Research into developing geochemical exploration techniques for marine mineral deposits commenced in the Applied Geochemistry Research Group in the early 1960s, continued throughout the remainder of the Group's existence and thereafter to the time of writing in other units of Imperial College. The minerals involved were placers, phosphorites, hydrothermal polymetallic sulphide deposits and manganese nodules. Two main approaches were used. First to be developed was an empirical approach based on the dispersion of elements away from the deposit being sought, the concentrations of which could be contoured and projected back to source. This technique found an application in developing geochemical exploration methods for placers, phosphorites and polymetallic sulphide deposits. The second technique to be developed was a deductive one based on as thorough an understanding as possible of the effects of the environment of deposition on the grade of the type of deposit being sought, thus hopefully enabling one to be able to predict where the highest grade varieties of such deposits might occur. This technique was used in developing exploration methods for manganese nodules.