The fractal microstructure of ancient sedimentary rocks

Small-angle neutron scattering (SANS), ultra-small-angle neutron scattering and scanning electron microscopy (SEM) were used to analyze the pore-fabri c interface in a 1400 million years old shale. The pore-rock fabric interfa ce is a surface fractal (of fractal dimension 2.82) over three orders of ma gnitude of the length scale and ten orders of magnitude in intensity (macro scopic differential cross section range 10(-1) -10(9) cm(-1)). Both SANS an d SEM indicate similar fractal dimension for scales less than 4 mu m and a breakdown of fractal properties for scales larger than 4 mu m.