Layering history shows how water and carbon dioxide have moved across Mars

Mars’ south polar layered deposits of H₂O and CO₂ ice report its local weather historical past. A brand new examine hyperlinks the long-term world motion of Mars’ water from midlatitude to pole to a perform of the planet’s orbital configuration with H₂O ice deposition reducing as an element of obliquity, or spin-axis tilt.

“No deposit but analyzed supplies a world water cycle record that may be tied to a selected orbital historical past. Right here, I fill this hole by analyzing H₂O ice layer formation in Mars’ south polar huge CO₂ ice deposit, a 510,000-year local weather report,” mentioned Peter B. Buhler, a Analysis Scientist on the Planetary Science Institute and lead creator of the paper “A 510,000-year Document of Mars’ Local weather” that seems in Geophysical Analysis Letters.

“Beforehand, solely deposition charges averaged over hundreds of thousands of years—which is about ten instances longer than Mars’ orbit cycles—had been derived,” he mentioned.

“Mars experiences 100,000-year cycles during which its poles range from tilting extra towards or away from the sun. These variations trigger the quantity of daylight shining on every latitude band, and thus the temperature of every band, to cycle, too. Water ice strikes from hotter to colder areas throughout these cycles, driving Mars’ primary long-term world water cycle,” Buhler mentioned. “Up till now, the quantitative charge at which water strikes by this cycle has been extremely unsure. This examine addresses this open query by deciphering the layered ice report in Mars’ south polar cap.

“This layering is necessary as a result of it’s a direct report of how water and carbon dioxide have moved round on Mars. The water layer thicknesses inform us how a lot water vapor has been in Mars’ ambiance and the way that water vapor has moved across the globe. The carbon dioxide layers inform us the historical past of how a lot of the ambiance froze onto the bottom, and thus how thick or skinny Mars’ ambiance was prior to now,” Buhler mentioned.

“The historical past of Mars’ atmospheric pressure and availability of water are essential info for understanding the essential workings of Mars’ local weather and near-surface geologic, chemical, and even perhaps biologic historical past. Particularly, the outcomes of this work present a serious step ahead for deciphering the essential workings of Mars’ water cycle and, by extension, the long-term availability of near-surface water ice and even liquid brines. The provision of close to floor water sources is essential for enabling near-surface life as we all know it.”