Supplementary data to: "Multi-isotopic and trace element evidence against different formation pathways for oyster microstructures" This upload compiles supplementary methods and results belonging to the manuscript titled “Multi-isotopic and trace element evidence against different formation pathways for oyster microstructures” submitted to Geochimica et Cosmochimica Acta and serves to provide additional information about the study not given in the main manuscript. The list in the document "Supplementary_Information.pdf" serves as a guideline for the reader to find the unprocessed data belonging to this manuscript in the online appendix.