New trends in quantitiative biostratigraphy
|Location||International Geological Congress,oslo 2008|
|Holding Date||03 September 2008|
Quantitative biostratigraphy is a small and dedicated branch of stratigraphic science that over the last decade has seen a consolidation of methods. A good understanding of their advantages and limitations has emerged. The modern biostratigraphic programs of choice for biozonation are Ranking and Scaling (RASC), Constrained Optimization (CONOP) and Unitary Association (UA). Each one exploits different properties of the (often complex) fossil record to arrive at an objective biozonation. RASC is optimal for larger datasets with many fossil events, and handles noise well, like outliers and missing data. RASC has excellent graphics output, and two independent zonal scaling options. CONOP has taken over in the niche of former ’graphic correlation’ users, and does so in a superior manner. It is good in handling and evaluating ranges. The results of RASC and CONOP often converge well on the same zonal answer, although methods and assumptions are entirely different. UA builds a robust zonation along the path of the concurrent range zone. A condition ’sine qua non’ to attract and serve users of the methods is easy and flexible data input, and easy data format conversion between programs. This is achieved with the Java program QSCREATOR, that can be downloaded with program RASC from www.rasc.uio.no. All three programs RASC, CONOP and UA are also available in program PAST (http://folk.uio.no/ohammer/past).