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Vínculos isotópicos entre la química atmosférica y el ciclo profundo del azufre en Marte
Heather B Franz1, Sang-Tae Kim2, James Farquhar3
11] Center for Research and Exploration in Space Science and Technology, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA [2] Department of Geology and Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20742, USA.
Nature
|April 18, 2014
Resumen
Los meteoritos marcianos revelan que la asimilación de azufre en magmas fue común a lo largo de la historia marciana. Este proceso, evidenciado por las firmas de isótopos de azufre, también destaca la química atmosférica distinta en Marte en comparación con la Tierra.
Área de la Ciencia:
- Ciencias planetarias Ciencias planetarias.
- La geoquímica es la geoquímica.
- La geoquímica de los isótopos es la geoquímica de los isótopos.
Sus antecedentes:
- Los meteoritos marcianos ofrecen información sobre los procesos geológicos y atmosféricos del planeta.
- Comprender la asimilación de magma del material de la corteza es crucial para interpretar las firmas geoquímicas.
- El origen de los elementos ligeros de tierras raras en las shergottites enriquecidas es objeto de debate (asimilación de la corteza frente a la mezcla del manto).
Objetivo del estudio:
- Para investigar la sistemática de isótopos de azufre en meteoritos marcianos para comprender la asimilación de la corteza.
- Para determinar el alcance y el momento de la asimilación de azufre en los magmas marcianos.
- Para comparar la química del azufre atmosférico marciano con la de la Tierra.
Principales métodos:
- Análisis isotópicos de azufre en 40 meteoritos marcianos, incluidas las shergottites, nakhlites, Allan Hills 84001 y Chassigny.
- Análisis de sulfuros y sulfatos ígneos para las firmas isotópicas de azufre.
Principales resultados:
- Fuerte evidencia de la asimilación generalizada de azufre en los magmas marcianos a lo largo de la historia geológica.
- Se observaron firmas isotópicas de azufre indicativas de fraccionamiento independiente de la masa (MIF).
- Las firmas MIF sugieren la asimilación de azufre durante el ascenso y el emplazamiento del magma.
- El procesamiento de azufre atmosférico marciano, conservado en meteoritos, muestra firmas distintas de las de la Tierra.
Conclusiones:
- La asimilación de azufre por los magmas marcianos fue un proceso generalizado a lo largo de la historia del planeta.
- Las firmas MIF observadas proporcionan evidencia de procesos de asimilación y emplazamiento de la corteza.
- Existen diferencias fundamentales en la química dominante del azufre entre las atmósferas de la Tierra y Marte.
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