Geochemistry today is diversified into many subfields, including aqueous geochemistry, cosmochemistry, inorganic geochemistry, isotope geochemistry, organic geochemistry, and trace-element geochemistry. Since most geological processes involve chemical reactions, geochemistry and geochemical data are also used to explain many of these processes in other areas of the geosciences. At Caltech GPS, geochemistry has been used since 1952 to study the distribution of chemical elements in the Earth and the solar system; to develop methods to date earth and solar system processes; to discover and observe the chemical composition of terrestrial and extraterrestrial materials; and to study chemical reactions in the interior of the Earth as well as its surface and in the solar system outside of the Earth.

The following is a list of materials required for a complete application for first-year admission. If your application is missing any one of these components, it will be considered incomplete. • Common Application or the Coalition Application with the Supplemental Application Essays • Caltech does not have a preference between the Common Application or the Coalition Application. We advise that you use the best platform for your application process. • Caltech is also a QuestBridge Partner. Students may apply for Caltech through the QuestBridge National College Match. • $75 application fee or fee waiver (by request) • Standardized tests • Teacher evaluations • Secondary School Report • This is a document that is sent to Caltech by your high school college counselor. It provides context about your school that helps the Admissions Committee evaluate your application holistically. • Academic transcripts • Additional requirements of our international citizen applicants: • TOEFL scores: Required of all international citizens unless 1) your native language is English or 2) you have studied for two or more years in a school where English is the language of instruction. The latter must be completed prior to the application deadline. We do not accept the IELTS or any other substitute for the TOEFL requirement. • International Financial Aid Statement of Intent: When an international citizen applies for freshman admission, the application prompts questions to confirm their understanding of our financial aid policy and thus confirm their financial aid intent towards Caltech. Caltech is need-sensitive for international citizens because the total amount of financial aid funds is limited for these students, and we remain committed to meeting the demonstrated need of all admitted students. See our International Citizens' page to read the full extent of our financial aid policy for international citizens.