Volcanic Inverted Topography

This lava flow at Petroglyph National Monument travelled in a topographic low after its eruption. Because the volcanic rock in the lava flow is more resistant to erosion than the other rocks in the region, erosion since the time of eruption has left the lava flow higher than the surrounding terrain.

NPS Photo.

Introduction

Inverted topography is a classic type of landform in the American southwest with its young monogenetic volcanic fields and rapid arid-land erosion. Many volcanic deposits, whether they are lava flows or ash-flow-tuffs, flow down river valleys and topographic lows and even fill them. Because they are resistant to erosion, the volcanic rocks may erode away more slowly than the rocks that had made the sides of the former valleys. With time and this process of differential erosion, lava flows that once travelled down valleys later stand as mesas. This process reverses the elevation of volcanic features relative to other features; e.g., lava-filled valleys become mesas, and, in turn, former topographic high points become valleys.

Inverted topography can sometimes help geologists determine the relative age of volcanic deposits. In areas with numerous lava flows of varying ages, the oldest will stand the highest above the current landscape with progressively younger flows becoming closer to the current land surface.

The most common type of inverted topography is formed by basaltic lava flows. But inverted topography can also form in locations of former valleys that were filled by ash-flow tuffs or lava domes as these rock types are also frequently harder than surrounding country rocks.

_{Figure (right): Schematic illustrations of the formation of inverted topography. Top graphic: Lava flows travel in topographic lows and valleys below surrounding topographic highs. Middle graphic: The hard volcanic rock protects the underlying country rock from erosion, eroding more slowly than the surrounding topography. Bottom graphic: stream valleys in which lava once flowed stand as high mesas above modern valleys.
NPS image by Trista Thornberry-Ehrlich after Muehlberger et al. (2005, p. 4).}

National Parks and Inverted Topography

At least ten units of the National Park System are in or near volcanic fields with examples of inverted topography.

Capulin Volcano National Monument

Capulin Volcano NM sits within the Raton-Clayton Volcanic Field which experienced three phases of activity during the last 9 million years. The older lava flows stand at an elevation above the current ground surface level, whereas younger lava flows, like those erupted from Capulin Volcano, are the current ground surface level.

Left image
The Johnson Mesa lava flow was erupted approximately 8 million years ago and now holds up a low mesa west of Capulin Volcano NM. Jose Butte is a cinder cone that erupted about 2.5 million years ago.
Credit: Photo by Allyson Mathis.

Right image
Photo with feature labels added
Credit: Photo by Allyson Mathis.

Grand Canyon National Park

Examples of inverted topography are found near Grand Canyon. Some of the basaltic lava flows capping mesas and buttes in the region provide important age constraints for the age of the landscape as geologists can determine the age of the lava flows and calculate rates of erosion using the age information and how high the lava flow is above the regional ground level.

Red Butte near the South Rim is a good example of inverted topography as the basaltic lava flow now capping the butte originally was on topographic low.

USGS photo.

Petrified Forest National Park

The Hopi Buttes Volcanic Field, which is mostly north of Petrified Forest NP but extends into the park, consists mostly of maar and diatreme volcanoes along with associated basaltic lava flows.

Inverted topography in the Hopi Buttes Volcanic Field.

From Benjamin Van Wyk de Vries et al. 2022. Inverted volcanic relief: Its importance in illustrating geological change and its geoheritage potential.

Petroglyph National Monument

West Mesa in Petroglyph National Monument is held up by resistant lava flows that now stand above the general elevation of the land. These lava flows were erupted approximately 200,000 years ago.

West Mesa in Petroglyph National Monument is a classic example of inverted topography.

Image © 2017 Google. Annotations by Jason Kenworthy—NPS Geologic Resources Division.

Geoheritage Values

Volcanic inverted topography is recognized for having geoheritage values since these landscapes can be easy to understand, can readily be observed, and result from the passage of geologic time and geologic change.

Learn More

• International Journal of Geoheritage and Parks—Inverted volcanic relief: Its importance in illustrating geological change and its geoheritage potential

National Park Sites in Areas with Inverted Topography

1. Capulin Volcano National Monument (CAVO), New Mexico—[CAVO Geodiversity Atlas] [CAVO Park Home ] [CAVO npshistory.com]

2. Chiricahua National Monument (CHIR), Arizona—[CHIR Geodiversity Atlas] [CHIR Park Home] [CHIR npshistory.com]

3. Grand Canyon National Park (GRCA), Arizona—[GRCA Geodiversity Atlas] [GRCA Park Home] [GRCA npshistory.com]

4. Grand Canyon-Parashant National Monument (PARA), Arizona—[PARA Geodiversity Atlas] [PARA Park Home] [PARA npshistory.com]

5. Lake Mead National Recreation Area (LAKE), Arizona and Nevada—[LAKE Geodiversity Atlas] [LAKE Park Home] [LAKE npshistory.com]

6. Petrified Forest National Park (PEFO), Arizona—[PEFO Geodiversity Atlas] [PEFO Park Home] [PEFO npshistory.com]

7. Petroglyph National Monument (PETR), New Mexico—[PETR Geodiversity Atlas] [PETR Park Home] [PETR npshistory.com]

8. Sunset Crater Volcano National Monument (SUCR), Arizona—[SUCR Geodiversity Atlas] [SUCR Park Home] [SUCR npshistory.com]

9. Zion National Park (ZION), Utah—[ZION Geodiversity Atlas] [ZION Park Home] [ZION npshistory.com]

Related Links

• NPS—Erosion: Water, Wind & Weather

Volcanoes, Craters, and Lava Flows