An interesting close-up of the ash layers
This stratification is primary and documents
periodic volcanic ash rain.
They occur in huge blocks in the moraine of the delta and were transported
to this location by a
dry ice glacier.
The cracks in the blocks are a good indication of such transports.
In further close-ups, the structure of the
deposits is clearly visible. Surprisingly, it is teeming of the "coffee
bean"-like globules therein.
And, if that is not volcanic ash, I am not a geologist anymore.
Example for more solidified cyclically deposited
Downfallen igneous boulders on eroded ash layers.
Two pieces of tiny-grained and coarse-grained volcanic ash side by side.