Organ Mountains
The Organ Mountains lie about 10 miles east of Las Cruces and are the predominant geologic
feature of this area. They are one of the most picturesque and rugged mountain ranges in the
Southwest and provide a great place to hike and explore that is only minutes from our home. The
Organs' name reflects their similarity in appearance (particularly the granite "needles" in the highest
part of the range) to pipes of an organ. The highest peak, Organ Needle, has an elevation of 8,990
feet.
The Organs lay near the southern end of a long line of mountains on the east side of the Rio
Grande's rift valley which runs through the center of New Mexico. The range is nearly contiguous
with the San Andres Mountains to the north and the Franklin Mountains to the south, but it is very
different geologically. Whereas the San Andres and Franklin Mountains were both formed from
mostly sedimentary rock, the Organ Mountains are made primarily of igneous rock and developed
about 30 million years ago during a period of extreme volcanism and uplift. These rocks are often
called "fire rocks" because they are formed by extreme heat either underground or above ground.
Underground, they are formed when the melted rock, called magma, slowly cools and solidifies. It is
then pushed to the surface by some uplifting process. Much of the granite found in the Organs are
of this type of igneous rock. Volcanoes also form igneous rocks when magma rises above the
earth's surface in the form of lava which then solidifies into rock when it cools. There is much
evidence of ancient volcanic activity, especially in the southern Organs. On the west side of the
Organs there is layered sedimentary rock dating back over 400 million years. This was formed when
this area was part of a shallow sea extending up from the south and then far to the north.
Areas of the Organs have been mined since the mid-1800s, mainly for silver and lead. A number of
other minerals were also the subject of commercial mining operations in the past, but there are
currently no active mines in the area. Abandoned mines are a common sight while hiking in this area.
The mountains harbor more than 800 plant species, including mesquite trees, creosote bushes,
lecheguilla agave, various juniper and oaks in the intermediate elevations; and ponderosa pine,
mountain mahogany in the higher elevations. The Organs have perhaps the richest assemblage of
ferns, mosses, and lichens in the West. Enriched by several permanent springs and various
intermittent streams, these mountains are host to some 80 species of mammals, ranging from the
Organ Mountain chipmunk to the mule deer and mountain lion; 185 species of birds, ranging from the
ruby-throated hummingbird to the golden eagle; and 60 species of reptiles and amphibians, from the
horned lizard to the western diamondback rattlesnake.
Here are some images that show the ever-changing view we have of the Organs....
feature of this area. They are one of the most picturesque and rugged mountain ranges in the
Southwest and provide a great place to hike and explore that is only minutes from our home. The
Organs' name reflects their similarity in appearance (particularly the granite "needles" in the highest
part of the range) to pipes of an organ. The highest peak, Organ Needle, has an elevation of 8,990
feet.
The Organs lay near the southern end of a long line of mountains on the east side of the Rio
Grande's rift valley which runs through the center of New Mexico. The range is nearly contiguous
with the San Andres Mountains to the north and the Franklin Mountains to the south, but it is very
different geologically. Whereas the San Andres and Franklin Mountains were both formed from
mostly sedimentary rock, the Organ Mountains are made primarily of igneous rock and developed
about 30 million years ago during a period of extreme volcanism and uplift. These rocks are often
called "fire rocks" because they are formed by extreme heat either underground or above ground.
Underground, they are formed when the melted rock, called magma, slowly cools and solidifies. It is
then pushed to the surface by some uplifting process. Much of the granite found in the Organs are
of this type of igneous rock. Volcanoes also form igneous rocks when magma rises above the
earth's surface in the form of lava which then solidifies into rock when it cools. There is much
evidence of ancient volcanic activity, especially in the southern Organs. On the west side of the
Organs there is layered sedimentary rock dating back over 400 million years. This was formed when
this area was part of a shallow sea extending up from the south and then far to the north.
Areas of the Organs have been mined since the mid-1800s, mainly for silver and lead. A number of
other minerals were also the subject of commercial mining operations in the past, but there are
currently no active mines in the area. Abandoned mines are a common sight while hiking in this area.
The mountains harbor more than 800 plant species, including mesquite trees, creosote bushes,
lecheguilla agave, various juniper and oaks in the intermediate elevations; and ponderosa pine,
mountain mahogany in the higher elevations. The Organs have perhaps the richest assemblage of
ferns, mosses, and lichens in the West. Enriched by several permanent springs and various
intermittent streams, these mountains are host to some 80 species of mammals, ranging from the
Organ Mountain chipmunk to the mule deer and mountain lion; 185 species of birds, ranging from the
ruby-throated hummingbird to the golden eagle; and 60 species of reptiles and amphibians, from the
horned lizard to the western diamondback rattlesnake.
Here are some images that show the ever-changing view we have of the Organs....
| Sunset light on the Organ Mountains |
| The Needles with old mine building in foreground |
| Looking east to the Organ Mountains after a winter snowfall |
| As one approaches Las Cruces from the West, the Organs are seen on the eastern horizon |