Martian Volcanoes

Table of Contents

• Introduction
• Views of Martian Volcanoes
• References

Introduction

Elysium Planitia is the second largest volcanic region on Mars. Elysium Planitia is centered on a broad dome that is 1700 x 2400 km in size. It has smaller volcanoes than the Tharsis region, but a more diverse volcanic history. The three volcanoes include Hecates Tholus, Elysium Mons and Albor Tholus.

The large shield volcanoes on Mars resemble Hawaiian shield volcanoes. They both have effusive eruptions which are relatively quite and basaltic in nature. Both have summit pits or calderas and long lava flows or channels. The biggest difference between Martian and Terrestrial volcanoes is size. The volcanoes in the Tharsis region are 10 to 100 times larger than those on Earth. They were built from large magma chambers deep within the Martian crust. The Martian flows are also much longer. This is probably due to larger eruption rates and to lower gravity. One of the reasons volcanoes of such magnitude were able to form on Mars is because the hot volcanic regions in the mantle remained fixed relative to the surface for hundreds of millions of years. On Earth, the tectonic flow of the crust across the hot volcanic regions prevent large volcanoes from forming. The Hawaiian islands were created as the Pacific plate moved northwest. These volcanoes have a relatively short life time. As the plate moves new volcanoes form and the old ones become silent.

Not all Martian volcanoes are classified as shields with effusive eruption styles. North of the Tharsis region lies Alba Patera. This volcano is comparable to Olympus Mons in its horizontal extent but not in height. Its base diameter is 1,500 km but is less than 7 km high. Ceraunius Tholus is one of the smaller volcanoes. It is about the size of the Big Island of Hawaii. It exhibits explosive eruption characteristics and probably consists of ash deposits. Tyrrhena Patera and Hadriaca Patera both have deeply eroded features which indicate explosive ash eruptions. Mt. Saint Helens is an example of a terrestrial ash eruption.

Views of Martian Volcanoes

This set of images was chosen to show some of the best examples of volcanic landforms on Mars.

Tharsis Montes (GIF, 483K; JPG, 48K; TIF, 1M)
The alignment of the three shield volcanoes that make up the Tharsis [THAR-siss] Montes region is clearly evident in this view. They are named Ascraeus Mons (top right), Pavonis Mons (middle) and Arsia Mons (bottom). Olympus Mons can be seen in the upper left hand corner. The three volcanoes are each somewhat smaller than Olympus Mons, varying from 350 to 450 km in horizontal extent and each rising about 15 km above the surrounding plains. The Tharsis Montes are located on the crest of a broad uplift of the Martian crust so that their summits are at about the same elevation as the summit of Olympus Mons. The fractures southeast of Pavonis Mons are named Noctis Labyrinthus; this region merges with the enormous Vallis Marineris canyon system to the east. (Credit: Calvin J. Hamilton, Los Alamos National Laboratory)

Elysium Planitia (GIF, 204K; JPG, 20K; TIF, 591K)
Elysium Planitia is the second largest volcanic region on Mars. It is located on a broad dome that is 1700 x 2400 km in size. The volcanoes Hecates Tholus, Elysium Mons and Albor Tholus can be seen going from north to south (top to bottom) in this image. Hectas Tholus is 160 x 175 km in size with a caldera complex 11.3 x 9.1 km in size. Elysium Mons is the largest volcano in this region. It has base dimensions of 420 x 500 x 700 km and rises 13 km above the surrounding plains. Its summit caldera is about 14.1 km in diameter. Albor Tholus measures 160 x 150 km with a summit caldera of 35 x 30 km. Its northwest flanks have been partially buried by lava flows from Elysium Mons. (Credit: Calvin J. Hamilton, Los Alamos National Laboratory)

Olympus Mons (GIF, 644K; JPG, 73K)
Olympus [oh-LIM-pus] Mons is the largest volcano known in the solar system. It is classified as a shield volcano, similar to volcanoes in Hawaii. The central edifice of Olympus Mons has a summit caldera 24 km above the surrounding plains. Surrounding the volcano is an outward-facing scarp 550 km in diameter and several kilometers high. Beyond the scarp is a moat filled with lava, most likely derived from Olympus Mons. Farther out is an aureole of characteristically grooved terrain, just visible at the top of the frame. (Courtesy NASA/JPL).

3D Olympus Mons (GIF, 211K; JPG, 24K)
This 3D image of Olympus Mons was created from several images taken from different spacecraft positions and combined with a computer model of the surface topography. The final mosaic shows Olympus as it would be seen from the northeast. It is possible that volcanoes of such magnitude were able to form on Mars because the hot volcanic regions in the mantle remained fixed relative to the surface for hundreds of millions of years. (Courtesy NASA/JPL).

Ascraeus Mons Summit (GIF, 173K; JPG, 24K)
This complex caldera is composed of several discrete centers of collapse where the older collapse features are cross-cut by more recent collapse events. The lowermost circular floor preserves the last lava flooding event that followed the last major collapse. The southern wall of the caldera has at least 3 km of vertical relief with an average slope of at least 26° (from horizontal). The caldera complex truncates several lava flows, indicating that the flows predate the collapse event and that their source areas have been destroyed by the caldera formation. (Credit: Calvin J. Hamilton, Los Alamos National Laboratory; Lunar and Planetary Institute)

For an 832x778 GIF image (337K) of the entire volcano click HERE.

Arsia Mons (GIF, 207K; JPG, 70K)
The caldera on Arsia Mons is considerably larger than the calderas on either Ascraeus Mons or Pavonis Mons. However, the last major collapse event on Arsia Mons was followed by a substantial outpouring of lava within the caldera. The caldera rim has been breached on the southwest side while the caldera floor lavas bury portions of the northeast rim. Aligned between these breaks in the caldera is a series of very subdued domes on the caldera floor, perhaps representing localized sources of the lava that flooded the caldera. The flaks of the shield have been deeply eroded near the locations of the breaks in the caldera rim and lava flows extend away from the volcanoes at these embayments. (Credit: Calvin J. Hamilton, Los Alamos National Laboratory; Lunar and Planetary Institute)

Apollinaris Patera (GIF, 234K; JPG, 44K)
This view of Apollinaris Patera, shows characteristics of an explosive origin and an effusive origin. Incised valleys in most of the flanks of Apollinaris Patera indicates ash deposits and an explosive origin. On the west side (left) landslides have shaped its surface also indicating ash deposits. Towards the south flank a large fan of material flowed out of the volcano. This indicates an effusive origin. Perhaps during its early development Apollinaris Patera had an explosive origin with effusive eruptions taking place later on. (Credit: Calvin J. Hamilton, Los Alamos National Laboratory)

Ceraunius Tholus and Uranius Tholus (GIF, 468K; JPG, 67K)
Ceraunius Tholus (bottom) shows several incised valleys cut into its flanks which indicate that it was easily eroded and probably consists of ash deposits due to explosive activity. Ceraunius Tholus is about the size of the Big Island of Hawaii. Uranius Tholus (Top) also shows similar characteristics to Ceraunius Tholus. (Credit: Calvin J. Hamilton, Los Alamos National Laboratory)

Ceraunius Tholus and Uranius Tholus - 3D (GIF, 133K; JPG, 30K)
This is a three dimensional view of Ceraunius Tholus (right) and Uranius Tholus (left). The view is from the northwest. (Credit: Calvin J. Hamilton, Los Alamos National Laboratory)

Tharsis Tholus (GIF, 113K; JPG, 14K)
Tharsis Tholus measures about 150 km across and 8 km high. The east and west flanks are indented giving it a strange appearance. One possible cause for its appearance is that when the lava supply drained away, the center of the volcano collapsed. An alternative is that big slump areas carried off portions of the flanks giving it the broken appearance. (Credit: Calvin J. Hamilton, Los Alamos National Laboratory)

Uranius Patera (GIF, 256K; JPG, 35K)
Uranius Patera is about the size of the Big Island of Hawaii. It is about 3 km in height. It has shallow slopes and lava flows. This indicates an effusive origin. The center caldera was formed when lava drained away and the volcano collapsed. (Credit: Calvin J. Hamilton, Los Alamos National Laboratory)

Ulysses Patera (GIF, 226K; JPG, 41K)
This feature is an example of a class of volcanoes that are considerably smaller than the broad shield volcanoes. The summit consists of a single, very circular caldera with a smooth floor that predates the ejecta from two large impact craters. The lower flanks of the volcano, including portions of the impact craters, have been buried by the material that makes up the surrounding plains. This superpositional relationship indicates that the plains were emplaced subsequent to both the volcano and the large impact craters on the volcano. The plains are probably made up of lava supplied from Tharsis Montes that flowed down the sides of the broad uplift associated with the Tharsis shields. Both the plains and the volcano are cut by a garben, indicating tectonic activity subsequent to the emplacement of the plains. (Credit: Calvin J. Hamilton, Los Alamos National Laboratory; Lunar and Planetary Institute)

Ulysses Patera in 3D (GIF, 162K; JPG, 32K)
This shows perspective view of Ulysses Patera looking from the north. (Credit: Calvin J. Hamilton, Los Alamos National Laboratory)

Tyrrhena Patera (GIF, 328K; JPG, 98K)
Volcanoes located within the densely cratered southern highlands have a very different morphology from either the Tharsis or Elysium volcanoes. Tyrrhena Patera has very little vertical relief (< 2 km), resulting in very shallow flank slopes. The flanks of the volcano are deeply eroded with many broad channels that radiate from the summit region. The low relief and easily erodible nature of the flank materials has been interpreted to indicate that the bulk of the volcano is composed of pyroclastic ash deposits. This interpretation implies that the style of eruption for the highland volcanoes like Tyrrhena Patera is significantly different from the repeated effusion of fluid lavas that built up the shield volcanoes. (Credit: Calvin J. Hamilton, Los Alamos National Laboratory; Lunar and Planetary Institute)

Tyrrhena Patera in 3D (GIF, 65K; JPG, 24K)
This shows perspective view of Tyrrhena Patera looking from the north. The vertical dimension has been greatly exaggerated to show detail. (Credit: Calvin J. Hamilton, Los Alamos National Laboratory)

Hadriaca Patera (GIF, 535K; JPG, 86K)
Much like Tyrrhena Patera, Hadriaca Patera is a deeply eroded feature having little vertical relief. Several impact craters are superimposed on the eroded flanks, indicating a great age for this volcano. A large channel has its source near the southeastern margin of the volcano; the fluid that carved the channel flowed southwest into the interior of the Hellas basin. (Credit: Calvin J. Hamilton, Los Alamos National Laboratory; Lunar and Planetary Institute)

Tempe Volcano (GIF, 198K)
Volcanic construct on Mars are not all enormous mountains like the Tharsis Montes. This elongate hill surmounted by a linear depression is interpreted to be a product of localized but not extremely voluminous eruptions. If the volcanic material was emplaced by ejection along a ballistic trajectory, this feature may be similar to a terrestrial cinder cone. This feature is aligned with several garbens in the area so that a structural weakness in the crust may have provided the conduit for the volcanic material to reach the surface. (Credit: Calvin J. Hamilton, Los Alamos National Laboratory; Lunar and Planetary Institute)

Hellas Mounds (GIF, 709K)
Numerous small mounds having summit craters are found in various locations on Mars. The mounds shown here are east of the Hellas basin. These features have been interpreted to be pseudocraters created by localized phreatic explosions where lava interacts with volatile-rich ground. Most of the mounds are between 400 m to 1 km across. Many have slotlike summit vents. However, images presently available do not have sufficient resolution to show conclusive evidence of a volcanic origin for the mounds. (Credit: Calvin J. Hamilton, Los Alamos National Laboratory; Lunar and Planetary Institute)

Beatty, J. K. and A. Chaikin, eds. The New Solar System. Massachusetts: Sky Publishing, 3rd Edition, 1990. (See Chapter 5, pp. 57-59.)

Carr M. H. "The Volcanoes of Mars." Scientific American, 1975, 234, 32-43.

Carr M. H. The Surface of Mars. Yale University Press, New Haven, 1981. (See Chapter 7, pp. 87-113.)

Greeley R. and Spudis P. D. "Volcanism on Mars." Reviews of Geophysics and Space Physics, 1981, 19, 13-41.

Mutch T. A., Arvidson R. E., Head J. W. III, Jones K. L., and Saunders R. S. The Geology of Mars. Princeton University Press, Princeton, 1976. (See Chapter 4, pp. 151-201.)

Robinson, Mark. "Exploring Small Volcanoes on Mars." Astronomy, April 1994, pp. 30-37.

Zimbelman, James R. Volcanoes on Mars Slide Set. Lunar and Planetary Institute.

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Copyright © 1995 by Calvin J. Hamilton. All rights reserved.
Last Modified: March 2, 1995