Two billion years of magmatism recorded from a single Mars meteorite ejection site

Thomas J Lapen; Minako Righter; Rasmus Andreasen; Anthony J Irving; Aaron M Satkoski; Brian L Beard; Kunihiko Nishiizumi; A J Timothy Jull; Marc W Caffee

doi:10.1126/sciadv.1600922

Two billion years of magmatism recorded from a single Mars meteorite ejection site

Sci Adv. 2017 Feb 1;3(2):e1600922. doi: 10.1126/sciadv.1600922. eCollection 2017 Feb.

Authors

Thomas J Lapen¹, Minako Righter¹, Rasmus Andreasen², Anthony J Irving³, Aaron M Satkoski⁴, Brian L Beard⁴, Kunihiko Nishiizumi⁵, A J Timothy Jull⁶, Marc W Caffee⁷

Affiliations

¹ Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX 77204-5007, USA.
² Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX 77204-5007, USA.; Department of Geoscience, Aarhus University, Aarhus, Denmark.
³ Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195-1310, USA.
⁴ Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706-1692, USA.; NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI 53706, USA.
⁵ Space Sciences Laboratory, University of California, Berkeley, Berkeley, CA, USA.
⁶ Department of Geosciences, University of Arizona, Tucson, AZ 85721, USA.
⁷ Department of Physics, Purdue University, West Lafayette, IN 47907-2036, USA.; Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN 47907-2051, USA.

Abstract

The timing and nature of igneous activity recorded at a single Mars ejection site can be determined from the isotope analyses of Martian meteorites. Northwest Africa (NWA) 7635 has an Sm-Nd crystallization age of 2.403 ± 0.140 billion years, and isotope data indicate that it is derived from an incompatible trace element-depleted mantle source similar to that which produced a geochemically distinct group of 327- to 574-million-year-old "depleted" shergottites. Cosmogenic nuclide data demonstrate that NWA 7635 was ejected from Mars 1.1 million years ago (Ma), as were at least 10 other depleted shergottites. The shared ejection age is consistent with a common ejection site for these meteorites. The spatial association of 327- to 2403-Ma depleted shergottites indicates >2 billion years of magmatism from a long-lived and geochemically distinct volcanic center near the ejection site.

Keywords: Early Amazonian Magmatism; Mars Geochemistry; Martian Mantle; Martian Meteorite.