Mars’ transition from wet to dry is a major ecological disaster, yet the spatial pattern, rhythm, and cause of drought are poorly constrained.
We generated a globally distributed database of the size constraints of ancient fossils on late-stage Mars relative to catchment area (dryness index), and found evidence for climate stratification as Mars dries up. Aridity increased over time in the mid-latitude southern uplands, where the lakes became relatively small as in modern-day Nevada. Meanwhile, wetter climates persisted intermittently in the tropical and boreal lowlands of the mid-latitudes.
This is consistent with a change in the Martian greenhouse effect that left highlands too cold for liquid water except for a short melt period, or alternatively with a lowering of the Martian water table. The data correspond to a switch of unknown cause in the dependence of the drought index on altitude, from high and wet early, to high and dry later. These results sharpen our view of the Martian climate as surface conditions become increasingly stressful for life.
Edwin S. Kite, Axel Nobelt
Comments: Geophysical Research Letters accepted
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Geophysics (physics.geo-ph)
Cited as follows: arXiv:2211.10552 [astro-ph.EP] (or arXiv: 2211.10552v1 [astro-ph.EP] for this version)
WHO: Edwin Kate
[v1] Saturday, November 19, 2022 01:03:58 UTC (40,815 KB)