Page 8 - Carbonate Facies in Geologic History

VIII Preface

regions include vast areas of carbonate rock. No personal or up-to-date knowledge
of the Great Basin, Australian or Siberian stratigraphy is included. Nevertheless,
it appears that sufficient stratigraphy is known to permit some valid generaliza-
tions of facies patterns and for them to be used as an effective tool in predicting
facies distribution in imperfectly known areas. The middle chapters of the book
repeat many patterns with different faunal variations because carbonates tend
to follow essentially one basic and fundamental depositional pattern which is
superficially modified by tectonic, climatic, and hydrologic factors, thus simplifying
our task of generalization.
With the task of synthesis in mind, the book abounds in classifications and
outlines attempting to organize and standardize information. This approach
includes:
1. Carbonate microfacies (24 SMF types, Standard Microfacies Types).
2. Terminology of carbonate buildups (23 definitions).
3. Types of shelf-margin profiles (3 types).
4. Facies belts along shelf margins (9 in an idealized profile).
5. Sequence in development of an ideal carbonate mound (7 facies).
6. Tectonic settings of carbonate buildups and facies patterns (4 major categories).
7. Carbonate cyclic sequences (5 types).
8. Organism development in carbonate buildups through geologic time (4 stages).
Certain aspects of carbonate sediments are not covered even in the review
in Chapter XII. Oceanic sediments, fresh-water and temperate-zone marine
carbonates are omitted because practically all common carbonate facies in the
geologic record were apparently deposited in shallow, tropical, marine environ-
ments. Descriptions of Holocene models of carbonate deposition which are basic
to our interpretation of ancient facies patterns have been given by Bathurst
(1971) and Milliman (1974), in numerous special publications and memoirs of the
AAPG and SEPM, in the Sedimenta Series of the University of Miami, the
Persian Gulf volume (Purser, 1973), and numerous guidebooks to the British
Honduras, Florida, Bahamas, and Yucatan areas.
The reader may find more serious omissions in the lack of discussion of
evaporites, which are an integral part of the carbonate depositional realm.
However, a general synthesis of evaporite literature is now available from
symposia by major geological societies and several books have appeared on the
subject. The related subject, dolomite origin and stratigraphy, is discussed briefly
in Chapter X. Tertiary buildups and patterns are not sufficiently known to the
author personally to permit accurate description; although they are not discussed,
they are equally important to petroleum exploration.
The writer hopes that the labor of reading and studying the book is not
quite so formidable a task as was its writing.

July 1975 lL.WILSON