Martian fractures reveal ancient forces and icy flows

Written by Copernical Team Saturday, 09 August 2025 07:42

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Paris, France (SPX) Aug 08, 2025

In a new release from the European Space Agency, Mars Express has revisited the western end of Acheron Fossae, a striking system of deep fissures on Mars shaped by ancient geological upheaval and later sculpted by ice-rich flows. The orbiter's High Resolution Stereo Camera first captured this area in April 2004, just months into its mission. These latest images reveal the faulted terrain's

Martian fractures reveal ancient forces and icy flows
by Erica Marchand
Paris, France (SPX) Aug 08, 2025

In a new release from the European Space Agency, Mars Express has revisited the western end of Acheron Fossae, a striking system of deep fissures on Mars shaped by ancient geological upheaval and later sculpted by ice-rich flows.

The orbiter's High Resolution Stereo Camera first captured this area in April 2004, just months into its mission. These latest images reveal the faulted terrain's horst and graben pattern, where raised and lowered blocks formed as molten material rose beneath the crust over 3.7 billion years ago, pulling the surface apart into kilometre-deep valleys stretching hundreds of kilometres.

The valley floors, now smoothed by slow-moving rock glaciers, offer evidence of repeated climate swings. These glaciers, similar to those on Earth, suggest cycles of cooling and warming that allowed ice to advance toward Mars's equator before retreating.

Such climate shifts stem from dramatic variations in Mars's axial tilt. Unlike Earth's relatively stable tilt, moderated by its Moon, Mars's tilt has swung between 15 and 45 degrees over the past 10 million years, amplifying the effects of Milankovitch cycles on its climate.

Toward the east, the fractured ground gives way to dark plains separated by mesas and rounded hills, remnants of an eroded rock layer. Channels snake between these features, carved by the persistent movement of ice and debris. To the west, smoother plains lie near the giant Olympus Mons, located some 1200 km beyond the image frame.

Mars Express, in orbit since 2003, continues to map the planet in colour and 3D, delivering data that reshapes our understanding of Mars's geological and climatic history.