As noted by Gavin Lucas in an article in CAJ, archaeology often deals with two temporal planes: the particular event (such as the production of the single artifact or its deposition or the sinking of Titanic) and the structure as an enduring set of practices or beliefs (cosmology and/or ideology). Lucas formulates the archaeological event as something not defined by its particularity but rather about reversibility. The event is the temporal concept that keeps us grounded in the archaeological data since we are dealing with residues of events. Events are assemblages of people and objects that persist for various durations. Archaeological events are tied to the degree of reversibility in organization that effect residuality. Change occurs more readily in assemblages with greater reversibility (such as a book collection or a floating iceberg). They also leave less material residues in the archaeological record. Assemblages with greater irreversibility changes little (traffic system or ocean going passenger lines) but they also leave more physical traces.
If we follow Whitehead’s definition of an event, an object is an event in itself or rather a series of events. An iceberg is actually happening, it is always a fresh creation, an event. The iceberg has a time in relation to Titanic. The time it takes for the collision to occur is not a continuous flow but rather an event. As time “moves on” the objects are recomposed and they can seldom be decomposed to their former objects according to Harman. The iceberg and Titanic formed a third object/event that changed the constitution of them both. One can never recompose this event/object on April 15 1912.
Lucas, Gavin (2008). Time and archaeological event. Cambridge Archaeological Journal 18(1): 59-65.