We can’t go a week without having some new research on Mars water. This fervor of news is largely associated with our desperate desire to understand “when was there water?” and “could it have allowed life to form?”

We know there was water. Mars is littered with water-formed features, ranging from lake beds to carved-out river valleys, and even the fan-shaped formations from where rivers emptied into oceans, plains, or lakes.

In a pair of new papers led by Alex Morgan and Edwine Kite that appear in Icarus and Science Advances, researchers look at both where fan-shaped features exist on Mars and when they existed. These observations were then compared to climate models to see if they can be used to predict how Mars’s temperatures and water changed over time.

According to Morgan: We’ve known for decades that Mars had rivers and lakes around 3.5 billion years ago, but in the past few years there has been a growing body of evidence that substantial amounts of liquid water continued to erode the Martian surface for hundreds of millions of years. The global distribution and morphologic characteristics of fan-shaped sedimentary landforms on Mars. Water-formed landforms, such as river deltas and alluvial fans, are the most unambiguous markers of past climate. So we conducted a global survey for these features and explored patterns in their distribution and morphologic properties. 

Alluvial is a fancy word to say “formed by fluids.”

In their studies, the research team found more fans more recently at mid-latitudes. This means that while water flowed over much of the world in the past, it flowed for a longer period of time in the warmer areas nearer the equator. Morgan goes on to explain: We used a climate model to examine what the climate was like during these two eras of Mars’ early history and compared model results to the distribution of valley networks, which date to the earlier era, and alluvial fans, which date to the later era. We found that even though Mars cooled over time, from globally average temperatures of at least 25 degrees Fahrenheit to about 5 degrees Fahrenheit, liquid water continued to be stable in select areas.

They find water may have flowed as recently as 2.5 to 3 billion years ago. At that time, Earth did have life, just not multicellular life, so while I still look forward to fossil hunting on Mars, don’t go expecting fossils that are too complex.

More Information

PSI press release

“The global distribution and morphologic characteristics of fan-shaped sedimentary landforms on Mars,” Alexander M. Morgan, Sharon A. Wilson, and Alan D. Howard, 2022 June 23, Icarus