Last updated: December 9, 2025
Place
Cerro La Jara Stop 6
NPS
So far, you have learned that about 1.2 million years ago, a giant volcanic eruption occurred and created Valles Caldera when the roof of the empty magma chamber collapsed. The material that was erupted (called the Bandelier Tuff) was deposited inside the new hole in the ground and on the surrounding landscape. Shortly after that, molten rock that was still under the caldera floor pushed the ground up to create the resurgent dome, Redondo Peak, that is now ahead of you. The volcanic domes Cerro La Jara – to your right, and South Mountain – to your left, were formed when thick, rhyolitic lava was extruded at the surface through vents and fissures that were located above the ring fracture system.
The volcanic dome, Cerro La Jara, is still to your right. This is a good place to see flow banding in the rocks. The banding looks like layers in the rock and indicates that either different lava textures or different lava composition, or both, made the rocks break down and weather differently.
Imagine a lake, right here where you are standing. Over the hundreds of thousands of years since it was formed, the caldera was sometimes home to a lake, or several lakes. Sediment deposits show that one of the lakes was about 75 feet deep here. The gently sloped mound ahead of you is made of a frothy rock called pumice that was floating on a lake and was left behind when the water broke through a lava dam and drained, leaving the pumice raft behind.
Lake deposits of mud, silt, and sand contain climate indicators such as pollen. Scientists use these to learn about past climates. The climate has changed many times since the creation of Valles Caldera and is changing today. Climate records from the last 100 years show the average yearly temperature in the area is increasing quickly and the average yearly precipitation is decreasing.
Continue on the trail to Stop 7, which is on a high point around the corner where you can see the road and mountains in the distance.
The volcanic dome, Cerro La Jara, is still to your right. This is a good place to see flow banding in the rocks. The banding looks like layers in the rock and indicates that either different lava textures or different lava composition, or both, made the rocks break down and weather differently.
Imagine a lake, right here where you are standing. Over the hundreds of thousands of years since it was formed, the caldera was sometimes home to a lake, or several lakes. Sediment deposits show that one of the lakes was about 75 feet deep here. The gently sloped mound ahead of you is made of a frothy rock called pumice that was floating on a lake and was left behind when the water broke through a lava dam and drained, leaving the pumice raft behind.
Lake deposits of mud, silt, and sand contain climate indicators such as pollen. Scientists use these to learn about past climates. The climate has changed many times since the creation of Valles Caldera and is changing today. Climate records from the last 100 years show the average yearly temperature in the area is increasing quickly and the average yearly precipitation is decreasing.
Continue on the trail to Stop 7, which is on a high point around the corner where you can see the road and mountains in the distance.
Hasta ahora, has aprendido que hace aproximadamente 1.2 millones de años se sucedió una erupción volcánica gigantesca que creó la caldera de Valles cuando se derrumbó el techo de la cámara magmática vacía. El material que entró en erupción (denominado toba de Bandelier) se depositó dentro del nuevo agujero en el suelo y en el paisaje circundante. Poco después, la roca fundida que aún se encontraba bajo el suelo de la caldera empujó el terreno hacia arriba y creó el domo resurgente, Redondo Peak, que ahora se encuentra frente a ti. Los domos volcánicos Cerro La Jara, a tu derecha, y South Mountain, a tu izquierda, se formaron cuando la lava riolítica espesa se extruyó en la superficie a través de conductos y fisuras que se encontraban sobre el sistema de fracturas anulares.
El domo volcánico, Cerro La Jara, sigue estando a su derecha. Este es un buen lugar para ver las bandas de flujo en las rocas. Las bandas parecen capas en la roca e indican que o bien diferentes texturas de lava o diferentes composiciones de lava, o ambas cosas, hicieron que las rocas se descompusieran y se erosionaran de manera diferente.
Imagina un lago justo aquí, donde estás parado. Durante los cientos de miles de años desde su formación, la caldera albergó en ocasiones un lago o varios lagos. Los depósitos de sedimentos muestran que uno de los lagos tenía aquí una profundidad de unos 23 metros. El monte que se encuentra frente a ti está formado por una roca espumosa llamada piedra pómez que flotaba en un lago y quedó atrás cuando el agua rompió una presa de lava y se drenó, dejando atrás la balsa de piedra pómez.
Los depósitos lacustres de lodo, limo y arena contienen indicadores climáticos como el polen. Los científicos los utilizan para obtener información sobre los climas del pasado. El clima ha cambiado muchas veces desde la creación de Valles Caldera y sigue cambiando en la actualidad. Los registros climáticos de los últimos 100 años muestran que la temperatura media anual de la zona está aumentando rápidamente y que la precipitación media anual está disminuyendo.
Continúe por el sendero hasta la parada 7, que se encuentra en un punto elevado a la vuelta de la esquina, desde donde se puede ver la carretera y las montañas en la distancia.