A line on a map or diagram connecting points beneath which a particular stratum or group of strata has the same thickness.
- ‘Likewise, using the isopachs, transition of bare sediment to seagrass was noted.’
- ‘The process of step-and-stair transgression thus continues until hydrostatic equilibrium is established as the intrusion tapers out at the zero isopach.’
- ‘The following section deals with the significance of the observation that the sill reaches the zero isopach within the sediments, mentioned in point 4, which was not fully appreciated by Francis.’
- ‘After mapping the chosen horizons throughout the study area, we constructed selected isopachs and structure maps.’
- ‘He believed that the feeder dykes terminated in the sediments at approximately the same depth as the zero isopach of the sill.’
Early 20th century: from iso- equal + Greek pakhus thick.