The Probable Range Concept Applied to the Biostratigraphy of Marine Microfossils

• Published in: The Journal of geology Vol. 90; no. 4; pp. 415 - 433
• Main Authors: Blank, Richard G., Ellis, C. Howard
• Format: Journal Article
• Language: English
• Published: University of Chicago Press 01-07-1982
• Subjects: Biostratigraphy; Data ranges; Datasets; Drilling; Fossils; Geology; Marine; Oceans; Seas; Stratigraphy; Taxa
• ISSN: 0022-1376; 1537-5269
• DOI: 10.1086/628694

The probable range of a taxon is its most frequently observed range defined for a set of geologic sections. The probable range concept is defined and demonstrated using two applications, both based on Deep Sea Drilling Project data. The first uses a Cenozoic and Mesozoic North Atlantic Ocean data set (calcareous nannoplankton, 228 taxa, 55 sections). The major result is a standardized rangechart at a definable level of minimum confidence for the data set that shows excellent correlation when compared with published range data. The second application uses a Pacific Ocean data set (calcareous nannoplankton, planktonic foraminifera, Radiolaria, 330 taxa, 32 sections). The application results in an estimated maximum attainable resolution of 100,000 years for the Tertiary. The quantitative application of the probable range concept offers the improvement of resolution beyond the 100,000 year level, equally reliable alternatives to standard biostratigraphic zonations, and objective limits of confidence or risk of error in using biostratigraphic sequence trends for age and paleoenvironmental interpretations.