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Mn/Model Research Design
Appendix G: Glossary of Terms
Accuracy - In this project, the ability of the archaeological predictive model to correctly predict site presence in a parcel of land (see Precision).
Biophysical Context - Characteristics of parcels of land composed of both biological (e.g., plant community type) and physical (e.g., soil type, distance to water) aspects of the natural environment that provide a setting, or context, against which archaeological site presence and absence can be measured.
Biostratigraphic Interpretation of Plant Macrofossils - The identification of plant seeds, bark, twigs, etc. buried within sediments. This procedure allows a scientist to correlate lithologic units within the river basin, region, and possibly the state.
Blowsand Analysis - The examination of quartz sand grains under a magnifying lens or microscope to determine if the grains are "frosted". Frosted grains occur only under wind blown conditions.
Buried Horizons - Any of the series of distinctive layers found in a vertical cross section of any well-developed soil or stratigraphic sequence. It is commonly used to describe a well-developed soil or strata that has subsequently been buried by more recent sediment.
By-Chance Locational Model - The "pure chance" probability that a land parcel does or does not contain archaeological resources. By-chance models are often calculated by determining the relative frequency of the presence or absence of resources in a random sample of surveyed land parcels. Since all land parcels are considered equal in this approach, predictive models that identify associations between resource presence and particular variable features of these parcels should provide higher predictive probabilities. By-chance locational models provide a baseline against which the performance of other predictive models can be judged.
Continuous Logistic Transformation Scale - A statistical scale along which various measures of association of "archaeological resource present" and different combinations of environmental variables fall. Decision rules are points along this scale above which there is a specifiable probability that an archaeological resource will be present. A goal of the project, for instance, is to determine the point above which an archaeological resource is highly likely for various parts of the state.
Cross-Cutting Relations - A geologic principle that states that any geologic stratum or unit that is truncated or cross-cut by another geologic unit must be the older of the two units. For example, a terrace inset beneath a higher terrace is younger than the higher terrace because of the principle of down cutting relations in a stream system.
Cultural Resources Management - A system designed to preserve archaeological or historic sites which are threatened by construction. (See Phase I, Phase II, and Phase III and Mitigation).
Decision Rules - In this project, statistical formulas that determine points along a continuous logistic transformation scale that permit decisions to be made about the presence or absence of archaeological resources. A predictive model is a decision rule that assigns a land parcel location to 'archaeological resource present or 'archaeological resource absent on the basis of the environmental characteristics of the location (see Continuous Logistic Transformation Scale).
Dependent Variable - Anything whose value, or presence or absence, depends on the values of other, independent variables (that is, anything on whom its value, or presence or absence, "depends"). In this project, the independent variables are "archaeological resource present" and "archaeological resource absent." The goal of the project is to determine which independent variables, or combinations of independent variables, most accurately and precisely predict the presence or absence of one or the other of these dependent variables.
Depositional Environment - The type of environment under which sediments are deposited (e.g., fluvial, eolian, glacial). The location of a cultural site in reference to the surrounding landscape plays an important factor in the changes that occur to it over time. Common natural processes that alter the site once it is abandoned include erosion and sedimentation. Lack of deposition may allow many cultures to exist on the same land surface over a great time span. Rapid deposition may diffuse those same cultures over a thick sedimentary sequence.
Environmental Variable - see Independent Variable
Geographic Information Systems (GIS) - An organized collection of computer hardware, software, geographic data, and personnel designed to efficiently capture, store, update, manipulate, analyze and display all forms of geographically referenced information. It incorporates the essential elements of computer cartography and relational databases into one system.
Geomorphology - The study of the characteristics, origin and evolution of both the present-day and ancient landscapes and landforms (e.g., river terraces, glacial moraines)
Geotechnical Borings - Borings or small holes drilled into the ground to determine the nature of the underlying sediments for the purpose of construction.
Giddings Soil Probe - A piece of hydraulic digging equipment similar to a drill-rig, but more cost effective and easier to operate and maneuver. The Giddings soil probe is limited to less than ten to fifteen meters depth.
Global Positioning System (GPS) - A highly specific locational device based on information transmitted by a constellation of 24 satellites orbiting the earth at a very high altitude.
Holocene - see Quaternary Period
Independent Variable - A variable in a functional relation whose value determines the value or values of other variables. For the predictive model, the independent variables will be environmental factors such as soil type, soil age, proximity to water, slope, etc.
Logistic Regression Technique - A nonparametric statistical procedure that, among other things, can be used to explore the varying strength of association of dependent and multiple independent variables. Logistic regression techniques have been widely used in archaeological modeling because they are robust (i.e., they can handle any distributional type), and can accommodate nominal, ordinal, and interval independent variables. This technique will be a valuable analytical tool in this project, for the presence of archaeological resources in the state may be associated with combinations of environmental variables rather than with a single environmental variable.
MIAC - Minnesota Indian Affairs Council
Mitigation - Steps taken to reduce the impact of a construction project on an historic site. Mitigation can range from site avoidance to excavation and thorough study.
MnDOT - Minnesota Department of Transportation
Multivariate - Having more than one variable.
National Register of Historic Places Criteria - Criteria established by the Secretary of the Interior for properties or sites to be included on the National Register of Historic Places. See Bulletin 16A for a description of these criteria.
Paleoenvironment - The environment of a former period of geologic time, including the climate, plant life, air water, minerals, organisms, etc.
Particle-Size Analysis - An examination of the three different particle sizes in sediments or soils (sand, silt and clay) in order to describe and interpret the natural processes responsible for their deposition. For example, firing-upward sequences are indicative of flood deposits that were deposited under decreasing energy.
Pattern Recognition - The identification of a pattern in the distribution of particular environmental variables across landscapes. Since some aspects of these patterns may be highly correlated with archaeological resource presence or absence, their identification is an essential component of a predictive archaeological resource modelling project.
Pattern Classification - In this project, the naming (or classification) of identifiable patterns of environmental variable associations in the landscape.
Patterned Variation - In this project, the correlated behavior of spatial phenomena; a descriptive phrase that defines the core attribute of spatial autocorrelation (see Spatial Autocorrelation).
Phase I - An exploratory survey of an area to determine location and boundaries of any historic or archaeological sites potentially eligible for the National Register of Historic Places.
Phase II - A thorough investigation of an historic or archaeological site to make recommendations regarding its eligibility for listing on the National Register of Historic Places.
Phase III - An excavation of an historic or archaeological site listed or eligible for listing on the National Register of Historic Places prior to its demolition for new construction.
Precision - In this project, the ability of the archaeological predictive model to correctly predict site presence at, let us say, 85 percent correct while mapping substantially less than this percent of the landscape to medium or high archaeological sensitivity zones. A model, for instance, that indicates archaeological potential at every location in a region would be 100 percent accurate but would lack any precision. An archaeological predictive model must be not only accurate but precise in its predictions.
Public Land Survey (PLS) - A survey of Minnesota conducted in the last half of the 19th century using a parcel size of 40 acres or a quarter-quarter section. The surveys described the vegetation and water resources usually prior to any major landscape modifications such as farming or logging.
Quaternary Period - The geologic period ranging from two million years ago to the present. It is divided into two epochs: the Holocene (10,000 years ago to the present) and the Pleistocene (two million to 10,000 years ago).
Radiocarbon Dating - Determination of the age of objects of organic origin by measuring the amount of carbon14 isotope they retain. It will be used in constructing the predictive model to determine the ages of soils.
Remote Sensing (RS) - A general term in this project for the acquisition of environmental data from "remote" sources, especially aircraft and satellites. Remotely-sensed data are an information source well suited to geographic information systems (GIS) in the creation of archaeological predictive models.
Resolution - One meaning of the term 'resolution is the process of separating something into its constituent parts. The term is used in this project to refer to the scale of maps and field search units, and to the balance of cost and detail (i.e., the identification of constituent parts) that accompanies maps and units of different scale. For instance, as the scale of a map or the size of a surveyed land parcel becomes larger, finer-scale environmental detail becomes lost. As a result, the gross environmental associations that can be measured may obscure finer-scale " environmental/archaeological resource present" associations. The use of maps and units of high resolution are often precluded, however, by cost and the absence of maps at that level of resolution. High resolution models are necessary when the goal is to predict the precise locations of archaeological resources.
SCS - Soil Conservation Service
Sedimentology - The study of sedimentary rocks formed by deposition of sediment.
SHPO - State Historic Preservation Office
Smirnov (Kolmogorov-Smirnov) test - A non-parametric statistical test used to determine if two separate samples could have been drawn from the same population, or populations with the same distributions.
Spatial Autocorrelation - A term that refers to patterned variation among spatial phenomena. The great majority of statistical inferential procedures used in archaeological predictive modeling assume independent observations, that is, that the values of some observations cannot be predicted (at a better than random chance) from the known values of other values. Since spatial phenomena generally exhibit patterned variation, or autocorrelation, the assumption of statistical independence is violated. As a result, statistical significance tends to be overestimated. In models of this kind, then, the effect of autocorrelation has to be controlled or at least taken into account.
Stratum - A single bed of sedimentary rock, generally consisting of one kind of matter representing continuous deposition.
Stratigraphy - A branch of geology dealing with the classification, nomenclature, correlation, and interpretation of stratified rocks.
Thematic Layer - In this project, an individual GIS map layer that represents an (independent) environmental variable, such as the spatial distribution of major soil types; the spatial distribution of early historic properties; and possibly the distribution of other kinds of spatially distributed information.
Transect - In this case used as a noun, a transverse path across a parcel of land. Parallel transects will be surveyed for archaeological sites for the predictive model.
Univariate - Having only one variable.
Acknowledgements
MnModel was financed with Transportation Enhancement and State Planning and Research funds from the Federal Highway Administration and a Minnesota Department of Transportation match.
Copyright Notice
The MnModel process and the predictive models it produced are copyrighted by the Minnesota Department of Transportation (MnDOT), 2000. They may not be used without MnDOT's consent.