Posthole - AbsoluteAstronomy.com

Archaeology

Archaeology, or archeology , is the study of human society, primarily through the recovery and analysis of the material culture and environmental data that they have left behind, which includes artifacts, architecture, biofacts and cultural landscapes...

a posthole is a cut

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...

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...

used to hold a surface timber or stone. They are usually much deeper than they are wide although truncation

Cut (archaeology)

may not make this apparent.
Although the remains of the timber may survive most postholes are mainly recognisable as circular patches of darker earth when viewed in plan. Archaeologists can use their presence to plot the layout of former structures as the holes may define its corners and sides.

Parts of a posthole

Although a very structure, and one of the most basic found in archaeology, correct interpretation relies on being able to tell the often subtle differences that distinguish the parts of the posthole. The components of an archaeological posthole are listed in order of creation and, in ideal circumstances, the reverse order of their excavation.

Posthole cut
The cut that formed the hole. It is cut from the ground surface level at time of construction. The sides of the hole may be distorted by later pressure on the post [as in the left hand example of the image, or later disturbance. Only careful excavation will be able to distinguish between the original cut profile and any later distortion.

The cut needs to be distinguished from the fill in any detailed stratigraphic analysis, in the same way that any pit fill has to post-date the cutting of the pit, even if by minutes.

Dug up soil
Soil excavated from the hole, usually sitting in a pile next to hole ready for backfilling. Ideal sequence will be that the dug up soil will have material dug through first at the bottom of the pile with material from deeper down on top of the pile. In optimal situations the location of dug up soil can be detected adjacent to filled postholes especially where subsoil differs markedly from the surface material.

Post
Normally a round or squared timber placed in the hole. Sometimes a stone may be set in the hole below the post to prevent the post sinking in soft ground or sticks and stones to keep the post properly aligned until it is filled. Many cultures charred their posts to slow down rate of decay in situ. This is sometimes mistaken for burning in situ. Posts may, in modern times, be soaked in creosote

Creosote

Creosote is the portion of chemical products obtained by the distillation of a tar that remains heavier than water, notably useful for its anti-septic and preservative properties...

or other decay inhibitors or termite

Termite

Termites are a group of eusocial insects that, until recently, were classified at the taxonomic rank of order Isoptera , but are now accepted as the epifamily Termitoidae, of the cockroach order Blattodea...

preventatives.

The post may survive as an element or have decayed [a postpipe], or been removed. Even if decayed there should be a dark organic stain that matches the original dimensions and extent of the post.

Posthole fill / Post packing
The dug up soil goes back in the hole once the post is in place. Sometimes structural needs require that the hole is also packed with rocks or smaller sticks to keep the post in desired position. Ideally dug out material returns to the pit in its original stratigraphic order but inevitably mixing occurs so that ground layers and posthole layers are distinguishable. Logically not all of the contents of the hole will fit back once the post is emplaced, so remaining soil may be left in a pile or scattered.

Postpipe or post mould
The decayed buried section of the post that remains in situ. Some archaeologists prefer ~pipe where it is predominantly still organic material and ~mould where this has been replaced by sediment.

Post void
Where a pipe has been removed. This may be uncovered as a cavity, although this is rare and usually a combination of slumping of posthole fill and inwashed deposits fill the position of the post, which is usually termed post mould.

Posthole
This is the generic term for all of the archaeological evidence contained within the cut, particularly when seen in plan view, including any artefacts that have been introduced during the cutting and filling sequence.

Interpretation of postholes

Postholes are different from stake holes in that the cut is dug for the post rather than created by the driving in of the stake. This means there is some voided space that has to be filled in once the post is in place. This material is post packing and is one the main ways of differentiating postholes from stake holes in plan. The shape and structure of the contexts within a posthole can also shed light on past activity. If a post was purposely removed, then the action of rocking it back and forth leaves tell-tale evidence in the profile of the posthole which archaeologists can recognise. A post may have rotted in place leaving a postpipe

Postpipe

In archaeology, a postpipe is the term given to the remains of an upright timber placed in a posthole. Given the right conditions, timbers may survive over long periods of time and a recovered postpipe can simply be of solid wood...

or still be surviving (See the section in Fig 1). Archaeologists can use their presence to plot the layout of former structures as the holes may define its corners and sides. postholes may also be dug on alignments

Alignment (archaeology)

An alignment in archaeology is a secondary or circumstantial form of evidence used to associate features such as postholes by virtue of their physical relationships rather than stratigraphic ones...

of backfilled ditches were boundaries have been upgraded from simple ditch enclosures into structural ones.

Dangers of posthole interpretation

The relative frequency of postholes as a feature in most eras combined with a lack of good information on the phasing

Archaeological phase

Archaeological phase and phasing refers to the logical reduction of contexts recorded during excavation to near contemporary archaeological horizons that represent a distinct "phase" of previous land use. These often but not always will be a representation of a former land surface or occupation...

of postholes, which often occurs onsite due to horizontal truncation or a failure to spot postholes at the level they were cut from, can lead to a clutter of postholes that invites imaginative interpretations. The human mind seems quite capable of creating patterns and the temptation to see structures that are not there or tenuous at best is quite strong. It is considered good practice that supporting evidence from multiple sources on site like the perceived structures alignments

Alignment (archaeology)

An alignment in archaeology is a secondary or circumstantial form of evidence used to associate features such as postholes by virtue of their physical relationships rather than stratigraphic ones...

with other features onsite should be taken into account before any hard interpretation is made as to whether postholes with no stratigraphic relationship

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...

to each other are truly 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:...

Parts of a posthole

Interpretation of postholes

Dangers of posthole interpretation

See also