High survivability of micrometeorites on Mars: Sites with enhanced availability of limiting nutrients
File(s)
Author(s)
Type
Journal Article
Abstract
NASA's strategy in exploring Mars has been to follow the water, because water is essential for life, and it has been found that there are many locations where there was once liquid water on the surface. Now perhaps, to narrow down the search for life on a barren basalt‐dominated surface, there needs to be a refocusing to a strategy of “follow the nutrients.” Here we model the entry of metallic micrometeoroids through the Martian atmosphere, and investigate variations in micrometeorite abundance at an analogue site on the Nullarbor Plain in Australia, to determine where the common limiting nutrients available in these (e.g., P, S, Fe) become concentrated on the surface of Mars. We find that dense micrometeorites are abundant in a range of desert environments, becoming concentrated by aeolian processes into specific sites that would be easily investigated by a robotic rover. Our modeling suggests that micrometeorites are currently far more abundant on the surface of Mars than on Earth, and given the far greater abundance of water and warmer conditions on Earth and thus much more active weather system, this was likely true throughout the history of Mars. Because micrometeorites contain a variety of redox sensitive minerals including FeNi alloys, sulfide and phosphide minerals, and organic compounds, the sites where these become concentrated are far more nutrient rich, and thus more compatible with chemolithotrophic life than most of the Martian surface.
Plain Language Summary
NASA's exploration program has allowed the scientific community to demonstrate clearly that Mars had a watery past, so the search for life needs to move on to identifying the places where water and nutrients coincided. We have investigated the relative abundance of micrometeorites on Mars compared to the Earth because these contain key nutrients that the earliest life forms on Earth used, and because their contained minerals can be used to investigate past atmospheric chemistry. We suggest that micrometeorites should be far more abundant on the Martian surface than on Earth's, and that wind‐driven modification of sediments is expected to concentrate micrometeorites, and their contained nutrients, in gravel beds and cracks in exposed bedrock.
Plain Language Summary
NASA's exploration program has allowed the scientific community to demonstrate clearly that Mars had a watery past, so the search for life needs to move on to identifying the places where water and nutrients coincided. We have investigated the relative abundance of micrometeorites on Mars compared to the Earth because these contain key nutrients that the earliest life forms on Earth used, and because their contained minerals can be used to investigate past atmospheric chemistry. We suggest that micrometeorites should be far more abundant on the Martian surface than on Earth's, and that wind‐driven modification of sediments is expected to concentrate micrometeorites, and their contained nutrients, in gravel beds and cracks in exposed bedrock.
Date Issued
2019-07
Date Acceptance
2019-06-17
Citation
Journal of Geophysical Research: Planets, 2019, 124 (7), pp.1802-1818
ISSN
2169-9097
Publisher
American Geophysical Union (AGU)
Start Page
1802
End Page
1818
Journal / Book Title
Journal of Geophysical Research: Planets
Volume
124
Issue
7
Copyright Statement
©2019. American Geophysical Union.All Rights Reserved.
Sponsor
Science and Technology Facilities Council (STFC)
Science and Technology Facilities Council (STFC)
Identifier
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019JE006005
Grant Number
ST/M003167/1
ST/N000803/1
Subjects
Science & Technology
Physical Sciences
Geochemistry & Geophysics
Mars
micrometeorites
cosmic dust
atmospheric chemistry
Mars biology
COSMIC SPHERULES
ACCRETION RATE
OXYGEN
DUST
IRON
PERCHLORATE
SEDIMENTARY
ATMOSPHERE
HYDROGEN
DEPOSITS
Publication Status
Published
Date Publish Online
2019-06-27