The Archaeological Research Process
The archaeological research process involves five primary steps. The first is the formation of research questions to test a hypothesis. These are often written up in a research design question that describes the scope of the work that will be done. The second step is the collection and recording of evidence to support the research question or questions and the hypothesis by accessing pre-existing collections in museums and research centers in addition to gathering information in the field through survey and excavation. The third step is processing and the analysis of the evidence that has been collected. This step tends to involve laboratory analysis and curation of the collection that has been assembled according to the research question. The fourth step is the interpretation of the information built from the data analysis. The fifth and last step is the dissemination and reporting of the results of the tests and analysis. This is done through publications, conference talks, etc. where the information is judged by the rest of academia, tests are rerun and heavy criticism can follow.
The research design is typically created before the fieldwork begins. It is meant to provide an outline for the project and can be used to apply for grants or funding for the project. The purpose of the research design is meant to identify what the objectives and goals of the project are and what the research may involve. This allows the design to identify what data is needed to address the research questions. This also selects the field and lab methods that will be needed to recover the data. During this process it is critical to also determine set plans for data conservation and curation following the research process.
Collection of evidence and its recording happens initially through excavation. Excavation is the exposure and recording of buried materials from the past. This involves digging into a site and collecting materials that are hidden beneath the surface. What is removed and completely unburied are materials which are specifically relevant to the research questions set out in the research design process. Anything that is not specific to the research question is dug up only to be reburied. It is not uncommon to find a site that has been disturbed with a coin from the year the archaeologist was there reburied with the site. Excavation types may vary greatly and the type used often depends on the location of the site and the research questions themselves. Standard excavation units formed are perfect squares created through the use of the Pythagorean Theorem. The squares are pre-mapped, transecting lines which are determined on the site map, so the exact location of where one is digging is known and recorded. The guiding rule of excavation is to record context of an object by recording its provenience. If the artifact is in-situ (an item discovered in place during excavations), them the specific location of the item is recorded thoroughly. The more information that is recorded during the excavation and the better the information is about an object, the quality interpretation made from that information is more accurate and likely closer to the truth of what the object could have been used for and how it was used. This is why looters are such a problem. When items are removed from their sites they are completely useless to the archaeological record because their provenience is lost the instant they are removed and taken to be sold on the black market. Provenience of an object is the specific horizontal and vertical position in the soil which the object is found. The context of the object is the relationship between the object and its surroundings. The context can consist of the provenience information, the surrounding soil, and its association with other artifacts, ecofacts, and/or remains found near and around the object in question. This information is necessary to understand an object beyond its immediate morphology.
Recording site context is a critical step in the process. Site maps are often created during surveys of the site in question. The site map will indicate the boundaries of the site, and its exact location, which is typically only understandable to other archaeologists. Maps can be altered during the excavation as more information is discovered about the site such as the location of artifacts and the discovery of ruins of any kind. Excavation maps also show the excavated portions of the site. Site datum points are determined by the map. A site datum is a fixed reference point which is used to keep control on a dig of where the pre-determined site excavation units will be placed. This is the point from which new excavation units are measured and it is used to record the location of the discovered materials. It is considered the zero or starting point of a site. The provenience of an object is measured using a unit datum. This datum point behaves the same way the site datum does, but it is used only in reference to a specific unit which is defined in the explanation of the provenience of the object. The unit datum is always place in the Southwest corner of the unit to provide consistency and allow laboratory technicians to interpret the information provided by the person who did the field work, as these are often done by different people. When measuring the horizontal provenience of an in-situ object, it is recorded by measuring along the two side walls of the unit. To measure the vertical provenience of an in-situ object or the object’s depth in the soil, a line level is used with a string attached to a datum marker. This marker can be a weight of any kind, but tends to most often be something like a nail in order to point directly at what is being measured while keeping the string taut, allowing for an accurate measurement.
Digging down in the unit can occur through either natural levels or arbitrary levels determined by the archaeologist. Natural levels are vertical subdivisions of an excavation unit and are most commonly used when natural strata levels are not visible. This method is preferred as it follows the site more accurately. Natural level change is often indicated by a shift in color of the soil. Arbitrary levels are based on arbitrary classification and exact measurements can vary between different archaeologists, but it tends to be between 10 centimeters and 20 centimeters. To record the context of displaced objects, which are those found during the screening process, archaeologists keep buckets of dirt labeled to belong to various levels and screen the soil to find objects that were too small to see in the initial digging or those that were missing by the archaeologist. Field archaeologists tend to rotate between digging down levels and screening their corresponding bucket of dirt from that level. The purpose of the screening is to recover any items that may have been missed during the original screening but the provenience of those objects is lost such as small bones, beads, seeds, etc. A general location and level is maintained within the site by keeping the buckets belonging to different levels separated and individually screened.
Recording the evidence discovered during the excavation is typically done in field notebooks, excavation forms, level and object record forms, photographs and drawings, and site and unit maps. Excavation forms tend to include the map of a unit, location of items found in that unit, descriptions of the sediment, beginning and ending elevations of levels, and object descriptions. Sometimes objects will be labeled out in the field and tags will be placed with the objects during collection during the excavation. When this happens, it is critical to never separate the tag from its respective object. If this happens, the object could no longer be useable to the archaeological record.
Laboratory work follows the excavation of the site and takes place in a controlled environment using all of the information that has been gathered during the excavation process. It involves the processing of objects from rough sorting to taking measurements followed by high level analysis of the objects based on the research questions and project goals defined in the original research design. Curation of the collection involves the preparation of objects and records for long term storage at a repository, research institution, or museum. When processing objects a catalog number must be assigned to be a unique identifier. A rough sorting of the materials then takes place to separate artifacts, ecofacts, etc. from each other. Cleaning of the objects will occur only if it is warranted, but cleaning is less common in recent years because cleaning can damage the object. Cleaning methods include dry brushing, water dipping, wet scrubbing, and chemical dipping. Afterwards, classifying material is necessary for analysis research, conservation, and eventual curation. It is important to identify material type, take measurements, weigh the object or objects, and label the artifacts themselves if it is warranted. After the appropriate amount of information is gathered, any additional comments are recorded and the artifact is placed into archival packaging such as vials, bags, boxes, etc. Archival labels for the artifacts are made to be kept with the artifacts themselves while cataloging and recordation is gathered into a database of information to be accessed when necessary.
The unique identifying numbers assigned to an object can include the unique number identifying the site which the object came from as well as the number assigned specifically to that object or group. The purpose of the catalog number is to link the object or grouping with its collected information. And accession number is one assigned by a museum or research institute. Examples of accession numbers are as follows: site trinomial + catalog number (CA-SDI-1444-005), collection number + catalog number (1000-005), institution + collection number + catalog number (SDAC-1000-005), or institution + collection number + site trinomial + catalog number (SDAC-1000-CA-SDI-1444-005). The specific group of numbers varies from institution to institution.
Part of defining an object involves classifying it and determining its typology. The typology is the systematic classification of artifacts into groups or types based on shared attributes such as characteristics and/or features. These groups can be formed using quantitative attributes which are measurable (length, thickness, width, weight) or qualitative attributes which are observable characteristics (material, surface decoration, color, shape). Common typologies are morphological types, functional types, or temporal types. Morphological types are grouped based on physical or material attributes. This is the most common type and is usually done for conservation, preservation, curation, and analysis. Common morphological types are lithics (chipped stone and ground stone), shell (modified and unmodified), bone (unmodified ecofacts and modified artifacts), human remains, ceramics, metal, glass, perishables, and historics. Historics is a catch-all category that includes anything that does not fit into the others. Functional types are grouped based on how they were used. Temporal types are grouped based upon the time range they were dated to be used and produced.
Archaeological cataloging is most often done on hand written paper records, spreadsheet programs, and databases. Digital storage has become more popular because the information does not degrade the same way stored paper records do. The issue with digital recordation is still how to maintain what houses the information as time can degrade storage items such as discs and dvds. It simply takes a bit longer. Hard drives seem to be a good alternative for the time being. The archaeological catalog contains the information about the item and the collection level including all of the information gathered through excavation, processing, analysis, and curation.