Harris matrix
Overview
 
The Harris matrix is a tool used to depict the temporal succession of archaeological context
Archaeological context
In archaeology, not only the context of a discovery is a significant fact, but the formation of the context is as well. An archaeological context is an event in time which has been preserved in the archaeological record. The cutting of a pit or ditch in the past is a context, whilst the material...

s and thus the sequence of deposition on a 'dry land' archaeological site. The matrix reflects the relative position and stratigraphic contacts of observable stratigraphic units, or contexts. The Matrix was developed in 1974 in Winchester, England, by Dr. Edward C. Harris.
However the concept of creating seriation
Seriation
Seriation is a way of situating an object within a series:*Seriation *Seriation...

 diagrams of archaeological strata based on the physical relationship between strata had had some currency in Winchester and other urban centres in England prior to Harris's formalisation.
Encyclopedia
The Harris matrix is a tool used to depict the temporal succession of archaeological context
Archaeological context
In archaeology, not only the context of a discovery is a significant fact, but the formation of the context is as well. An archaeological context is an event in time which has been preserved in the archaeological record. The cutting of a pit or ditch in the past is a context, whilst the material...

s and thus the sequence of deposition on a 'dry land' archaeological site. The matrix reflects the relative position and stratigraphic contacts of observable stratigraphic units, or contexts. The Matrix was developed in 1974 in Winchester, England, by Dr. Edward C. Harris.
However the concept of creating seriation
Seriation
Seriation is a way of situating an object within a series:*Seriation *Seriation...

 diagrams of archaeological strata based on the physical relationship between strata had had some currency in Winchester and other urban centres in England prior to Harris's formalisation. One of the end results of Harris's work was the realisation that sites had to be excavated stratigraphically, in the reverse order to that in which it was created, without the use of arbitrary measures of stratification such as spits or planums. Harris first articulated (In Principles of archaeological stratigraphy) the need for each unit of stratification to have its own graphic representation, usually in the form of a measured plan. In articulating the laws of archaeological stratigraphy and developing a system in which to simply and graphically demonstrate the sequence of deposition or truncation on a site, it has been argued that Harris has followed in the footsteps of the truly great stratigraphic archaeologists such as Wheeler, without necessarily being a great excavator himself. Harris's work was a vital pre-cursor to the development of single context planning by the Museum of London and also the development of land use diagrams, all facets of a suite of archaeological recording tools and techniques developed in the UK which allow indepth analysis of complex archaeological data sets, usually from urban excavations.

Harris's Laws of Archaeological Stratigraphy

The law of superposition
Law of superposition
The law of superposition is a key axiom based on observations of natural history that is a foundational principle of sedimentary stratigraphy and so of other geology dependent natural sciences:...


In a series of layers and interfacial features, as originally created, the upper units of stratification
Stratification (archeology)
Stratification is a paramount and base concept in archaeology, especially in the course of excavation. It is largely based on the Law of Superposition...

 are younger and the lower are older, for each must have been deposited on, or created by the removal of, a pre-existing mass of archaeological stratification.

Law of Original Horizontal
Any archaeological layer deposited in an unconsolidated form will tend towards a horizontal disposition. Strata which are found with tilted surfaces were so originally deposited, or lie in conformity with the contours of a pre-existing basin of deposition.

Law of Original Continuity
Any archaeological deposit, as originally laid down, will be bounded by the edge of the basin of deposition, or will thin down to a feather edge. Therefore, if any edge of the deposit is exposed in a vertical plane view, a part of its original extent must have been removed by excavation or erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

: its continuity must be sought, or its absence explained.

Law of Stratigraphic Succession
Any given unit of archaeological stratification
Stratification (archeology)
Stratification is a paramount and base concept in archaeology, especially in the course of excavation. It is largely based on the Law of Superposition...

 takes its place in the stratigraphic sequence of a site from its position between the undermost of all units which lie above it and the uppermost of all those units which lie below it and with which it has a physical contact, all other superpositional relationships being regarded as redundant.

These laws were published in 1979. A fifth law of archaeological stratigraphy has also been added following papers presented at the "Interpreting Stratigraphy a Review of the Art" conferences http://www.york.ac.uk/depts/arch/strat/ in the UK from 1992 - 2003.

Harris matrix in use

In constructing a matrix, the latest contexts
Archaeological context
In archaeology, not only the context of a discovery is a significant fact, but the formation of the context is as well. An archaeological context is an event in time which has been preserved in the archaeological record. The cutting of a pit or ditch in the past is a context, whilst the material...

 sit on top of the matrix and the earliest at the bottom with the lines that link them together representing direct stratigraphic contact (though note that though all stratigraphic relationships are physical, not all physical relationships are stratigraphic). The matrix thus demonstrates the temporal relationship between any two units of archaeological Stratification
Stratification (archeology)
Stratification is a paramount and base concept in archaeology, especially in the course of excavation. It is largely based on the Law of Superposition...

. While excavating, it is best practice to compile the area and site stratigraphic matrices during the progress of an excavation through reference to both the drawn and written record. Regular daily checking of the record and the compilation of the matrix itself both help inform the individual archaeologist on the physical processes of site formation and highlight any areas where dubious relationships such as H relationships or loops in the recorded sequence may occur. Loops are sequences in the matrix that produce temporal anomalies so that the earliest context in a sequence of context appears to be later than the latest context by virtue of errors in excavation or recording. Urban archaeological sites are complex affairs, often generating thousands of units of archaeological stratigraphy (contexts)
Archaeological context
In archaeology, not only the context of a discovery is a significant fact, but the formation of the context is as well. An archaeological context is an event in time which has been preserved in the archaeological record. The cutting of a pit or ditch in the past is a context, whilst the material...

 It is of even more vital importance when excavating such sites to compile the matrix as the excavation progresses. Such sites by definition produce multi-linear sequences of succession and to date the best way to get a handle of these sequences is to compile the matrix by hand based on the drawings and the context sheets. This ensures an internally consistent record and that the complexity of the site is given due regard. Computer programmes do exist which can aid the production of a matrix, though at the moment these tend towards articulating linear sequences rather than multi-linear sequences.

The Harris matrix is a tool that aids the accurate and consistent excavation of a site and articulates complex sequences in a clear and understandable way. Harris matrices play an invaluable role in the articulation of sequence and provide the building blocks from which higher order units of stratigraphically related events can be constructed.

Example of the Harris matrix


Take this hypothetical section
Archaeological section
In archaeology a section is a view in part of the archaeological sequence showing it in the vertical plane, as a cross section, and thereby illustrating its profile and stratigraphy. This may make it easier to view and interpret as it developed over time....

 as an example of matrix formation. Here there are twelve contexts
Archaeological context
In archaeology, not only the context of a discovery is a significant fact, but the formation of the context is as well. An archaeological context is an event in time which has been preserved in the archaeological record. The cutting of a pit or ditch in the past is a context, whilst the material...

, each numbered thus:
  1. A horizontal layer
  2. Masonry wall remnant
  3. Backfill of the wall construction cut (sometimes called construction trench
    Trench
    A trench is a type of excavation or depression in the ground. Trenches are generally defined by being deeper than they are wide , and by being narrow compared to their length ....

    )
  4. A horizontal layer, probably the same as 1
  5. Construction cut for wall 2
  6. A clay floor abutting
    Relationship (archaeology)
    An archaeological relationship is the position in space and by implication, in time, of an object or context with respect to another. This is determined, not by linear measurement but by determining the sequence of their deposition - which arrived before the other...

     wall 2
  7. Fill of shallow cut 8
  8. Shallow pit cut
  9. A horizontal layer
  10. A horizontal layer, probably the same as 9
  11. Natural sterile ground formed before human occupation of the site
  12. Trample in the base of cut 5 formed by workmen's boots constructing the structure wall 2 and floor 6 is associated
    Archaeological association
    Association in archaeology has more than one meaning and is confusing to the layman. Archaeology has been critiqued as a soft science with a somewhat poor standardization of terms.-Finds and objects:...

     with.


The order in which these events occurred and the reverse order they should have been excavated with would be demonstrated by the following Harris matrix

The completed matrix


The later a context's formation is, the higher it is in the matrix, and conversely the earlier it is, the lower. Relationships
Relationship (archaeology)
An archaeological relationship is the position in space and by implication, in time, of an object or context with respect to another. This is determined, not by linear measurement but by determining the sequence of their deposition - which arrived before the other...

 between contexts are recorded in the sequence of formation, so even though wall 2 is physically higher than other contexts in section, its position in the matrix is immediately under backfill 3 and below floor 6. This is because the formation of the backfill and floor happened later. also note the matrix splits into two parts below the construction cut 5. This is because the relationships across the section have been destroyed by the cutting of construction cut 5 and even if it is likely that layers 1 and 4 are probably the same deposit the information can not be guaranteed if the only information we had was this section. However the position of cut 5 and natural layer 11 "ties" the matrix together above and below the split in the matrix.

Interpretation

Starting at the bottom the order events occurred in this section is revealed by the matrix as follows. Natural ground formation 11 was followed by the laying down of layers 9 and 10 which "probably" occurred as the same event. Then a shallow pit 8 was cut and then back filled with 7. This pit feature
Feature (archaeology)
Feature in archaeology and especially excavation has several different but allied meanings. A feature is a collection of one or more contexts representing some human non-portable activity that generally has a vertical characteristic to it in relation to site stratigraphy. Examples of features are...

 in turn was "sealed" by the laying down of layer 1 which is probably the same event as layer 4. Following this a major change in land use occurs as construction cut 5 is dug and immediately followed by trample off the feet of people 12 working in the construction cut 5 who then build wall 2 after which they backfill excess space between the wall 2 and cut 5 with backfill 3. Finally clay floor 6 is laid down to the right of wall 2 over backfill 3 indicating a probable interior surface. The nature of archaeological investigation and the subjective nature of all human experience means that a degree of interpretive activity obviously occurs during the process of excavation, the Harris matrix itself however serves to provide a check on observable quantifiable physical phenomena and relies on the excavator understanding which way in the sequence is 'up' and the ability of the excavator to excavate and record honestly, accurately and stratigraphically. The process of excavation destroys the context and requires the excavator to be able and willing to make informed (by experience and where necessary collaboration) decisions about which context(s) lay at the top of the sequence. As long as undercutting is not endemic, in practice onsite errors in judgment should become evident especially if temporary sections are kept for stratigraphic control in areas of a site that are hard to discern. However archaeological sections, while being useful and valuable only ever present a slice, a caricature, of a sequence often underrepresenting its complexity. The use of archaeological sections when dealing with stratigraphic complexity is limited and their use should be context sensitive rather than as a running arbiter of sequence.

Carver matrix

Professor Martin Carver
Martin Carver
Martin Oswald Hugh Carver FSA , is Emeritus Professor of Archaeology at the University of York, England, director of the Sutton Hoo Research Project and a leading exponent of new methods in excavation and survey. He specialises in the archaeology of early Medieval Europe...

 of the University of York
University of York
The University of York , is an academic institution located in the city of York, England. Established in 1963, the campus university has expanded to more than thirty departments and centres, covering a wide range of subjects...

 has also developed a seriation diagram, known as the Carver matrix (Not to be confused with the military term also named CARVER matrix
CARVER matrix
The CARVER matrix was developed by the United States special operations forces during the Vietnam War. CARVER is an acronym that stands for Criticality, Accessibility, Recuperability, Vulnerability, Effect and Recognizability and is a system to identify and rank specific targets so that attack...

). This diagram, which is based on the Harris matrix is designed to represent the time lapse in use of recognizable archaeological entities such as floors and pits. Like Ed Harris he used contexts numbered and defined on site as the basic elements of the sequence, but he added higher order groupings ("feature" and "structure") to increase the interpretive power. Several other people such as Norman Hammond
Norman Hammond
Norman Hammond is a British archaeologist, academic and Mesoamericanist scholar, noted for his publications and research on the pre-Columbian Maya civilization. Educated at Peterhouse, Cambridge, Hammond is a professor in the Archaeology Department at Boston University's College of Arts and...

 looked to develop similar systems in the 1980s and 90s

See also

  • Archaeological plan
    Archaeological plan
    An archaeological plan in an archaeological excavation, is a drawn record of features in the horizontal plane.- Overview :Archaeological plan can either take the form of...

  • Archaeological association
    Archaeological association
    Association in archaeology has more than one meaning and is confusing to the layman. Archaeology has been critiqued as a soft science with a somewhat poor standardization of terms.-Finds and objects:...

  • Cut (archaeology)
    Cut (archaeology)
    In Archaeology and archeological stratification a cut or truncation is a context that represents a moment in time when other archaeological deposits were removed for the creation of some feature such as a ditch or pit...

  • Archaeological section
    Archaeological section
    In archaeology a section is a view in part of the archaeological sequence showing it in the vertical plane, as a cross section, and thereby illustrating its profile and stratigraphy. This may make it easier to view and interpret as it developed over time....

  • Feature (archaeology)
    Feature (archaeology)
    Feature in archaeology and especially excavation has several different but allied meanings. A feature is a collection of one or more contexts representing some human non-portable activity that generally has a vertical characteristic to it in relation to site stratigraphy. Examples of features are...

  • Dating methodology (archaeology)
    Dating methodology (archaeology)
    Dating material drawn from the archaeological record can be made by a direct study of an artifact or may be deduced by association with materials found in the context the item is drawn from or inferred by its point of discovery in the sequence relative to datable contexts...

  • Reverse stratigraphy
    Reverse stratigraphy
    Reverse stratigraphy is the result of a process whereby one sediment is unearthed by human or natural actions and moved elsewhere, whereby the latest material will be deposited on the bottom of the new sediment, and progressively earlier material will be deposited higher and higher in the...


External links


Matrix builder programs

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