Is the Jezero Crater a landscape of an wind-eroded glacier moraine?

(and the delta is an eroding remnant of the moraine)

Norbert Brügge, Germany
Dipl.-Geol.

Update: 02.11.2021

The hope that rover Perseverance's mission will find traces of life will not come true. The photos available so far from the mast- camera suggest that the landsscape in the Jezero crater is a wind-eroded glacier moraine, and the delta is the eroded remnant of this glacier moraine. The deposits in the delta are stratified, but contain a lot of boulders. Such boulders are abundant in the run-up to the delta. All boulders are remnants of the eroded part of the formerly larger delta. "Fresh" boulders are slightly or not rounded and do NOT indicate transport by running water. The moraine contains both "fresh" and disintegrated boulders that shoulded come from above the Jezero crater. The stratification of the fine sediments in the delta can only mean periodic activities of the glacier. The fine parts in the moraine probably consist of grains from completely disintegrated boulders, mixed with the decomposed olivines,so as we be found the mix on the bottom of the crater. It could also contain a lot of volcanic ash. The different stages of disintegration of the boulders are an indication of the age of their entry into the moraine. The "fresh" boulders are part of the upper part of the moraine. In the sandy elevations in the crater, in which boulders of different ages were stacked, are almost completely missing the blown-out fine components of the moraine. Disintegration and bleaching of the boulders could have been caused by chemical processes in the glacier moraine.The glacier could have been mostly dry ice (frozen carbon dioxide).

Publication 2021, October:
"Perseverance rover reveals an ancient delta-lake system and flood deposits at Jezero crater, Mars"
N. Mangold & S.Gupta, et al. –  https://www.science.org/doi/10.1126/science.abl4051

My comment: In this article, the hasty and daring thesis is propagated that the delta in the Jezero crater is of a fluvial origin  (deposits of a river) and that the fine, partly stratified deposits consist of sand and clay.
It is more than astonishing that another 37 co-authors agree with a thesis for which there is no evidence. It is absolutely impossible, despite optical zooming, to get a reliable forecast of the fine components in the deposits over a distance of 1 km or more. It can also be volcanic ash deposited in the moraine of a dry ice glacier.
Attempts to find any structures in the sliding outcrops at the scaps of the eroding delta that indicate flowing water are also not convincing.
So far, the assumptions about a former lake in the Jezero crater can be ruled out. There is no trace of sediment deposited of a lake. There are only dunes and indications of tectonic processes that are responsible for the broken and piled up igneous bedrock the bottom of the crater. Some of the rocks are so huge that they could never have been transported by water.
It is also to be expected that these outcrops of the bedrock have mixed with the boulders from parts of the wind-eroded delta.

Delta Scarp

 




 






  Fluvial cross-bedding in the delta is that NOT. This are secondary structures that were come by periodic ice pressure






Holey boulder with former olivine phenocrysts

Sliding boulder has destroyed the stratification

Boulders on top of the moraine

 

Massive and layered material of previously unknown composition in mostly broken state

 

Delta remnant

     
The zoom view of an isolated remnant of the delta shows partly evenly layered deposits

 

Elevations with partly phenomenal boulders


What an impressive photo. It exclude that this block was placed  by running water or by drifted death-ice on a lake

Sol 106 Sol 112 sol 155-158
sol 155-158 sol-164 Sol 168

Two possibilities of interpretation:

1.) These unique boulders to be documented the enormous energy of the former glacier, which abrased compact blocks of igneous rocks and transported than them with the moraine.These boulder, which are often angular, are scattered everywhere, apart from the levels with "paving stones". The elevations with the accumulations of this large boulders must depict a special accumulation in the past parts of the eroded moraine. It is possible that they are still lying on the remains of this moraine that are not visible today. There are no large boulders on the "paving stone" plains. Here the obviously younger part of the moraine was eroded to the "paving stone" level. The dense arrangement of the heavily weathered "paving stones" suggests that they are part of an older moraine that is still partly intact in the subsurface. This interpretation is no longer plausible.

 2.) These unique boulders included the "paving stones" are the bedrock of the crater. In any case, the composition of the rocks is identical to the boulders from the moraine of the delta.
Due to the concentration of this sometimes enormous size of boulders along the mysterious linear extent of the elevation, a tectonic event should be considered. Then these huge boulders could be a component of uplifted bedrock. The crumbly "paving stones" then are an equivalent of the flat stone layers on the uplift.
This interpretation is more plausible and can now be further specified.