A hard mineral crust formed at or near the surface of soil in semiarid regions by the evaporation of groundwater.
- ‘The more water soluble duricrusts, such as calcrete and gypcrete, can have solution holes or pits.’
- ‘The Molopo River was sampled by first removing the duricrust and then sampling the underlying sediments.’
- ‘A resistant rock cap such as a hard sandstone or a duricrust is one possibility.’
- ‘This duricrust has hindered mineral exploration, beyond the valley floors, for the past 70 years.’
- ‘Due to the scarceness of datable sediments saprolites and duricrusts were widely used as defining features.’
1920s: from Latin durus ‘hard’ + crust.
We take a look at several popular, though confusing, punctuation marks.