 | This article needs additional citations for verification .(October 2006) |
In archaeology a fill is the material that has accumulated or has been deposited into a cut feature such as ditch or pit of some kind of a later date than the feature itself. [1] Fills are an important part of the archaeological record as their formation and composition can throw light on many aspects of archaeological study.
A primary fill is the context that first appears in the sequence after the context representing the cut it "fills". In many cases this will be a silt or naturally accumulating material that forms in the base of some hole or trench before its function is realized. For example, a medieval rubbish pit may be open for some time before rubbish is placed in it allowing natural processes to silt up the base, but the interpretation may mark the end of a cut feature's use. Similarly, a ditch that silts up by neglect could represent the start of the end of the features function in the record. Secondary and subsequent fills all form above the primary fill. [ citation needed ]
Primary fills, in the plural sense, are all the fills within a feature that are sealed by layer(s) possibly representing a change in phase or function. [ citation needed ]
Slumping is a process that can occur to any context in the archaeological record and not just fills. Slumping represents how a context's deposition morphology may deform from its original position by natural settling action. This is readily apparent with fills which have a tendency to settle radically over time. This settling is termed slumping and has a bearing on the excavation of cut features. As fills slump the overlying layers which seal the feature will slump in sympathy creating false impressions of fills below the lip of the cut and introduce the possibility of contaminated dating evidence into the features excavation. (See archaeological section in fig 1). also the degree of slumping of the primary fills compared to the slumping of overlying sealing layers is a possible measure of time differences between the formation of the fills the overlying sequence. This is because sealing layers laid down over a slumping feature with the intent of leveling the area for a specific purpose such as construction will either conform to the slumped fills as though the slump has occurred at the time of the sealing layers formation. Or the sealing layers will not take into account the slumping because the slumping is yet to occur. This can lead to sympathetic slumping up the sequence of other features including later structures.
Tip lines are an intrinsic characteristic of fills, but they can apply to many other types of context such as dumps. Tip lines are the angles which the contexts form as an indicator of action in the past. As fills of a feature form stratigraphically, the direction off the horizontal by which they form may give us information. For example, a ditch that has fills all angled, so one side of each fill is higher on a specific side of the ditch, would suggest that the ditch was backfilled from the side where the fills were highest. (See archaeological section in fig 2). This can be circumstantial evidence for features or detail not preserved in the archaeological record. This reading of a fills deposition morphology is an example of why deposits and contexts are important discoveries in themselves independent of whether they represent structures or contain artifacts.
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles to settle in place. The particles that form a sedimentary rock are called sediment, and may be composed of geological detritus (minerals) or biological detritus. The geological detritus originated from weathering and erosion of existing rocks, or from the solidification of molten lava blobs erupted by volcanoes. The geological detritus is transported to the place of deposition by water, wind, ice or mass movement, which are called agents of denudation. Biological detritus was formed by bodies and parts of dead aquatic organisms, as well as their fecal mass, suspended in water and slowly piling up on the floor of water bodies. Sedimentation may also occur as dissolved minerals precipitate from water solution.
In archaeology, excavation is the exposure, processing and recording of archaeological remains. An excavation site or "dig" is the area being studied. These locations range from one to several areas at a time during a project and can be conducted over a few weeks to several years.
Sedimentology encompasses the study of modern sediments such as sand, silt, and clay, and the processes that result in their formation, transport, deposition and diagenesis. Sedimentologists apply their understanding of modern processes to interpret geologic history through observations of sedimentary rocks and sedimentary structures.
Duggleby Howe is one of the largest round barrows in Britain, located on the southern side of the Great Wold Valley in the district of Ryedale, and is one of four such monuments in this area, known collectively as the Great barrows of East Yorkshire. Duggleby Howe is believed on the basis of artefacts recovered to be of Late Neolithic date, but no radiocarbon dates are available. Howe as a place name is believed to have originated from the Old Norse word haugr.
The law of superposition is an axiom that forms one of the bases of the sciences of geology, archaeology, and other fields pertaining to geological stratigraphy. In its plainest form, it states that in undeformed stratigraphic sequences, the oldest strata will lie at the bottom of the sequence, while newer material stacks upon the surface to form new deposits over time. This is paramount to stratigraphic dating, which requires a set of assumptions, including that the law of superposition holds true and that an object cannot be older than the materials of which it is composed. To illustrate the practical applications of superposition in scientific inquiry, sedimentary rock that has not been deformed by more than 90° will exhibit the oldest layers on the bottom, thus enabling paleontologists and paleobotanists to identify the relative ages of any fossils found within the strata, with the remains of the most archaic lifeforms confined to the lowest. These findings can inform the community on the fossil record covering the relevant strata, to determine which species coexisted temporally and which species existed successively in perhaps an evolutionarily or phylogenetically relevant way.
In archaeological excavation, a feature is a collection of one or more contexts representing some human non-portable activity, such as a hearth or wall. Features serve as an indication that the area in which they are found has been interfered with in the past, usually by humans.
In archaeology a posthole or post-hole is a cut feature used to hold a surface timber or stone. They are usually much deeper than they are wide; however, truncation 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. Construction using postholes is known as earthfast or post in ground construction.
Stratigraphy is a key concept to modern archaeological theory and practice. Modern excavation techniques are based on stratigraphic principles. The concept derives from the geological use of the idea that sedimentation takes place according to uniform principles. When archaeological finds are below the surface of the ground, the identification of the context of each find is vital in enabling the archaeologist to draw conclusions about the site and about the nature and date of its occupation. It is the archaeologist's role to attempt to discover what contexts exist and how they came to be created. Archaeological stratification or sequence is the dynamic superimposition of single units of stratigraphy, or contexts.
The Harris matrix is a tool used to depict the temporal succession of archaeological contexts and thus the sequence of depositions and surfaces on a 'dry land' archaeological site, otherwise called a 'stratigraphic sequence'. The matrix reflects the relative position and stratigraphic contacts of observable stratigraphic units, or contexts. It was developed in 1973 in Winchester, England, by Dr. Edward C. Harris.
In archaeological excavation, a plan is a drawn record of features and artifacts in the horizontal plane.
Relative dating is the science of determining the relative order of past events, without necessarily determining their absolute age. In geology, rock or superficial deposits, fossils and lithologies can be used to correlate one stratigraphic column with another. Prior to the discovery of radiometric dating in the early 20th century, which provided a means of absolute dating, archaeologists and geologists used relative dating to determine ages of materials. Though relative dating can only determine the sequential order in which a series of events occurred, not when they occurred, it remains a useful technique. Relative dating by biostratigraphy is the preferred method in paleontology and is, in some respects, more accurate. The Law of Superposition, which states that older layers will be deeper in a site than more recent layers, was the summary outcome of 'relative dating' as observed in geology from the 17th century to the early 20th century.
Bay mud consists of thick deposits of soft, unconsolidated silty clay, which is saturated with water; these soil layers are situated at the bottom of certain estuaries, which are normally in temperate regions that have experienced cyclical glacial cycles. Example locations are Cape Cod Bay, Chongming Dongtan Reserve in Shanghai, China, Banc d'Arguinpreserve in Mauritania, The Bristol Channel in the United Kingdom, Mandø Island in the Wadden Sea in Denmark, Florida Bay, San Francisco Bay, Bay of Fundy, Casco Bay, Penobscot Bay, and Morro Bay. Bay mud manifests low shear strength, high compressibility and low permeability, making it hazardous to build upon in seismically active regions like the San Francisco Bay Area.
In archaeology, a phase refers to the logical reduction of contexts recorded during excavation to nearly 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 level and all associated features that were created into or from this point in time. A simplified description of phase would be that "a phase is a view of a given archaeological site as it would have been at time X".
In archaeology and archaeological 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. In layman's terms, a cut can be thought of as a hole that was dug in the past, though cut also applies to other parts of the archaeological record such as horizontal truncations like terraced ground. A cut context is sometimes referred to as a "negative context", as opposed to a "positive context". The term denotes that a cut has removed material from the archaeological record or natural at the time of its creation, as opposed to a positive context, which adds material to the archaeological record. A cut has zero thickness and no material properties of its own and is defined by the limits of other contexts. Cuts are seen in the record by virtue of the difference between the material it was cut through and the material that back-fills it. This difference is seen as an "edge" by the archaeologists on site. This is shown in the picture, where a half sectioned Saxon pit has had half its backfill removed and we can clearly see a difference between the ground the pit was cut into, and the material originally filling the pit. Sometimes these differences are not clear and an archaeologist must rely on experience and insight to discover cuts.
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. The key to this is stratigraphy.
Sedimentary structures include all kinds of features in sediments and sedimentary rocks, formed at the time of deposition.
Soft-sediment deformation structures develop at deposition or shortly after, during the first stages of the sediment's consolidation. This is because the sediments need to be "liquid-like" or unsolidified for the deformation to occur. These formations have also been put into a category called water-escape structures by Lowe (1975). The most common places for soft-sediment deformations to materialize are in deep water basins with turbidity currents, rivers, deltas, and shallow-marine areas with storm impacted conditions. This is because these environments have high deposition rates, which allows the sediments to pack loosely.
The Dox Formation, also known as the Dox Sandstone, is a Mesoproterozoic rock formation that outcrops in the eastern Grand Canyon, Coconino County, Arizona. The strata of the Dox Formation, except for some more resistant sandstone beds, are relatively susceptible to erosion and weathering. The lower member of the Dox Formation consists of silty-sandstone and sandstone, and some interbedded argillaceous beds, that form stair-stepped, cliff-slope topography. The bulk of the Dox Formation typically forms rounded and sloping hill topography that occupies an unusually broad section of the canyon.
This page is a glossary of archaeology, the study of the human past from material remains.
Badshot Lea Long Barrow, also known as Farnham Long Barrow, was an unchambered long barrow located near the village of Badshot Lea in the south-eastern English county of Surrey. It was probably constructed in the fourth millennium BCE, during Britain's Early Neolithic period.