IPA: /ˌdaɪəˈdʒɛnɪkli/
KK: /daɪəˈdʒɛnɪkli/
In a way that relates to the process of diagenesis, which is the physical and chemical changes occurring in sediments after their initial deposition.
The rock layers were formed diagenetically over millions of years, changing their structure and composition.
Diagenetically → It is formed from "dia-" (meaning through or across) and "genesis" (from Greek "genesis", meaning origin or creation) and the suffix "-ically" (meaning in a manner relating to). The word "diagenetically" refers to processes that occur through the formation or origin of sedimentary rocks and their changes over time.
Think of processes happening 'through' ('dia-') the 'creation' ('genesis') of rocks — that's how diagenetically relates to geological changes.