THE ROLE OF MUDSTONE BAFFLES IN CONTROLLING FLUID PATHWAYS IN A FLUVIAL SANDSTONE: A STUDY IN THE PENNSYLVANIAN-PERMIAN FOUNTAIN FORMATION, NORTHERN COLORADO, U.S.A.

摘要

Along the western edge of the Denver Basin, the arkosic Pennsylvanian-Permian Fountain Formation exposes hematite-bearing redbeds that have been partially whitened by the passage of reducing paleo-fluids. The fluids migrated mainly parallel to bedding, producing whitening displayed today by about 15% of the exposed surface area of the formation. The relationship between whitening and outcrop-scale stratigraphy suggests that the position of relatively impermeable beds controlled which of the more permeable beds carried the migrating fluids.