HERMES: A DATABASE FOR PALEOCHEMICAL PROXY DATA IN THE CHRONOS SYSTEM

The Earth's biologic, chemical, and climatic complexity is increasingly revealed through the application of geochemical proxies that provide records of past temperatures, sea-water composition, elemental cycles, weathering rates, atmospheric composition, and meteorite impacts. To help utilize these proxies fully, we introduce the relational database HERMES for paleochemical data, part of the CHRONOS system. HERMES contains both data and comprehensive metadata, the latter allowing extensive evaluation of the data and sample quality.

Schema development is built on feedback from workshops, individuals, and data submitted to CHRONOS, with important concepts being derived from SedDB, Paleostrat, and EarthChem. The database schema is implemented in PostgreSQL 8.x, is designed to record hierarchy-based sample data, and is scalable. Its data classes include Reference, Location, Station, Sample, Sample Interpretation, and Geochemistry. Each data class consists of a set of tables and attributes that have similar and related function in the database system. Constraints for primary and foreign keys are used to set up relationships between tables in order to promote efficiency in performance and provide quality control of data. A vertical table-structure for geochemical measurements permits rapid addition of new proxy types without needing to change the basic schema.

An important feature of the database is its ability to allow users to create age models for a section. Age datums can be from a single reference age model or from multiple reference age models. A user may apply existing or new, user-defined, age models to a section, its samples, and its geochemical data.

For data entry, paleochemists and chemostratigraphers will upload their personal spreadsheets into the HERMES database using a system for mapping a user-supplied spreadsheet to the database schema. CHRONOS will provide seamless connectivity between HERMES, the Neptune database, and remote databases and data repositories (e.g. Pangaea, PaleoStrat, SedDB), and access to tools for plotting, modeling, stratigraphic correlation, time-scale development, age modeling, standardization, normalization, and more. Many of these features are now available online at http://www.chronos.org/.