Transition Metals in Gale Crater, Mars: Perspectives on Global
Abundances and Future Exploration
Abstract
Through rover missions and martian meteorites received on Earth, the
surface of Mars has showed unexpectedly elevated concentrations of
transition metals usually measured in minor and trace concentrations in
silicate rocks compared to the average crust. Gale crater presents one
of the most diverse geological records in terms of its complex fluid and
magmatic history described through the sedimentary and igneous records,
respectively. Transition metals, such as Mn, Co, Ni, Cu, and Zn, are
highly concentrated within various sedimentary rocks and diagenetic
features, suggesting their mobilization through fluid circulation. This
paper presents the first compilation of elevated concentrations of
transition metals measured by the Curiosity rover and reviews the
origin of such metals in Gale crater, highlighting the existence of a
hydrothermal or magmatic-hydrothermal deposit in its vicinity. The
discovery of felsic magmatism on Mars opens up to novel perspectives in
terms of the type of metal deposits that current and future exploration
could evidence at the surface of Mars and raise questions about the
global abundance of such metals. Constraining the abundance of
transition metals is also a central question for exobiology purposes.
Because on Earth living organisms use transition metals for their
survival and functioning, should live have arisen on Mars, the
availability of such chemical elements at the surface could have been
essential for its development. An accurate assessment of in situ
metal resources and potential risks for health will be key for the
preparation of human exploration of Mars as recently announced by NASA.