The question how canyons and valleys formed on Mars 3.8 billion years ago, if the planet was believed to be dead frozen, has been answered by a new study.
Attributing drastic fluctuations in ancient Mars' temperature to greenhouse gas accumulation in the atmosphere, the study says dry weather and drought that lasted millions of years might have deglaciated the planet.
Contrast this with Gale Crater on Mars that was full with liquid water for 10 million years, according to Mars Science Laboratory.
The study was published in the journal Earth and Planetary Science Letters.
The long and warm period explains how deep canyons and extensive valleys as on the Earth's surface were formed on Mars as well. The water features on the surface of Mars were a fall out of the dramatic climate cycles that had long warm spells drying up the planet, the study asserted.
Long Warm Periods
The glacier-covered early Mars experienced long warm periods and that lasted up to 10 million years when the atmosphere was thick with carbon dioxide and hydrogen.
"With the cycling hypothesis, you get these long periods of warmth that give you sufficient time to form all the different Martian valley networks," said study co-author Natasha Batalha, a graduate student in astronomy and astrophysics, Penn State.
Glaciation And Deglaciation
The new model looks more convincing as a geophysical mechanism as it harps on dramatic climate cycles for extended glaciation dotted with similar long periods of warming up to 10 million years.
That unusually longer warming models are dictated by low stellar insolation and carbon dioxide outgassing that was not at pace with carbon dioxide consumption from silicate weathering.
However, the new model does not say carbon dioxide fully deglaciated Mars as the greenhouse effect was also accentuated by substantial amounts of hydrogen emissions from the Mars' crust and mantle.
Precarious Climate
The conundrum of Martian climate was explained by Natasha who noted that the Mars was in a precarious position and at the outer edge of the habitable zone.
Receiving less solar flux makes it start with a glaciated state. In mitigating volcanic outgassing, the deposition of carbon back into the planet's surface was not adequate because of the colder climate. That increases atmospheric buildup and rise in temperature on the planet.
The new model negates previous studies that harped on asteroid impacts as the cause of planet's warming and steamed atmosphere before rain followed. Researchers found it less plausible as warm periods might have been shorter from such conditions to produce enough water.
Jim Kasting, Evan Pugh Professor of geosciences, Penn State, and co-author, noted that Mars was warm for millions to tens of millions of years.
The research noted that valleys on the Martian surface were looking similar in size to the Colorado River Canyons. The latter took almost 16 million years to shape the nearby Grand Canyon from the discharge of snow melts from the Rocky Mountains.
