GEOCLIM.jl, written in Julia, replicates some features of the original GEOCLIM model written in Fortran. It also extends the original weathering equations WHAK and MAC, which ignore direct dependence on pCO2 and include direct pCO2 dependence respectively. The code estimates global silicate weathering rates from gridded climatology. GEOCLIM.jl estimates weathering during periods of Earth history when the continental configuration was radically different, typically more than 100 million years ago, and includes functions to compute, for example, land/ocean fraction, area-weighted average, area-weighted sum, and land mass perimeter, among other values.