We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Local Ice Mass Balance Rates via Bayesian Analysis of Mars Polar Trough Migration.
- Authors
Izquierdo, Kristel; Bramson, Ali M.; McClintock, Thomas; Laferriere, Kris L.; Byrne, Shane; Bapst, Jonathan; Smith, Isaac
- Abstract
With the aim of better understanding the past depositional environment of the north polar region of Mars, we infer local ice accumulation and retreat rates in the area between 86° and 87°N and 16°–20°E. We follow a novel approach utilizing a Bayesian framework with observations of bounding surfaces associated with the migration of two polar spiral troughs. Over time, spiral troughs have migrated toward the north pole due to ice accumulation, sublimation, and wind transport. We relate the record of trough migration with local ice accumulation and retreat rates using a phenomenological migration model and explore the climate parameters that affect these rates using a Markov chain Monte Carlo algorithm. Using this data‐driven approach, we find best fit mean accumulation rates of 0.11–0.18 mm/yr in the upper 500 m of the stratigraphy of our study region. These mean accumulation rates correspond to trough ages of over 4 Myr, which implies that the north polar cap is older than most current assumptions. We also find that the relationship between accumulation rates and the obliquity of Mars is complex, with periods of positive correlation occurring in the last several Myr. Future work extending this analysis to all troughs in the cap will further constrain these relationships and ages. Plain Language Summary: The polar spiral troughs of Mars are curved depressions in the north polar ice cap. The location of these depressions has changed with time, migrating upward with accumulating ice and toward the north pole because of local sublimation. The previous locations of troughs are recorded as discontinuities in the subsurface layers, and we use them as constraints on the past ice accumulation and sublimation rates that produced the path that the troughs have followed. Finding the values of the accumulation of ice with time provides insight into the past climate of Mars. In this work, we use the migration paths of two troughs in the region between 86 and 87°N and 16–20°E to constrain the local accumulation and sublimation rates. We explore a large range of candidate dependencies between accumulation and sublimation rates to orbital parameters and time. We use an algorithm that compares the path produced by the candidate model to the observed path recorded in the ice. Using this data‐driven approach, we find that the local mean accumulation rate in the region is lower than previously proposed, suggesting that the north polar cap may have grown more slowly and started earlier than the currently accepted range of ages. Key Points: We infer past local ice accumulation and retreat rates at the north polar cap constrained by two trough migration paths (TMPs)0.11–0.18 mm/yr accumulation rates from the best‐fit to the TMPs indicate that troughs may be older than previously assumedWe explore different relationships between climate and orbital parameters of Mars reflective of the past 5 Myr consistent with the TMPs
- Subjects
POLAR wandering; BAYESIAN analysis; MARKOV chain Monte Carlo; MARS (Planet); SEA ice; ANTARCTIC ice
- Publication
Journal of Geophysical Research. Planets, 2023, Vol 128, Issue 10, p1
- ISSN
2169-9097
- Publication type
Article
- DOI
10.1029/2023JE007964