A record of ancient tectonic stress on Mars

November 3, 2016, European Space Agency
This part of Acheron Fossae was imaged by the High Resolution Stereo Camera on ESA’s Mars Express on 4 May 2016 during orbit 15641. The image is centred on 36ºN/142ºW and the ground resolution is about 18 m per pixel. Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

Sets of ridges and troughs some 1000 km north of the giant Olympus Mons volcano contain a record of the intense tectonic stresses and strains experienced in the Acheron Fossae region on Mars 3.7–3.9 billion years ago.

This scene, captured by ESA's Mars Express on 4 May, focuses on the western part of Acheron Fossae, an isolated block of ancient terrain that covers an area about 800 km long and 280 km wide and stands up to 2 km higher than the surrounding plains.

Acheron Fossae is part of a network of fractures that radiates from the Tharsis 'bulge' some 1000 km to the south, home to the largest volcanoes on Mars. As the Tharsis region swelled with hot material rising from deep inside Mars as the volcanoes formed, it stretched and pulled apart the crust along lines of weakness over a wide area.

This process gave rise to the classic 'horst and graben' system – a series of depressions (graben) bounded by faults and uplifted blocks (horsts) either side of the graben.

The pattern of cross-cutting faults seen in various places in Acheron Fossae implies the region experienced stresses from different directions over time, suggesting a complex history.

Part of a dominant, curved ridge that extends through the entire region is seen in the lower left of the scene. It may be an ancient graben that has since been filled with material that has flowed along it, possibly from rock-laden glaciers that were deposited in more recent cold climatic conditions, long after the graben itself formed.

This context image shows part of Acheron Fossae on Mars imaged by Mars Express on 4 May 2016 during orbit 15641 (outlined by the large white box). Credit: NASA MGS MOLA Science Team

Acheron Fossae has been likened to Earth's continental rift systems. Major rift zones on Earth are associated with plate tectonics, such as mid-ocean ridges that are spreading apart.

On Mars, rifts are important for studies of the general evolution of the crust as well as the thermal evolution of the deeper subsurface.

The colour-coded topographic view shows relative heights and depths of terrain in the western portion of the Acheron Fossae region on Mars. Browns and whites represent the highest terrain (lower left), which transition through red, to yellow, green and blue in the upper right, representing progressively lower terrain. The image is based on a digital terrain model of the region, from which the topography of the landscape can be derived. The region was imaged by the High Resolution Stereo Camera on ESA’s Mars Express on 4 May 2016 during orbit 15641. The image is centred on 36ºN/142ºW and the ground resolution is about 18 m per pixel. Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO
This anaglyph image showing part of the Acheron Fossae region on Mars provides a 3D view of the landscape when viewed using stereoscopic glasses with red–green or red–blue filters. The image is based on data acquired by the nadir channel and one stereo channel of the High Resolution Stereo Camera on Mars Express on 4 May 2016 during orbit 15641. The main image is centred on 36ºN/142ºW and the ground resolution is about 18 m per pixel. Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

Explore further: Space Image: Claritas Fossae , Mars

Related Stories

Space Image: Claritas Fossae , Mars

November 22, 2011

(PhysOrg.com) -- Mars' Claritas Fossae region is characterized by systems of "graben" running mainly north-west to south-east.

Image: Cut crater in Memnonia Fossae

May 17, 2016

An extensive network of fault lines cut through this region of Mars, including one that slices clean through an ancient 52 km-wide crater.

Cutting through Martian history

July 9, 2015

This colourful image resembles an abstract watercolour, but it is in fact a colour-coded topographic map of one of the most geologically diverse regions on Mars.

Mars Express sees deep fractures on Mars

May 6, 2011

Newly released images from ESA's Mars Express show Nili Fossae, a system of deep fractures around the giant Isidis impact basin. Some of these incisions into the martian crust are up to 500 m deep and probably formed at the ...

ESA image: Martian labyrinth

January 29, 2016

This block of martian terrain, etched with an intricate pattern of landslides and wind-blown dunes, is a small segment of a vast labyrinth of valleys, fractures and plateaus.

Recommended for you

Semimetals are high conductors

March 18, 2019

Researchers in China and at UC Davis have measured high conductivity in very thin layers of niobium arsenide, a type of material called a Weyl semimetal. The material has about three times the conductivity of copper at room ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.