, been heated by the geothermal gradient, and returned to the surface along faults and fractures.
Native peoples have used the Gila Hot Springs area in various ways for thousands of years. The Mimbres-Mogollon farmed the valleys. The Apache soaked in the soothing waters between battles and revered the springs for their medicinal and spiritual values.
As the European settlers arrived and began to move north into the forest, they also discovered the benefits and comforts of the hot springs. The early mountain men and trappers used the valley, as did the miners and the soldiers who set up an outpost.
Within the wilderness, the water chemistry of the hot springs shows no evidence of a magma body. It is most likely that the water has seeped deep into the earth, been heated by the geothermal gradient, and returned to the surface along faults and fractures.
Native peoples have used the Gila Hot Springs area in various ways for thousands of years. The Mimbres-Mogollon farmed the valleys. The Apache soaked in the soothing waters between battles and revered the springs for their medicinal and spiritual values.
As the European settlers arrived and began to move north into the forest, they also discovered the benefits and comforts of the hot springs. The early mountain men and trappers used the valley, as did the miners and the soldiers who set up an outpost.
New Mexico Highway 15 between Sapillo Creek
and Gila Cliff Dwellings National Monument winds through a complex geologic story
that presents some of the Byway's most striking
scenery.
Panoramic vistas allow you to survey the remnants of once active volcanoes. Close inspection of road cuts reveal layers of colorful ash flows and evidence of a once Yellowstone-like hot springs environment.
The area's youngest
rock layer is the Gila
Conglomerate. This
sedimentary rock
marks the time when
the older volcanic
rocks began to break
down. Over time,
large fault blocks
called grabens and
the waters of rivers
and creeks helped to
shape the topography
and carve deep canyons into the already dramatic
landscape. Rock minerals have broken down to create
soil. Plants began to grow, animals migrated, and
people eventually settled.
Panoramic vistas allow you to survey the remnants of once active volcanoes. Close inspection of road cuts reveal layers of colorful ash flows and evidence of a once Yellowstone-like hot springs environment.
The area's youngest
rock layer is the Gila
Conglomerate. This
sedimentary rock
marks the time when
the older volcanic
rocks began to break
down. Over time,
large fault blocks
called grabens and
the waters of rivers
and creeks helped to
shape the topography
and carve deep canyons into the already dramatic
landscape. Rock minerals have broken down to create
soil. Plants began to grow, animals migrated, and
people eventually settled.