As part of my PhD research, the GSTAR project, I’ve been doing some more detailed work data modelling using the CRM-EH extensions to the CIDOC CRM, looking specifically at the concepts of ‘context’ aka ‘stratigraphic unit’ and how to model stratigraphy and context specialisms and relationships. Also the related processes by which objects become deposited in archaeological contexts and are subsequently found.
I will hopefully be publishing this work more fully in due course but for now here is a taster of some of the preliminary results.
This is very much open for discussion so any comments gratefully received.
Contexts and Stratigraphy: Positive and Negative Stratigraphic Units and related Events
The context is the fundamental unit of recording in many archaeological recording systems. We can think of archaeological contexts, representing discreet stratigraphic units, as being of two basic classes: Positive and Negative.
Positive Stratigraphic Units describe layers and deposits, ie the result of some material being deposited in a place whilst Negative Stratigraphic Units represent cuts, ie the result of some material being removed from a place.
Stratigraphy can be seen as the relative sequence of events resulting in these changes to archaeological deposits. A shortcut is used here for stratigraphically above/below (more accurately stratigraphically before/after) to provide a short chain representing this much longer sequence of events and event relationships.
Context Types and Relationships
All types of contexts have physical relationships with other contexts. The types of relationships depends on the type of context. Properties inherited from parent classes likewise.
Contexts can all be seen as subclasses of an overarching concept, the stratigraphic unit. These subclasses are generally represented in recording systems using different context sheets each holding common properties such as UIDs and classifications and also type specific properties such as physical relationships. Subtypes include masonry, timber and skeletons.
Finds can be seen as ending up in archaeological deposits through some move event which could be a deliberate action or otherwise (eg an accidental loss). This forms one of the chain of events relating to objects beginning with their creation and initial use and/or display and eventually continuing beyond their rediscovery into the display and changes of custody in the world of museums and collections.
In addition to the act of discovery, however that may occur, a whole sequence of events then results in assignment of identifiers and classification using typologies.