Mariner's Canyon was founded by Mariner 9 in 1972SpacecraftIt is found that its length is equivalent to the distance between New York and Los Angeles.The largest canyon in the solar system has drawn a wide cut on the face of Mars. The magnificent valley called Sailor's Canyon stretches more than 4500 kilometers back and forth, with the widest part more than 600 kilometers wide, and about 8 kilometers deep.The east-west range of Shouhao Valley is 267.3 degrees east longitude to 331.1 degrees east longitude, which is adjacent to the westNoctis Labyrinthus East into a large area of chaotic terrain;The north-south range is 2.96 degrees south latitude to 19.09 degrees south latitude.
stayMarsThere is a rough geological "scar" in the hinterland ofNew YorkreachLos AngelesThe distance is equivalent.This huge fault zone on the Martian crust is called Sailor Valley. It was founded by Sailor 9 in 1972SpacecraftFound.The Sailor's Valley, which is composed of several parallel grooves, makes the Grand Canyon of the Earthbe inferior by comparison。It is wider, longer, deeper and older than the Grand Canyon. It is the king of the canyon.
Altitude topographic map of Mariner Canyon
This mosaic image of Sailor's Valley is colored to show the surface of Mars.It is composed of the thermal radiation imaging system (THEMIS), which is installed in the NASA Mars "Odyssey"OrbiterA visible and infrared induction camera on the.The Mars "Odyssey" spacecraft is manufactured by Lockheed Martin, and the Jet Propulsion Laboratory is responsible for its flight control.This mosaic of more than 500 daytime infrared photos shows more details of the valley than any previous composite photo.This valley is extremely wide, and its western part runs through the Noctis Labyrinthus, with a total length of about 3000 kilometers (2000 miles).Nevertheless, tiny details like the size of a football field (100 meters, 328 feet) can still be recognized in the image.
geologistIt is believed that the geological fault in the front of Sailor's Valley began to form about 3.5 billion years ago.The fault is caused by the change of geological structure and the continuous growth of the giant volcano Tharsis in the west.When molten rock (magma) flows into Tahis Mountain from the crust, the whole area begins to rise, and then the surrounding crustal rocks are continuously stretched until the faults and cracks are formed.
When the crack unfolds, the ground will sink, just as the keystone will fall when the arch moves.At the same time, the fault also opens a channel for the flow of groundwater, which destroys the surface and expands the fault area.In countless places of Sailor's Valley, steep and newly exposed cliffs have become very unstable, and the resulting landslides have widened the canyon.
It is not clear when Sailor's Valley will stop growing, because there are still smallLandslideappear.But its main activities ended about 2 billion years ago.Several places of Sailor's Valley show different stages of its formation and development.These examples will help scientists better understand its context.
Causes
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As the Sahis Volcano Province, where Mars Olympus Mountain is located, is constantly uplifting, resulting in the tensile collapse of the Martian crust in the adjacent area, the Mariner Grand Canyon was formed.[1]
Geographic description
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Mariner's Canyon: the Grand Canyon of Mars
By contrast, located inU.S.AArizonaThe Grand Canyon is about 800 kilometers long, 30 kilometers wide and 1.8 kilometers deep.Although there is a major hypothesis that billions of years agoplanetWhen cooling down, a crack later evolved into today's canyon, and the true cause of Mariner's Canyon is still uncertain.We have identified several kinds ofgeologyEvolution process.
Under pressure
Sailor's Valley was initially split under the slow and irresistible pulling force.When geological tectonic movement drags MarsCrustWhen the Tahis Mountains were formed, their fractures formed cracks across hundreds of miles on the surface of the earth.The cracks seen today are just remnants of a common phenomenon in the formation of Sailor's Valley.The curved shape of these faults indicates that the area does not move as hard as the marble on the kitchen top.Instead, it is more like a large piece of chocolate cake sliding down from the cake paper, soft and curved.The other fault is located in the north of Tahis volcano.There, Huangquangou was cut by dozens of curved fault zones.
Gradual widening
When the surface splits, water and melted underground ice and snow flow downstream, causing the ground to collapse and some areas to be washed away.Different sections of Sailor's Valley provide snapshots of different stages of this process.
For example, the faults here have formed collapse pits, and some pits are connected with each other, forming a large area of depression.This process continuously erodes the ground until the land between two adjacent faults is completely destroyed.
Chaotic terrain
At the eastern end of the valley,scientistThere were unmistakable signs of flooding.The ground here was once completely immersed in water. When the flood receded, the ground almost collapsed, leaving only isolated mountains and hills.Therefore, scientists call such a zone "chaotic terrain"nothing surprisingHas.
The flood finally flowed into the northern lowlands through several scouring channels.From the eastern end of Sailor's Valley, the flood flows through a series of rivers and finally reaches Chrysebasin。In the northwest of Sailor's Valley, similar floods gushed out from a depression called Echus Chasma, forming the scouring channel of Kasei Valles.
Is it the result of an overwhelming huge flood flowing into the river, or is it the result of repeated scouring by small-scale floods?This is still an unsolved mystery.Evidence shows that the flood occurred in several stages, and at least once there was a huge flood.
Although it happened millions of years ago, this flood phenomenon occurred in a period called Hesperian in the history of Mars.This period is after the Noachian, which formed the largest meteorite crater and volcanic activity, and before the Amazonianperiod of transition。These three periods are named after three specific regions: Noachis Terra, Hesperia Planum, andAmazonAmazon is Planitia.
Although the time span of the "Western Period" can only be roughly inferred, scientists believe that this period began about 3.5 billion years ago and ended about 2 billion years ago.During this period, in addition to large-scale flooding and growth of Tharsis, Mars experienced several slow impacts and formed someMeteoriteThe climate of pits and basins and Mars is getting colder and drier.
Weaken resistance
Not all erosion in the valley will lead to catastrophic flooding.In Louros Valley and other places, a large number of tributary canyons intrude into the southern edge of the valley, and the canyon is continuously widened with slight erosion.The main parts of these canyons and valleys are probably formed under the same principle, namely, the loss of groundwater, but these canyons have less water, smaller scale, and more concentrated results.As geologists speculate, water flows down the cliffs of the canyon in the form of springs or seeps and washes away the sediment.The result of this gradual erosion process is a dome valley that slowly slopes backward from the edge of the canyon.The faults and cracks in the rock guide the direction of erosion, so the growing valley forms a unique dendritic shape.
The tributary canyon seen here is comparable to the famous Grand Canyon in northern Arizona.The Grand Canyon meanders about 800 kilometers (500 miles), while these tributary canyons are only 140 kilometers (72 miles) long.But the junction between this canyon and Sailor's Valley is more than 3800 meters (12500 feet) deep, which is more than twice the depth of the Grand Canyon on earth.
The effect of groundwater can also be observed in the center of the crater bottom.At the crater, there is a thin layer of debris about 7 kilometers (4.5 miles) wide with a convex outer edge.Scientists call it Barrier Crater.Scientists said that the skirt shaped debris layer showed that there was a large amount of water or ice on the surface when the impact occurred.The heat generated by the impact released the water on the surface and wetted the flying debris, thus forming a semi-solid diffusion circle about 70 meters high (240 feet) surrounded by barriers.
Continuous landslide
Under the constant erosion of water, cliffs and valley walls are usually not firm, and many places in Sailor's Valley are widened due to landslides.This particular landslide collapsed thousands of feet, with a maximum length of 100 kilometers (60 miles).Further observation shows that several landslides have occurred here, and new landslides continue to bury the previous one.
Just like landslides on the earth, landslides on Mars can cover a long distance, especially whenrockWhen the pieces contain water or gas, which greatly reduces the friction.Scientists even believe that the thin air on Mars may also be one of the reasons for this huge landslide.Similarly, if the length is shortened, the landslide will cover most areas of Sailor's Valley and help to widen the valley.
Default History
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The history of Martian Sailor Valley is not only eroded.Melas Chasma, Candor Chasma, Ophir Chasma and other places are shown, and high sediments are accumulated at the bottom of the valley.Geologists call them internal stack sediments.The origin and characteristics of these substances may be the biggest mystery in Sailor's Valley.In places such as Chasma Hebes, the sediments are stacked layer by layer, almost reaching the edge of the valley.They present eroded rock ridges and terraces, isolated hills, flat topped platforms and other different forms.In some places, the sediments are covered by rock fragments from landslides.So where did these sedimentary layers come from?This is still an unknown.
Another puzzling mystery is how wet the environment was in the history of Mars?Inside the Sailor's Valley, the bottom of the Ganges Chasma contains olivine rich basalt, but in other parts of the canyon system, such as the Candor Chasma, the acidity of water is also lower than that found by the Opportunity rover in the Meridiani Plain.Because of its outstanding characteristics, Sailor's Valley obviously occupies an important part in the history of Mars.Although scientists have been able to outline the history of Mars, it is difficult to study the details.
No matter how the story of Sailor's Valley develops, the process of solving these or those unsolved mysteries will enable scientists to better study the history of the red world next to the earth.
Main partition
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Coprates Chasma
To the east of this canyon system is the Coprates Chasma, which is very similar to the Ius and Titonorn canyons, except for its geographical location.Copuletus Canyon also contains alluvial and aeolian sediments.Copritus Canyon, like the Yius Canyon, has multiple layers of sediment, although the sediment stratification in Copritus Canyon is more obvious.These sediments are older than the formation of Mariner Canyon System, so it is believed that erosion and sedimentation are later than the formation of Mariner Canyon System.come fromMars Global Surveyor The new data from theColluviumThe bottom of the lake is covered with liquid water or ice layer by layer. If it is the bottom of the lake, the canyon around the Mariner Canyon may have been an isolated lake formed by erosion collapse.Other sources of formation sediments may be caused by wind, but the formation conditions show that wind is not the main source.At the same time, it is also found that only the upper layer is thin, while the lower layer is quite thick, which means that the lower layer is formed by the collapse of a large number of rocks, and the upper layer is from other sources.Some strata may be transferred to the bottom of the valley due to landslides, and half of them are intact, but they look like highly deformed strata, whose bottom will become thicker or thinner, and there are multiple folds.This complex terrain may only come from the eroded sediments at the bottom of an ancient lake, and it looks very complex;This is because we view the geological map from the bird's eye view, and there is not enough elevation data to confirm whether the bottom is flat.
Eos and Ganges Valley
To the east are Eos Chasma and Ganges Chasma.The valley bottom in the west of Eos Canyon is mainly a large amount of material eroded by Martian wind after the sediments formed by volcanism or wind deposition are eroded;In the east, there are large areas of linear objects and longitudinal stripes.It is generally believed that the plateau sediment is transported to the local deposit after being eroded by fluid.Ganges Valley is an east-west branch of Eos Valley.The bottom of the Ganges River Valley is mainly composed of water sediment from the cliff of the canyon.
Chryse Planitia
At the eastern end of the Eos and Ganges canyons is the end of the Mariner canyon, which flows into MarsNorthern Great PlainThe attached Chris Plain is only about 1km higher than the lowest point in Mariner Canyon (located in Miras Canyon).The terrain of this area flowing out to the northern Great Plain is quite similar tomars pathfinder The landing place of.stayearthUpper andMarsOutflow channels are similar to the Channeled Scablands in the eastern Washington State.The Scablands in eastern Washington State were caused by the formation of Glacial Lake Missoula during the late Pleistocene and the multiple cycles of floods after the ice dam broke.The ice dam may block the river water for a period of time, but when the dam breaks, the ice may float in a large number of floods, and the surface soil and vegetation in a large area will also be taken away, leaving a barren area dominated by teardrop islands, longitudinal trenches and river terraces.Similar terrain can be seen in the outflow dredging on Mars, but on a larger scale.
These outward flows continuously pass through severalChaotic terrain: Aurorae Chaos and Hydraotes Chaos, finally entering through West Mudd Valley and Tyre ValleyChryse Planitia 。
Perplexing Riddle
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Where do sedimentary layers come from?
This kind of flat and untwisted stacking indicates that the sediments were accumulated in a calm geological environment.For example, falling from the skyash, or sediment deposited in lakes or large areas of static waters.But if the source of sediment is lake sediments, how did they enter the valley?This is still an unknown.
What kind of wet environment did Mars have in its history?
Inside Sailor's Valley,Ganges Chasma The valley bottom of GangesChasma contains basalt rich in olivine.olivineIt is a green mineral. When it is placed in water, it will soon be eroded into other forms by water.The olivine in the Ganges Valley shows that there was only a relatively small amount of water in the history of the canyon.
But in other parts of the canyon system, such asCandor Chasma （candorChasma），Scientists discovered clay minerals.This indicates that rocks and rock debris were seriously eroded by water.In addition, the acidity of water here is also higher thanOpportunity Mars RoverThe value found in the Meridiani Plain is lower.
