Abstract

In shallow-marine and coastal-plain strata, sequence boundaries are easily recognized at the base of incised valley fills. Between valleys, however, it is more difficult to recognize sequence boundaries where they are expressed as interfluve paleosols. We suggest that interfluve paleosols can be most reliably identified using a combination of (1) stratigraphic position; (2) field observations such as thickness, structure, color, and degree of rooting; and (3) micromorphological features such as bioturbation fabric, clay coatings, ferruginous features, and siderite and barite. Only micromorphology permits recognition of temporal changes in drainage, surface stability, and protracted pauses in sedimentation that typify these surfaces. This three-part approach has been successfully employed to identify interfluve sequence-bounding paleosols in the Cenomanian Dunvegan Formation in Alberta and British Columbia, Canada.

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