Communicating methods of stratigraphic reasoning with semiotics and certainty estimation
Cognitive and conceptual uncertainties are critical elements in stratigraphy from the earliest data collection stage to concluding interpretations. How a geologist conceptually weighs the importance of various data influences final interpretations. In order for the process of data selection and interpretation to be transparent and repeatable, field methods and analyses should be able to communicate these cognitive processes.
Semiotics and expert systems are used to frame discussion of the methods of stratigraphic reasoning and develop a field-based and analytical method to communicate cognitive and conceptual uncertainty from data collection to final interpretation. In semiotics, signs are the meanings an observer gives to an object to reach an interpretation. Uncertainty in knowledge is derived from problems in recognizing objects and judgment of inferred relevance to a larger interpretation. A final measure of stratigraphic interpretation certainty (IC) can be derived from the product of the confidence factor (CF) of a measurement and the relevance factor (RF) of that object to an interpretation. The methods described in this paper provide a framework to examine and communicate levels of geologists confidence and uncertainty. Communicating levels of certainty, relevance, and significance allows geologic investigations to be more transparent to subsequent researchers, future readers, and even to the original investigator.
