An ancient Martian meteorite records water alteration about 4.1 billion years ago

A NASA-funded study applied in-situ rubidium-strontium dating to the Martian meteorite Teghaza 001, analysing individual mineral grains on its surface rather than dissolving the whole rock. The result shows alteration by Martian water about 4.1 billion years ago, so the rock itself formed earlier. Oxygen isotopes, texture and chemistry also point to a more dynamic early Martian water cycle. The team used a fragment smaller than a fingernail, combining precision and speed with preservation of a rare sample. Global chemistry and mineral maps identify 13 possible source regions but no unique impact location, and one meteorite cannot represent all of Mars.