Carbonate formation and fluctuating habitability on Mars

Creators: Kite, Edwin S.¹; Tutolo, Benjamin M.²; Turner, Madison L.¹; Franz, Heather B.³; Burtt, David G.³; Bristow, Thomas F.⁴; Fischer, Woodward W.⁵; Milliken, Ralph E.⁶; Fraeman, Abigail A.⁷; Zhou, Daniel Y.¹

1. University of Chicago
2. University of Calgary
3. Goddard Space Flight Center
4. Ames Research Center
5. California Institute of Technology
6. Brown University
7. Jet Propulsion Lab

Abstract

The cause of Mars's loss of surface habitability is unclear, with isotopic data suggesting a 'missing sink' of carbonate1. Past climates with surface and shallow-subsurface liquid water are recorded by Mars's sedimentary rocks, including strata in the approximately 4-km-thick record at Gale Crater2. Those waters were intermittent, spatially patchy and discontinuous, and continued remarkably late in Mars's history3—attributes that can be understood if, as on Earth, sedimentary-rock formation sequestered carbon dioxide as abundant carbonate (recently confirmed in situ at Gale4). Here we show that a negative feedback among solar luminosity, liquid water and carbonate formation can explain the existence of intermittent Martian oases. In our model, increasing solar luminosity promoted the stability of liquid water, which in turn formed carbonate, reduced the partial pressure of atmospheric carbon dioxide and limited liquid water5. Chaotic orbital forcing modulated wet–dry cycles. The negative feedback restricted liquid water to oases and Mars self-regulated as a desert planet. We model snowmelt as the water source, but the feedback can also work with groundwater as the water source. Model output suggests that Gale faithfully records the expected primary episodes of liquid water stability in the surface and near-surface environment. Eventually, atmospheric thickness approaches water's triple point, curtailing the sustained stability of liquid water and thus habitability in the surface environment. We assume that the carbonate content found at Gale is representative, and as a result we present a testable idea rather than definitive evidence.

Copyright and License

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Acknowledgement

We thank M. A. Mischna, D. P. Mayer, J. Sneed, M. A. Kahre, I. Halevy, J. Frydenvang, J. Schieber and A. Yen. We thank D. P. Mayer and J. Sneed for the mound mapping in Fig. 3. Funding: NASA (NNX16AG55G, 80NSSC20K0144, 80NSSC22K0731). A portion of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004).

Data Availability

All data are available through the NASA Planetary Data System (https://pds.nasa.gov/). The topographic contours on the maps shown in Fig. 3, and Extended Data Figs. 1 and 8 are made using MATLAB from publicly available Mars Orbiter Laser Altimeter gridded records (https://pds-geosciences.wustl.edu/missions/mgs/megdr.html).

Code Availability

Our Mars climate evolution model code, together with our analysis scripts, is open-sourced on Zenodo at https://doi.org/10.5281/zenodo.11489512 (ref. ¹¹⁷).

Files

s41586-025-09161-1.pdf

Files (18.0 MB)

Name	Size	Download all
s41586-025-09161-1.pdf md5:7f635cb2e7707caf33d7340cda167126	18.0 MB	Preview Download

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes