facies models response to sea level change - Materials of A. Shipunov

Facies RESPONSE TO SEA LEVEL-CHANGE Edited by Rwer G. Walker and Noel P. James

F,$ . '2, I

A

/jFb>-.7L2

.

c >

I

5 '.

--

Geological Association of Canada L'Association geologique du Canada

-

4

w

.. .

FACIES MODELS RESPONSE TO SEA LEVEL CHANGE

Edited by

Roger G. Walker Department of Geology McMaster University Hamilton, Ontario L8S 4M1 Canada

and

Noel P. James Department of Geological Sciences Queen's University Kingston, Ontario K7L 3N6 Canada

Geological Association of Canada L'Association giologique du Canada

June 1992

i

.. -

.

'.

-

Canadian .. Cataloguing in Publication Data

-

Main entry under title: , Facies models :

.

=. .

. .

-

I

t

response to sea level change

Includes bibliograph~calreferences. ISBN 0-919216-49-8 1. Facies (Geology). I. Walker, Roger G. 11. James, Noel P. 111. Geological Association of Canada QE651.F25

1992

551.7

C92-090412-2

Illustration Concept: Peter Russell, Waterloo

Additional copies may be obtained by writing to: Geological Association of Canada Publications Department of Earth Sciences Memorial University of Newfoundland St. John's, NewfoundlandA1 B 3x5 Canada

0 1992 ISBN 0-919216-49-8 Typesetting and Printing Love Printing Service Ltd. Stittsville, Ontario

Authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted by the Geological Association of Canada for libraries and other users registered with the Copyright Clearance Center (CCC) Transactional Reporting Service, provided that the base fee of $3.00 per copy is paid directly to CCC, 21 Congress Street, Salem, Massachusetts 01970, USA. 0-919216-49-8 $3.00 + 0.00. The above permission does not extend to other kinds of copying, such as copying for general distribution, for advertising or promotional purposes, for creating new collective works, or for resale. For such copying, arrangements must be made with the publisher in advance of publication. L'Association geologique du Canada accorde I'autorisation de photocopier des documents pour un usage interne au personnel, ou pour I'utilisation interne ou personnelle de clients particuliers, aux bibliotheques et autres utilisateurs inscrits au Copyright Clearance Center (CCC) Transactional Reporting Service, a la condition que le tarif de base de 3$ par copie soit soit paye directement au Centre, 21 Congress Street, Salem, Massachusetts 01970, USA. 0-919216-49-8 $3.00 + 0.00. Le presente permission ne s'applique pas a d'autres genres de reproduction, notamment la reproduction en vue d'une distribution generale, a des fins de publicite au de promotion, pour la creation de nouveaux travaux collectifs ou pour la revente. Dans ces cas, il faut prendre les dispositions qui s'imposent en communiquant en advance avec I'editeur de I'Association.

CONTENTS PART I - PRINCIPLES, TOOLS AND CONCEPTS 1. Facies, facies models and modern stratigraphic concepts Roger G. Walker

..................................................... 1

2. Control of sea level change .................................................................................................. 15 A. Guy Plint, Nicholas Eyles, Carolyn H. Eyles and Roger G. Walker 3.

Subsurface facies analysis Douglas J. Cant

................................................................................................... 27

4. Trace fossil facies models: environmental and allostratigraphic significance S. George Pemberton, James A. MacEachern and Robert W. Frey

...................... 47

PART I1 - TERRIGENOUS CLASTIC FACIES MODELS 5. Glacial depositional systems ................................................................................................. 73 Nicholas Eyles and Carolyn H. Eyles 6. Volcaniclastic rocks ............................................................................................................. 101 Jean Lajoie and John Stix 7. Alluvial deposits Andrew D. Miall

.................................................................................................................. 119

8.

Eolian systems .................................................................................................................... 143 Michael E. Brookfield

9.

Deltas .................................................................................................................................. 157 Janok P. Bhattacharya and Roger G. Walker

10. Transgressive barrier island and estuarine systems Gerald E. Reinson 11. Tidal depositional systems Robert W. Dalrymple

........................................................... 179

..................................................................................................195

12. Wave- and storm-dominated shallow marine systems Roger G. Walker and A. Guy Plint 13. Turbidites and submarine fans Roger G. Walker

....................................................... 219

............................................................................................239

PART I11 - CARBONATE AND EVAPORITE FACIES MODELS 14. Introduction to carbonate and evaporite facies models Noel P. James and Alan C. Kendall

......................................................265

15. Shallow platform carbonates ...............................................................................................277 Brian Jones and Andre Desrochers 16. Peritidal carbonates ............................................................................................................ 303 Brian R. Pratt, Noel P. James and Clinton A. Cowan 17. Reefs and mounds .............................................................................................................. 323 Noel P. James and Pierre-Andre Bourque

18. Carbonate slopes ................................................................................................................ 349 Mario Coniglio and George R. Dix 19. Evaporites ........................................................................................................................... 375 Alan C. Kendall

Preface In the summer of 1989, the Geological Association of Canada asked us whether it was worthwhile to reprint the second edition of Facies Models. Most of the authors felt that the world of sedimentary geology had changed dramatically since the second edition was published in 1984. Rewriting rather than reprinting was necessary. There is now much more information on specific facies. Some fundamental concepts have changed and, most importantly, stratigraphy has re-emerged as a primary analytical ttiol. Dynamic controls on sedimentation in the form of sea level change, tectonics, climate and biotic evolution, must be incorporated into contemporary facies modelling. This volume is not a third edition, nor is it part of the Geoscience Canada reprint series. Depositional environments have been subdivided in different ways, authors have taken on new responsibilities, new authors are involved, and the volume goes beyond being a mere revision. When preliminary plans for this volume circulated "through the grapevine", Brian Rust was one of the first to volunteer to update his chapter. We discussed plans for this on the day before his trip to Zambia in 1990, where he contracted a fatal case of malaria. We have missed his enthusiasm and knowledge. We will also miss, in the future, the contributions of Bob Frey, who died in January, 1992. His knowledge has enhanced the chapter on Trace Fossils, both in the second edition and in this book. Of the new concepts incorporated in this book, perhaps the most important concerns the dynamic control of sea level change. Eustatic cycles form the basis of sequence stratigraphy, and the bounding discontinuities in the geologic record that formed as a response to sea level change allow allostratigraphic subdivision of the stratigraphic column. These fundamental concepts, reviewed in chapter 1, form the underlying theme of the book. All authors have tried to emphasize not only the individual depositional environments, but where appropriate, their response to fluctuations in sea level and other dynamic factors. Modelling, however, remains an important focus. Models are built on the comparison of modern and ancient examples. In the second edition it seemed possible, when distilling all variables into a static model, to achieve a certain sedimentological synthesis which served as a norm, a guide for observations, a predictor, and a basis for interpretation. As more variables are introduced, it is harder to select a group of examples that are homogeneous and can be combined into a model. For example, you might be able to combine the sedimentological features of ten wavedominated deltas into one model. If sea level change is

added as an important descriptive parameter, there may be three deltas that have responded to a relative rise, four to a fall and three in which sea level has not fluctuated. There are now insufficient examples to make powerful integrated models. If tectonic parameters, and the evolving terrestrial biota are included, the problem becomes much worse. In this book we have staked the middle gound. We have tried to explain how the various depositional systems work, and how they respond in general terms to sea level fluctuation and where appropriate, other dynamic factors. At the same time we have still emphasized as much generality as possible (modelling). The models we do present are more complex, and harder to illustrate in block diagrams. The book is aimed at a general audience, and at students. It is not intended as an advanced research text. All authors have therefore tried to keep the number of citations to a minimum, and we have not necessarily cited the source of every idea presented. The references at the end of each chapter begin with basic sources of information, where more detail on the subject can be found; these references are annotated. The other references are simply in alphabetical order, and are only occasionally annotated. As editors, we thank the individual authors for building their contributigns around the ideas of sedimentation dynamics, in particular the response to sea level change. Although the contributions are largely reviews, there is a lot of original research incorporated in them. Over the years, much of this research has been supported by the Natural Sciences and Engineering Research Council of Canada, and by various universities and government agencies where the authors work. Editors and authors gratefully acknowledge this support. Bob Baragar (Geological Association of Canada) was extremely helpful in getting this book moving, and Monica Easton took over toward the end and has helped with the technical side of communicating our wishes to the printer. However, there are many other large steps to be taken between writing a manuscript, editing it for technical content, and seeing it appear between the covers of a book. We particularly thank Judith James for editing all nineteen chapters and ensuring that they all follow the same overall style. She has checked on all of those little details that make a contribution as consistent and readable as possible, despite the differing styles of the authors.

Roger G. Walker Hamilton, Ontario

Noel P. James Kingston, Ontario

WALKER

bined (groups) (Fig. 2). Formal methods and rules are given in the North American Stratigraphic Code (NACSN, s t r a t i a m 1983). AJernative schemes of increasina importance emphssize the bounding discont&ities rather than the internal jithological .- -- - hGmo_geneity: This type of subdivision has been formalized as allostratigraphy (Fig. 2 ; NACSN, 19 8 ' m m stratigraphy is purely descriptive; sequence stratigraphy (Van Wagoner

et a / . , 1990) also recognizes units defined by discontinuities and uncon---formities,-. but relates them to cycles of sea level fluctuat&n. Systems tracts are linkages of contemporaneous depositional systems. However, different depositional systems occur at different positions of relative sea level, and allow the definition of three main systems tracts; lowstand, transgressive and highstand. Certain facies successions and

facies geometries in the geological record appear to be characteristic of certain depositional environments. Similar successions and geometries of various ages can be compared with the facies, facies successions and facies geometries observed in modern sediments (Fig. 1). In this way, the general characteristics of various depositional environments can be defined, and used to interpret other parts of the geological record. The

rphological subdivision of a particular depositionalsystem characterized by a distinctive assemblage of

Depositional Environment - geographic andlor geomorphic area Depositional System - 'three dimensional assemblage of lithofacies, genetically linked by active or inferred processes and environments" (Posamentier et a/.,1988, p. 110). It embraces depositional environments and the processes acting therein. Downiap - the situation where "an initially inclined layer terminates downdip against an initially horizontal or inclined surface" (Mitchum eta/.,1977, p. 58). Eustasy - a world-wide change of sea level relative to a fixed point such as the centre of the earth. Eustatic changes result from variations in the volume of water in the ocean basins (glacial control), or a change in the volume of the basins themselves (related to rates of ocean ridge building and rates of seafloor spreading). The eustatic sea level curve describes cyclic changes in sea Facies - a body of rock characterized by a particular combination of lithology, physical and biological structures that bestow an aspect ("facies")different from the bodies of rock above, below and laterally adjacent. Facies Association - "groups of facies genetically related to one another and which have some environmental significance" (Collinson, 1969, p. 207). Facies Succession - a vertical succession of facies characterized by a progressive change in one or more parameters, e.g., abundance of sand, grain size, or sedimentary structures Facies Model - a general summary of a particular depositional system, involving many individual examples from recent sediments and ancient rocks. Genetic Stratigraphic Sequence - "the sedimentary product of a depositional episode" (Galloway, 1989, p. 125), where a depositional episode "is bounded by stratal surfaces that reflect major reorganizations in basin paleogeographicframework" (Galloway, 1989, p. 128). These stratal surfaces are maximum flooding surfaces, not the unconformities used to define stratigraphic Lithostratigraphy - "a defined body of sedimentary... strata which is distinguished and delimited on the basis of lithic characteristics and stratigraphic position" (NACSN, 1983). It is internally lithologically homogeneous. Marine Flooding Surface - "a surface separating younger from older strata across which there is evidence of an abrupt increase in water depth" (Van Wagoner eta/.,1990, p. 8). Maximum Flooding Surface - a surface separating a transgressive systems tract (below) from a highstand systems tract (above). it is commonly characterized by a condensed horizon reflecting very slow deposition; markers in the overlying systems tract downlap onto the MFS.

and their correlative surfaces" (Posamentier et ab, 1988, p. 110). conformable succession of genetically related strata bounded at its top and base by unconformitiesand their ties...it is composed of a succession of systems tracts and is interpreted to be deposited between eustatic(Posamentier etal., 1988, p. 110).

WALKER

bined (groups) (Fig. 2). Formal methods and rules are given in the North American Stratigraphic Code (NACSN, 1983). A - l t e v a p h i c s&eem_es of increasina importance-emphasize the bounding discontinuities rather than the internal jithological homogeneity, This type of subdivision h a s b e e n formalized as allostratigraphy (Fig. 2; NACSN, 198T~-ilo--stratigraphy is p u r e l y d e s c r i p t i v e ; sequence stratigraphy (Van Wagoner

-

et a / . , 1990) also recognizes units defined by discontinuities and unconformities_I but relates -- _-__--them to cycles of sea level fluctualkon. Systems tracts a r e linkages of contemporaneous depositional systems. However, different depositional systems occur at different positions of relative s e a level, a n d a l l o w t h e d e f i n i t i o n of t h r e e m a i n systems tracts; lowstand, transgressive and highstand. Certain facies successions a n d

facies geometries in t h e geological record appear to be characteristic of certain depositional environments. Similar successions and geometries of various ages can be compared with t h e facies, facies successions and facies geometries observed in modern sediments (Fig. 1). I n this way, the g e n e r a l c h a r a c t e r i s t i c s of v a r i o u s d e p o s i t i o n a l environments c a n b e defined, a n d used to interpret other parts of the geological record. T h e

1 1

I

Table 1

Glossary of terms used b this chapter and throughout the book,

.&Yw-m-

subdivision of the stratigraphic record into mappable rock bodies "defined and identified on the basis of their bounding discontinuities"(NACSN, 1983, p. 865). 'Architectural Element a morphological subdivision of a particular depositional system characterized by a distinctive assemblage of facies, facles geometries, and depositional processes. Bounding Discontinui-v =@aterally traceable discontinui can be an unconformity, ravinement surface, onlap or downlap surface, hi@arisksli"l' condensed horizon or hardgroi7W.Depositional Environment - geographic andlor geomorphic area Depositional System - "three dimensional assemblage of lithofacies, genetically linked by active or inferred processes and environments" (Posamentier eta/., 1988, p. 110). It embraces depositional environments and the processes acting therein. Downlap - the situation where "an initially inclined layer terminates downdip against an initially horizontal or inclined surface" (Mitchum etal., 1977, p. 58). Eustasy a world-wide change of sea level relative to a fixed point such as the centre of the earth. Eustatic changes result from variations in the volume of water in the ocean basins (glacial control), or a change in the volume of the basins themselves (related to rates of ocean ridge building and rates of seafloor spreading). The eustatic sea level curve describes cyclic changes in sea level. Facies - a body of rock characterized by a particular combination of lithology, physical and biological structures that bestow an aspect ("facies") different from the bodies of rock above, below and laterally adjacent. Facies Association - "groups of facies genetically related to one another and which have some environmental significance" (Collinson, 1969, p. 207). Facles Succession - a vertical succession of facies characterized by a progressive change in one or more parameters, e.g., abundance of sand, grain size, or sedimentary structures Facles Model - a general summary of a particular depositional system, involving many individual examples from recent sediments and ancient rocks. Genetic Stratigraphic Sequence - "the sedimentary product of a depositional episode" (Galloway, 1989, p. 125), where a depositional episode "is bounded by stratal surfaces that reflect major reorganizations in basin paleogeographicframework" (Galloway, 1989, p. 128). These stratal surfaces are maximum flooding surfaces, not the unconformities used to define stratigraphic sequences. Lithostratigraphy - "a defined body of sedimentary... strata which is distinguished and delimited on the basis of lithic characteristics and stratigraphic position" (NACSN, 1983). It is internally lithologically homogeneous. Marine Flooding Surface - "a surface separating younger from older strata across which there is evidence of an abrupt increase in water depth" (Van Wagoner etal., 1990, p. 8). Maximum Flooding Surface - a surface separating a transgressive systems tract (below) from a highstand systems tract (above). It is commonly characterized by a condensed horizon reflecting very slow deposition; markers in the overlying systems tract downlap onto the MFS. Onlap -the situation where "an initially horizontal stratum laps out against an initially inclined surface" (Mitchum et a/., 1977, p. 5758). Parasequence - "a relatively conformable succession of genetically related beds or bedsets bounded by marine flooding surfaces and their correlative surfaces" (Posamentier et a/., 1988, p. 110). Ravinement Surface - an erosion surface produced during marine transgression of a formerly subaerial environment. "a geological approach to the stratigraphic interpretationof seismic data" (Vail and Mitchum, 1977, p. 51). Seismic Stratigraphy Sequence - "a relatively conformable succession of genetically related strata bounded at its top and base by unconformitiesand their correlative conformities...it is composed of a succession of systems tracts and is interpreted to be deposited between eustaticfall inflection points" (Posamentier et a/., 1988, p. 110). ,S @ b / A " ~ t r ~ t ~"the ~ pstudy ~ +of rock relationships within a chronostratigraphic framework wherein the succession of rocks is cyclic and is composed of genetically related stratal units (sequences and systems tracts)" (Posamentier eta/., 1988, p. 110). S)@@@@TrE&t - "a linkage of contemporaneousdepositional systems" (Posamentier etal., 1988, p. 110). Unconforniity - "a surface separating younger from older strata, along which there is evidence of subaerial erosional truncation...or subaerial exposure, with a significant hiatus indicated" (Posamentier etal., 1988, p. 110). This is an extremely restricted definition; Posamentier (personal communication, 1990) now accepts that the "evidence" may be inferred rather than real.

-

k

-

*

I

1.

Facies, Facies Models and Modern Stratigraphic Concepts

Roger G. Walker, Department of Geology, McMaster University, Hamilton, Ontario L8S 4M1

OBJECTIVES OF FACIES MODELLING Features of recent sediments and ancient sedimentary rocks can be combined and condensed into idealizations or models that characterize particular sedimentary environments. This combination of features from modern and ancient situations has been emphasized from the earliest days; in 1893 Johannes Walther (quoted by Middleton, 1973, p. 981) "explained that the most satisfying genetic explanations of ancient phenomena were by analogy with modern geological processes". A good model embodies a large amount of information from different examples of the same depositional system, for instance, meandering river channels. It is therefore an excellent point of reference for the interpretation of new examples of the same system, and allows predictions to be made from limited amounts of data. The predictive capabilities of models have largely been used in the exploration for oil and gas (e.g., Chapters 3, 12, 13, 16, 17), and to a lesser extent in exploration for minerals hosted by sedimentary rocks. However, the broad understanding of depositional systems is becoming increasingly important in modelling the movement of ground water and pollutants through surficial unconsolidated sediments, where the movement is partly a function of the geometry of permeable and impermeable layers (Chapter 5). This geometry largely depends on the depositional processes operating in the original sedimentary environment. Facies models also embody ideas about how natural sedimentary systems work, and to what extent they can be "managed". For example, a general understanding of beaches and barriers (Chapter 10) contributes to the solution of coastal erosion problems. In the Mississippi Delta, there is a large annual land loss

due to regional subsidence and delta inundation; these aspects of delta behaviour are part of the general deltaic facies model (Chapter 9). In the first two editions of Facies Models, we tried to synthesize and idealizq the features of some modern deposihonal environments and systems (terminology defined in Table I ) , and show how their deposits could be identified in the geological record. The models we built tended to be snapshots of specific systems at one time (static block diagrams). They emphasized the sedimentary processes operating within the systems rather than processes external to the environments, such as fluctuations of relative s s l , and tectonics. The major conceptual change since the second edition (1984) has been the recognition of the impoftance of relative sea level fluctuation (Chapter 2). This concept now permeates stratigraphy and sedimentology, and brings a dynamic quality to models of depositional environments. Spemc st b e modelled a videos rather than snapshots. The Sntheses in this book will attempt to convey how the environments respond to sea level fluctuation. ----

-

-

A SEDIMENTOLOGICAL MODUS OPERAND1 Over the years, many different methods and concepts have been used in the study of sedimentary rocks. The modus operandi, or way of working on sedimentary rocks, depends on the objectives. Studies of ancient depositional environments commonly begin with stratigraphic measurements and correlations, in order to define the rock types present, their three-dimensional geometry, and their internal sedimentary structures.

Overview of terminology A glossary of terminology used in this

I

chapter, and throughout the book, is given in Table 1. Themeasurementof -