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This image shows the fourth of five broad channels on Mercury for which names were recently approved (see Timgad Vallis). The valleys are named according to the theme of "abandoned cities (and towns and settlements) of antiquity" that was developed especially for these landforms.
The vallis shown in this figure is named for Timgad, a Roman colonial town in the Algerian Aurès Mountains, founded around 100 CE. The city was abandoned after an Arab invasion in the 8th century CE, before being covered by the Sahara. The city ruins were excavated in 1881. The city’s population may have been as great as 15,000. This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit.
Date Created: March 26, 2013
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Feature Latitude Range: 59.6° N to 62.0° N
Feature Longitude Range: 114.3° E to 119.9° E
Feature Diameter: 116 km
Projection: Azimuthal equidistant
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
This image shows the fourth of five broad channels on Mercury for which names were recently approved (see Paestum Vallis). The valleys are named according to the theme of "abandoned cities (and towns and settlements) of antiquity" that was developed especially for these landforms.
The vallis shown in this figure is named for Paestum, a major Greco-Roman city in the Campania region of Italy. The city may have been founded in the 7th century BCE, but became a Roman city in 273 BCE. Paestum is renowned for its remaining Doric temples and a number of painted tombs, which date from the 5th century BCE. This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit.
Date Created: March 26, 2013
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Feature Latitude Range: 59.1° N to 61.0° N
Feature Longitude Range: 124.0° E to 128.5° E
Feature Diameter: 96 km
Projection: Azimuthal equidistant
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
This image shows the second of five broad channels on Mercury for which names were recently approved (see Cahokia Vallis). The valleys are named according to the theme of "abandoned cities (and towns and settlements) of antiquity" that was developed especially for these landforms.
The vallis shown in this figure is named for Cahokia Mounds, a Native American city that was the largest urban settlement in Mississippian culture (approx. 800-1500 CE). Cahokia contained hundreds of earthen mounds that supported the city's buildings. At its peak, the city may have been home to between 6,000 and 40,000 inhabitants. This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit.
Date Created: March 26, 2013
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Feature Latitude Range: 64.9° N to 66.7° N
Feature Longitude Range: 124.4° E to 128.5° E
Feature Diameter: 77 km
Projection: Azimuthal equidistant
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
On April 30, 2013 the International Astronomical Union (IAU) Working Group for Planetary System Nomenclature approved new names for five broad valleys on Mercury (Angkor Vallis). These valleys have been interpreted by MESSENGER team scientists as having formed due to mechanical and thermal erosion of Mercury's surface by hot, low-viscosity, quickly-flowing lavas.
Each image this week will feature one of these five broad valleys, now termed "valles" (sing. "vallis") by the IAU. The valleys are named according to the theme of "abandoned cities (and towns and settlements) of antiquity" that was developed especially for these landforms.
The vallis shown in this figure is named for Angkor city in Cambodia, the largest pre-industrial city in the world, and once the seat of the Khmer Empire. At its peak, Angkor hosted over 1,000 temples, including the world's largest religious monument. With a suburban footprint of ca. 1,000 km², Angkor at one time may have had a population of over 1 million people. This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit.
Date Created: March 26, 2013
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Feature Latitude Range: 56.2° N to 58.4° N
Feature Longitude Range: 112.7° E to 115.6° E
Feature Diameter: 95 km
Resolution: 250 meters/pixel
Projection: Azimuthal equidistant
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit. The scene shows a region of smooth, volcanic plains that have been heavily modified by tectonic structures termed "wrinkle ridges." Occurring on the Moon and Mars as well as on Mercury, wrinkle ridges are low, sinuous features that form when lavas cool and subside, causing the crust to contract horizontally. These landforms are often concentrated around buried crater rims, forming circular wrinkle ridges like those in the center right of the image.
While the innermost planet hosts thousands of wrinkle ridges, they are largely confined to its smooth plains, and are morphologically different to the larger, longer faults that comprise Mercury's fold-and-thrust belts. By studying how the different types of tectonic features are distributed across Mercury, MESSENGER scientists can begin to document in detail how the planet has deformed through time.
Date Created: February 10, 2012
Instrument: Mercury Dual Imaging System (MDIS)
Latitude Range: 49.6° N to 60.9° N
Longitude Range: 16.5° E to 48.5° E
Resolution: 400 meters/pixel
Scale: Hokusai, the large, fresh impact crater at top left, is 90 km (56 mi.) in diameter.
Projection: Azimuthal equidistant
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit. Of particular note is the flat-floored, southeast-trending valley in the center of the image, which starts near several depressions to the top left of the image, and connects with the Kofi crater (center right).
This valley is interpreted by MESSENGER team scientists as a broad lava channel, formed by the mechanical and thermal erosion of Mercury's surface by hot, low-viscosity, quickly-flowing lavas. The pits to the top left may be source vents for the lava flows that formed the channel; these flows then filled the Kofi crater at the channel's other end. Another lava channel, with a similar southeast trend, lies at the top right of the image, and there is a total of five broad channels in this region.
Determining how these channels formed, how rapidly they shaped the landscape, and how they relate to other volcanic features on Mercury -- such as expansive smooth plains nearby -- is important in understanding the role of volcanism on Mercury. Moreover, similar broad channels do not appear to exist elsewhere on Mercury, making this region a particularly interesting locale.
Date Created: February 10, 2012
Instrument: Mercury Dual Imaging System (MDIS)
Latitude Range: 54.3° N to 61.3° N
Longitude Range: 109.4° E to 121.6° E
Resolution: 146 meters/pixel
Scale: Kofi, the large impact crater at center right, is approximately 135 km (84 mi.) in diameter
Projection: Azimuthal equidistant
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit. Caloris Basin, the largest young impact crater on Mercury, dominates the scene. With an east-west diameter of 1,640 km, Caloris hosts a wide variety of tectonic features, including graben, ridges, and Pantheon Fossae. MESSENGER team members are in the process of mapping the tectonic features within the Caloris basin and deciphering their complicated relationships.
MESSENGER scientists are interested in the tectonic features of Caloris as the basin shows widespread evidence of both extension and compression, an uncommon tectonic combination on Mercury. Since different processes produce extensional and contractional landforms, the Caloris basin has clearly had a complex and detailed geological history. Understanding how these structures developed will yield an insight into tectonism in Mercury's largest basin, and large impact craters in general.
Date Created: February 10, 2012
Instrument: Mercury Dual Imaging System (MDIS)
Latitude Range: 12° N to 52° N
Longitude Range: 139° E to 187° E
Resolution: 1720 meters/pixel
Scale: The large crater at center right (Atget crater) is 100 km (63 mi.) in diameter
Projection: Azimuthal equidistant
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
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