Britannica Online: Academic Edition

Electronic version of the Encyclopaedia Britannica. (DTM and GL use only.)

Encyclopedia of Earth

Open-access resource with thousands of quality, authoritative articles on environment, climate, and general earth sciences.

Treatise on Geochemistry

10-volume compendium on the chemistry of the Earth (crust, mantle, core, oceans, and atmosphere) and solar system (meteorites, comets, planets, and satellites). (DTM and GL use only.)

Treatise on Geophysics

Comprehensive, state-of-the-art summary of solid-earth geophysics and planetary physics, written by more than two hundred leading specialists. (DTM and GL use only.)

Wikipedia

The world's biggest online free-content encyclopedia.