The Importance of the Climate Record in the Martian Polar Layered Deposits

P Becerra ,Andrea Coronato,Nicolas Thomas,Anna Grau Galofre,Jorge Rabassa,Ganna Portyankina,A C Pascuzzo ,Michael M Sori ,L K Tamppari ,B Horgan ,J J Plaut ,Rachel W Obbard ,M E Landis ,S Diniega ,P O Hayne ,A M Bramson ,Adrian Brown ,N E Putzig ,S Byrne ,I B Smith ,Christine S Hvidberg ,J L Whitten

doi:10.3847/25c2cfeb.90c37f59

Abstract

The Importance of the Climate Record in the Martian Polar Layered Deposits

Highlights

SummaryDeciphering the climate record stored in the polar ice sheets of Mars is a high priority goal of the current Decadal Survey (2013-2023) and of the Mars Exploration Program Analysis Group (MEPAG)
Background and MotivationThe ice deposits of Mars are some of the most scientifically interesting features in the solar system due to their similarity to terrestrial ice, their accessibility for exploration, and their potential to contain a decipherable record of climate
A combination of images, radar, gravity, and spectroscopic data as well as thermal and rheological arguments were used by various authors [Mellon et al 1996; Nye et al 2000; Picardi et al 2005; Zuber et al 2007] to determine that the bulk composition of the polar layered deposits (PLD) is pure water ice with only small amounts of dust (10% in the South [Picardi et al 2005], and 5% in the North [Grima et al 2009]). Analysis of both images (Fig.1ce) [Laskar et al 2002; Milkovich and Head, 2005; Fishbaugh and Hvidberg, 2006; Limaye et al 2012; Becerra et al 2017,2019] and radar (Fig.1b) [Putzig et al 2009; Smith et al 2016; Whitten et al 2017] have connected recurring patterns in the PLD layering to periodic oscillations of the Martian polar insolation due to orbital cycles. This resulted in estimates of net accumulation rates for the North PLD (NPLD), which in turn allowed the construction of models of its formation and accumulation based on the obliquity history over the last few million years [Levrard et al 2007; Hvidberg et al 2012] that can recreate several observed aspects of NPLD stratigraphy

Summary

Deciphering the climate record stored in the polar ice sheets of Mars is a high priority goal of the current Decadal Survey (2013-2023) and of the Mars Exploration Program Analysis Group (MEPAG). Deciphering the polar record will require knowing the thickness of annual layers and absolute ages of specific strata, along with in situ measurements of the processes and materials that form a new layer This will allow us to associate possible climate scenarios with specific accumulation or ablation periods, and accurately “read” the only other known detailed climate record on any planetary body besides Earth, in much the same way we read that of the Earth. Achieving this goal will have profound implications for our understanding of astronomically forced climates of planetary bodies, and it can help us infer whether Mars could have had habitable environments in the recent past

Background and Motivation

Critical knowledge gaps

How to address knowledge gaps in the next decade

Chronology 2b