Creating stratigraphic matrices by combining plan matrices
1
© Chiz Harward, 2006, revised 2014 Urban Archaeology contact: [email protected] Urban Archaeology ...define, record, remove... Urban excavation factsheet 5 Creating a Stratigraphic matrix by combining Plan Matrices The stratigraphic matrix for an individual trench, or a whole site, can be constructed by amalgamating all the plan matrices (see Urban Archaeology Factsheet 4), and then adding unplanned contexts in their correct stratigraphic order. The advantage of creating a matrix in this way is that it is systematic, it is based on the recorded plans and context sheets, and helps to check that these records were correctly recorded. This method is best used after excavation is finished, or when a single layer is reached across the area of excavation. The process is simple and logical: ? Check that the context sheets are correctly filled in, the strat matrix boxes will be adjusted at the end of the process ? Check plan matrices for each plan square ? Amalgamate the plan matrices –creating an area wide matrix of all planned contexts ? Add unplanned contexts to create the stratigraphic matrix ? Add the correct strat relationships to the context and enviro sheets Check whether there are any sections for your area, if there are then create a matrix for each section, and amalgamate these with the rest of the plan matrices. Once the individual plan matrices have been checked for an area, write out all the plan matrices on a sheet of paper. The process of amalgamation (which can also be done using the Bonn computer program) adds each plan matrix to another in turn, ending up with a single unified plan matrix containing all the relationships. Some of the matrices will be more complex, and some may be simpler. The simplest way of starting to amalgamate the matrices is to cross through matrices that are COMPLETELY duplicated in another plan square, and then combine the simplest matrices -or strands of matrices- gradually adding all the relationships to create a single matrix, making sure that each relationship is correctly added. If there is a 'cycle' in the matrix where in one grid square a context is above a plan it is shown as being underneath elsewhere, then go back to the plans and fix this problem. You will now have a combined plan matrix for the area. However this is only of the planned contexts, you need to add unplanned contexts to create the stratigraphic matrix. Using the context sheets add the fills, deposits, and contexts recorded in section into the matrix. Be aware that if you had any multi-context plans then there may be other cuts to add too (often the case with post or stake holes). Be also aware that not all fills may be below the capping layer, especially if the feature is truncated. Check that all the contexts are on the matrix that should be by crossing them off a list as you go. The matrix will then be complete. Draw it out neatly and annotate with any comments, and note whether it is the complete matrix, or just done to a certain point, to avoid unnecessary repetition later. Add the correct stratigraphic relationships to the context and enviro sheets. Check the details in the context, enviro and section registers are correct, file the checked sheets in the 'to be checked' file and have a cup of tea.
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Urban Archaeology factsheet describing the process for combining multiple Plan Matrices to create a Stratigraphic matrix. This logical and simple process causes more grief on excavations than many harder processes. Take it slow, break it down to tasks, and take it steady!
Transcript of Creating stratigraphic matrices by combining plan matrices
© Chiz Harward, 2006, revised 2014 Urban Archaeology contact: [email protected]
Urban Archaeology ...define, record, remove...
Urban excavation factsheet 5
Creating a Stratigraphic matrix by combining Plan Matrices
The stratigraphic matrix for an individual trench, or a whole site, can be constructed by amalgamating all the plan matrices (see Urban Archaeology Factsheet 4), and then adding unplanned contexts in their correct stratigraphic order. The advantage of creating a matrix in this way is that it is systematic, it is based on the recorded plans and context sheets, and helps to check that these records were correctly recorded. This method is best used after excavation is finished, or when a single layer is reached across the area of excavation.
The process is simple and logical:
?Check that the context sheets are correctly filled in, the strat matrix boxes will be adjusted at the end of the process
?Check plan matrices for each plan square
?Amalgamate the plan matrices –creating an area wide matrix of all planned contexts
?Add unplanned contexts to create the stratigraphic matrix
?Add the correct strat relationships to the context and enviro sheets
Check whether there are any sections for your area, if there are then create a matrix for each section, and amalgamate these with the rest of the plan matrices.
Once the individual plan matrices have been checked for an area, write out all the plan matrices on a sheet of paper. The process of amalgamation (which can also be done using the Bonn computer program) adds each plan matrix to another in turn, ending up with a single unified plan matrix containing all the relationships.
Some of the matrices will be more complex, and some may be simpler. The simplest way of starting to amalgamate the matrices is to cross through matrices that are COMPLETELY duplicated in another plan square, and then combine the simplest matrices -or strands of matrices- gradually adding all the relationships to create a single matrix, making sure that each relationship is correctly added.
If there is a 'cycle' in the matrix where in one grid square a context is above a plan it is shown as being underneath elsewhere, then go back to the plans and fix this problem.
You will now have a combined plan matrix for the area. However this is only of the planned contexts, you need to add unplanned contexts to create the stratigraphic matrix. Using the context sheets add the fills, deposits, and contexts recorded in section into the matrix.
Be aware that if you had any multi-context plans then there may be other cuts to add too (often the case with post or stake holes). Be also aware that not all fills may be below the capping layer, especially if the feature is truncated. Check that all the contexts are on the matrix that should be by crossing them off a list as you go.
The matrix will then be complete. Draw it out neatly and annotate with any comments, and note whether it is the complete matrix, or just done to a certain point, to avoid unnecessary repetition later. Add the correct stratigraphic relationships to the context and enviro sheets. Check the details in the context, enviro and section registers are correct, file the checked sheets in the 'to be checked' file and have a cup of tea.
