Re-using a paper from one class for another?
Almost invariably, the answer to "Is it OK to submit X for a class assignment?" is "Ask the instructor.".

You do need to ask yourself whether your objective for the geochemistry class is to get a good grade, or to improve your knowledge and skills in the area of geochemistry, or both. Even if the instructor agrees with recycling the old paper, you may get more out of the class if you pick a different topic and write a new paper.