Stratified Ejecta Blocks (The Stripy Boulder Hunt!)
Another hunt….and this time it’s stripy!
Katie Joy from the Moon Zoo team says:
We would like you to take a closer look at large boulders in Moon Zoo images. We want people to spot boulders that have layers cutting across the rock. There are some examples of the features we are interested in this LROC post and in this fascinating Lunar and Planetary Science Conference abstract.
Please look for layers that are as clearly spotted as those in the examples – ideally more than five obvious bands in the boulder (dark to light layers). Look at boulders that have rolled down slopes, those that are sitting in rubble-filled gullies and even boulders that are just sitting on their own. Please provide images of features you find and if you can state the location of the NAC frame where the boulder was found would be a big help.
Finding such boulders is really exciting as they suggest that large blocks of ‘bedrock’ are exposed and that could potentially be sampled by astronauts of robotic missions to the Moon. Lunar bedrock is normally hidden from view under a soil-like covering called regolith – the Apollo missions never sampled rocks from bedrock units (although layers of rock were seen from afar in the walls of Hadley Rille at Apollo 15 – see the astronaut’s comments at 165:23:26 available here!). Sampling bedrock layers that have a stratigraphic sequence (layers that have built up in a time-sequential manner) will provide unique information about how lunar rocks have formed with time. They will likely contain a temporal archive of lunar and Solar System processes (see this research about accessing a record of the Moon’s interaction with Space), and therefore are time capsules that provide a view to processes occurring millions, if not billions of years ago.
Happy stripy boulder hunting, and thank you once again for all your help,
Well to kick things off, forum members Half65 and Tom128 found these examples of stratified bouders in Aristarchus. I think this is the type of boulder we should look out for as the LPI paper Katie links to shows some similar boulders in Aristarchus.
Hopefully a team member will come along and comment. The NAC image is M111904494RE
Jules is a volunteer moderator for the Moon Zoo forum