Shallow Radar correlation of discrete units in one of the Red Planet’s largest ice reservoirs suggests that its material was emplaced as a single, regional deposit.
One of Mars’s largest water ice reservoirs, the south polar layered deposits, consists of a thick stack of alternating bands of dust and ice that encompasses an area nearly the size of Alaska. Previous studies have suggested that variations in the obliquity of the Red Planet’s axis, which can wobble up to 10° from its current 25° tilt, have controlled the accretion of these layers and that they therefore preserve a long-term record of Mars’s ancient climate.
Building upon earlier research, which identified four distinct periods of ice accumulation in the south polar deposits, Whitten and Campbell [writing in the Journal of Geophysical Research] utilize Shallow Radar (SHARAD) data collected by the Mars Reconnaissance Orbiter to investigate the structure and continuity of the deposits’ subsurface layers…
[From the paper’s abstract:] “Only one major deviation from near- horizontality of the reflectors, located to the east of Australe Mensa, was identified. There is no evidence for major unconformities that suggest multiple depositional centers that later merged into the South Polar Layered Deposits. Instead, SHARAD data suggest that the materials of the SPLD were deposited regionally, superposing materials from previous depositional episodes.” [More at links]