Mercury Craters
Spring 2003
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Hummocky and Smooth Plains: This image (FDS 108), acquired
during the spacecraft's first encounter with Mercury, is located about 500
km east of the Caloris basin. The image shows hummocky plains interpreted
as Caloris ejecta in the upper half of the picture and smooth plains in
the lower half. Elongated hummocks and troughs aligned concentrically to
the rim of the Caloris are well developed in the upper right part of the
picture. A part of the pre-Caloris basin (240-km in diameter) seen in the
lower part of the picture is filled with smooth plains. At the western
margin of this basin is a west facing scarp that forms the boundary
between hummocky plains (west) and smooth plains (east). |
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Large Mercurian Crater: This image (FDS 166), acquired during
the spacecraft's first encounter with Mercury, features a 140 kilometer
diameter crater and its surrounding zone of secondary craters. The narrow
width of the rim facies, the prominent subradial secondary crater chains,
and grooves are representative of the larger mercurian craters. |
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Young Craters on Smooth Plains: Young craters (the largest of
which is about 100 kilometers in diameter) superposed on smooth plains.
Larger young craters have central peaks, flat floors, terraced walls,
radial ejecta deposits, and surrounding fields of secondary craters.
Smooth plains have well-developed ridges extending NW and NE. This image
(FDS 167), acquired during the spacecraft's first encounter with Mercury,
is located approximately 60°N, 175°W. |
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Terraced Craters: This crater (98 km diameter) illustrates
the narrow hummocky rim facies, radial ridges, and surrounding extensive
field of secondary craters. The well-developed interior terraces and
central peaks are typical for mercurian craters in this size range. Note
that the smaller craters in the foreground (25-km diameter) also are
terraced. This image (FDS 80) was taken during the spacecraft's first
encounter with Mercury. |
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Terraced Craters: This crater (98 km diameter) illustrates
the narrow hummocky rim facies, radial ridges, and surrounding extensive
field of secondary craters. The well-developed interior terraces and
central peaks are typical for mercurian craters in this size range. Note
that the smaller craters in the foreground (25-km diameter) also are
terraced. This image (FDS 80) was taken during the spacecraft's first
encounter with Mercury. |
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Prominent Rayed Craters: These two prominent rayed craters
are located at 40°N, 124°W. Bright halos extend as far as 2 crater
diameters beyond crater rims. Individual rays extend from halo. Bright
streak extending from middle top to lower is unrelated to the two craters.
Craters are 40 km in diameter. This image (FDS 275) was taken during the
spacecraft's first encounter with Mercury. |
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Fresh Crater in Center of Older Crater Basin: A fresh new
crater in the center of an older crater basin is shown in this picture
(FDS27459) of the surface of Mercury taken March 29, by Mariner 10. The
newer crater (almost centered in the photo) is about 12 kilometers (7.5
miles) across. The picture, which covers an area 130 by 170 kilometers (90
by 105 miles), was taken from a distance of about 20,700 kilometers
(12,860 miles) a half-hour before Mariner 10 made its closest flyby of
Mercury. |
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Kuiper Crater: The Mariner 10 Television-Science Team has
proposed the name 'Kuiper' for this very conspicuous bright Mercury crater
(top center) on the rim of a larger older crater. Prof. Gerard P. Kuiper,
a pioneer in planetary astronomy and a member of the Mariner 10 TV team,
died December 23, 1973, while the spacecraft was enroute to Venus and
Mercury. Mariner took this picture (FDS 27304) from 88,450 kilometers
(55,000 miles) some 2 1/2 hours before it passed Mercury on March 29. The
bright-floored crater, 41 kilometers (25 miles) in diameter, is the center
of a very large bright area which could be seen in pictures sent from
Mariner 10 while Mercury was more than two million miles distant. The
larger crater is 80 kilometers (50 miles) across. |
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