MACHENT, PHILIP G., Manchester Metropolitan University, Dept. of Environmental Geographical Sciences, Manchester, UK

ABSTRACT: Spatial Distribution and Style of Carbonate Cements in Distal, Sandstone Sequences: Upper Cretaceous Panther Tongue, Member and Kenilworth Member, Book Cliffs, East-Central Utah, USA

Cemented zones can have a profound influence on the performance of hydrocarbon reservoirs and. cement geometry prediction will have a beneficial impact on recovery strategies. Extensive cementation observed in Book Cliffs and elsewhere has only recently been associated with significant stratigraphic surfaces and variation in relative sea-level. By linking the sub-disciplines of sedimentary geochemistry and sequence, stratigraphy this project aims to establish how large scale sedimentary processes dictate the style of, and controls on cementation, especially in the mid-proximal to distal setting and, develop a predictive framework for diagenetic modification.

The Panther Tongue regressive wedge only hosts carbonate concretions in a distal setting. Concretions in the distal sandy siltstones of the aggradational to progradational Kenilworth Member are limited and smaller. Flooding surface sandstones are laterally cemented in a proximal direction, but lack concretions. This contrasting cement style indicates differing controls on precipitation and distribution. This project will test the hypothesis that the Panther Tongue dolomites were sourced from the, remobilisation of updip detrital dolomite by meteoric fluids during relative sea-level fall. The Kenilworth dolomites and calcites being initiated beneath marine flooding surfaces during relative sea-level rise and continued burial diagenesis.

Geochemical analysis will provide data on the nature of. diagenetic reactions and carbon and oxygen isotope studies will constrain the carbonate source and precipitating fluid composition.

AAPG Search and Discovery Article #90909©2000 AAPG Foundation Grants-in-Aid