The #Perseverance press conference panel consists of 5 NASA managers and 1 Mars researcher - so the topic is likely some follow-up to "the
discovery of a potential #biosignature" in an outcrop reported earlier this year in https://ntrs.nasa.gov/api/citations/20250001217/downloads/Hurowitz%20et%20al%20LPSC.pdf while the specific rock to be discussed today was shown in April in https://science.nasa.gov/resource/meet-the-mars-samples-sapphire-canyon-sample-25/ and mentioned in August in https://www.eurekalert.org/news-releases/1094171 and the O-PTIR #spectroscopy method to hunt for microbial markers was discussed in March in https://www.u-tokyo.ac.jp/focus/en/press/z0508_00392.html

Redox-driven mineral and organic associations in Jezero Crater, #Mars: https://www.nature.com/articles/s41586-025-09413-0 -> "Here we report a detailed geological, petrographic and geochemical survey of these rocks and show that organic-carbon-bearing mudstones in the Bright Angel formation contain submillimetre-scale nodules and millimetre-scale reaction fronts enriched in ferrous iron phosphate and sulfide minerals, likely vivianite and greigite, respectively. This organic carbon appears to have participated in post-depositional redox reactions that produced the observed iron-phosphate and iron-sulfide minerals. Geological context and petrography indicate that these reactions occurred at low temperatures. Within this context, we review the various pathways by which redox reactions that involve organic matter can produce the observed suite of iron-, sulfur- and phosphorus-bearing minerals in laboratory and natural environments on Earth. Ultimately, we conclude that analysis of the core sample collected from this unit using high-sensitivity instrumentation on Earth will enable the measurements required to determine the origin of the minerals, organics and textures it contains."

An earlier video about the #Mars rock Sapphire Canyon: https://www.youtube.com/watch?v=9bLhVJKoIOg. And a press release from today: https://www.jpl.nasa.gov/news/nasa-says-mars-rover-discovered-potential-biosignature-last-year/. And a thread about the ongoing press conference: https://x.com/SpaceflightNow/status/1965794069042634837