Oct 27 2010

The Kwisatz Haderach of Mars

Much like the final scene in the cult favorite Dune (1984) where Paul becomes the Kwisatz Haderach by spectacularly making torrential rain and oceans appear on the desert planet, something similar is happening now with Mars. For the first time, the ancient Martian ocean is being directly revealed.

If you want to go deep on Mars, you go to Leighton crater’s central peak; it shows “one of the best exposures of deep crust seen on Mars.”
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(Courtesy the University of Arizona)

Two planetary scientists — Joseph Michalski (Planetary Science Institute, Tucson and Université Paris Sud, France) and Paul Niles (NASA Johnson Space Center) — recently reported (Nature Geoscience, 10/10/10) strong evidence in the form of carbonate rocks and hydrated silicates conveniently excavated by an ancient asteroid impact.

Once upon a time Mars may have had a major liquid water ocean covering a large fraction of its surface. “Oceanus Borealis” could have filled most of the northern hemisphere basin which is 4-5 km below the mean surface level on Mars. Popular proposals for a Martian ocean go back to the early 1990s and are based on geological evidence for shorelines and abundant steam channels, plus evidence for a warmer, more Earth-like Martian climate almost 4 billion years ago.

Key macroeconomic indicators and global trends — both recent and over the last 200 years — point to a new international Space Age igniting by 2015. As the real, science-based Kwisatz Haderaches reveal growing evidence for Mars having an early major ocean, a thick atmosphere, and even habitable environments, Mars may become viewed gobally as Earth II. It will likely become the prime target for a number of major international exploration initiatives as humans surge into the cosmos.

But the major question has always been: Where are the carbonates? A water ocean would have absorbed CO2 from Mars’ atmosphere and precipitated it in the form of carbonate rocks on the ocean bottom.

As the greenhouse weakened and temperatures plummeted on Mars, its oceans froze and were eventually covered by wind-blown dust, volcanic eruptions, and impact ejecta.

However, the carbonates should still exist in some form at depth. And this is why the Michalski/Niles discovery is so important.

Leighton, a 60 km-wide crater on the western flanks of Syrtis Major volcano, presents a plethora of clues for the interplanetary sleuth. When the ancient impact occurred, the deepest rocks exhumed were exposed at the central peak, and based on terrestrial crater analogs, this bedrock was uplifted about 6 km.

New spectral evidence reveals the central peak material consists of carbonates, clays (kaolinites) and hydrated ferromagnesian silicates. The carbonates are identified by specific spectral fingerprints between 2.35 and 3.9 micrometers, and suggest the presence of calcite or siderite.

Michalski/Niles’ preferred model features carbonate sediments – presumably formed in an ancient ocean underlying a thick CO2 atmosphere – and other local materials that are buried and altered by lavas from Syrtis Major, and eventually by hydrothermal circulations…

Heat from the overlying lavas and/or magmatic sources below would have caused liberation of fluids from … hydrated phases, as well as aqueous CO2 from the carbonates.

This cocktail can produce significant methane and is the probable source for telescopically observed CH4 above Syrtis Major. Although their model provides no direct evidence for Martian life, Michalski/Niles speculate that the hydrothermal hotspots are “a high-priority site for future
exobiological exploration.”

The probable existence of ancient hydrothermal systems on Mars brings to mind an early assessment of Mars’ natural resource potential (i.e., ore bodies) that I presented at the 2nd Case for Mars Conference in July, 1984 at CU in Boulder. I identified several possible mechanisms and regions on Mars that might be capable of mineralization, and concluded that…

Nothing we know about the physics and chemistry of mineralization, ore body tectonics, or the geology of Mars precludes the existence of significant ore bodies on Mars …

Terrestrial hydrothermal, dry-magma, and sedimentary mineral concentration processes have been identified which may have operated on Mars. In particular, mineral-rich Africa seems to share many volcanic and tectonic characteristics with portions of Mars and may be suggestive of the potential mineral wealth of Mars …

Assuming that ground ice is, and has been, widespread, and that magma bodies have produced hydrothermal solutions often during the history of Mars, the Martian mining economy should be booming by the middle of the 21st century.

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