Below are links to additional, non-IU resources for field camp scholarships. You’ll see that the general timeframe for application deadlines is listed. Take a look at the webpage for each scholarship to find the specific due date for any given year.
Note that membership in some of the relevant societies is required to apply for the scholarships. Plan ahead to research these opportunities and their requirements so that you have plenty of time to apply.
The National Association of Geoscience Teachers (NAGT) also has a scholarship program that is open to all students attending a field course. Visit their website for more information or to apply for the scholarship.