The Geology of Jezero Crater, Observations & Findings Options

[nprev]

This thread is for those rockhounds among us to discuss the new terrain we'll see as Perseverance scoots around her new home. Let's get dirty & technical!

[Blue Sky]

If the crater floor is covered by ash or other volcanic material, if Perseverence heads up the delta toward the inflowing river bed, would it be able to find any of the original river- or lake-bed shallow enough that its instruments can reach it? I suppose this area is a major destination for the helicopter.

[JRehling]

It's virtually certain that some of the material from the lake – pebbles here and there – would be part of the regolith around Perseverance, but lacking context, they won't be as valuable to study as the rock in layers where the relative ordering is known.

The original lake bed is certainly not within reach soon. That said, the end of the lake was probably not a completely binary event, and there may have been some time near the end when the lake was first dry, and then later got a little bit of temporary recharge. The 2020 USGS publication about Jezero notes the possibility that the landing site had been reworked with later lacustrine environments. This would be of interest, but clearly secondary interest, as a place that was "habitable" for a few days or months would be much less interesting than a place that was "habitable" for a million years.

Remember, Spirit completely failed to access the original lakebed of Gusev, but surprisingly found evidence of aqueous evolution in the Columbia Hills. While we certainly don't see a Columbia Hills very close to Perseverance now, it would be hard to rule out later aqueous activity in the layer where it landed. But the actual delta layers are going to take a while to access.

Curiosity reached Yellowknife Bay on Sol 125. Perseverance has about twice that distance to go before reaching the delta, and it's possible that the morphology of the edge of the delta will keep us from touching that material without considerably longer traversals to the south (or north). I don't think we've had a chance yet to see the material – wherever it is – where Perseverance will first sample the delta layers. And we possibly will still be saying that in June and July.