Examinando por Autor "Gago Duport, L."

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Constraining the preservation of organic compounds in Mars analog nontronites after exposure to acid and alkaline fluids.
(Nature Research Journals, 2020-09-15) Gil Lozano, C.; Fairén, Alberto G.; Muñoz Iglesias, V.; Fernández Sampedro, M.; Prieto Ballesteros, O.; Gago Duport, L.; Losa Adams, E.; Carrizo, D.; Bishop, J. L.; Fornaro, T.; Mateo Martí, Eva; European Research Council (ERC); Agencia Estatal de Investigación (AEI); European Commission (EC); 0000-0002-5536-2565; 0000-0003-1932-7591; 0000-0002-1159-9093; 0000-0003-3500-2850; 0000-0002-2278-1210; 0000-0002-2646-5995; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The presence of organic matter in lacustrine mudstone sediments at Gale crater was revealed by the Mars Science Laboratory Curiosity rover, which also identified smectite clay minerals. Analogue experiments on phyllosilicates formed under low temperature aqueous conditons have illustrated that these are excellent reservoirs to host organic compounds against the harsh surface conditions of Mars. Here, we evaluate whether the capacity of smectites to preserve organic compounds can be influenced by a short exposure to different diagenetic fluids. We analyzed the stability of glycine embedded within nontronite samples previously exposed to either acidic or alkaline fluids (hereafter referred to as "treated nontronites") under Mars-like surface conditions. Analyses performed using multiple techniques showed higher photodegradation of glycine in the acid-treated nontronite, triggered by decarboxylation and deamination processes. In constrast, our experiments showed that glycine molecules were preferably incorporated by ion exchange in the interlayer region of the alkali-treated nontronite, conferring them a better protection against the external conditions. Our results demonstrate that smectite previously exposed to fluids with different pH values influences how glycine is adsorbed into their interlayer regions, affecting their potential for preservation of organic compounds under contemporary Mars surface conditions.
Restringido
Long-lasting habitable periods in Gale crater constrained by glauconitic clays
(Springer Link, 2021-06-28) Losa Adams, E.; Gil Lozano, C.; Fairén, Alberto G.; Bishop, J. L.; Rampe, E. B.; Gago Duport, L.; European Research Council (ERC); Xunta de Galicia
In situ investigations by the Mars Science Laboratory Curiosity rover have confirmed the presence of an ancient lake that existed in Gale crater for up to 10 million years. The lake was filled with sediments that eventually converted to a compacted sandstone. However, it remains unclear whether the infilling of the lake was the result of background sedimentation processes or represents punctual flooding events in a largely isolated lake. Here, we used the X-ray diffraction data obtained with the Chemistry and Mineralogy instrument onboard the Curiosity rover to characterize the degree of disorder of clay minerals in the Murray formation at Gale crater. Our analysis shows that they are structurally and compositionally related to glauconitic clays, which are a sensitive proxy of quiescent conditions in liquid bodies for extended periods of time. Such results provide evidence of long periods of extremely low sedimentation in an ancient brackish lake on Mars, the signature of an aqueous regime with slow evaporation at low temperatures. More in general, the identification of lacustrine glauconitic clays on Mars provides a key parameter in the characterization of aqueous Martian palaeoenvironments that may once have harboured life.