Abstract: Deposition and Diagenesis along a First-Order Bounding Surface in the Navajo Sandstone

BRYANT, GERALD C. 

The goal of this study is to describe the sequence of sedimentary events and diagenetic processes that produced a laminated carbonate lens in a particular sandstone outcrop at Lake Powell, Arizona. The occurrence of a stratigraphically discrete carbonate deposit suggests discontinuity in the cyclic processes of bedform migration that characterize the Navajo Sandstone as a whole. This study will analyze relationships between sedimentary processes active in the formation of the carbonate in relationship to the processes that produced the bounding surface along which the carbonate lens is situated. In this way, the lens can be understood as an element in the stratigraphic architecture of the sandstone deposit in which it occurs.

Large porosity and permeability variations have been described from the sandstones encasing carbonate lenses in Navajo outcrops east of the study location. The present study will consider similar features at the Lake Powell site. The diagenetic history through which these variations were developed will be analyzed in the context of the stratigraphic context in which they occur. In particular, diagenetic events will be considered as aspects of the development of a certain type of bounding surface. This analysis could lead to more generally applicable criteria for the evaluation of reservoir characteristics in the Navajo and other, similar, sandstones.  

AAPG Search and Discovery Article #90940©1997 AAPG Foundation Grants-in-Aid