eogenesis refers to the early stages of diagenesis. this can take place at very shallow depths, ranging from a few meters to tens of meters below the surface. the changes that occur during this diagenetic phase mainly relate to the reworking of the sediments. compaction and grain repacking, bioturbation, as well as mineralogical changes all occur at varying degrees. due to the shallow depths, sediments undergo only minor compaction and grain rearrangement during this stage. organisms rework sediment near the depositional interface by burrowing, crawling, and in some cases sediment ingestion. this process can destroy sedimentary structures that were present upon deposition of the sediment. structures such as lamination will give way to new structures associated with the activity of organisms. despite being close to the surface, eogenesis does provide conditions for important mineralogical changes to occur. this mainly involves the precipitation of new minerals.