An optimum sequence can be derived by graphically correlating a series of sections and establishing a composite standard—a database of the maximum time-stratigraphic ranges for a particular area under study. A composite standard should provide a relatively complete biostratigraphic representation of geologic time. On graphic correlation plots, apparent hiatuses are defined and quantified in time (composite standard units) by horizontal terraces. Fossil ranges in a composite standard are subject to alteration with each new graphic correlation, making it a complex, evolving database that usually requires computerized data management and applications. | An optimum sequence can be derived by graphically correlating a series of sections and establishing a composite standard—a database of the maximum time-stratigraphic ranges for a particular area under study. A composite standard should provide a relatively complete biostratigraphic representation of geologic time. On graphic correlation plots, apparent hiatuses are defined and quantified in time (composite standard units) by horizontal terraces. Fossil ranges in a composite standard are subject to alteration with each new graphic correlation, making it a complex, evolving database that usually requires computerized data management and applications. |