Skolithos piperock from the Lower Devonian storm beds

Abstract

Skolithos piperock is prevalent in Cambrian shallow marine deposits but diminishes throughout the Paleozoic. This study reports an interval with Skolithos piperock from the upper Furnas Formation (Lower Devonian), offering insights into the paleoenvironmental interpretation of nearshore sandstones. The studied section comprises eight sedimentary facies, transitioning from sandstone-dominated intervals indicative of nearshore environments to siltstone and mudstone facies representing lower energy transitional offshore conditions. Trace fossils are grouped into six ichnocoenoses, reflecting varying depositional settings from proximal to distal in the coastal zone. Notable shifts in ichnocoenosis composition, particularly the transition from Skolithos piperock to the Asterosoma ichnocoenosis, mark stratigraphic boundaries and highlight a transgressive trend between the Furnas and Ponta Grossa formations. The identification of Skolithos piperock provides evidence of storm-generated deposits and reworking activities, which can be applied to basin-scale correlations. This occurrence of a Skolithos piperock is interpreted as the result of several erosive processes triggered by storms, generating a time-averaged ichnoassemblage.