Mercury: Hero Rupes: lobate scarp

    Caption 1: "Hero Rupes is a lobate scarp on Mercury ≥ 300 km long located in Mercury's southern hemisphere. Discovered by the Mariner 10 spacecraft (1973--1975) in 1974, it was formed by a thrust fault thought to have occurred due to the shrinkage of Mercury's core and mantle as they cooled and contracted over time when Mercury's lithosphere had already solidified." (Somewhat conflated and edited from Wikipedia: Hero Rupes and Wikipedia: Mercury: Internal structrure).

    Features:

    1. Lobate scarps are common geological features of Mercury and also of the Moon where they are, however, much smaller in height and much less conspicuous than on Mercury.

    2. On Mercury, the lobate scarps are giant curved cliffs that rise as high as 3 km and can stretch over hundreds of kilometers (Se-460, HI-165).

    3. The cooling and contraction of the Mercury's core and mantle (mentioned above in the preamble) caused crinkling or faulting on the outside of Mercury's lithosphere which led to the lobate scarps.

      It is thought that Mercury's radius decreased by a few kilometers overall (Se-460).

    4. Mercury's lithosphere when Mercury was still quite on hot on the inside was probably rather thin compared to the lunar lithosphere.

      mercury_007_scarp

    5. The thicker and perhaps stronger lunar lithosphere probably did NOT contract so much as Mercury's lithosphere during the cooling phase. However, small lobate scarps on the Moon show that some faulting and contraction occurred. The Moon's radius may have decreased by ∼ 100 m in the last gigayear. See NASA's LRO Reveals 'Incredible Shrinking Moon', 2010 Aug19. Until circa 2010, it seesm there was little discussion of the Moon's lobate scarps and NOT much was inferred from them.

    Caption 2: A cartoon of a scenario for the formation of Mercury's lobate scarps (HI-165).

    But does "curved" refer to slope or the line of the lobate scarp on the ground?

    Images:

    1. Credit/Permission: NASA, Mariner 10 spacecraft (1973--1975), 2000 (when added to an online archive: uploaded to Wikimedia Commons by User:Ruslik0, 2010) / Public domain.
      Image link: Wikimedia Commons: File:Hero Rupes.jpg.
    2. Credit/Permission: © David Jeffery, 2003 / Own work.
      Image link: Itself.
    Local file: local link: mercury_lobate_scarps.html.
    File: Mercury file: mercury_lobate_scarps.html.