Curiosity Finds Chemical Traces of Ancient Shallow Lake in Gale Crater
Using data from the ChemCam instrument on NASA’s Curiosity rover, planetary scientists discovered minerals containing large amounts of iron, manganese and zinc in ripple beds preserved in the rocks of Gale Crater, indicating the high probability that a shallow lake existed there.
This image shows the Amapari Marker Band, a winding region where NASA’s Curiosity rover discovered unexpected signs of an ancient lake. Image credit: NASA/JPL-Caltech.
Curiosity’s ChemCam instrument uses a technique called laser-induced decay spectroscopy to zap rocks to create plasma, then collect light from that plasma to understand what elements are present on the planet’s surface.
Its goal is to establish the past habitability of Mars, addressing the question of whether Mars was once suitable for life.
The rover recently explored a large sedimentary mound that researchers say shows the transition from a warm, wet Mars (rich in phyllosilicate) to a cold, drier Mars (rich in sulfates).
The discovery of redox-active metals such as iron and manganese could indicate that life would have thrived in this lake if life had existed on Mars.
Some forms of microbial life on Earth can use these metals as energy sources.
“The metals were found in preserved ripples, which is the clearest evidence we have of the presence of a lake in Gale Crater,” said Dr. Patrick Gasda, a member of the ChemCam Instrument science team and a researcher at Los Alamos National Laboratory.
“But what is more surprising is that this lake existed high on Mount Sharp, where the rover explored rocks deposited at a time on Mars when the climate was drying.”
“Ancient Mars was much wetter and lakes in craters were common then.”
“It appears that as Mars became drier and colder, the lakes that formed less frequently were very short-lived.”
Detection of iron, manganese and zinc deposits can lay the foundation for future research on Mars.
They can help scientists decide where Curiosity should explore next or determine locations for possible sample return missions.
“Given the exciting astrobiological implications raised by the Amapari marker band, these types of materials should be prioritized for future Curiosity chemical analyzes or for returning samples from Jezero Crater to Mars, should the opportunity present itself,” Dr Gasda said.
An article about the discovery was published this month in the Geophysical Research Journal: Planets.
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PJ Gasda and others. 2026. Metal enrichments of the Amapari marker band: potential mechanisms and implications for surface and groundwater and alteration in Gale Crater. JGR: Planets 131 (4): e2025JE009153; doi:10.1029/2025JE009153
