X-RAY COMPUTED MICROTOMOGRAPHY OF CROSS-TROUGH LAMINATED SANDSTONE: APPLICATIONS IN SEDIMENTOLOGY, STRATIGRAPHY AND HYDROGEOLOGY

Computed X-ray microtomography (CMT) was used to reconstruct 3-dimensional images of field-oriented, fine to medium-grained, micaceous, cross-trough laminated sandstone samples from the Towaco Formation (Newark Supergroup) in New Jersey. CMT analysis was done using beamline X27a at the National Synchrotron Light Source, Brookhaven National Laboratory. 3-D CMT images allow us to determine lamination orientation, thickness, and cyclical patterns for sedimentologic and stratigraphic analysis. Digital CMT images, with resolutions between 3.4 and 6.8 microns, also allow us to quantify the spatial distribution, shape, orientation and connectivity of porosity for these sandstones. Standard petrographic and volumetric calculations of porosity for these samples agree with the values obtained by CMT techniques. Porosity characteristics correlate with the type, scale and orientation of macroscopic cross-lamination features. Understanding the correlation between micro-porosity structure and macroscopic sedimentary structure will allow us to better predict fluid flow anisotropy based on macroscopic features.