Tenure-track geoscience faculty progress steadily through the academic ranks from assistant professor to full professor by the age of 60. Full professors tend to work later into their career, and there is a cross-over in the population of full professors and emeritus in the 71-75 age range.
The low numbers of faculty under the age of 40 likely reflects the growing tendency for geoscientists to take post-doctoral fellowships prior to entering the faculty ranks. Lecturers, instructors, and visiting professors comprise less than 5% of each age group. Adjunct professors, however, comprise 5-10% of each age group. This consistent percentage regardless of age, reflects a trend of multiple academic appointments in geoscience faculty careers.