TIMESCALE CREATOR VISUALIZATION SYSTEM OF EARTH HISTORY

A joint project of the International Commission on Stratigraphy (ICS) and CHRONOS database program 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, astronomical cycles and basin lithologic successions. For ease in updating to future enhancements of the numerical time scale, the ages of all datums are derived from relational equations of their documented or estimated inter-calibrations. The current (July 2007) database contains about 11,000 event-age items, plus a suite of geochemical and sea-level curves, with numerical ages calibrated to Geologic Time Scale 2004. This public database is being progressively enhanced with contributions from the subcommissions of the ICS and by other stratigraphic and regional experts, and all entries are annotated with details of their calibration.

On-screen display and production of user-tailored time-scale charts is provided by the TimeScale Creator, a Java package freely available from the ICS/CHRONOS websites (www.stratigraphy.org or www.chronos.org). After specifying the time interval by stage or millions of years and the vertical scale, a user selects a subset of stratigraphic columns and trends. The TimeScale Creator generates an on-screen rendition. In addition to screen views and a scalable-vector graphics (SVG) file for importation into popular graphics programs, the on-screen display also has “hot-curser-points” to open windows providing additional information on events, zones and boundaries and a variety of display options. 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.