Glauconite is generally agreed to be a reliable indicator of low sedimentation rate, but little systematic work has been done to specify the role of glauconite in a sequence-stratigraphic framework. Glauconite from Ocean Drilling Program Leg 174A was analyzed with binocular microscope, XRD, and SEM to determine the degree of maturity to relate to depositional environment. Seismic data was used to locate sequence boundaries. Samples from Site 1073 were determined to have formed within a lowstand systems tract, and as part of a distal condensed section within a transgressive systems tract. These results are similar to those from nearby Site 903 of Leg 150 which indicated much the same depositional setting for glauconite. Glauconites at Sites 1071 and 1072 likely formed in the transgressive systems tract. Onshore, glauconite occurs mainly in the transgressive systems tract. The Miocene appears to be the limit of glauconitization onshore, as sea-levels became too low to maintain sediment-free environments. This same process did not occur offshore until the Plio-Pleistocene.