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Lookup NU author(s): Dr Stephen Brough
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).
Although a substantial ice cover has been identified within the mid-latitudes of Mars, there is uncertainty regarding the formation, current and former volume, and dynamic evolution of these ice masses. Here, we present the first comprehensive ice volume estimate of martian glacier-like forms (GLFs) from systematic population scale mapping and volumetric analysis. The outlines of 1243 GLFs were manually delineated from 6 m per pixel Context Camera (CTX) images and the volume of each determined using a volume–area scaling approach. Our results show that GLFs cover a surface area of 11344 ± 393 km2 and have a total volume of 1744 ± 441 km3. Using two end-member scenarios for ice concentration by volume of 30% (pore ice) and 90% (debris-covered glacier ice), we calculate the volume of ice contained within GLFs to be between 523 ± 132 km3(480 ± 121 Gt) and 1570 ± 397 km3(1439 ± 364 Gt), equivalent to a mean global water layer 3 to 10 mm thick. We investigate the local topographic setting of each GLF by reference to the Mars Orbiter Laser Altimeter (MOLA) digital elevation model. Our analysis reveals that globally GLFs are on average larger in latitudes >36◦and on slopes between 2 and 8◦. In the northern hemisphere GLFs between 500 and 2500 m in elevation and in the southern hemisphere GLFs with a northern aspect are also larger on average. The observed spatial patterns of GLF landform and volume distribution suggests that regional to local meteorological and topographical conditions play an important role in GLF ice accumulation and/or preservation. Assuming a net accumulation rate of 10 mm a−1 typical of climatic excursions with high obliquity, we estimate a period of at least 13 ka is required to yield the average calculated GLF ice thickness of ∼130 m. Such a period is well within the timeframe of a high obliquity cycle (20–40 ka), suggesting that the current GLF volume could have formed during a single climate excursion.
Author(s): Brough S, Hubbard B, Hubbard A
Publication type: Article
Publication status: Published
Journal: Earth and Planetary Science Letters
Year: 2019
Volume: 507
Pages: 10-20
Print publication date: 01/02/2019
Online publication date: 04/12/2018
Acceptance date: 21/11/2018
Date deposited: 02/12/2018
ISSN (print): 0012-821X
ISSN (electronic): 1385-013X
Publisher: Elsevier BV
URL: https://doi.org/10.1016/j.epsl.2018.11.031
DOI: 10.1016/j.epsl.2018.11.031
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