The presence of H2O on Mars has been theorized for centuries. Early telescopes revealed H2O ice caps, together with early on astronomers noted channels that were hypothesized to endure natural rivers or creature-created canals.
 |
| The physiography of Gale Crater shown inward a HiRISE map [Credit: Geological Society of America] |
Since its landing on the "Red Planet" inward August of 2012, Curiosity Rover has traveled nigh xx kilometers inside Gale Crater. The rover has examined nigh 400 meters of sedimentary stone that exists inward the crater, says Ezat Heydari of Jackson State University inward Jackson, Mississippi -- including rocks idea to endure 3.7 to 4.1 billion years sometime (Noachian time).
Heydari together with colleagues used these images of sedimentary rocks to translate the geologic processes that occurred billions of years agone on Mars. He is presenting their findings on Dominicus at the Geological Society of America Annual Meeting inward Indianapolis, Indiana.
Within those 400 meters of rock, the researchers identified 4 dissimilar units that stand upward for dissimilar types of deposition, together with Heydari says that "in my opinion, deposition of all of these packages involved water."
One of those packages, called the Hummocky Plain Unit, is a conglomerate alongside grains upward to xx centimeters inward size. The Curiosity images showed ridges inward the Hummocky Plain Unit, filled alongside rounded cobbles together with cross beds reaching 4 meters high -- indications that deposition was done past times moving water.
In addition, some of the images accept meridian information that tin practise a topographic profile of the surface, revealing the profiles of the ridges. "These ridges are asymmetric," says Heydari. "In other words, they were formed past times i directional current."
After seeing the images, Heydari says he straightaway idea of the Channelized Scablands inward Washington State. The Mars ridges are as spaced, he says, adding that they are nigh twice the size of those inward the Scablands. The ridges on Mars together with basis had like characteristics, simply it wasn't until he saw the cross beds that Heydari concluded the Mars deposits were made past times large-scale flooding.
Using comparisons to basis rivers, Heydari notes that to practise cross beds 4 meters high, the flowing H2O would accept been nigh ten to xx meters deep. "That's i of the reasons I country these deposits are related to floods, rather than a puny river," he says.
Heydari says that the Noachian sedimentary rocks flora inward Gale Crater may accept been deposited inward a like setting as Pleistocene basis (about 2 meg years to 12,000 years ago), alongside large-scale global H2O ice together with dramatic flare-up floods.
"On both planets, i hemisphere was covered past times H2O ice -- northern Hemisphere on Earth, versus the Southern Hemisphere inward Mars -- together with the other hemisphere was warm," says Heydari. He adds that this comparing is of import because it shows that ancient Mars appears to endure real like to Pleistocene Earth, where liquid H2O is stable together with able to back upward life.
Source: Geological Society of America [November 05, 2018]
Sumber http://archaeologynewsnetwork.blogspot.com
Within those 400 meters of rock, the researchers identified 4 dissimilar units that stand upward for dissimilar types of deposition, together with Heydari says that "in my opinion, deposition of all of these packages involved water."
 |
| Geology inside the landing ellipse of the Curiosity Rover. The Hummocky Plains Unit, the sedimentary stone unit that contains cross bedded conglomerate idea to endure deposited inward an flare-up flood, is shown inward sage greenish [Credit: Geological Society of America] |
In addition, some of the images accept meridian information that tin practise a topographic profile of the surface, revealing the profiles of the ridges. "These ridges are asymmetric," says Heydari. "In other words, they were formed past times i directional current."
After seeing the images, Heydari says he straightaway idea of the Channelized Scablands inward Washington State. The Mars ridges are as spaced, he says, adding that they are nigh twice the size of those inward the Scablands. The ridges on Mars together with basis had like characteristics, simply it wasn't until he saw the cross beds that Heydari concluded the Mars deposits were made past times large-scale flooding.
Using comparisons to basis rivers, Heydari notes that to practise cross beds 4 meters high, the flowing H2O would accept been nigh ten to xx meters deep. "That's i of the reasons I country these deposits are related to floods, rather than a puny river," he says.
 |
| Close upward of a Mastcam icon mosaic (Mcam02603) acquired on Sol 620. This conglomerate has grains upward to ten centimeters inward diameter together with some are good rounded. The grains also are business office of a 2-meter-high cross bed [Credit: Geological Society of America] |
"On both planets, i hemisphere was covered past times H2O ice -- northern Hemisphere on Earth, versus the Southern Hemisphere inward Mars -- together with the other hemisphere was warm," says Heydari. He adds that this comparing is of import because it shows that ancient Mars appears to endure real like to Pleistocene Earth, where liquid H2O is stable together with able to back upward life.
Source: Geological Society of America [November 05, 2018]
Sumber http://archaeologynewsnetwork.blogspot.com
Buat lebih berguna, kongsi:
