“Time-Scale Creator” Visualization Tool and Phanerozoic Database
James George Ogg1, Adam Lugowski1, and Felix Gradstein2
1 Purdue University, West Lafayette, IN
2 University of Oslo, Oslo, Norway
A joint project of the CHRONOS database program and the International Commission on Stratigraphy (ICS) is to provide detailed global and regional “reference” scales of Earth history. Such scales integrate biostratigraphy (zones, datums for marine and terrestrial realms), sea-level (curves, sequences), geochemistry (trends, events), magnetic polarity chrons and astronomical cycles. These summarize our current consensus on the inter-calibration of events, their relationships to international divisions of geologic time and their estimated numerical ages.
An initial Phanerozoic database (6000 events and zones in October 2005) includes definitions of geologic stages, major zonations and markers of all significant fossil groups, primary and secondary magnetic polarity scales, and other stratigraphic information. Annotations on each entry include source, reliability, selected taxonomic notes, inter-calibrations, and methods of interpolating numerical age. This database will be enhanced through the efforts of the period-level subcommissions of the ICS and other stratigraphic and regional experts.
On-screen display and production of user-tailored time-scale charts is provided by the Time-Scale Creator, a JAVA package available from the ICS/CHRONOS websites. After specifying the time interval and vertical scale, a user selects a subset of stratigraphic columns and trends. In addition to screen views and a scalable-vector graphics (SVG) file for importation into popular graphics programs (e.g., Adobe Illustrator), the on-screen display has “hot-curser-points” to open windows providing additional information on events, zones and boundaries.
The database and visualization package are envisioned as a convenient reference tool, chart-production assistant, and a window into the geologic history of our planet.