Taphonomy of a Panopea Ménard de la Groye, 1807 shell bed from the Pisco Formation (Miocene, Peru)

Invertebrate taphonomy can provide significant information about the post-mortem processes that affected fossil record. In East Pisco Basin of southern Peru, a Panopea Ménard de la Groye, 1807 shell bed was found in upper Miocene strata Formation, hinting at peculiar biostratinomic and diagenetic history. This contains abundant invertebrate molds cemented by dolomite. The specimens deep infaunal bivalve, sp., occur together with bivalves representative shallow species (Trachycardium sp. Dosinia ponderosa [Gray, 1838]) balanid barnacles, which are sessile encrusters. host compound evidencing an encrusting fauna, including serpulids, ?foraminifera, bryozoans, barnacles colonized inner surfaces valves before their final burial. We hypothesize short-term, storm-related exhumed living bivalves, resulting sedimentological concentration relatively well-preserved shells. After death articulated shells, representing hard-substratal, sheltered environments on otherwise unstable sandy seafloor (i.e., “benthic islands”), were different organisms. Following burial, dolomite precipitated, cementing sediment infill valves. Lastly, decrease pH occurred sulfate reduction-methanogenesis boundary, inducing dissolution carbonate.