Field for Action Keyed Date?

Summary:

What is the field in Oracle BIP Reporting for the date an Action is keyed?

Content (required):

Hello,

What is the field that shows when an action is keyed in the Oracle HCM Tables that Oracle BIP Reporting uses?

For Example, looking at the PER_ALL_ASSIGNMENTS_M table, I can look at all RESIGNATION action codes, but what date on that table (or another table) would I look at to see when that action was keyed for a worker? We've tried using "LAST_UPDATE_DATE" but with terminations, the terminated row sits on top of the stack with no end date, which means if the row containing the termination is updated after the fact, the "LAST_UPDATE_DATE" also changes, so given that, how can I reliably see when the termination was keyed (note, not when it's effective, when it was actually keyed)?