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Advanced Communication Technology Satellite (ACTS) and 2001 Mars Odyssey from 2002
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Auqakuh Valles
PIA03824
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Auqakuh Valles |
| Original Caption Released with Image |
(Released 7 June 2002) The Science This ancient sinuous river channel, located near 30° N, 299° W (61° E), was likely carved by water early in Mars history. Auqakuh Valles cuts through a remarkable series of rock layers that were deposited and then subsequently eroded. This change from conditions favoring deposition to those favoring erosion indicates that the environment of this region has changed significantly over time. In addition, the different rock layers seen in this image vary in hardness, with some being relatively soft and easily eroded, whereas others are harder and resistant. These differences imply that these layers vary in their composition, physical properties, and/or degree of cementation, and again suggest that major changes have occurred during the history of this region. Similar differences occur throughout the southwest U.S., where hard rock layers, such as the limestones and sandstones in the Grand Canyon, form resistant cliffs, whereas softer mudstones are easily eroded to form broad slopes. The Martian layers, such as the smooth, dark-toned mesas visible in numerous places to the right (east) of the channel, were once continuous across the region. As these layers have eroded, they have produced a wide array of textures, from smooth surfaces, to knobby terrains, to the unusual lobate patterns seen in the upper right of the image. The most recent activity in the region appears to be the formation of mega-ripples by the wind. These ripples, spaced approximately 75 m apart, form perpendicular to the wind direction, and can be seen following the pattern of the channel floor as it curves through this region. This pattern shows that even this relatively small channel, which varies in width from about 500 to 750 m throughout this image, acts to funnel the wind down the channel. The Story Auqakuh Vallis, an ancient river channel that winds its way down the center of this image, is the "fossil" remains of an earlier, probably more watery time in Martian history. Now, you might think that Auqakuh has something to do with Aqua, the Latin word for water. Instead, Auqakuh is the word for Mars in the Quechuan language of the Incan Empire that once stretched across vast portions of South America. This Inca-honoring river channel cuts through a remarkable series of rock layers that expose a history of climate change in the region. The coarse, rugged, and wildly textured terrain was created as rock layers were first deposited, then eroded over time. Some of the rock layers are soft and easily eroded, while others are clearly harder and more resistant. From these differences, geologists can tell that the layers are made up of different materials, have different physical characteristics, and are either loosely or strongly cemented together. That suggests major environmental changes over time as well, since different kinds of rocks form under different conditions. Similar differences in rock layers occur throughout the Southwest of the, United States. The next time you're visiting the Grand Canyon or hiking in similar terrain, notice where hard rock layers, such as limestones and sandstones, form resistant cliffs, whereas softer mudstones are easily eroded to form broad slopes along the canyon. Just in case the river channel in the above image looks more like a raised vein rather than a hollowed out channel, try looking at the half-circle depression on the left-hand side of the image, about a third of the way up. The bright features on the upper half streak down toward the bottom of the bowl. Once you focus on this for a while, your brain figures out that the channel must be depressed as well. Now that you can see that the channel cuts into the surface, click on the image for a closer look at the bottom of the channel. Mega-ripples about 82 yards apart line the channel floor as it curves through the region. This pattern shows that even this relatively small channel, which varies from about one-third to a half of a mile in width, funnels the wind down its curving length, creating perpendicular piles of waving texture on the channel's floor. East of the channel, smooth, dark-toned mesas are visible, providing a scant reminder that they were once continuous across the region. As these layers have eroded, they've produced a wide array of textures, from smooth surfaces, to knobby terrains, to the unusual curved, lobe-like patterns seen in the upper right of the image. |
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Auqakuh Valles
PIA03824
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Auqakuh Valles |
| Original Caption Released with Image |
(Released 7 June 2002) The Science This ancient sinuous river channel, located near 30° N, 299° W (61° E), was likely carved by water early in Mars history. Auqakuh Valles cuts through a remarkable series of rock layers that were deposited and then subsequently eroded. This change from conditions favoring deposition to those favoring erosion indicates that the environment of this region has changed significantly over time. In addition, the different rock layers seen in this image vary in hardness, with some being relatively soft and easily eroded, whereas others are harder and resistant. These differences imply that these layers vary in their composition, physical properties, and/or degree of cementation, and again suggest that major changes have occurred during the history of this region. Similar differences occur throughout the southwest U.S., where hard rock layers, such as the limestones and sandstones in the Grand Canyon, form resistant cliffs, whereas softer mudstones are easily eroded to form broad slopes. The Martian layers, such as the smooth, dark-toned mesas visible in numerous places to the right (east) of the channel, were once continuous across the region. As these layers have eroded, they have produced a wide array of textures, from smooth surfaces, to knobby terrains, to the unusual lobate patterns seen in the upper right of the image. The most recent activity in the region appears to be the formation of mega-ripples by the wind. These ripples, spaced approximately 75 m apart, form perpendicular to the wind direction, and can be seen following the pattern of the channel floor as it curves through this region. This pattern shows that even this relatively small channel, which varies in width from about 500 to 750 m throughout this image, acts to funnel the wind down the channel. The Story Auqakuh Vallis, an ancient river channel that winds its way down the center of this image, is the "fossil" remains of an earlier, probably more watery time in Martian history. Now, you might think that Auqakuh has something to do with Aqua, the Latin word for water. Instead, Auqakuh is the word for Mars in the Quechuan language of the Incan Empire that once stretched across vast portions of South America. This Inca-honoring river channel cuts through a remarkable series of rock layers that expose a history of climate change in the region. The coarse, rugged, and wildly textured terrain was created as rock layers were first deposited, then eroded over time. Some of the rock layers are soft and easily eroded, while others are clearly harder and more resistant. From these differences, geologists can tell that the layers are made up of different materials, have different physical characteristics, and are either loosely or strongly cemented together. That suggests major environmental changes over time as well, since different kinds of rocks form under different conditions. Similar differences in rock layers occur throughout the Southwest of the, United States. The next time you're visiting the Grand Canyon or hiking in similar terrain, notice where hard rock layers, such as limestones and sandstones, form resistant cliffs, whereas softer mudstones are easily eroded to form broad slopes along the canyon. Just in case the river channel in the above image looks more like a raised vein rather than a hollowed out channel, try looking at the half-circle depression on the left-hand side of the image, about a third of the way up. The bright features on the upper half streak down toward the bottom of the bowl. Once you focus on this for a while, your brain figures out that the channel must be depressed as well. Now that you can see that the channel cuts into the surface, click on the image for a closer look at the bottom of the channel. Mega-ripples about 82 yards apart line the channel floor as it curves through the region. This pattern shows that even this relatively small channel, which varies from about one-third to a half of a mile in width, funnels the wind down its curving length, creating perpendicular piles of waving texture on the channel's floor. East of the channel, smooth, dark-toned mesas are visible, providing a scant reminder that they were once continuous across the region. As these layers have eroded, they've produced a wide array of textures, from smooth surfaces, to knobby terrains, to the unusual curved, lobe-like patterns seen in the upper right of the image. |
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Dust Devil Tracks
PIA03791
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Dust Devil Tracks |
| Original Caption Released with Image |
(Released 8 May 2002) The Science This image, centered near 50.0 S and 17.7 W displays dust devil tracks on the surface. Most of the lighter portions of the image likely have a thin veneer of dust settled on the surface. As a dust devil passes over the surface, it acts as a vacuum and picks up the dust, leaving the darker substrate exposed. In this image there is a general trend of many of the tracks running from east to west or west to east, indicating the general wind direction. There is often no general trend present in dust devil tracks seen in other images. The track patterns are quite ephemeral and can completely change or even disappear over the course of a few months. Dust devils are one of the mechanisms that Mars uses to constantly pump dust into the ubiquitously dusty atmosphere. This atmospheric dust is one of the main driving forces of the present Martian climate. The Story Vrrrrooooooooom. Think of a tornado, the cartoon Tasmanian devil, or any number of vacuum commercials that powerfully suck up swirls of dust and dirt. That's pretty much what it's like on the surface of Mars a lot of the time. Whirlpools of wind called |
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Candor Chasma
PIA03838
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Candor Chasma |
| Original Caption Released with Image |
(Released 27 June 2002) The Science This THEMIS visible image shows the effects of erosion on a beautiful sequence of dramatically layered rocks within Candor Chasma, which is part of the Valles Marineris. These layers were initially deposited within Candor, and have subsequently been eroded by a variety of processes, including wind and downslope motion due to gravity. The effect of erosion is manifest differently in the different layers and at different locations within the layered material. For example, the upper portion of the Candor deposit seen in the lower one-third of the image appears more intact, whereas downslope there is pronounced fluting to create produced "spur and gully" slopes. Relatively dark materials are seen throughout the image and appear to mantle select areas of the layered deposits. When seen in other areas by THEMIS, and at higher resolution by the Mars Global Surveyor camera, these dark materials often form sand dunes. The dark mantling material in Candor is likely dark sand as well. Several particularly dark patches can be seen near the left (western) edge of the image, approximately one quarter of the way up from the bottom of the image. Very few impact craters of any size can be seen in this image, indicating that the erosion and transport of material is occurring at a relatively rapid rate, so that any craters that form are rapidly buried or eroded. The Story The smooth, triangular shape near the center of this image is the plateau of a canyon, with walls that dramatically descend on either side. This canyon is named Chasma, which means "blaze" or "white" in Latin. The lighter, brighter material of the southern canyon wall displays erosional streaks that almost do happen to look like a white blaze. Toward the bottom left of the image, you can see how the relatively brighter material from the top has been carried down to the bottom. Notice that the upper, grayer part of the southern canyon walls don't seem to have the same erosional flutes as the brighter material just below it. By looking at such differences on the same canyon wall, geologists can begin to understand the kinds of materials that make up each layer of the canyon wall, and how resistant each is to erosion. No matter what part of the canyon you look at, erosion has created the beautiful sequence of layered rocks within Candor. Sometimes it's the wind that acts, and sometimes gravity, which pulls material from the upper parts of the canyon downslope. Be sure to click on the above image for a close-up view of all of the subtle layers and ripples. Look also for some dark, almost black patches (bottom left, about a quarter of the way up). These dark splotches are most likely made of sand. In fact, much of the darker areas seen in this image are probably made of sand. The sand often forms in dunes, as both THEMIS and the higher resolution camera on Mars Global Surveyor, Odyssey's sister orbiter, have shown. With all of the wind and downslope erosion,, , this area is fairly active geologically. You can tell because there are very few impact craters of any size to be seen. That means material is being transported at a rate that's rapid enough to bury or erode any craters that do form. Candor Chasma is part of Valles Marineris, the large canyon system that slices across a large part of the red planet. If Valles Marineris were located on Earth, it would stretch all the way from the west coast to the east coast of the United States. |
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Candor Chasma
PIA03838
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Candor Chasma |
| Original Caption Released with Image |
(Released 27 June 2002) The Science This THEMIS visible image shows the effects of erosion on a beautiful sequence of dramatically layered rocks within Candor Chasma, which is part of the Valles Marineris. These layers were initially deposited within Candor, and have subsequently been eroded by a variety of processes, including wind and downslope motion due to gravity. The effect of erosion is manifest differently in the different layers and at different locations within the layered material. For example, the upper portion of the Candor deposit seen in the lower one-third of the image appears more intact, whereas downslope there is pronounced fluting to create produced "spur and gully" slopes. Relatively dark materials are seen throughout the image and appear to mantle select areas of the layered deposits. When seen in other areas by THEMIS, and at higher resolution by the Mars Global Surveyor camera, these dark materials often form sand dunes. The dark mantling material in Candor is likely dark sand as well. Several particularly dark patches can be seen near the left (western) edge of the image, approximately one quarter of the way up from the bottom of the image. Very few impact craters of any size can be seen in this image, indicating that the erosion and transport of material is occurring at a relatively rapid rate, so that any craters that form are rapidly buried or eroded. The Story The smooth, triangular shape near the center of this image is the plateau of a canyon, with walls that dramatically descend on either side. This canyon is named Chasma, which means "blaze" or "white" in Latin. The lighter, brighter material of the southern canyon wall displays erosional streaks that almost do happen to look like a white blaze. Toward the bottom left of the image, you can see how the relatively brighter material from the top has been carried down to the bottom. Notice that the upper, grayer part of the southern canyon walls don't seem to have the same erosional flutes as the brighter material just below it. By looking at such differences on the same canyon wall, geologists can begin to understand the kinds of materials that make up each layer of the canyon wall, and how resistant each is to erosion. No matter what part of the canyon you look at, erosion has created the beautiful sequence of layered rocks within Candor. Sometimes it's the wind that acts, and sometimes gravity, which pulls material from the upper parts of the canyon downslope. Be sure to click on the above image for a close-up view of all of the subtle layers and ripples. Look also for some dark, almost black patches (bottom left, about a quarter of the way up). These dark splotches are most likely made of sand. In fact, much of the darker areas seen in this image are probably made of sand. The sand often forms in dunes, as both THEMIS and the higher resolution camera on Mars Global Surveyor, Odyssey's sister orbiter, have shown. With all of the wind and downslope erosion,, , this area is fairly active geologically. You can tell because there are very few impact craters of any size to be seen. That means material is being transported at a rate that's rapid enough to bury or erode any craters that do form. Candor Chasma is part of Valles Marineris, the large canyon system that slices across a large part of the red planet. If Valles Marineris were located on Earth, it would stretch all the way from the west coast to the east coast of the United States. |
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