Tolstoj is a large, ancient
impact crater
An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact crater ...
on
Mercury. It was named after
Leo Tolstoy
Count Lev Nikolayevich TolstoyTolstoy pronounced his first name as , which corresponds to the romanization ''Lyov''. () (; russian: link=no, Лев Николаевич Толстой,In Tolstoy's day, his name was written as in pre-refor ...
. The
albedo feature Solitudo Maiae appears to be associated with this crater.
[Davies, M. E., Dwornik, S. E., Gault, D. E., and Strom, R. G., 1978, Atlas of Mercury: National Aeronautics and Space Administration Special Publication SP-423, 128 p.]
The impact that produced the Tolstoj Basin occurred very early in the history of Mercury. Two ragged, discontinuous rings approximately 356 km and 510 km in diameter encompass the structure but are poorly developed on its north and northeast sides; a third partial ring with a diameter of 466 km occurs on its southeast side. Diffuse patches of material of dark
albedo
Albedo (; ) is the measure of the diffuse reflection of solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that refl ...
lie outside the innermost ring. The central part of the basin is covered by a high reflectance smooth plains (HRP) material.
[ The bright interior of the basin is noticeably redder than the surrounding plains, which are made of a bluer low reflectance material (LRM). The dark annulus of ejecta around Tolstoj is one of the darkest places on the surface of Mercury.]
The depth of Tolstoj is estimated to be from the stereo derived digital elevation models based on '' Mariner 10'' images of the planet. This is significantly less than the depth of lunar basins of the similar size indicating that Tolstoj probably has relaxed from its post impact shape.
The Tolstoj basin is used to define a time-stratigraphic system, the Tosltojan system, with the age of around 4.0–3.9 billion years. The older system (< 4.0 billion years) is called pre-Tosltojan, while the younger is called Calorian (3.9–3.5 billion years).
Despite Tolstoj's great age and its embayment
A bay is a recessed, coastal body of water that directly connects to a larger main body of water, such as an ocean, a lake, or another bay. A large bay is usually called a gulf, sea, sound, or bight. A cove is a small, circular bay with a na ...
by the ancient inter-crater plains, it retains an extensive and remarkably well preserved, radially lineated ejecta blanket around two-thirds of its circumference. Part of the ejecta was disrupted by the impact of the crater Liszt
Franz Liszt, in modern usage ''Liszt Ferenc'' . Liszt's Hungarian passport spelled his given name as "Ferencz". An orthographic reform of the Hungarian language in 1922 (which was 36 years after Liszt's death) changed the letter "cz" to simpl ...
. The ejecta tends to be blocky and only weakly lineated between the inner and outer rings. Radial lineations with a slight swirly pattern are best seen on the southwest side of Tolstoj. The unusual rectilinear map pattern of the ejecta suggests: (1) control of the ejecta pattern by prebasin structures, (2) preferential burial along structural trends of an originally symmetrical ejecta blanket by the intercrater plains material, or (3) formation of Tolstoj by an oblique impact from the northwest that produced an ejecta blanket with bilateral symmetry and little or no deposition uprange. Analysis of stereophotography of Tolstoj ejecta northeast of the crater suggests that this deposit has been upwarped to a higher elevation relative to the surrounding plains.
Views
File:Tolstoj crater and Basho crater MESSENGER WAC IGF to RGB.jpg, Enhanced color image of Tolstoj crater (top center) and Bashō crater (lower left)
File:Tolstoj Basin topography JMARS Colorized Shade 2km.jpg, Topographic map centered on Tolstoj
File:Tolstoj basin Mariner 10 image 0167020.png, Mariner 10 image with Tolstoj at bottom
File:Mercury h08 Tolstoj quadrangle.png, Tolstoj is at lower right on this map
File:Tolstoj crater EW0227961993G.jpg, Distant oblique view
File:Tolstoj crater EN0262456904M.jpg, Northern Tolstoj crater
References
Further reading
* Prepared for the National Aeronautics and Space Administration by U.S. Department of the Interior, U.S. Geological Survey. Published in hardcopy as USGS Miscellaneous Investigations Series Map I–1199, as part of the Atlas of Mercury, 1:5,000,000 Geologic Series. Hardcopy is available for sale from U.S. Geological Survey, Information Services, Box 25286, Federal Center, Denver, CO 80225)
External links
Tolstoj quadrangle maps
{{Leo Tolstoy
Impact craters on Mercury
Leo Tolstoy