CHRONOS-GEOCHEMICAL CYCLES: PAINTING EARTH SYSTEM HISTORY WITH NUMBERS

Earth history is archived in the chemical composition of sediments and their contained fossils. This archive provides evidence for meteorite impacts, mass extinctions, gas hydrate expulsions, climate cycles, and the beginnings of life. The paleochemical record in sediments also provides a means of global correlation through variations in the isotopic records of C, Sr, S, and others elements. With the explosion of data on geochemical proxies obtainable with modern automation, the time is ripe to develop a paleochemical database and IT system for visualizing, manipulating, and modeling those data. We describe progress made towards creating such a system - the Geochemical Cycles Domain of CHRONOS (CHRONOS-GC). To launch this effort, 27 geoscientists met last June to discuss: (1) appropriate data and metadata, (2) visualization and computational tools, (3) outreach and education opportunities, and (4) community support and participation. Participants agree that all geochemical data related to Earth history would be welcome. These include stable isotopes, radioisotopes, trace metals and anions, biomarkers, organic elemental ratios, and sediment composition. Metadata will be an important measure of data quality and will include information on investigators, sample material and quality, sample locality and stratigraphic position, and analytical methods. The system must be able to plot and correlate isotopic, chemical, and paleobiologic records from different localities using different user-defined age models and correlation schemes. Improved age models and correlation schemes will permit rigorous testing of the timing and synchronicity of isotopic and paleobiologic events and more accurate evaluation of the rates of global change. Educational efforts will include problem-oriented tasks that can be linked to textbooks and lab manuals, focusing on exciting scientific issues. Workshop participants have formed working groups defined by measurement (e.g., O and C isotopes, X/Ca ratios) and materials (e.g., marine carbonates, barite, phosphates). These working groups are open to all and will (1) help design and review database schema, metadata needs, and visualization and computational tools; (2) answer queries from IT specialists; and (3) enlist community support for populating and using CHRONOS-GC.