Lecturer says conventional ideas to be challenged

Mars Explorer to Look for Organic Carbon

John Grotzinger
John Grotzinger

When John Grotzinger talks about thinking big, he’s not just being hyperbolic.

He’s not even exaggerating.

“Being an explorer means thinking out of the box,” Grotzinger said, “and in our case, the search for organic carbon on Mars will challenge all of our conventional ideas.”

You heard right … Mars.

Grotzinger, who is professor of geology at California Institute of Technology, and the chief scientist for the Mars Science Laboratory, is this year’s Michel T. Halbouty Lecturer at the upcoming AAPG Annual Convention and Exhibition in Long Beach, Calif. – and he is searching for carbon on another planet.

In fact, the name of the lecture that he’ll be presenting in Long Beach is just that: “Mars Science Laboratory Rover Mission: The Search for Source Rocks.”

And this big idea isn’t confined to “just” a theoretical paper or symposium – the laboratory, a rover named “Curiosity,” is hurtling toward Mars while you read this.

Out of the box enough for you?

“I feel honored to have been given this chance with AAPG,” he says of the chance to be the Halbouty lecturer, “and to share what we feel should be a thrilling mission of exploration.”

That thrill began last November, when Curiosity was launched and began its journey to the Gale Crater on Mars. And providing there are no complications, it is expected to arrive this August.

Its mission, Grotzinger said, is to assess whether Mars had life environment able to support microbial like and, more importantly, if rocks or soil might preserve some of that organic carbon.

“It’s a different planet,” he said, “with different processes and different products.”

A different planet, perhaps, but Grotzinger is hoping not a different world.

“We are confident,” he said, “that the time-honored principles of geology, mapping and stratigraphy will still apply.”

Mars Needs … Exploring

The challenge, he maintains, will be to construct predictive models for exploration in such a foreign environment – and to do so using only a robot.

So far, so good.

The past decade of Mars exploration has shown the surface is covered with layers of sedimentary rocks, in some places over five kilometers thick – a fact, Grotzinger said, that debunks the biggest myth about Mars, that it’s a volcanic planet.

“We also know now that water is very abundant at times in the deep geologic past, and potentially could have formed these sedimentary rocks,” he said. “We see thick sequences of evaporites.

“The evidence has created a compelling case for our mission,” he continued. “Curiosity’s precursors, Sprit and Opportunity, have discovered a wealth of evidence pointing to early Mars as a much wetter planet, with a prolonged history of rock-water interaction” than previously thought.

The question now, he believes, is “whether or not there was ever a biosphere – and, if so, did it preserve any evidence in the form of organic carbon?”

Grotzinger is hoping that answer will be coming.

“Specifically, Curiosity will take us to places few have ever dreamed of,” he said.

And he means that both figuratively and literally.

“Our target is a mountain of strata, over 15,000 feet high,” he said. “It may be the thickest stratigraphic section in the solar system that is continuously exposed in outcrop.”

Grotzinger reports that remote sensing data “tell us the base of the mountain contain rocks formed in water, and our prospects for discovering environments that might have been formerly habitable by microorganisms are high.”

The Billion Dollar Question

Curiosity is equipped with a set of instruments more sophisticated than any previous mission sent to space.

“If she lives long enough, we may someday make it to the top of that mountain and will have deciphered the record of the earliest history of Mars,” he said, “and whether or not this involved the preservation of organic carbon.”

The prospects are good.

“We can now map the planet globally using hyperspectral cameras that provide even more evidence of vast terrains that interacted with water.

“We think we have a good chance to discover environments that might have been habitable by microorganisms in the geologic past, provided that life ever evolved on Mars,” he said. “Habitable environments are those characterized by a source of water, energy and carbon.”

It’s tough to quantify what that would mean if it were true – but Grotzinger has a figure in mind.

“The billion dollar question, literally, is whether or not any of those environments preserve vestiges of organic carbon,” he said. “This will be a tough nut to crack, because it’s well known on Earth that during the conversion of sediment to rock that organic materials can become oxidized [and this rock is four billion years old].

“That’s why we’ll need a Mars-specific exploration model to guide our search for favorable windows of preservation.”

Touch Down

And about that guide, that exploration model …

Maybe another billion dollar question is, what about the prospect of a manned mission to the planet?

Grotzinger is ready – both for the question and the journey.

“It’s an inevitable challenge for future exploration,” he said.

But first it’s necessary to see if it’s feasible.

“These robotic precursors are important, because they show us how to get there and what we’re up against,” he said. “Our mission carries an instrument – it’s actually operating now as the rover flies through space on its journey between Earth and Mars – that will measure the background cosmic and solar radiation that would be harmful to humans.

“We’ll measure the radiation in space, and once we land we’ll measure the same radiation on Mars where a human would be protected only by Mars’ very thin atmosphere,” he said.

The Halbouty Lecture usually concerns matters a little closer to earth – 33,926,867.096 miles closer, to be exact. Grotzinger, obviously, is very excited about the prospects of discussing Curiosity and Mars and the possibilities of both with those coming to Long Beach.

He also wants to express his gratitude to some of them.

“I would like to thank AAPG for this wonderful chance to give the Halbouty Lecture,” he said, adding that AAPG members helped select the landing site at Gale Crater – including Kevin Bohacs, a past AAPG Distinguished Lecturer, co-author of AAPG’s best-selling text on Field Safety and a member of the Explorers Club.

Safety and exploration – obviously, this was a good match to make when planning a journey across the universe.

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Award Presentation

John Grotzinger, professor of geology at the California Institute of Technology in Pasadena, Calif., and the chief scientist for the Mars Science Laboratory, will present the annual Michel T. Halbouty Lecture at 5:10 p.m. Monday, April 23, at the AAPG Annual Convention and Exhibition in Long Beach, Calif.

His lecture is titled “Mars Science Laboratory Rover Mission: The Search for Source Rocks.”

The Halbouty lecture, supported by the AAPG Foundation’s Michel T. Halbouty Lecture Fund, annually deals with wildcat exploration in any part of the world – or, in this case, space exploration, where astrogeological knowledge would further mankind’s ability to develop resources on earth and in our solar system.

The Michel T. Halbouty lecture series is in its twelfth year. Previous lecturers have been Aubrey McClendon, Guilherme Estrella, Ray L. Hunt, Kurt Randolph, Harrison H. “Jack” Schmitt, John Robbins, Brian Maxted, Bill Barrett, Peter Dea, David Rainey and Carolyn Shoemaker.

Emphasis: Annual Convention