About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 66 (1982)

Issue: 5. (May)

First Page: 604

Last Page: 604

Title: Canadian "Deep-Water" Carbonate Deposits: Distinction from "Analogous" Siliciclastic Deposits and Their Hydrocarbon Potential: ABSTRACT

Author(s): I. A. McIlreath

Article Type: Meeting abstract

Abstract:

"Deep-water" carbonates accumulate by gravitational processes which have many similarities to, but important differences from, those responsible for "analogous" siliciclastic deposits. For example, recently there has been much emphasis on the accumulation of "deep-water" siliciclastics in submarine channel-fan complexes. In contrast to this type of point source origin, carbonate basin slopes are mainly the result of processes from shelf and slope-centered linear sources, and processes from basin water-mass-centered area sources. The resulting carbonate slope accumulation is most commonly a debris apron which has a geometry and petroleum potential that is distinct from a fan.

Much of the worldwide petroleum interest in deep-water carbonates is in chalks which in the last 100 million years have become the major type of deep-water carbonate accumulation. However, in Canada almost all of our major deep-water carbonates are Paleozoic or older and, therefore, we are confronted with mainly hemipelagic slope deposits and peri-platform talus. There will be no new advances in understanding the process of accumulation of these latter types of basinal carbonate deposits until the premise that the processes and their resultant deposits are identical to those responsible for similar siliciclastic deposits is examined critically. An understanding of the obvious differences, combined with recognition of interactions between carbonate processes and process sets and of the factors that modulate carbonate process systems, leads to a more realistic understanding of the resulting "deep-water" facies and the physical and chemical controls on diagenesis.

The spectrum of Canadian deep-water carbonate basinal slope deposits which will be discussed cannot be integrated into one single model. Four major depositional facies models will be presented which are dependent on the nature of the adjacent margins (by-pass versus depositional) and type of margin sediment (reef versus lime sands). These models can be distinguished as separate seismic facies. Still other models are possible, underlining both the complexity of this type of carbonate accumulation and the challenge involved in its exploration, especially in the frontier areas.

End_of_Article - Last_Page 604------------

Copyright 1997 American Association of Petroleum Geologists