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Magnetite Authigenesis and the Warming of Early Mars
The Curiosity rover has documented lacustrine sediments at Gale Crater, but how liquid water became physically stable on the early Martian surface is a matter of significant debate. To constrain the composition of the early Martian atmosphere during sediment deposition, we experimentally investigate...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6092749/ https://www.ncbi.nlm.nih.gov/pubmed/30123317 http://dx.doi.org/10.1038/s41561-018-0203-8 |
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author | Tosca, Nicholas J. Ahmed, Imad A.M. Tutolo, Benjamin M. Ashpitel, Alice Hurowitz, Joel A. |
author_facet | Tosca, Nicholas J. Ahmed, Imad A.M. Tutolo, Benjamin M. Ashpitel, Alice Hurowitz, Joel A. |
author_sort | Tosca, Nicholas J. |
collection | PubMed |
description | The Curiosity rover has documented lacustrine sediments at Gale Crater, but how liquid water became physically stable on the early Martian surface is a matter of significant debate. To constrain the composition of the early Martian atmosphere during sediment deposition, we experimentally investigated the nucleation and growth kinetics of authigenic Fe-minerals in Gale Crater mudstones. Experiments show that pH variations within anoxic basaltic waters trigger a series of mineral transformations that rapidly generate magnetite and H(2)(aq). Magnetite continues to form through this mechanism despite high P(CO2) and supersaturation with respect to Fe-carbonate minerals. Reactive transport simulations that incorporate these experimental data show that groundwater infiltration into a lake equilibrated with a CO(2)-rich atmosphere can trigger the production of both magnetite and H(2)(aq) in the mudstones. H(2)(aq), generated at concentrations that would readily exsolve from solution, is capable of increasing annual mean surface temperatures above freezing in CO(2)-dominated atmospheres. We therefore suggest that magnetite authigenesis could have provided a short-term feedback for stabilizing liquid water, as well as a principal feedstock for biologically relevant chemical reactions, at the early Martian surface. |
format | Online Article Text |
id | pubmed-6092749 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
record_format | MEDLINE/PubMed |
spelling | pubmed-60927492019-03-01 Magnetite Authigenesis and the Warming of Early Mars Tosca, Nicholas J. Ahmed, Imad A.M. Tutolo, Benjamin M. Ashpitel, Alice Hurowitz, Joel A. Nat Geosci Article The Curiosity rover has documented lacustrine sediments at Gale Crater, but how liquid water became physically stable on the early Martian surface is a matter of significant debate. To constrain the composition of the early Martian atmosphere during sediment deposition, we experimentally investigated the nucleation and growth kinetics of authigenic Fe-minerals in Gale Crater mudstones. Experiments show that pH variations within anoxic basaltic waters trigger a series of mineral transformations that rapidly generate magnetite and H(2)(aq). Magnetite continues to form through this mechanism despite high P(CO2) and supersaturation with respect to Fe-carbonate minerals. Reactive transport simulations that incorporate these experimental data show that groundwater infiltration into a lake equilibrated with a CO(2)-rich atmosphere can trigger the production of both magnetite and H(2)(aq) in the mudstones. H(2)(aq), generated at concentrations that would readily exsolve from solution, is capable of increasing annual mean surface temperatures above freezing in CO(2)-dominated atmospheres. We therefore suggest that magnetite authigenesis could have provided a short-term feedback for stabilizing liquid water, as well as a principal feedstock for biologically relevant chemical reactions, at the early Martian surface. 2018-08-06 2018-09 /pmc/articles/PMC6092749/ /pubmed/30123317 http://dx.doi.org/10.1038/s41561-018-0203-8 Text en Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:http://www.nature.com/authors/editorial_policies/license.html#terms |
spellingShingle | Article Tosca, Nicholas J. Ahmed, Imad A.M. Tutolo, Benjamin M. Ashpitel, Alice Hurowitz, Joel A. Magnetite Authigenesis and the Warming of Early Mars |
title | Magnetite Authigenesis and the Warming of Early Mars |
title_full | Magnetite Authigenesis and the Warming of Early Mars |
title_fullStr | Magnetite Authigenesis and the Warming of Early Mars |
title_full_unstemmed | Magnetite Authigenesis and the Warming of Early Mars |
title_short | Magnetite Authigenesis and the Warming of Early Mars |
title_sort | magnetite authigenesis and the warming of early mars |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6092749/ https://www.ncbi.nlm.nih.gov/pubmed/30123317 http://dx.doi.org/10.1038/s41561-018-0203-8 |
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