Brown papers reveal widespread, hardworking water on ancient Mars

July 17, 2008

For decades, scientists have theorized - romanticized, even - that Mars has harbored water. The evidence has grown stronger as recent missions to the Red Planet have revealed in stunning detail Martian topography, mineralogy and clues to past climate. But how much water, where it was or is located and what it was doing have been hard to pin down.

"We've seen all this evidence of water on Mars," said John Mustard, a Brown professor of planetary geology, "but did it do any work?"

Now, papers by Mustard and Brown graduate student Bethany Ehlmann provide some key insights into these questions.

Reporting for the first time results obtained from an instrument aboard the Mars Reconnaissance Orbiter (MRO), Mustard and colleagues have found that vast regions of the ancient southern highlands of Mars hosted a water-rich environment. In a paper that appears in the July 17 issue of Nature, Mustard's team found evidence that water played a sizable role in changing the minerals of a variety of terrains in the Noachian period - about 4.6 billion to 3.8 billion years ago.

To support the claim, Mustard's team relied on data supplied by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), the instrument for which he is the deputy principal investigator. The researchers investigated the pervasive presence of phyllosilicates, clay-like minerals that preserve a record water's interaction with rocks.

Mustard homed in on intriguing phyllosilicate deposits in localized spots such as craters, valleys and dunes all over the planet. Among the highlights, he detected the clay-like minerals in fans and deltas within three regions, most notably the Jezero crater. That discovery marks the first time hydrated silicates have been found in sediments "clearly lain by water," Mustard wrote as lead author of the paper, in which scientists from 13 other institutions participated.

The team also found phyllosilicate deposits in thousands of places in and around craters, including the pointed peaks located at the center of some of the depressions. The latter example suggests that water was present 4-5 kilometers below the ancient Martian surface, the team wrote, due to the generally accepted principle that crater-causing collisions excavate underground minerals that are then exposed on the crater peaks.

"Water must have been creating minerals at depth to get the signatures we see," Mustard said.

The clay minerals were formed at low temperatures (100-200°C) - an important clue to understanding the Red Planet's potential for habitability during the Noachian period.

"What does this mean for habitability? It's very strong," Mustard said. "It wasn't this hot, boiling cauldron. It was a benign, water-rich environment for a long period of time."

In a companion paper published June 2 in Nature Geoscience, Ehlmann and colleagues from Brown and other institutions analyzed sediment deposits in two exquisitely preserved deltas in the Jezero crater, which held an ancient lake slightly larger than Lake Tahoe. The deltas suggest a flow from rivers carrying the clay-like minerals from an approximate 15,000-square kilometer watershed during the Noachian period.

Ehlmann said scientists cannot determine whether the river flow was sporadic or sustained, but they do know it was intense and involved a lot of water.

"So not only was water active in this region to weather the rocks, but there was enough of it to run through the beds, transport the clays and run into the lake and form the delta," said Ehlmann, who has a National Science Foundation Graduate Research Fellowship.

The deltas appear to be excellent candidates for finding stored organic matter, Ehlmann said, because the clays brought in from the watershed and deposited in the lake would have trapped any organisms, leaving in essence a cemetery of microbes.

"If any microorganisms existed on ancient Mars, the watershed would have been a great place to live," Ehlmann said.

Brown University

---

---

	Martian Outpost: The Challenges of Establishing a Human Settlement on Mars (Springer Praxis Books / Space Exploration) by Erik Seedhouse (Author) Mars Outpost provides a detailed insight into the various technologies, mission architectures, medical requirements, and training needed to send humans to Mars. It focuses on mission objectives and benefits, and the risks and complexities that are compounded when linked to an overall planet exploration program involving several expeditions and setting up a permanent presence on the surface. The first section provides the background to sending a human mission to Mars. Analogies are made with early polar exploration and the expeditions of Shackleton, Amundsen, and Mawson. The interplanetary plans of the European Space Agency, NASA, and Russia are examined, including the possibility of one or more nations joining forces to send humans to Mars. Current mission architectures, such as...
	The Martian Climate Revisited: Atmosphere and Environment of a Desert Planet (Springer Praxis Books / Geophysical Sciences) by Peter L. Read (Author), Stephen R. Lewis (Author) The atmosphere and climate of Mars is a crucial factor, both for understanding the planet's past and appreciating the possibilities of its future. Given the high level of current interest in Mars, and the major advances afforded by recent space exploration, this book seeks to examine and review our knowledge and understanding of the meteorology and climate of Mars in its present state. This is based not only upon direct observations, but also on the newer techniques of modelling: numerical simulation and data assimilation. This authoritative discussion of Mars' atmosphere and climate gives a balanced review of some of the hottest issues concerning Mars' environments, its present and past climate and potential to support life, and its possible future following manned exploration.
	A Traveler's Guide to Mars by William K. Hartmann (Author) In this extraordinary Baedeker—accessible, up-to-date, and prodigiously illustrated with photographs from Mariner 9, Viking, Pathfinder, the Hubble Space Telescope, and the ongoing mars Global Surveyor spacecraft—visitors will encounter: Olympus Mons, the largest volcano in the solar system, rising three times as high as Mount Everest and covering an area the size of Missouri Tharsis Planitia, the "high plains of Mars," with plains rising 29,000 feet—wide enough to cover Europe. Valles Marineris, an equatorial canyon so vast that America's Grand Canyon would be a mere tributary. Plus: the "face" on Mars, the White Rock, the "Canals" of Xanthe—and the first possible evidence of an ancient Martian...
	Geographies of Mars: Seeing and Knowing the Red Planet by K. Maria D. Lane (Author) One of the first maps of Mars, published by an Italian astronomer in 1877, with its pattern of canals, fueled belief in intelligent life forms on the distant red planet—a hope that continued into the 1960s. Although the Martian canals have long since been dismissed as a famous error in the history of science, K. Maria D. Lane argues that there was nothing accidental about these early interpretations. Indeed, she argues, the construction of Mars as an incomprehensibly complex and engineered world both reflected and challenged dominant geopolitical themes during a time of major cultural, intellectual, political, and economic transition in the Western world. Geographies of Mars telescopes in on a critical period in the development of the geographical imagination, when European...
	The Mars Mystery: The Secret Connection Between Earth and the Red Planet by Graham Hancock (Author) An asteroid transformed Mars from a lush planet with rivers and oceans into a bleak and icy hell. Is Earth condemned to the same fate, or can we protect ourselves and our planet from extinction? In his most riveting and revealing book yet, Graham Hancock examines the evidence that the barren Red Planet was once home to a lush environment of flowing rivers, lakes, and oceans. Could Mars have sustained life and civilization? Megaliths found on the parched shores of Cydonia, a former Martian ocean, mirror the geometrical conventions of the pyramids at Egypt's Giza necropolis. Especially startling is a Sphinx-like structure depicting a face with distinguishable diadem, teeth, mouth and an Egyptian-style headdress. Might there be a connection between the structures of Egypt and...
	Destination Mars: New Explorations of the Red Planet by Rod Pyle (Author) An exciting inside look into missions to MarsIn the next decade, NASA, by itself and in collaboration with the European Space Agency, is planning a minimum of four separate missions to Mars. Clearly, exciting times are ahead for Mars exploration.In Destination Mars, award-winning science writer and documentary producer Rod Pyle provides an insider's look into the amazing projects now being developed here and abroad to visit the legendary red planet. Drawing on his contacts at NASA and the Jet Propulsion Laboratory, Pyle provides stunning insights into the history of Mars exploration and the difficulties and dangers of traveling there.After an entertaining survey of the human fascination with Mars over the centuries, the author offers an introduction to the geography, geology, and water...
	The Case for Mars: The Plan to Settle the Red Planet and Why We Must by Robert Zubrin (Author), Richard Wagner (Contributor) Since the beginning of human history, Mars has been an alluring dream—the stuff of legends, gods, and mystery. The planet most like ours, it has still been thought impossible to reach, let alone explore and inhabit. But all that changed when leading space exploration authority Robert Zubrin crafted a daring new blueprint, Mars Direct. When it was first published in 1996, The Case for Mars became an instant classic, lauded widely for its game-changing perspective by those who would see the American space program rise to the challenge of Mars; Carl Sagan called Zubrin the man who, “nearly alone, changed our thinking on this issue.” Now, fifteen years later, Zubrin brings readers up to date in this revised and updated anniversary edition filled with spectacular illustrations,...
	Landscapes of Mars: A Visual Tour by Gregory L. Vogt (Author) Containing beautiful and exiting images that will spark the imagination, this is essentially a picture book providing a visual tour of Mars. All the major regions and topographical features are shown and supplemented with chapter introductions and extended captions. In a way, think of the book as a visual tourist guide. Other topics covered include Martian uplands, Giant volcanoes, the Grand Canyon of Mars, and much more. At the end of the book is an exciting gallery of the best 3D images of Mars making the book a perfect tool for understanding Mars and its place in the solar system.
	The Scientific Exploration of Mars by Fredric W. Taylor (Author) What do we know about Mars? What remains to be understood? Is there evidence of life there? Will humans ever travel there? The dream of exploring Mars has been around since the early days of human civilization and still forms part of our vision of the future for the human race. Today, we send unmanned spacecraft to explore this neighboring world to examine its climate, search for evidence of past or present life, and learn how conditions there relate to those on Earth. Plans are now being prepared for a manned mission to Mars, set against an uncertain background of political, practical, technical and financial considerations. This unique book provides a complete description of the past, present and future of Mars exploration. Written by a scientist intimately involved with missions to...
	The Cosmos of Soul: A Wake-Up Call For Humanity (Sirian Revelations) by Patricia Cori (Author) The first of the pioneering trilogy, The Sirian Revelations, offers cosmic wisdom to help humankind realize its highest potential. The Cosmos of Soul offers a bracing tonic to the shadow of war, disease, and other grim phenomena of contemporary life. The solution, according to noted clairvoyant Patricia Cori, is to awaken into the richer, more meaningful, and empowered existence that is our true fate. Through her psychic contacts with more evolved beings, Cori offers timely insights into the ethics of cloning, the dangers of the Internet, the truth about the AIDS virus, genetic engineering, and other information. Of special interest are the author’s predictions of what to expect after 2012, the closing of the Mayan Calendar—a time of galactic events that may change life...