geology of mars

Layers of meaning! These rocks show the deep and shallow waters of an ancient Martian lake could’ve supported different kinds of microbes. This evenly layered rock imaged in 2014 by my Mastcam shows a pattern typical of a lake-floor sedimentary deposit near where flowing water entered a lake. Shallow and deep parts of an ancient Martian lake left different clues in mudstone formed from lakebed deposits. Credit: @nasa/NASAJPL-Caltech/MSSS


The HiRise camera on the Mars Reconnaissance Orbiter Spacecraft has been taking pictures of the planet’s surface for more than a decade now. At its highest resolution, it can see features less than a meter across - the scale of geologic units, sand dunes, and boulders. It can also be targeted by request from literally anyone, if you had a site you wanted to image. Using the publicly available photographs from HiRISE, this video is stitched together as a flight over Mars, including a glimpse of its moon Phobos.

Explore the craters, mountains, and valley networks of the red planet. Somehow both geologic and yet different from what we’re used to.


Jessica Watkins came to Caltech to collaborate with scientists and engineers across disciplines—and, of course, as a fan of space exploration, to be a part of the Caltech-JPL connection. For a recent PhD interested in studying Mars and mining the trove of information being collected by the Curiosity rover, there was no better place to pursue postdoctoral study. Today, as a member of the Mars Science Laboratory Science Team, Watkins is helping to plan the rover’s activities and analyze its data to understand the history of how the Gale Crater on Mars was formed. She also finds time to assistant-coach the Caltech Women’s Basketball team, write short stories, rock climb, and fly planes.

In this video, Watkins, a Chair’s Postdoctoral Scholar in Caltech’s Division of Geological and Planetary Sciences, talks about her longstanding passion for Mars’ geology, why it’s an exciting time to be studying the Red Planet, and how her privately funded fellowship fuels her creativity.

Astronaut candidate Jessica Watkins discusses her research with the MSL team!


** Synopsis: Some scientists have interpreted water-carved valleys on Mars formed within the last few billion years as a sign of either an active groundwater system or of transient warm periods in the atmosphere. But new research shows that snow and ice melted by hot impact ejecta could have produced enough water to carve those valleys with no groundwater or heat wave required. **

Present-day Mars is a frozen desert, colder and more arid than Antarctica, and scientists are fairly sure it’s been that way for at least the last 3 billion years. That makes a vast network of water-carved valleys on the flanks of an impact crater called Lyot – which formed somewhere between 1.5 billion and 3 billion years ago – something of a Martian mystery. It’s not clear where the water came from.

Now, a team of researchers from Brown University has offered what they see as the most plausible explanation for how the Lyot valley networks formed. They conclude that at the time of the Lyot impact, the region was likely covered by a thick layer of ice. The giant impact that formed the 225-kilometer crater blasted tons of blazing hot rock onto that ice layer, melting enough of it to carve the shallow valleys.

“Based on the likely location of ice deposits during this period of Mars’ history, and the amount of meltwater that could have been produced by Lyot ejecta landing on an ice sheet, we think this is the most plausible scenario for the formation of these valleys” said David Weiss, a recent Ph.D. graduate from Brown and the study’s lead author.

Weiss co-authored the study, which is published in Geophysical Research Letters, with advisor and Brown planetary science professor Jim Head, along with fellow graduate students Ashley Palumbo and James Cassanelli.

There’s plenty of evidence that water once flowed on the Martian surface. Water-carved valley networks similar to those at Lyot have been found in several locations. There’s also evidence for ancient lake systems, like those at Gale Crater where NASA’s Curiosity rover is currently exploring and at Jezero Crater where the next rover may land.

Most of these water-related surface features, however, date back to very early in Mars’ history – the epochs known as the Noachian and the Hesperian, which ended about 4 billion and 3 billion years ago respectively. From about 3 billion years ago to the present, Mars has been in a bone-dry period called the Amazonian.

The valley networks at Lyot therefore are a rare example of more recent surface water activity. Scientists have dated the crater itself to the Amazonian, and the valley networks appear to have been formed around the same time or shortly after the impact. So the question is: Where did all that water come from during the arid Amazonian?

Scientists have posited a number of potential explanations, and the Brown researchers set out to investigate several of the major ones.

One of those potential explanations, for example, is that there might have been a vast reservoir of groundwater when the Lyot impact occurred. That water, liberated by impact, could have flowed onto the surface along the periphery of the crater and carved the valleys. But based on geological evidence, the researchers say, that scenario is unlikely.

“If these were formed by deep groundwater discharge, that water would have also flowed into the crater itself,” Weiss said. “We don’t see any evidence that there was water present inside the crater.”

The researchers also looked at the possibility of transient atmospheric effects following the Lyot impact. A collision of this size would have vaporized tons of rock, sending a plume of vapor into the air. As that hot plume interacted with the cold atmosphere, it could have produced rainfall that some scientists think might have carved the valleys.

But that, too, appears unlikely, the researchers concluded. Any rain related to the plume would have fallen after the rocky impact ejecta had been deposited outside the crater. So if rainwater carved the valleys, one would expect to see valleys cutting through the ejecta layer. But there are almost no valleys directly on the Lyot ejecta. Rather, Palumbo said, “The vast majority of the valleys seem to emerge from beneath the ejecta on its outer periphery, which casts serious doubt on the rainwater scenario.”

That left the researchers with the idea that meltwater, produced when hot ejecta interacted with an icy surface, carved the Lyot valleys.

According to models of Mars’ climate history, ice now trapped mainly at the planet’s poles often migrated into the mid-latitude regions where Lyot is located. And there’s evidence to suggest that an ice sheet was indeed present in the region at the time of the impact.

Some of that evidence comes from the scarcity of secondary craters at Lyot. Secondary craters form when big chunks of rock blasted into the air during a large impact fall back to the surface, leaving a smattering of small craters surrounding the main crater. At Lyot, there far fewer secondary craters than one would expect, the researchers say. The reason for that, they suggest, is that instead of landing directly on the surface, ejecta from Lyot landed on a thick layer of ice, which prevented it from gouging the surface beneath the ice. Based on the terrain on the northern side of Lyot, the team estimates that the ice layer could have been anywhere from 20 to 300 meters thick.

The Lyot impact would have spat tons of rock onto that ice layer, some of which would have been heated to 250 degrees Fahrenheit or more. Using a thermal model of that process, the researchers estimate that the interaction between those hot rocks and a surface ice sheet would have produced thousands of cubic kilometers of meltwater – easily enough to carve the valley seen at Lyot.

“What this shows is a way to get large amounts of liquid water on Mars without the need for a warming of the atmosphere and any liquid groundwater,” Cassanelli said. “So we think this is a good explanation for how you get these channels forming in the Amazonian.”

And it’s possible, Head says, that this same mechanism could have been important before the Amazonian. Some scientists think that even in the early Noachian and Hesperian epochs, Mars was still quite cold and icy. If that was the case, then this meltwater mechanism might have also been responsible for at least some of the more ancient valley networks on Mars.

“It’s certainly a possibility worth investigating,” Head said.

IMAGE….Valley NetworksLyot Crater, rendered here with elevations exaggerated, is home to relatively recent water-carved valleys (white streaks). New research suggests the water came from melting snow and ice present at the time of the crater-forming impact.David Weiss/NASA/Brown University

Okay, so, me uploading posts regularly has been a thing of the past recently, but hopefully I will be back at it again soon. Until then, I shall continue with my planet series by blogging about our lovely neighbour Mars. The fourth planet from the Sun has been a fascination to humans for centuries, mostly due to its proximity and its potential for extra-terrestrial life. With a diameter of ~6800km, it is one of the smallest planets in the Solar System, whilst having ~10% the mass of Earth. Mars is the home to Olympus Mons, which is the largest volcano in the entire Solar System.

Mercury | Venus | Earth | Mars

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The Evidence For Water On Mars Is Overwhelming

“Hematite spherules, known as “Martian blueberries,” provided strong indirect evidence of water. As water diffuses through the surface rock, minerals precipitate out of solution and form erosion-resistant spheres: geologically forming concretions. But by far the strongest evidence comes from the recurring slope lineae.”

Ever since we first began observing Mars up close, there was well-founded speculation that there was a watery past. What appeared to be water-ice features and water-based clouds were abundant, and indirect clues like sedimentary rock, dried-up riverbeds and deposits that appeared to have a watery origin appeared to be everywhere we looked. But the strongest evidence is recent, and came from looking at the sloping, linear features inside the crater walls. We’ve seen them increase in size over time, and when we measure them with orbiting spectral devices, we find evidence of salt deposits. This means that, on the surface, there’s flowing briny, liquid water! The water evaporates, leaving the salt deposits behind.

The evidence for water on Mars is indeed overwhelming at present; come and see it for yourself today!


Scientists To Plan Missions And Explore Mars Through Holograms 

For planetary scientists, a hologram of a distant planet might be the next best thing to being there. While NASA’s goal to send astronauts to Mars sometime in the 2030s is still a long time off, researchers will start setting their feet down on a data-based three-dimensional representation of the red planet later this year.

In other words, the first iteration of a NASA science holodeck is here.

It was just yesterday that Microsoft announced its HoloLens, what the company bills as a powerful holographic computing headset. “For the first time ever, Microsoft HoloLens brings high-definition holograms to life in your world, where they integrate with your physical places, spaces, and things,” the company says.

While many applications for virtual and augmented reality systems have already been identified thanks to projects like Google Glass and Oculus Rift, the U.S. space agency is sounding vocal support for the science applications of HoloLens from the get-go.

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Mars Study Yields Clues to Possible Cradle of Life

Fast Facts:

› A long-gone sea on southern Mars once held nearly 10 times as much water as all of North America’s Great Lakes combined, a recent report estimates.

› The report interprets data from NASA’s Mars Reconnaissance Orbiter as evidence that hot springs pumped mineral-laden water directly into this ancient Martian sea.

› Undersea hydrothermal conditions on Mars may have existed about 3.7 billion years ago; undersea hydrothermal conditions on Earth at about that same time are a strong candidate for where and when life on Earth began.

› The report adds an important type of wet ancient Martian environment to the diversity indicated by previous findings of evidence for rivers, lakes, deltas, seas, groundwater and hot springs.

The discovery of evidence for ancient sea-floor hydrothermal deposits on Mars identifies an area on the planet that may offer clues about the origin of life on Earth.

A recent international report examines observations by NASA’s Mars Reconnaissance Orbiter (MRO) of massive deposits in a basin on southern Mars. The authors interpret the data as evidence that these deposits were formed by heated water from a volcanically active part of the planet’s crust entering the bottom of a large sea long ago.

“Even if we never find evidence that there’s been life on Mars, this site can tell us about the type of environment where life may have begun on Earth,” said Paul Niles of NASA’s Johnson Space Center, Houston. “Volcanic activity combined with standing water provided conditions that were likely similar to conditions that existed on Earth at about the same time – when early life was evolving here.”

Mars today has neither standing water nor volcanic activity. Researchers estimate an age of about 3.7 billion years for the Martian deposits attributed to seafloor hydrothermal activity. Undersea hydrothermal conditions on Earth at about that same time are a strong candidate for where and when life on Earth began. Earth still has such conditions, where many forms of life thrive on chemical energy extracted from rocks, without sunlight. But due to Earth’s active crust, our planet holds little direct geological evidence preserved from the time when life began. The possibility of undersea hydrothermal activity inside icy moons such as Europa at Jupiter and Enceladus at Saturn feeds interest in them as destinations in the quest to find extraterrestrial life.

Observations by MRO’s Compact Reconnaissance Spectrometer for Mars (CRISM) provided the data for identifying minerals in massive deposits within Mars’ Eridania basin, which lies in a region with some of the Red Planet’s most ancient exposed crust.

“This site gives us a compelling story for a deep, long-lived sea and a deep-sea hydrothermal environment,” Niles said. “It is evocative of the deep-sea hydrothermal environments on Earth, similar to environments where life might be found on other worlds – life that doesn’t need a nice atmosphere or temperate surface, but just rocks, heat and water.”

Niles co-authored the recent report in the journal Nature Communications with lead author Joseph Michalski, who began the analysis while at the Natural History Museum, London, andco-authors at the Planetary Science Institute in Tucson, Arizona, and the Natural History Museum.

The researchers estimate the ancient Eridania sea held about 50,000 cubic miles (210,000 cubic kilometers) of water. That is as much as all other lakes and seas on ancient Mars combined and about nine times more than the combined volume of all of North America’s Great Lakes. The mix of minerals identified from the spectrometer data, including serpentine, talc and carbonate, and the shape and texture of the thick bedrock layers, led to identifying possible seafloor hydrothermal deposits. The area has lava flows that post-date the disappearance of the sea.

The researchers cite these as evidence that this is an area of Mars’ crust with a volcanic susceptibility that also could have produced effects earlier, when the sea was present.

The new work adds to the diversity of types of wet environments for which evidence exists on Mars, including rivers, lakes, deltas, seas, hot springs, groundwater, and volcanic eruptions beneath ice.

“Ancient, deep-water hydrothermal deposits in Eridania basin represent a new category of astrobiological target on Mars,” the report states.

It also says, “Eridania seafloor deposits are not only of interest for Mars exploration, they represent a window into early Earth.” That is because the earliest evidence of life on Earth comes from seafloor deposits of similar origin and age, but the geological record of those early-Earth environments is poorly preserved.

The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, built and operates CRISM, one of six instruments with which MRO has been examining Mars since 2006. NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the project for the NASA Science Mission Directorate in Washington. Lockheed Martin Space Systems of Denver built the orbiter and supports its operations.

TOP IMAGE….This view of a portion of the Eridania region of southern Mars shows fractured, dismembered blocks of deep-basin deposits that have been surrounded and partially buried by younger volcanic deposits. The image was taken by the Context Camera on NASA’s Mars Reconnaissance Orbiter.
The area covered by this view spans about 12 miles (20 kilometers) across. The shape and texture of the thick bedrock layers in the Eridania basin, together with the mix of minerals identified from orbit, led researchers to identify this as the site of possible seafloor hydrothermal deposits. A schematic cross section of this terrain shows an interpretation of its origin. The mineral identifications were made from observations by the Mars Reconnaissance Orbiter’s Compact Reconnaissance Imaging Spectrometer for Mars.

CENTRE IMAGE….The Eridania basin of southern Mars is believed to have held a sea about 3.7 billion years ago, with seafloor deposits likely resulting from underwater hydrothermal activity. This graphic shows estimated depths of water in that ancient sea.
A recent estimate of the total water volume of the ancient Eridania sea is about 50,000 cubic miles (210,000 cubic kilometers), about nine times the total volume of North America’s Great Lakes. The map covers an area about 530 miles (850 kilometers) wide.
The reference bar indicates color coding of depth, from red, at right, showing depth of about 300 feet (100 meters) to black showing depth more than 10 times that depth. This graphic was included in a 2017 report “Ancient hydrothermal seafloor deposits in Eridania basin on Mars” in Nature Communications.

LOWER IMAGE….This diagram illustrates an interpretation for the origin of some deposits in the Eridania basin of southern Mars as resulting from seafloor hydrothermal activity more than 3 billion years ago.
The ground level depicted is an exaggerated topography of a transect about 280 miles (450 kilometers) long. Blue portions of the diagram depict water-depth estimates and the possibility of ice covering the ancient sea.
Thick, clay-rich deposits (green) formed through hydrothermal alteration of volcanic materials in deep water, by this model. Notations indicate deep-water reactions of iron and magnesium ions with silicates, sulfides and carbonates. Deep-seated structural discontinuities could have facilitated the ascent of magma from a mantle source. Chloride deposits formed from evaporation of seawater at higher elevations in the basin.
This graphic was included in a 2017 report “Ancient hydrothermal seafloor deposits in Eridania basin on Mars” in Nature Communications.