Why do Great Plains soils contain carbonates in their lower layers?

The soils of the Great Plains typically feature an accumulation of carbonates in their lower horizons because these minerals are translocated downward by infiltrating water.1

As precipitation moves through the soil profile, it carries dissolved carbonates from the upper layers and deposits them at greater depths. The depth at which these carbonates are found is closely linked to the regional climate; as one moves from the more humid eastern regions to the drier western areas of the Great Plains, the depth of these carbonate accumulations decreases.1