Light and dark in the Phoenix Lake

Nov 12, 2010
Phoenicis Lacus on Mars

(PhysOrg.com) -- They say you can't judge a book by its cover but, with planets, first impressions do count. New images show where complex fault lines in Mars’ Phoenicis Lacus region have resulted in terrain with a distinctly contrasting appearance.

Nineteenth-century astronomers were the first to see Phoenicis Lacus on Mars. They identified it as a dark spot, and thought that it resembled a sea. Now we know that it is not a body of water but the southwestern extension of the complex Noctis Labyrinthus system, which stretches away from the giant volcanoes of Mars’s Tharsis region.

Phoenicis Lacus shown in context

The brightness of a surface feature is still the first thing planetary astronomers notice. It is known as the albedo and is partly determined by the composition of the surface material. For example, ice is more reflective than rock. The texture of the surface also plays a part, with rough surfaces reflecting less sunlight and so appearing darker than smooth surfaces.

Phoenicis Lacus has an area of 8100 sq km (59.5 x 136 km), which corresponds to the size of Corsica. Only a small portion of it appears in this image, which was obtained on 31 July 2010 using the High-Resolution Stereo Camera (HRSC) on ESA’s Express spacecraft.

Elevation of Phoenicis Lacus region

Phoenicis Lacus was formed by the uplift of the Tharsis plateau. The continual episodes of strong volcanic activity in Tharsis not only lifted the plateau, but also deformed Phoenicis Lacus, creating blocks and multiple fault lines at different orientations. Extension has taken place here, resulting in this characteristic ‘horst-and-graben’ (cliffs and valleys) landscape.

A prominent collapse feature in this region is also visible. It shows as a long pit and sinks to a depth of about 3 km below the surrounding plains. Its walls give a glimpse of extensive basalt layers and a small field of sand dunes covers the floor.

Phoenicis Lacus perspective view

An impact crater can be seen on the left of the image. It was elongated during the spreading of the graben and evolved from a circular to an ellipsoidal form.

The other large bowl-shaped structures in this image do not have distinct rims like impact craters, so they are most likely collapsed structures.

Explore further: SpaceX launches supplies to space station (Update)

add to favorites email to friend print save as pdf

Related Stories

Just how low can Mars go?

Oct 08, 2010

There are few places on Mars lower than this. On the left of this image, the floor of Melas Chasma sinks nine kilometres below the surrounding plains. New images from ESA’s Mars Express highlight the ...

Rocky mounds and a plateau on Mars

Jun 28, 2010

(PhysOrg.com) -- When Mars Express set sail for the crater named after Portuguese navigator Ferdinand Magellan, it found a windblown plateau and mysterious rocky mounds nearby.

Lava tubes on Pavonis Mons

May 23, 2006

These images, taken by the High Resolution Stereo Camera (HRSC) on board ESA's Mars Express, show Pavonis Mons, the central volcano of the three 'shield' volcanoes that comprise Tharsis Montes.

Volcanic ash in Meridiani Planum

May 12, 2010

Deposits of volcanic ash colour this view of the Meridiani Planum, as seen by the Mars Express High Resolution Stereo Camera. They also give clues to the prevailing wind direction in this region of Mars.

Mars Photos: 3D Image of Solis Planum

Sep 12, 2004

These images, taken by the High Resolution Stereo Camera (HRSC) on board ESA’s Mars Express spacecraft, show part of a heavily eroded impact crater at Solis Planum, in the Thaumasia region of Mars. The images wer ...

Recommended for you

NASA's space station Robonaut finally getting legs

5 hours ago

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Sun emits a mid-level solar flare

Apr 18, 2014

The sun emitted a mid-level solar flare, peaking at 9:03 a.m. EDT on April 18, 2014, and NASA's Solar Dynamics Observatory captured images of the event. Solar flares are powerful bursts of radiation. Harmful ...

Impact glass stores biodata for millions of years

Apr 18, 2014

(Phys.org) —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...

The importance of plumes

Apr 18, 2014

The Hubble Space Telescope is famous for finding black holes. It can pick out thousands of galaxies in a patch of sky the size of a thumbprint. The most powerful space telescope ever built, the Hubble provided ...

User comments : 0

More news stories

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Cosmologists weigh cosmic filaments and voids

(Phys.org) —Cosmologists have established that much of the stuff of the universe is made of dark matter, a mysterious, invisible substance that can't be directly detected but which exerts a gravitational ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.