Decametre-thick remnant glacial ice deposits on Mars

Research areas:
Year:
2014
Authors:
Journal:
Geophysical Research Letters
Volume:
41
Number:
15
Pages:
5402-5409
Abstract:
On Mars a smooth, draping unit - the “Latitude Dependant Mantle” (LDM) believed to comprise meters-thick layers of dust and ice - extends from the mid-latitudes to the poles, covering at least 23\% of the surface [Kreslavsky and Head, 2000; Mustard et al., 2001]. We show that the LDM can be 30 m deep on pole-facing crater walls and, by measuring the erosional and depositional volumes of small gullies that incise these LDM deposits, we show that it must contain between 46\% and 95\% ice by volume. Extrapolating to a global scale, these deposits account for {\textasciitilde}104 km3 of near-surface ice, doubling previous LDM volume estimates [Kreslavsky and Head, 2002]. Thick LDM deposits can be emplaced during the many orbital variation-driven climate excursions [Jakosky and Carr, 1985] that occurred during the Amazonian. We suggest LDM deposits are similar to ice-sheets composed of massive ice with a surface lag.