"And what we found, is not what we expected to find."-Ken Farley
JPL used to have a good monthly lecture called the Von Karmen lecture series. It still exists, but about three years ago they turned to dumpster juice, "discussions", severely dumbed down past the point of not being worth watching. The old ones are still good, though some seem to be missing. Currently however, they seem to be trying to compromise some sort of internal stressor by keeping aspects of the discussion (which inherently are a waste of time and are still a burden on the videos) but have someone actually show up with slides and information. So I'm willing to watch them, and I can tell you where the good timestamps are.
This JPL however is a "news briefing" video, less risky than the current Von Karmen lectures. This one is from mid-September of this year.
- Skip ahead to 7:13. Just hype prior.
- At 10:00 Ken Farley mentions one of Percy's major finds so far; the Jezero floor is covered in Igneous, not Sedimentary material, implying that the most recent major deposition events in this basin were not water related. "Crystalized from a melt", consistent with one or several impact pyroclastic flows.
- KF also mentions a very important Mars thing... we don't actually know any dates on the ages of things. We can relatively date things, Law of superposition and whatnot. There is plenty of that, but all Mars dates have a ton of error involved currently. We need sample returns to constrain that, and that alone will settle a great many backoffice arguments.
- About 15:50 David Shuster referring to 'wildcat-ridge' mentions that this mudstone bears sulfates, and is salty "possibly in the lake evaporation stage." So Hesperian (because sulfates) and water is depleting. That's no revelation, but the twist is that while this kind of stone is a good preservative of biological organics, as opposed to chemical organics, anything that might be biological is much less likely in the Hesperian.
- Q&A at 37:35.