{"id":16768,"date":"2014-12-11T00:10:27","date_gmt":"2014-12-10T16:10:27","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/rover-data-suggest-mars-crater-once-contained-long-lived-lake\/"},"modified":"2014-12-11T00:10:27","modified_gmt":"2014-12-10T16:10:27","slug":"rover-data-suggest-mars-crater-once-contained-long-lived-lake","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/rover-data-suggest-mars-crater-once-contained-long-lived-lake\/","title":{"rendered":"Rover data suggest Mars crater once contained long-lived lake"},"content":{"rendered":"
\"This
This illustration depicts a lake of water partially filling Mars\u2019 Gale Crater, receiving runoff from snow melting on the crater\u2019s northern rim. Credit: NASA\/JPL-Caltech\/ESA\/DLR\/FU Berlin\/MSSS<\/figcaption><\/figure>\n

Scientists analyzing imagery from NASA\u2019s Curiosity Mars rover believe sediments left by an ancient lake more than three billion years ago formed a towering mountain that is set to be the robot\u2019s research subject for the rest of its mission on the red planet.<\/p>\n

The evidence indicates Mars may have once been sufficiently warm and wet to support lakes lasting up to tens of millions of years \u2014 and maybe longer \u2014 enough time for basic life forms to take hold.<\/p>\n

Curiosity is exploring a 96-mile-wide impact basin named Gale Crater, where the rover touched down in August 2012. Scientists cited a three-mile-high peak named Mount Sharp in the center of the crater as the reason for landing the rover at Gale Crater after observations from Mars orbiters showed the mountain harbored clay minerals that likely formed in the presence of water.<\/p>\n

The rover already found proof that ancient rivers once coursed through the crater, supporting an environment that was \u2014 at least intermittently \u2014 habitable to microbial life.<\/p>\n

Using images of inclined rock formations at the base of Mount Sharp, scientists have surmised a lake \u2014 or a series of lakes \u2014 at least a few meters deep once filled the crater.<\/p>\n

Runoff from melting snow at the rim of the crater could have formed seasonal streams feeding into the lake system. Evidence of sedimentary deposits from small river deltas support this hypothesis, scientists said.<\/p>\n

\u201cThe puzzle pieces are coming together, and we are now able to answer two big questions about Gale Crater,\u201d said Michael Meyer, NASA\u2019s lead Mars scientist. \u201cHow did Mount Sharp form, and how long was there water to support microbial life?\u201d<\/p>\n

The rivers may have taken tens of millions of years to lay down the sediment that eventually formed Mount Sharp, giving scientists an idea of how long the region was habitable.<\/p>\n

\u201cLooking at the size of the lake in Gale Crater, and the length of the time \u2026 that water was showing up, that implies that there may have been sufficient time for life to get going and thrive,\u201d Meyer said.<\/p>\n

One question still unanswered is how long it takes for organic building blocks to come together and create basic microorganisms.<\/p>\n

\u201cThese are things that we don\u2019t have a very good handle on here on Earth, much less the possibilities on another planet,\u201d Meyer said.<\/p>\n

Curiosity\u2019s findings are suggestive of a much different Martian environment billions of years ago, said Ashwin Vasavada, the rover mission\u2019s deputy project scientist at NASA\u2019s Jet Propulsion Laboratory.<\/p>\n

\u201cThe landscapes of Mount Sharp indicate that rivers, lakes and ground water were present over millions of years, something that would be impossible on Mars today,\u201d Vasavada said.<\/p>\n

\"This
This evenly layered rock photographed by the Mast Camera (Mastcam) on NASA\u2019s Curiosity Mars Rover shows a pattern typical of a lake-floor sedimentary deposit not far from where flowing water entered a lake. Credit: Image Credit: NASA\/JPL-Caltech\/MSSS<\/figcaption><\/figure>\n

For Mars to support such a wet environment, the planet\u2019s atmosphere must have been much thicker, it must have been warmer, and the Martian climate system must have been loaded with water, Vasavada said.<\/p>\n

\u201cThis is a critical point,\u201d Vasavada said. \u201cTo sustain a lake at Gale Crater for millions of years, Mars would need a vigorous hydrological cycle to keep the atmosphere humid.\u201d<\/p>\n

A large ocean would keep the planet\u2019s atmosphere humid enough to keep the crater filled with water, according to Vasavada. He said Mars could also been warmed enough to melt its frozen ice caps through a series of volcanic eruptions, asteroid impacts, or other disconnected events.<\/p>\n

\u201cAs we continue studying Mount Sharp, one question we\u2019ll ask is whether temporary climate fluctuations could form what we see geologically, or whether a long-lived warm climate was truly necessary,\u201d Vasavada said.<\/p>\n

\u201cI think at this point the jury is out,\u201d Vasavada said. \u201cThere seem to be reasonable explanations for either forming these features through a series of short-lived episodes or a sustained warmer climate, but we\u2019ll be able to add to that with the evidence that we find in our study of Mount Sharp.\u201d<\/p>\n

Many scientists already conjectured Gale Crater was once home to a lake.<\/p>\n

\u201cWhat is new is the way that we deduced its presence by using rover-based observations,\u201d said John Grotzinger, Curiosity\u2019s project scientist at JPL.<\/p>\n

The rover crossed over a boundary from an area with rock deposits that were laid down by flowing water into a new geologic zone with rock layers that show signs they formed in a standing body of water.<\/p>\n

\u201cWe found sedimentary rocks suggestive of small, ancient deltas stacked on top of one another,\u201d said Sanjeev Gupta, a member of the Curiosity science team from Imperial College London. \u201cCuriosity crossed a boundary from an environment dominated by rivers to an environment dominated by lakes.\u201d<\/p>\n

In between the two regions, imagery from the rover showed rock layers at an incline, a feature often seen at the mouths of rivers.<\/p>\n

\"This
This image taken by the Mast Camera (Mastcam) on NASA\u2019s Curiosity Mars rover just north of the \u201cKimberley\u201d waypoint shows beds of sandstone inclined to the southwest toward Mount Sharp and away from the Gale Crater rim. The inclination of the beds indicates build-out of sediment toward Mount Sharp. Credit: NASA\/JPL-Caltech\/MSSS<\/figcaption><\/figure>\n

\u201cWhen rivers encounter a lake, the water in the river channel decelerates, then all the sediments carried in the river abruptly deposit,\u201d Gupta said.<\/p>\n

The deposits are tilted to the south, suggesting water was flowing toward Mount Sharp.<\/p>\n

The observation set up a paradox for the rover science team. The inclined rocks indicated the rivers emptied into a lake where Mount Sharp sits today, with the water appearing to flow uphill.<\/p>\n

\u201cWhen we saw the inclined strata and they were dipping toward Mount Sharp, that was really a great surprise,\u201d Grotzinger said.<\/p>\n

To solve the riddle, Grotzinger said rover scientists proposed the hypothesis that Mount Sharp was not there when the rivers were active.<\/p>\n

Gupta said the rover\u2019s camera has identified inclined rock beds higher up on the mountain, a sign that the site experienced multiple episodes of river flows or precipitation, perhaps separated by periods of evaporation when the lake dried up.<\/p>\n

\u201cWe don\u2019t imagine that this environment was just a single lake that stood for millions of years, but rather a system of alluvial fans, deltas, lakes and dry deserts that alternated probably for millions, if not tens of millions of years, as a connected system,\u201d Grotzinger said.<\/p>\n

Once the rivers dropped their sediments into the crater, the material hardened into rock and was eroded to shape Mount Sharp.<\/p>\n

\u201cWe are beginning to think that maybe Mount Sharp formed in a series of episodes involving sedimentation and erosion stacked by different processes,\u201d Grotzinger said.<\/p>\n

\"This
This Mastcam image shows inclined beds characteristic of delta deposits where a stream entered a lake, but at a higher elevation and farther south than other delta deposits north of Mount Sharp. This suggests multiple episodes of delta growth building southward. Credit: NASA\/JPL-Caltech\/MSSS<\/figcaption><\/figure>\n

Vasavada said the rover\u2019s discoveries could help answer key questions about the climate on ancient Mars that can\u2019t be addressed from remote sensing instruments in orbit.<\/p>\n

\u201cWhat\u2019s new with Curiosity is that this evidence is from close-up study of sediments carried by the water, and in that respect provides more clues than the existing wealth of evidence for early wet Mars based on only studying landforms from orbit like the valley networks on Mars\u2019 highlands,\u201d Vasavada said.<\/p>\n

\u201cRecent studies of all these data tend to push warm and wet Mars a little later in its history than we previously thought to about three-and-a-half billion years ago,\u201d Vasavada said. \u201cIt also extends the time over which potentially habitable enviornments may have been present.\u201d<\/p>\n

Proof that an ocean once filled a giant basin in the Martian northern hemisphere has been hard to come by. Channels carved out of highland regions appear to lead into the theorized ocean, but hard evidence the sea ever existed has eluded scientists.<\/p>\n

Curiosity\u2019s upcoming research campaign could help contribute to that line of study, Vasavada said.<\/p>\n

\u201cOther than the geologic evidence, there\u2019s a way to infer an ocean from the climatology,\u201d Vasavada said. \u201cIf we require precipiation at Gale Crater over a long period of time, if we have a long-standing lake for millions of years, the atmospheric humidity practically requires a standing body of water like an ocean to keep Gale from evaporating and to keep a vigorous hydrological cycle going. We\u2019ll continue to look at that and add to that pretty intriguing question.\u201d<\/p>\n

Scientists plan to use the rover to test their lake hypothesis and get a better understanding of what was happening on Mars before Mount Sharp formed.<\/p>\n

\u201cWe\u2019d like to see if there are times when the lake freshens, if there are times when the lake becomes salty, (or) if there are times when it evaporates completely and leaves behind aeolian sand dune deposits,\u201d Grotzinger said. \u201cThat will really begin to tell us about the climate history of Mars at a higher level of resolution.\u201d<\/p>\n

Follow Stephen Clark on Twitter: @StephenClark1.<\/i><\/b><\/p>\n","protected":false},"excerpt":{"rendered":"

This illustration depicts a lake of water partially filling Mars\u2019 Gale Crater, receiving runoff from snow melting on the crater\u2019s northern rim. Credit: NASA\/JPL-Caltech\/ESA\/DLR\/FU Berlin\/MSSS Scientists analyzing imagery from NASA\u2019s Curiosity Mars rover believe sediments left by an ancient lake more than three billion years ago formed a towering mountain that is set to be […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[2927,2942,4129,367,2944,4223],"class_list":["post-16768","post","type-post","status-publish","format-standard","hentry","category-news","tag-curiosity","tag-gale-crater","tag-jpl","tag-mars","tag-mount-sharp","tag-water"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/16768"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=16768"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/16768\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=16768"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=16768"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=16768"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}