Details

Autor(en) / Beteiligte

• Cohen, Benjamin E.
• Mark, Darren F.
• Cassata, William S.
• Lee, Martin R.
• Tomkinson, Tim
• Smith, Caroline L.

Titel

Taking the pulse of Mars via dating of a plume-fed volcano

Ist Teil von

• Nature communications, 2017-10, Vol.8 (1), p.640-9, Article 640

Ort / Verlag

London: Nature Publishing Group UK

Erscheinungsjahr

2017

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Mars hosts the solar system’s largest volcanoes. Although their size and impact crater density indicate continued activity over billions of years, their formation rates are poorly understood. Here we quantify the growth rate of a Martian volcano by 40 Ar/ 39 Ar and cosmogenic exposure dating of six nakhlites, meteorites that were ejected from Mars by a single impact event at 10.7 ± 0.8 Ma (2 σ ). We find that the nakhlites sample a layered volcanic sequence with at least four discrete eruptive events spanning 93 ± 12 Ma (1416 ± 7 Ma to 1322 ± 10 Ma (2 σ )). A non-radiogenic trapped 40 Ar/ 36 Ar value of 1511 ± 74 (2 σ ) provides a precise and robust constraint for the mid-Amazonian Martian atmosphere. Our data show that the nakhlite-source volcano grew at a rate of ca. 0.4–0.7 m Ma −1 —three orders of magnitude slower than comparable volcanoes on Earth, and necessitating that Mars was far more volcanically active earlier in its history. Mars hosts the solar system’s largest volcanoes, but their formation rates remain poorly constrained. Here, the authors have measured the crystallization and ejection ages of meteorites from a Martian volcano and find that its growth rate was much slower than analogous volcanoes on Earth.