Sandstones of unexpectedly high diffusibility

► We measured diffusion coefficients for intact saturated redbed sandstone samples. ► Tracers were amino-G-acid and calcium bromide solutions, and inert. ► Diffusibilities were ≤ 4x those reported previously for other redbed sandstones. ► We suggest an open fabric, a result of the shallow depth of the sandstone. ► We speculate that other shallow sandstones may have similarly high diffusibilities.