2026-10-29 NASA
＜関連情報＞
- https://www.nasa.gov/solar-system/planets/mars/nasa-funded-study-details-one-of-oldest-mars-meteorites-ever-found/
- https://www.science.org/eprint/6FRMXEUFASPRPAFJRZ64/full
- https://www.science.org/doi/10.1126/sciadv.aea3420
41億年以上前に形成された火星隕石は、火星の初期の地殻とマントルのサンプルを含んでいる論文タイトル A Martian meteorite that formed ≳4.1 billion years ago samples Mars’ early crust and mantle
Yang Liu, Lee M. Saper, Elizabeth Ann Bell, Chi Ma, Haoyu Li, Jinping Hu, Yunbin Guan, Hayward Melton, Alicia M. Cruz-Uribe, […] , and Carl B. Agee
Science Published:29 Oct 2026
DOI:https://doi.org/10.1126/science.adz5646
Abstract
Martian meteorites provide a record of the planet’s geological history. However, most are geologically young samples that are not representative of Mars’ surface, which is dominated by ancient rocks. We describe the Martian meteorite Teghaza 001 (Teg 001), a slowly cooled igneous rock that formed at least 4.1 billion years ago. Its composition, mineralogy, and texture are distinct from other Martian meteorites. We determine that Teg 001 is a sample of ancient crust, which formed from a geochemically distinct mantle source with primordial composition. The presence of aqueously altered minerals, combined with bulk and mineral-specific oxygen isotope measurements, indicate that Teg 001 experienced reactions with fluids enriched in 18O, before ejection into space by an impact.
41億年前の火星隕石テガザ001に含まれるノアキアン時代の水圏成分 A Noachian hydrosphere component in the 4.1-Ga Martian meteorite Teghaza 001
Lee Saper , Yang Liu , Yunbin Guan, Chi Ma , Elizabeth Ann Bell , and Carl B. Agee
Science Advances Published:10 Jun 2026
DOI:https://doi.org/10.1126/sciadv.aea3420
Abstract
The recent discovery of a 4.1-billion-year-old (Ga) Martian gabbroic diorite enables an assessment of water reservoirs on early Mars. Measurements of H2O and D/H in igneous Ca-phosphates record mixing between D-poor magmatic water and a D-rich component that retains an imprint of the ancient Martian hydrosphere. The D/H ratio of magmatic water is similar in Martian magmas with different ages and mantle sources, indicating that early differentiation processes did not fractionate H isotopes in the primordial Martian mantle. The D-rich component was assimilated by migrating magmas that interacted with aqueously altered basaltic crust. Our minimum bound on the D/H ratio of the Martian hydrosphere at 4.1 Ga (~2× the D/H ratio of Earth seawater) supports models of rapid H loss to space from Mars’ juvenile atmosphere.
