Pre-Tolstojan
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| Pre-Tolstojan | |
|---|---|
| Etymology | |
| Alternate spelling(s) | Pretolstojan |
| Usage information | |
| Celestial body | Mercury |
| Time scale(s) used | Mercurian Geologic Timescale |
| Definition | |
| Chronological unit | Period |
| Stratigraphic unit | System |
Pre-Tolstojan, also Pretolstojan Period, refers to the oldest period of the history of Mercury, c. 4500–3900 million years ago. It is the first period of the Eomercurian Era and of the Mercurian Eon,[citation needed] as well as being the first period in Mercury's geologic history, and refers to its formation and the 600 million or so years in its aftermath.[1] Mercury was formed with a tiny crust, mantle, and a giant core and as it evolved it faced heavy bombardments that created most of the craters and intercrater plains seen on the planet's surface today.[2] Many of the smaller basins and multi-ring basins were created during this period.[3] Considered a "dead" planet, its geology is highly diverse with craters forming the dominant terrain.[2]
The name Pre-Tolstojan refers to the time before the formation of the Tolstoj crater on the surface of Mercury, which is believed to have been formed by an impact c. 3900 million years ago. The latter has been named after the Russian writer Leo Tolstoy.
