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Collection:
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NASA Planetary Photo Journal Collection
Collection
NASA Planetary Photo Journal Collection
Collection
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Title:
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Ulysses Patera
Title
Ulysses Patera
Title
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Original Caption Released with Image:
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Original_Caption_Rel eased_with_Image
Original Caption Released with Image
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Original Caption Released with Image:
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(Released 18 July 2002)
It is helpful to look at the context for this THEMIS image, which covers a large area over the summit of Ulysses Patera. Ulysses Patera is one of the many volcanoes that make up the giant Tharsis volcanic province, although Ulysses itself is fairly small in comparison to the other volcanoes in this area. In the context image, there are 3 circular features near the top of the volcano. The large, central feature is called a "caldera", and is the result of volcanic activity at Ulysses. The other two circular features are impact craters. The THEMIS image primarily spans across the central caldera, but also covers a portion of the northernmost impact crater. We know that the large central caldera must have formed earlier than the two craters, because its circular form has been cut by the smaller crater rims.
In the THEMIS image, there are stair-stepping plateaus in the northern portion of the image. These are part of the rim of the northern crater, and are caused by collapse or subsidence after the impact event. Just to the south of this crater, "rayed" patterns can be seen on part of the caldera floor. The rayed pattern is most likely due to a landslide of material down the crater rim slope. Another possibility is that the impact that formed the northern crater caused material to be ejected radially, and then parts of the ejecta have either been buried or eroded away. Other signs of mass movement events in this image are dark streaks, caused by dust avalanches, visible in the caldera's northern wall. In the central portion of the image, there are two lobe-shaped features-one overlaps the other-that appear to have flowed westward. It is likely that these features are ejecta lobes, because they are located adjacent to the southeastern crater (see context image). The fluidized appearance of these ejecta lobes is probably due to a significant amount of ice or water being present in the soil at the time of impact. We know that the southeastern crater must have formed after the northern crater, because the fluidized ejecta lobe overlies the rayed pattern. A close-up look at the fluidized ejecta lobes reveals a different surface "texture" than the surrounding caldera floor. This could be due to compressional features that formed during the lobe emplacement, or to contrasting surface properties that cause the flows to be eroded differently than the caldera floor. In the lower portion of the image, there is a cluster of small circular features in the southernmost part of the central caldera. These features may be layered material that has since been eroded into circular plateaus, or they may be degraded volcanic cones, which would indicate a later stage of smaller-scale volcanism within the caldera. Volcanic cones are common in many calderas on Earth, and are formed after the initial stage of volcanic activity in that caldera. Finally, in the southern wall of the caldera, there is classic "spur-and-gully" morphology. This type of
Original_Caption_Rel eased_with_Image
(Released 18 July 2002)
It is helpful to look at the context for this THEMIS image, which covers a large area over the summit of Ulysses Patera. Ulysses Patera is one of the many volcanoes that make up the giant Tharsis volcanic province, although Ulysses itself is fairly small in comparison to the other volcanoes in this area. In the context image, there are 3 circular features near the top of the volcano. The large, central feature is called a "caldera", and is the result of volcanic activity at Ulysses. The other two circular features are impact craters. The THEMIS image primarily spans across the central caldera, but also covers a portion of the northernmost impact crater. We know that the large central caldera must have formed earlier than the two craters, because its circular form has been cut by the smaller crater rims.
In the THEMIS image, there are stair-stepping plateaus in the northern portion of the image. These are part of the rim of the northern crater, and are caused by collapse or subsidence after the impact event. Just to the south of this crater, "rayed" patterns can be seen on part of the caldera floor. The rayed pattern is most likely due to a landslide of material down the crater rim slope. Another possibility is that the impact that formed the northern crater caused material to be ejected radially, and then parts of the ejecta have either been buried or eroded away. Other signs of mass movement events in this image are dark streaks, caused by dust avalanches, visible in the caldera's northern wall. In the central portion of the image, there are two lobe-shaped features-one overlaps the other-that appear to have flowed westward. It is likely that these features are ejecta lobes, because they are located adjacent to the southeastern crater (see context image). The fluidized appearance of these ejecta lobes is probably due to a significant amount of ice or water being present in the soil at the time of impact. We know that the southeastern crater must have formed after the northern crater, because the fluidized ejecta lobe overlies the rayed pattern. A close-up look at the fluidized ejecta lobes reveals a different surface "texture" than the surrounding caldera floor. This could be due to compressional features that formed during the lobe emplacement, or to contrasting surface properties that cause the flows to be eroded differently than the caldera floor. In the lower portion of the image, there is a cluster of small circular features in the southernmost part of the central caldera. These features may be layered material that has since been eroded into circular plateaus, or they may be degraded volcanic cones, which would indicate a later stage of smaller-scale volcanism within the caldera. Volcanic cones are common in many calderas on Earth, and are formed after the initial stage of volcanic activity in that caldera. Finally, in the southern wall of the caldera, there is classic "spur-and-gully" morphology. This type of
Original Caption Released with Image
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Original Caption Released with Image:
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morphology is often formed on steep slopes, where variations in wall resistance cause the surface to be eroded more easily in some areas.
Original_Caption_Rel eased_with_Image
morphology is often formed on steep slopes, where variations in wall resistance cause the surface to be eroded more easily in some areas.
Original Caption Released with Image
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Image Credit:
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NASA/JPL/Arizona State University
Image_Credit
NASA/JPL/Arizona State University
Image Credit
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Produced By:
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Arizona State University
Produced_By
Arizona State University
Produced By
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Mission:
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2001 Mars Odyssey
Mission
2001 Mars Odyssey
Mission
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Spacecraft:
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2001 Mars Odyssey
Spacecraft
2001 Mars Odyssey
Spacecraft
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Target Name:
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Mars
Target_Name
Mars
Target Name
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Is a satellite of:
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Sol (our sun)
Is_a_satellite_of
Sol (our sun)
Is a satellite of
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Instrument:
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Thermal Emission Imaging System
Instrument
Thermal Emission Imaging System
Instrument
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Product Size:
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1239 samples x 3043 lines
Product_Size
1239 samples x 3043 lines
Product Size
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Producer ID:
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20020718A
Producer_ID
20020718A
Producer ID
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facet_what:
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Sun
facet_what
Sun
facet_what
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facet_what:
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Crater
facet_what
Crater
facet_what
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facet_what:
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Earth
facet_what
Earth
facet_what
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facet_what:
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Mars
facet_what
Mars
facet_what
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facet_what:
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2001 Mars Odyssey
facet_what
2001 Mars Odyssey
facet_what
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facet_what:
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Ulysses
facet_what
Ulysses
facet_what
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facet_what:
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Patera
facet_what
Patera
facet_what
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facet_what:
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Thermal Emission Imaging System (THEMIS)
facet_what
Thermal Emission Imaging System (THEMIS)
facet_what
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facet_where:
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Mars
facet_where
Mars
facet_where
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facet_where:
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Arizona
facet_where
Arizona
facet_where
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facet_where:
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Jet Propulsion Laboratory (JPL)
facet_where
Jet Propulsion Laboratory (JPL)
facet_where
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facet_when:
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18 July 2002
facet_when
18 July 2002
facet_when
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facet_when_year:
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2002
facet_when_year
2002
facet_when_year
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Image #:
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PIA03900
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UID:
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SPD-PHOTJ-PIA03900
UID
SPD-PHOTJ-PIA03900
UID
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orignial url:
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orignial_url
orignial url
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