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TOPIC: Mars geology
Blobrana


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RE: Mars plate tectonics
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UCLA scientist discovers plate tectonics on Mars

For years, many scientists had thought that plate tectonics existed nowhere in our solar system but on Earth. Now, a UCLA scientist has discovered that the geological phenomenon, which involves the movement of huge crustal plates beneath a planet's surface, also exists on Mars.

"Mars is at a primitive stage of plate tectonics. It gives us a glimpse of how the early Earth may have looked and may help us understand how plate tectonics began on Earth" - An Yin, a UCLA professor of Earth and space sciences and the sole author of the new research.

Yin made the discovery during his analysis of satellite images from a NASA spacecraft known as THEMIS (Time History of Events and Macroscale Interactions during Substorms) and from the HIRISE (High Resolution Imaging Science Experiment) camera on NASA's Mars Reconnaissance Orbiter. He analysed about 100 satellite images - approximately a dozen were revealing of plate tectonics.

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Blobrana


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RE: Mars geology
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 Surface of Mars - Janice Bishop (SETI Talks)

The surface mineralogy of Mars provides clues to its geologic history, including aqueous processes. Phyllosilicates and sulphates are key indicators of water on Mars and appear to have occurred in the Noachian and Hesperian, respectively. Dr. Bishop will discuss what we know about Martian mineralogy from orbital and landed missions, meteorites, and terrestrial analogue studies.



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Blobrana


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Periodic bedrock ridges
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Title: Periodic bedrock ridges on Mars
Authors: David R. Montgomery, Joshua L. Bandfield, Scott K. Becker

Evidence for sediment transport and erosion by wind is widespread over the surface of Mars today and was likely a major geomorphic process for much of its geological past. Although Martian surface features resembling aeolian dunes and ripples have been recognised since the Mariner and Viking missions, such features have been interpreted previously as active, indurated, or exhumed sedimentary forms. Here we report evidence based on High Resolution Imaging Science Experiment images that show some megaripple forms are eroded into cohesive substrate rather than being composed of loose granular material or fossilised dunes.

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Blobrana


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RE: Mars geology
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Mars 'dominantly composed of glass'

The surface of Mars comprised a number of lava flows and other signs of effusive volcanism.
Although models suggest that explosive volcanism should also have produced extensive deposits, direct evidence for large-scale explosive volcanism on Mars has been scarce.
A new investigation by Briony Horgan and James F. Bell III of the mineralogy of dark regions covering more than ten million square kilometers in the northern hemisphere of Mars has revealed that these regions are dominantly composed of glass.
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Blobrana


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Title: Widespread weathered glass on the surface of Mars
Authors: B. Horgan, J.F. Bell III, School of Earth and Space Exploration, Arizona State University

Low-albedo sediments mantle the northern lowlands of Mars and form the north polar sand sea, which encircles the north polar cap. Unlike many other low-albedo regions on Mars, most of the northern lowlands does not exhibit spectral characteristics consistent with a typical basaltic surface. In the mid-infrared, the model-derived composition of these deposits requires a poorly crystalline high-silica phase, the nature of which is not well constrained.
Previous studies in the near-infrared (NIR) have not resolved this ambiguity, as the dark plains are nearly spectrally featureless. Here we show that the overall continuum shape and subtle absorptions in NIR spectra of the northern plains are consistent with iron-bearing glass partially obscured by a silica-enriched leached glass rind, potentially implying widespread acidic leaching and a history of explosive volcanism in the northern plains.

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Blobrana


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Posts: 131433
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Periodic bedrock ridges
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Geologists discover new class of landform - on Mars

An odd, previously unseen landform could provide a window into the geological history of Mars, according to new research by University of Washington geologists.
They call the structures periodic bedrock ridges (and they use the abbreviation PBRs to evoke a favourite brand of beer). The ridges look like sand dunes but, rather than being made from material piled up by the wind, the scientists say the ridges actually form from wind erosion of bedrock.
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Blobrana


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Martian Caves
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Caves and Craters

Marscave.jpg
Expand (557kb, 1024 x 768)
Credit: NASA/JPL/University of Arizona

Earlier this year, the CTX camera team saw a crater containing a dark spot on the dusty slopes of the Pavonis Mons volcano. We took a closer look at this feature with HiRISE and found this unusual geologic feature.
The dark spot turned out to be a "skylight," an opening to an underground cavern, that is 35 meters across.
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Blobrana


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Nili Fossae
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Mars Express sees deep fractures on Mars

Newly released images from ESA's Mars Express show Nili Fossae, a system of deep fractures around the giant Isidis impact basin. Some of these incisions into the martian crust are up to 500 m deep and probably formed at the same time as the basin.
Nili Fossae is a 'graben' system on Mars, northeast of the Syrtis Major volcanic province, on the northwestern edge of the giant Isidis impact basin. Graben refers to the lowered terrain between two parallel faults or fractures in the rocks that collapses when tectonic forces pull the area apart. The Nili Fossae system contains numerous graben concentrically oriented around the edges of the basin.
The company was also selling water to other contractors at the site.
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Blobrana


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RE: Mars geology
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Silica on a Mars Volcano Tells of Wet and Cosy Past

Light-coloured mounds of a mineral deposited on a volcanic cone more than three billion years ago may preserve evidence of one of the most recent habitable microenvironments on Mars.
Observations by NASA's Mars Reconnaissance Orbiter enabled researchers to identify the mineral as hydrated silica and to see its volcanic context. The mounds' composition and their location on the flanks of a volcanic cone provide the best evidence yet found on Mars for an intact deposit from a hydrothermal environment -- a steam fumarole, or hot spring. Such environments may have provided habitats for some of Earth's earliest life forms.
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Blobrana


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Mars volcanic deposit tells of warm and wet environment

Roughly 3.5 billion years ago, the first epoch on Mars ended. The climate on the red planet then shifted dramatically from a relatively warm, wet period to one that was arid and cold. Yet there was at least one outpost that scientists think bucked the trend.
A team led by planetary geologists at Brown University has discovered mounds of a mineral deposited on a volcanic cone less than 3.5 billion years ago that speak of a warm and wet past and may preserve evidence of one of the most recent habitable microenvironments on Mars.
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