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!

[Andreas Plesch]

Yes, these lineations may have formed from aeolian erosion, indicating prolonged surface exposure (perhaps when there was still more of an atmosphere). The apparent stretching may be from obliquely cutting through vesicles. Since the holes seem to appear on all sides of imaged examples, I think it is less likely that they are potholes from scouring and milling. But it would be insightful to drill to see if there are similar holes in the interior of a large block.

I would also the envision the drying of the lake as a longer process, with wetter and drier periods. Are there thoughts on potentially multiple lake filling events ? After drying up substantially ?

Here is a cool new image of that outlier, first pointed out over in the general thread:

https://mars.nasa.gov/mars2020-raw-images/p...6_110085J01.png

There is nice stratigraphic layering, perhaps cyclic, and what appears to be a thick layer of foresets prograding outwards, above halfway up the slope or so. It may be possible to find the same sequence in the main delta (if and when the rover can get closer).

[JRehling]

Great look at the layering in the outlier, Andreas.

Another possibility would be to find a match between those layers and the ones in the crater wall, in case this is something that formed before the delta and remained intact through martian history.

[Andreas Plesch]

Great look at the layering in the outlier, Andreas.

Another possibility would be to find a match between those layers and the ones in the crater wall, in case this is something that formed before the delta and remained intact through martian history.

For convenience, reproduced here, with grey lines indicating potential foresets in a massive layer:

[serpens]

For convenience, reproduced here, with grey lines indicating potential foresets in a massive layer:

This post correlates to Demko's post #392 in the Perseverance Lands In Jezero Crater thread. The direction of sediment flow raised by Tim's assessment has implications for the original size and configuration of the delta and potentially interactions between the two deltas.

[Andreas Plesch]

This post correlates to Demko's post #392 in the Perseverance Lands In Jezero Crater thread. The direction of sediment flow raised by Tim's assessment has implications for the original size and configuration of the delta and potentially interactions between the two deltas.

Yes, agreed. I was more cautious in my interpretation but had the same impression regarding the lower set of foresets, in the shaded, right portion. In fact, I think now that the lower massive bed can be traced all the way to the base of the cliff on the right side where it is exposed again. There is the implication that there were two large scale cycles of progradation followed by regression and possibly erosion which is very typical and commonly observed in terrestrial analogues.