Manuscript submitted in Sedimentology (17.01.2018). This draft is part 3 of a project about the dune bedforms from the 2006 pyroclastic currents of Tungurahua volcano (Ecuador), where a dataset of sediment plates (lacquer peels) enabled a detailed description of the fine-scale sedimentary structures created by dilute, turbulent, pyroclastic currents. Companion manuscript 1: "Revisiting the lacquer peels method with pyroclastic deposits: Sediment plates, a precise, fine-scale imaging method and powerful outreach tool." by Douillet et al. (accepted in Journal of Applied Volcanology) Companion manuscript 2: "Pyroclastic dune bedforms: macroscale structures and lateral variations. Examples from the 2006 pyroclastic currents at Tungurahua (Ecuador)." by Douillet et al. (submitted to Sedimentology on 13.06.2018) Companion manuscript 3: "Shark fins: overturned flame patterns due to waves at the shear horizon of a flow-bed boundary. Examples from the 2006 pyroclastic currents deposits at Tungurahua" (submitted to Sedimentology on 17.01.2018)