Encyclopedia of Earth Sciences SeriesENCYCLOPEDIA OF SEDIMENTS AND SEDIMENTARY ROCKSVolume Editor

Gerard V. Middleton is Professor Emeritus of Geology at McMaster University, Hamilton, Ontario, Canada. He was co-author of "Origin of Sedimentary Rocks" (Prentice-Hall), "Mechanics in the Earth and Environmental Sciences" (Cambridge), and author of "Data Analysis in the Earth Sciences using MATLAB" (Prentice-Hall). He is a Fellow of the Royal Society of Canada, and in 2003 received the Twenhofel Prize of SEPM, the Society for Sedimentary Geology. Aim of the Series The Encyclopedia of Earth Sciences Series provides comprehensive and authoritative coverage of all the main areas in the Earth Sciences. Each volume comprises a focused and carefully chosen collection of contributions from leading names in the subject, with copious illustrations and reference lists. These books represent one of the world's leading resources for the Earth Sciences community. Previous volumes are being updated and new works published so that the volumes will continue to be essential reading for all professional earth scientists, geologists, geophysicists, climatologists, and oceanographers as well as for teachers and students. See the back of this volume for a current list of titles in the Encyclopedia of Earth Sciences Series. Go to www.eseo.com to visit the "Earth Sciences Encyclopedia Online" - the online version of this Encyclopedia Series.About the Editors

Professor Rhodes W. Fairbridge has edited more than 30 Encyclopedias in the Earth Sciences Series. During his career he has worked as a petroleum geologist in the Middle East, been a WW II intelligence officer in the SW Pacific and led expeditions to the Sahara, Arctic Canada, Arctic Scandinavia, Brazil and New Guinea. He is currently Emeritus Professor of Geology at Columbia University and is affiliated with the Goddard Institute for Space Studies. Professor Michael Rampino has published more than 100 papers in professional journals including Science, Nature, and Scientific American. He has worked in such diverse fields as volcanology, planetary science, sedimentology, and climate studies, and has done field work on six continents. He is currently Associate Professor of Earth and Environmental Sciences at New York University and a consultant at NASA's Goddard Institute for Space Studies.

Contents

List of Contributors Preface Guide to the Reader Algal and Bacterial Carbonate Sediments Roberl Riding Allophane and Imogolite Roger L. Parfitt Alluvial Fans Adrian M. Harvey Anabranching Rivers Gerald C. Nanson and Martin R. Gihling Ancient Karst Brian Jones Angle of Repose Paul D. Komar Anhydrite and Gypsum Lawrence A. Hardie Ankerite (in Sediments) James P. Hendry Armor Rob Ferguson Atterberg Limits Michael J. Bovis Attrition (Abrasion), Fluvial Michael Church Attrition (Abrasion), Marine Hillert Ibbeken

xiii xxvii xxix 1

Authigenesis James R. Boles Autosuspension Henry M. Pantin Avalanche and Michael J. Bovis

11

30

31

3 Avulsion Norman D. Smith 5 Bacteria in SedimentsNora Nofjfke

34

37

11

Ball-and-Pillow (Pillow) Structure Geraint Owen Bar, Littoral Brian Greenwood Barrier Islands Duncan M. FilzGerald and Ilya V Buynevich Bauxite Ray L.Frost Beachrock Eberhard Gischler Bedding and Internal Structures Franco Ricci-Lucchi and Alessandro Amorosi

39

40

15

43

16

48

19

5 1

2'

53

24

Bedset and Laminaset John S. Bridge Bentonites and Tonsteins D. Alan Spears

59

25

61

CONTENTS

Berthierine FredJ. Longstaffe Bioclasts Paul Enos Bioerosion Markus Bertling Biogenic Sedimentary Structures S. George Pemberton Black Shales Juergen Schieber Braided Channels Peter Ashmore Calcite Compensation Depth Sherwood Wise Caliche - Calcrete V.Paul Wright Carbonate Diagenesis and Microfabrics Robin G. C. Bathurst Carbonate Mineralogy and Geochemistry Fred T. Mackenzie Carbonate Mud-Mounds Pierre-Andre Bourque Cathodolumineseence (applied to the study of sedimentary rocks) Stuart D. Burley Cation Exchange Balwant Singh Cave Sediments Brian Jones Cements and Cementation Peter A. Scholle and Dana Ulmer-Scholle Chalk Ida L. Fabricius Charcoal in Sediments Andrew C. Scott Chlorite in Sediments Stephen Hillier Classification of Sediments and Sedimentary Rocks Gerald M. Friedman

64

Clastic (Neptunian) Dykes and Sills A. Demoulin Clathrates Miriam Kaslner Clay Mineralogy Stephen Hillier Climatic Control of Sedimentation Greg H. Mack Coal Balls Andrew C. Scott Coastal Sedimentary Faeies H. Edward Clifton Colloidal Properties of Sediments Sandip and Devamita Chattopadhyay Colors of Sedimentary Rocks Paul Myrow

136

66

137

70

139

71

142

83

146

85

149 157

159

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Compaction (Consolidation) of Sediments Knut Bjorlykke Convolute Lamination Gerard V. Middleton Coring Methods, Cores ArnoldH. Bouma Cross-Stratification DavidM. Rubin Cyclic Sedimentation Robert K. Goldhammer Debris Flow Jon J. Major Dedolomitization Mario Coniglio Deformation of Sediments John D. Collinson Deformation Structures and Growth Faults John D. Collinson Deltas and Estuaries Janok Bhattacharya Depositional Fabric of Mudstones Juergen Schieber

11 6

93

168

100

168

102 106

170

173

109110

186188

119

190

121

193

123

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127

203

CONTENTS

Desert Sedimentary Environments Joseph P. Smoot Desiccation Structures (Mud Cracks, etc.) P.W. Geoff Tanner Diagenesis Kitty L. Milliken Diagenetic Structures Peter Mozley Diffusion, Chemical Bernard P. Boudreau Diffusion, Turbulent Andrew J. Hogg Dish Structure Zoltan Sylvester and Donald R. Lowe Dolomite Textures Duncan Sibley Dolomites and Dolomitization Hans G. Machel Dunes, Eolian Nicholas Lancaster Earth Flows Rex L. Baum Encrinites William I. Ausich Eolian Transport and Deposition Cheryl McKenna Neuman Erosion and Sediment Yield Robert F Stallard Evaporites Lawrence A. Hardie and Tim K. Lowenstein Extraterrestrial Material in Sediments Christian Koeberl Fabric, Porosity, and Permeability Gerard V Middleton Faeies Models Harold G. Reading Fan Delta George Postma

207

Features Indicating Impact and Shock Metamorphism WolfUweReimold Feldspars in Sedimentary Rocks Sadoon Morad Flame Structure Gerard V Middleton Flaser Burghard W Flemming Flocculation Morten Pejrup Floodplain Sediments Andres Asian Floods and Other Catastrophic Events Victor R. Baker Flow Resistance Robert Millar Fluid Escape Structures Zoltan Sylvester and Donald R. Lowe Fluid Inclusions Robert H. Goldstein Flume Basil Gomez Forensic Sedimentology Raymond C. Murray Gases in Sediments Chris J. Clayton Geodes Kitty L. Milliken Geophysical Properties of Sediments (Acoustical, Electrical, Radioactive) Anthony L. Fndres Geothermic Characteristics of Sediments and Sedimentary Rocks Daniel F. Merriam Glacial Sediments: Processes, Environments and Faeies Michael J. Hambrey and Neil F. Glasser Giaucony and Verdine Alessandro Amorosi Grading, Graded Bedding Richard N. Hiscott

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212

278

214

281

282

219

284

225

285

226

287

230

293

231

294

234

297

243

300

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301

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249

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257

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263

314

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316

268

331

111

333

CONTENTS

Grain Flow Charles S. Campbell Grain Settling Paul D. Komar Grain Size and Shape Michael J. Church Grain Threshold Paul D. Komar Gravity-Driven Mass Flows Richard M. Iverson Gutters and Gutter Casts Paul Myrow Heavy Mineral Shadows Rick Cheel Heavy Minerals Andrew C. Morton Hindered Settling Jon J. Major Humic Substances in Sediments Laura J. Crossey Hummocky and Swaley Cross-Stratification Rick Cheel Hydrocarbons in Sediments Martin Fowler Hydroxides and Oxyhydroxide Minerals Helge Stanjek Iliite Group .Clay Minerals Jan Srodoii Imbrication and Flow-Oriented Clasts Cyril Galvin Impregnation Scott F Lamoureux Iron-Manganese Nodules Stephen E. Calvert Ironstones and Iron Formations Bruce M. Simonson Isotopic Methods in Sedimentology FredJ. Longstaffe

335

Kaolin Group Minerals Rossman F. Giese, Jr. Kerogen Raphael A.J. Wust and R. Marc Bustin Lacustrine Sedimentation Robert Gilbert Laterites Yves Tardy Lepispheres Sherwood W. Wise, Jr.

398 400

336

404 408 411

338

345

347Liquefaction and Fluidization Charles S. Campbell 412

353

Load Structures John R.L.Allen Lunar Sediments Abhijit Basu Magadiite Robin W. Renaut Magnetic Properties of Sediments Mark J. Dekkers Mass Movement Michael J. Bovis Maturation, Organic R. Marc Bustin and Raphael A.J. Wust Maturity: Textural and Compositional Raymond V Ingersoll Meandering Channels Edward J. Hickin Melange; Melange John WF Waldron Micritization Ian G. Macintyre and R. Pamela Reid Microbially Induced Sedimentary Structures Nora Noffke Milankovitch Cycles Linda Hinnov Mixed Siliciclastic and Carbonate Sedimentation Robert K. Goldhammer Mixed-Layer Clays Jan Srodoh

413

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415

356

417

358

418

361

424

362

425

364 366

429

430

369

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371

436

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439

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441

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443 447

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CONTENTS

Mixing Models Bernard P. Boudreau Mudrocks Paul E. Potter Neomorphism and Recrystallization JA.D. Dickson Nepheloid Layer, Sediment /. Nicholas McCave Neritic Carbonate Depositional Environments Noet P. James Numerical Models and Simulation of Sediment Transport and Deposition Rudy L. Slingerland Oceanic Sediments Robert G. Douglas Offshore Sands Serge Berne Oil Sands Daryl M. Wightman Oolite and Coated Grains Fredrick D. Siewers Ophicalcites Denis Lavoie Paleocurrent Analysis Andrew D. Miall Parting Lineations and Current Crescents Rick Cheel Peat Barry G. Warner Petrophysics of Sand and Sandstone Robert Ehrlich Phosphorites Craig R. Glenn and Robert F. Garrison Physics of Sediment Transport: The Contributions of R.A. Bagnold Colin R. Thorne Pillar Structure Zoltan Sylvester and Donald R. Lowe Placers, Fluvial WK. Fletcher

450

Placers, Marine Davids. Cronan Planar and Parallel Lamination John S. Bridge Porewaters in Sediments Jeffreys. Hanor Pressure Solution Francois Renard and Dag Dysthe Provenance Abhijit Basu Pseudonodules Geraint Owen Quartz, Detrital Harvey Blatt

532 534 537 542

451 460 462

464

544 549 552

475

481 Red Beds Peter Turner 492 Reefs Wolfgang Kiessling 499 Relict and Palimpsest Sediments Donald JP Swift 502 Relief Peels Robert W. Dalrymple 506 Resin and Amber in Sediments Ken B. Anderson 509 Ripple, Ripple Mark, Ripple Structure Jaco H. Baas 512 Rivers and Alluvial Fans Gerald C. Nanson and Martin R. Gibling 514 Sabkha, Salt Flat, Salina Lawrence A. Hardie 516 Salt Marshes Daniel F. Belknap 519 Sands, Gravels, and their Lithified Equivalents Andrew D. Miall 527 Sapropel Stephen E. Calvert Scour, Scour Marks John R.L.Allen Seawater: Temporal Changes in the Major Solutes H. Wayne Nesbitt 588 586 584 568 565 563 561 560 557 555

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CONTENTS

Sediment Fluxes and Rates of Sedimentation James P. M. Syvitski Sediment Transport by Tides Robert W. Dalrymple and Kyungsik Choi Sediment Transport by Unidirectional Water Flows John S. Bridge Sediment Transport by Waves Brian Greenwood Sedimentary Geology Gerard V. Middleton Sedimentary Structures as Way-up Indicators Robert H. Dott, Jr. Sedimentology, History Gerard V. Middleton Sedimentology: History in Japan Hakuyu Okada SedimentologyOrganizations, Meetings, Publications Gail M. Ashley Sedimentologists: Ralph Alger Bagnold (1896-1990) Colin R. Thome Joseph Barrel! (1869-1919) Robert H. Dott, Jr. Robin G.C. Bathurst (1920-) Gerard V. Middleton Lucien Cayeux (1864-1944) Albert V. Carozzi Carl Wilhelm Correns (1893-1980) Karl Hans Wedepohl Robert Louis Folk (1925-) Earle E. McBride Grove Karl Gilbert (1843-1918) Rudy Slingerland Amadeus William Grabau (1870-1946) Markes E. Johnson Amanz Gressly (1814-1865) Gerard V Middleton William Christian Krumbein (1902-1979) Daniel F. Merriam Paul Dimitri Krynine (1902-1964) Gerard V. Middleton Philip Henry Kuenen (1902-1976) Gerard V. Middleton John Murray (1841-1914) and the Challenger Expedition Gerard V. Middleton Francis J. Pettijohn (1904-1999) Paul E. Potter Rudolf Richter (1881-1957) and the Senckenberg Laboratory S. George Pemberton

600 606 609

619

Henry Clifton Sorby (1826-1908) Gerard V. Middleton William H. Twenhofel (1875-1957) Robert H. Dott, Jr. Johan August Udden (1859-1932) Earle E. McBride T. Wayland Vaughan (1870-1952) Ellis L. Yochelson Johannes Walther (1860-1937) Eugen and Use Seibold Sediments Produced by Impact Christian Koeberl Septarian Concretions Mark W. Hounslow Silcrete M" Angeles Bustillo Siliceous Sediments L. PaulKnauth Slide and Slump Structures OleJ. Martinsen Slope Sediments RichardN. Hiscott Slurry Jon J. Major Smectite Group Stephen P. Altaner Solution Breccias Derek Eord Speleothems Derek Eord Spiculites and Spongolites Paul R. Gammon Stains for Carbonate Minerals J A. D. Dickson Statistical Analysis of Sediments and Sedimentary Rocks Daniel E. Merriam Storm Deposits Paul Myrow Stromatactis Pierre-Andre Bourque Stromatolites Brian R. Pratt

649 650 651 652 653 653 657

626

627

659

628

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635

637

666

668

638 638 639 640 641 642

674

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642 643 644

681

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684

647 648

687

648

CONTENTS

Stylolites L. Bruce Railsback Submarine Fans and Channels Gerard V. Middleton Substrate-Controlled Ichnofacies S. George Pemberton Sulfide Minerals in Sediments Richard T. Wilkin Surface Forms John B. Southard Surface Textures W. Brian Whalley Swash and Backwash, Swash Marks Michael G. Hughes Syneresis P.W. Geojf Tanner Talc Richard H. April Taphonomy: Sedimentological Implications of Fossil Preservation Carlton E. Brett Tectonic Control of Sedimentation Greg H. Mack Tidal Flats Burghard W. Elemming Tidal Inlets and Deltas Duncan M. EitzGerald and Ilya V. Buynevich Tides and Tidal Rhythmites Erik P Kvale Tills and Tillites John Menzies

690 692 698

Tool Marks Gerard V. Middleton Toxicity of Sediments G. Allen Burton, Jr. and Peter E Landrum Tracers for Sediment Movement Marwan A. Hassan

747

748

752

701 703 712 717 718 721Tufas and Travertines Martyn H. Pedley Tsunami Deposits Andrew Moore Turbidites Ben C. Kneller Upweliing Graham Shimmield Varves Robert Gilbert Vermiculite Prakash B. Malla Weathering, Soils, and Paleosols Gregory J. Retallack X-ray Radiography Arnold H. Bouma Zeolites in Sedimentary Rocks Richard L. Hay Index of Authors Cited Subject Index

753

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757

761

764

766

723 729 734 737 741 744

770

777

779

781 805

Contributors

John R.L. Allen Research Institute for Sedimentology University of Reading P.O. Box 227 Whiteknights, Reading Berkshire RG6 6AB England, UK e-mail: j.r.l.allen@reading.ac.uk Load Structures Scour, Scour Marks Stephen P. Altaner Department of Geology, 1301 W. Green St University of Illinois Urbana IL 61801 USA e-mail: altaner@uiuc.edu Smectite Group Alessandro Amorosi Department di Scienze della Terra Universita di Bologna Via Zamboni 67 Bologna 40127 Italy e-mail: amorosi@geomin.unibo.it Bedding and Internal Structures Glaucony and Verdine Ken B. Anderson Chemistry Division Argonne National Laboratory Argonne IL 60439 USA e-mail: kbanderson@anl.gov Resin and Amber in Sediments Richard April Department of Geology Colgate University Hamilton NY 13346 USA e-mail: Rapril@mail.colgate.eduTalc

Gail M. Ashley Department of Geological Sciences Rutgers University 610 Taylor Road Piscataway NJ 08854-8066 USA e-mail: gmashley@rci.rutgers.edu Sedimentology - Organizations. Meetings, Publications Peter Z. Ashmore Department of Geography University of Victoria PO Box 3050, Stn CSC Victoria BC V8W 3P5 Canada e-mail: pashmore@julian.uwo.ca Braided Channels Andres Asian Department of Physical and Env. Sciences Mesa State College Grand Junction CO 81501-7682 USA e-mail: aaslan@mesastate.edu Floodplain Sediments William I. Ausich Department of Geological Sciences Ohio State University, 155 S. Oval Columbus OH 43210-1398 USA e-mail: ausich.l@osu.edu Encrinites Jaco H. Baas Department of Earth Sci. University of Leeds Leeds LS2 9JT England, UK e-mail: j.baas@earth.leeds.ac.uk Ripple. Ripple Mark, Ripple Structure

CONTRIBUTORS Victor R. Baker Department Hydrology & Water Resources University of Arizona bldg 11, North Campus Drive Tucson AZ 85721-0011 USA e-mail: baker@hwr.arizona.edu Floods and Other Catastrophic Events Abhijit Basu Department of Geological Sciences Indiana University 1005 East 10th Street Bloomington IN 47405 USA e-mail: basu@indiana.edu Provenance Lunar Sediments Robin G.C. Bathurst Derwen Deq Fawr Llanfair D.C. Ruthin Denbighshire, LL15 2SN North Wales, UK Carbonate Diagenesis and Microfabrics Rex L. Baum Central Region Geol. Hazards U.S. Geological Survey Box 25046, M.S. 966 Denver CO 80225-0046 USA e-mail: baum@usgs.gov Earth Flows Daniel F. Belknap Department of Geological Sciences 117 Bryand Global Sciences Bldg. University of Maine Orono ME 04469-5790 USA e-mail: belknap@maine.edu Salt Marshes Serge P. Berne IFREMER, DRO-GM B.P. 70 Plouzane 29280 France e-mail: Serge.Berne@ifremer.fr Offshore Sands Markus Bertling Geologisch-Palaeontologisches Institute u. Museum Pferdegasse 3 Muenster D-48143 Germany e-mail: bertlin@uni-muenster.de Bioerosion P. Andre Bourque Department de Geologie et de Genie geologique Universite Laval Quebec PQ G I K 7P4 Canada e-mail: bourque@ggl.ulaval.ca Carbonate Mud-Mounds Stromatactis Janok Bhattacharya Department of Geosciences University of Texas at Dallas P.O. Box 830688 Dallas TX 75083-0688 USA e-mail: janokb@utdallas.edu Deltas and Estuaries Knut Bjorlykke Department of Geology, Box 1047 University of Oslo Oslo 0316 Norway e-mail: knut.bjorlykke@geologi.uio.no Compaction (Consolidation) of Sediments Harvey Blatt Institute of Earth Sci, Hebrew University Givat Ram Jerusalem 91904 Israel e-mail: harvey@vms.huji.ac.il Quartz, Detrital James R. Boles Department of Geological Sciences University California Santa Barbara Santa Barbara CA 93106-9630 USA e-mail: boles@magic.ucsb.edu Authigenesis Bernard P. Boudreau Department of Oceanography Dalhousie University Halifax NS B3H 4JI Canada e-mail: bpboudre@is.dal.ca Diffusion, Chemical Mixing Models Arnold H. Bouma Department Geology/Geophysics Louisiana State University Baton Rouge LA 70803 USA e-mail: bouma@geol.lsu.edu Coring Methods, Cores X-radiography

CONTRIBUTORS Michael J. Bovis Department of Geography University of Bdtish Columbia 1984 West Mall Vancouver BC V6T IZ2 Canada e-mail: mbovis@geog.ubc.ca Atterberg Litriits Avalattch and Rockfall Mass Movement Carleton E. Brett Department of Geology University of Cincinnati Cincinnati OH 45221-0013 USA e-mail: brettce@email.uc.edu Taphonomy: Sedimentohgical hnplications of Fossil Preservation John S. Bridge Department Geol. Sci., SUNY P.O. Box 6000 Binghamton NY 13902-6000 USA e-mail: jbridge@binghamton.edu Bedset and Laminaset Planar and Parallel Lamination Sediment Transport by Unidirectional Waterflows Stuart D. Burley Subsurface Technology, BG Group 100 Thames Valley Park Reading RG6 IPT England, UK e-mail: stuart.burley@bg-group.com Cathodoluntinescence G. Allen Burton, Jr Department Biological Sciences Wright State University Dayton OH 45435 USA e-mail: allen.burton@wright.edu Toxicity of Sediments M. Angeles Bustillo Museo Nacional de Ciencias Naturales Dpto de Geologia Jose Gutierrez Abascal no. 2 Maddd 28006 Spain e-mail: abustillo@mncn.csic.es Silcrete Robert M. Bustin Department Birth and Ocean Sciences, University Bdtish Columbia 6270 University Blvd Vancouver BC V6T 1Z4 Canada e-mail: bustin@unixg.ubc.ca Kerogen Maturation, Organic Ilya V. Buynevich Geology and Geophysics Department Woods Hole Oceanographic Institution Woods Hole, MA 02543 USA e-mail: ibuynevich@whoi.edu Barrier Islands Tidal Inlets and Deltas Stephen E. Calvert Department of Oceanography, 1461-6270 University Blvd. University of Bdtish Columbia Vancouver BC V6T 1Z4 Canada e-mail: calvert@eos.ubc.ca Iron-Manganese Nodules Sapropel Charles S. Campbell Department of Mechanical Engineering University of Southern California Los Angeles CA 90089-1453 USA e-mail: campbell@rfc.usc.edu Grain Flow Liquefaction andFluidization Albert V. Carozzi Department of Geology, University Illinois 245 Natural History Bldg. 1301 W Green Urbana IL 61801-2999 USA Present address: 7530 Lead Mine Road, #304 Raleigh, NC 27615-4897 USA Sedimentologists: Lucien Cayeux Devamitta Chattopadhyay ARCADIS 6397 Emerald Parkway, Suite 150 Dublin, OH 43016 USA e-mail: dchattopadhyay@arcadis-us.co Colloidal Properties of Sediments Sandip Chattopadhyay Battelle Memorial Institute Environmental Restoration Department 505 King Avenue Columbus Ohio 43230 USA e-mail: chattopadhyays@battelle.org Colloidal Properties of Sediments Richard J. Cheel Dept of Geological Sciences Brock University St Cathednes ON L2S 3A1 Canada e-mail: rcheel@craton.geol.brocku.ca Heavy Mineral Shadows Hummocky and Swaley Cross-Stratification Parting Lineation and Current Crescents

CONTRIBUTORS

Kyungsik Choi Department of Geological Sciences and Geological Engineering Queen's University Kingston, Ontario K7L 3N6 Canada Sediment Transport by Tides Michael J. Church Department of Geography University of British Columbia Vancouver BC V6T 1Z2 Canada e-mail: mchurch@geog.ubc.ca Grain Size and Shape Attrition, Eluvial Chris J. Clayton 16 Latimer Road TeddingtonTWll 8QA England, UK e-mail: geochem@c-clayton.u-net.com Gases in Sediments H. Edward Clifton 1933 Fallen Leaf Lane Los Altos CA 94024 USA e-mail: eclifton@earthlink.net Coastal Sedimentary Eacies John D. Collinson 1 Winchester Drive Westlands Newcastle-undor-Lyme Staffs ST5 3JH United Kingdom e-mail: johncollinson@c-j-c.demon.co.uk Deformation of Sediments Deformation Structures and Growth Eaults Mario Coniglio Department of Earth Sciences University of Waterloo Waterloo ON N2L 3G1 Canada e-mail: coniglio@sciborg.uwaterloo.ca Dedolomitization David S. Cronan T.H. Huxley School of Environment Imperial College London SW7 2BP England, UK e-mail: d.cronan@ic.ac.uk Placers, Marine Laura J. Crossey Department of Earth and Planetary Sciences University of New Mexico Albuquerque NM 87131 USA e-mail: lcrossey@unm.edu Humic Substances in Sediments

Robert W. Dalrymple Department of Geological Sci. Queens University Kingston ON K7L 3N6 Canada e-mail: dalrymple@geol.queensu.ca Relief Peels Sediment Movement by Tides Mark J. Dekkers Paleomagnetic Laboratory Budapestlaan 17 Utrecht 3584 CD The Netherlands e-mail: dekkers@geo.uu.nl Magnetic Properties of Sediments A. Demoulin Departement de Geographie physique Universite de Liege AUee du 6 Aout, Sart Tilman Liege B 4000 Belgium e-mail: ademoulin@nlg.ac.be Clastic (Neptunian) Dykes and Sills J.A.D. Dickson Department of Earth Sci., University of Cambridge Downing St Cambridge CB2 3EQ England, UK e-mail: jaddl@esc.cam.ac.uk Neomorphism andRecrystallization Stainsfor Carbonate Minerals Robert H. Dott Geol. & Geophysics, University Wisconsin 1215 W. Dayton St Madison WI 53706-1692 USA e-mail: rdott@geology.wisc.edu Sedimentologists: Joseph Barrell Sedimentologists: William H. Twenhofel Sedimentary Structures as Way-up Indicators Robert G. Douglas Department of Earth Sciences University of Southern California Los Angeles CA 90089-0740 USA e-mail: rdouglas@usc.edu Oceanic Sediments Dag Dysthe Center for Advanced Study 78 Drammersveien N-0271 Oslo Norway e-mail: d.k.dysthe@fys.uio.no Pressure Solution

CONTRIBUTORS

Robert Ehrlich Energy and Geoscience Institute University of Utah 423 Wakara Way Ste 300 Salt Lake City UT 84108-3537 USA e-mail: bobehrlich@attbi.com Petrophysics of Sand and Sandstones Anthony L. Endres Department of Earth Sciences University of Waterloo Waterloo ON N2L 3G1 Canada e-mail: tendres@cgrnserc.uwaterloo.ca Geophysical Properties of Sediments Paul Enos Department of Geology, 120 Lindley Hall University of Kansas, 1475 Jayhawk Drive Lawrence KS 66045 (785) 864-2744 e-mail: enos@falcon.cc.ukans.edu Bioclasts Ida L. Fabricius IGG, DTU b204. Technical University of Denmark Lyngby DK 2800 Denmark e-mail: iggill@pop.dtu.dk Chalk Rob Ferguson Department of Geography, Winter St Sheffield University Sheffield SIO 2TN England, UK e-mail: R.Ferguson@sheffield.ac.uk Armor Duncan M. Fitzgerald Department Earth Sciences, Boston University 675 Commonwealth Ave Boston MA 02215-2530 USA e-mail: dunc@bu.edu Barrier Islands Tidal Inlets and Deltas Burghard W. Flemming Senckenberg Institute Schleusenstrasse 39A Wilhemshaven 26382 Germany e-mail: bw.flemming@sam.terramare.de Elaser Tidal Elats

William K. Fletcher Department of Earth & Ocean Sciences 6339 Stores Rd University British Columbia Vancouver BC V6T 1Z4 Canada e-mail: fletcher@unixg.ubc.ca Placers, Eluvial Derek Ford School of Geography & Geology McMaster University, 1280 Main W Hamilton ON L8S4M1 Canada e-mail: dford@mcmaster.ca Solution Breccias Speleothems Martin Fowler Geological Survey of Canada 3303-33rd St NW Calgary Alberta T2L 2A7 Canada e-mail: MFowler@NRCan.gc.ca Hydrocarbons in Sediments Gerald M. Friedman Brooklyn College, Rensselaer Center P.O. Box 746 Troy NY 12181 USA e-mail: gmfriedman@juno.com Classification of Sediments and Sedimentary Rocks Ray L. Frost Centre for Instrumental and Developmental Chemistry School of Physical Sciences P.O. Box 2434 GPO Brisbane QLD 4001 Australia e-mail: r.frost@qut.edu.au Bauxite Cyril Galvin Coastal Engineer P.O. Box 623 Springfield VA 22150 USA e-mail: galvincoastal@juno.com Imbrication andElow-Oriented Clasts Paul R. Gammon Department of Geology and Geophysics Adelaide University Adelaide 5005 Australia e-mail: paul.gammon@adelaide.edu.au Spiculites and Spongolites Robert E. Garrison Department of Ocean Sciences Earth and Marine Sciences Bldg University of California Santa Cruz CA 95064 USA e-mail: regarris@cats.ucsc.edu Phosphorites

CONTRIBUTORS

Martin R. Gibling Department of Earth Sciences Dalhousie University Halifax, Nova Scotia B3H 3J5 Canada e-mail: mgibling@is.dal.ca Anabranching Rivers Rivers and Alluvial Eans Rossman F. Giese Department of Geology, SUNY 711 Natural Sci. Complex Buffalo NY 14260 USA e-mail: glgclay@acsu.buffalo.edu Kaolin Group Minerals Robert Gilbert Department of Geography Queens University Kingston ON K7L 3N6 Canada e-mail: gilbert@lake.geog.queensu.ca Lacustrine Sedimentation Varves Eberhard Gischler Geologisch-Palaeontologishes Institut Johann Wolfgang Goethe-Universitaet Senckenberglage 32-34 Frankfurt am Main D-60054 Germany e-mail: gischler@em.uni-frankfurt.de

Robert H. Goldstein Department of Geology, University of Kansas 120 Lindley Hall Lawrence KS 66045-7613 USA e-mail: gold@ukans.edu Eluid Inclusions Basil Gomez Geomorphology Laboratory Indiana State University 455 N 6th St Terre Haute IN 47809-0001 USA e-mail: bgomez@indstate.edu Elume Brian Greenwood Environmental Sci., University Toronto 1265 Military Trail Scarborough ON MIC 1A4 Canada e-mail: greenw@scar.utoronto.ca Bar, Littoral Sediment Transport by Waves Michael J. Hambrey Centre for Glaciology University of Wales Aberystwyth Wales SY23 3DB United Kingdom e-mail: mjh@aber.ac.uk Glacial Sediments: Processes, Environments and Eacies

Jeffrey S. Hanor Department of Geology and Geophysics Louisiana State University Beaehrock Baton Rouge LA 70803 USA e-mail: hanor@unixl.sncc.lsu.edu Neil F. Glasser Porewaters in Sediments Centre for Glaciology Lawrence A. Hardie University of Wales Department of Earth and Planetary Sciences Aberystwyth Wales SY23 3DB The Johns Hopkins University United Kingdom Baltimore MD 21218 e-mail: mjh@aber.ac.uk USA Glacial Sediments: Processes, Environments and Eacies e-mail: hardie@ekman.eps.jhu.edu Anhydrite and Gypsum Craig R. Glenn Evaporites Department of Geology and Geophysics Sabkha, Salt Elat, Saline University of Hawaii Adrian M. Harvey Honolulu, HI 96822 Department of Geography USA University of Liverpooi, P.O. Box 147 e-mail: glenn@soest.hawaii.edu Liverpool L69 3BX Phosphorites England, U.K. e-mail: amharvey@liverpool.ac.uk Robert K. Goldhammer Alluvial Ean Department of Geological Sciences Marwan Hassan University of Texas Department of Geography Austin TX 78712-1101 University of British Columbia USA Vancouver BC V6T 1Z2 Canada e-mail: goldhrk@mail.utexas.edu Cyclic Sedimentation e-mail: mhassan@geog.ubc.ca Mixed Siliciclastic and Carbonate Sedimentation Tracersfor Sediment Movement

CONTRIBUTORS

Richard L. Hay 4320 N Alvernon Way Tucson AZ 85718-6180 USA e-mail: rhay@dakotacom.net Zeolites in Sedimentary Rocks James P. Hendry School of Earth and Environmental Sci. University of Portsmouth, Burnaby Bldg. Burnaby Rd., Portsmouth POl 3QL England (UK) e-mail: jim.hendry@port.ac.uk Ankerite E.J. Hickin Department of Earth Sciences Simon Fraser University 8888 University Drive Burnaby BC V5A 1S6 Canada e-mail: hickin@sfu.ca Meandering Channels Stephen Hillier Macauley Land Use Research Institute Craigiebuckler Aberdeen AB15 8QH Scotland, UK e-mail: S.HiIlier@macauley.ac.uk Chlorite in Sediments Clay Mineralogy Linda A. Hinnov Department of Earth & Planetary Sci. Johns Hopkins University Baltimore MD 21218 USA e-mail: hinnov@jhu.edu Milankovitch Cycles Richard N. Hiscott Department of Earth Sciences Memorial University of Newfoundland St John's NF AIB 3X5 Canada e-mail: rhiscott@sparky2.esd.mun.ca Grading, Graded Bedding Slope Sediments Andrew J. Hogg Centre for Environmental & Geophysical Flows School of Mathematics, University Walk Bristol BS8 ITW England, UK e-mail: A.J.Hogg@bristol.ac.uk Diffusion, Turbulent

Mark W. Hounslow Centre for Environmental Magnetism and Paleomagnetism Lancaster Environmental Centre, Geography Department Lancaster University Bailrigg, Lancaster LAI 4YW England, UK e-mail: m.hounslow@lancaster.ac.uk Septarian Concretions Michael G. Hughes Div. of Geology and Geophysics Edgeworth David Bldg. (F05) University of Sydney Sydney NSW 2006 Australia e-mail: michaelh@mail.usyd.edu.au Swash and Backwash, Swash Marks Hillert Ibbeken Instut flir Geologie Frei Universitiit Berlin Berlin D 12249 Germany e-mail: Hillert.Ibbeker@t-online.de Attrition (Abrasion), Marine Raymond V. Ingersoll Department of Earth and Space Sciences University of California Los Angeles CA 90095-1567 USA e-mail: ringer@ess.ucla.edu Maturity: Textural and Compositional Richard M. Iverson US Geological Survey 5400 Mac Arthur Blvd. Vancouver WA 98661 USA e-mail: riverson@usgs.gov Gravity-Driven Mass Elows Noel P. James Department of Geological Sciences Queens University Kingston ON K7L 3N6 Canada e-mail: james@geol.queensu.ca Neritic Carbonate Depositional Environments Markes E. Johnson Department of Geosciences, Williams College 947 Main St Williamstown MA 01267-2606 USA e-mail: markes.e.johnson@williams.edu Sedimentologists: Amadeus William Grabau Brian Jones Department of Earth and Atmospheric Sciences University of Alberta Edmonton AB T6G 2E3 Canada e-mail: brian.jones@ ualberta.ca Ancient Karst Cave Sediments

CONTRIBUTORS

Miriam Kastner Geoscience Research Division Seripps Institute of Oceanography La Jolla CA 92093-0220 USA e-mail: mkastner@ucsd.edu Clathrates Wolfgang Kiessling Museum fiir Naturkunde HU Berlin Invalidenstrasse 43 10115 Berlin Germany e-mail: Wolfgang.kiesslingij Jmuseum.hu-berhn.de Reefs Paul L. Knauth Department of Geology, Box 871404 Arizona State University Tempe AZ 85287-1404 USA e-mail: Knauth@asu.edu Siliceous Sediments Ben C. Kneller Institute for Crustal Studies, Girvetz Hall University of California Sanata Barbara CA 93101 USA e-mail: ben@crustal.ucsb.edu Turbidites Christian Koeberl Institute of Geochemistry University of Vienna, Althanstrasse 14 Vienna A-1090 Austria e-mail: Christian.koeberl@univie.ac.at Extraterrestrial Material in Sediments Sediments Produced by Impact Paul D. Komar College of Oceanography Oregon State University Corvallis OR 97331 USA e-mail: pkomar@oce.orst.edu Angle of Repose Grain Settling Grain Threshold Erik P. Kvale Indiana Geol. Survey/Department Geol. Sci. Indiana University, 611 N. Walnut Grove Bloomington IN 47405 USA e-mail: kvalee@indiana.edu Tides and Tidal Rhythmites Peter F. Landrum Great Lakes Environmental Research Laboratory NOAA Ann Arbor, Ml 48105 USA Toxicity of Sediments

Scott F. Lamoureux Department of Geography, EVEX Lab Queens University Kingston ON K7L 3N6 Canada e-mail: lamoureux@lake.geog.queensu.ca Impregnation Nicholas Lancaster Desert Research Institute 2215 Raggio Parkway Reno NV 89512-1095 USA e-mail: nick@dri.edu Dunes, Eolian Denis Lavoie Centre Geoscientifique de Quebec Commission Geologique du Canada 880 Chemin Ste-Foy, P.O. Box 7500 Quebec G1V4C7 Canada e-mail: delavoie@nrcan.gc.ca Ophicalcites Frederick J. Longstaffe Department of Earth Sciences University of Western Ontario London ON N6A 5B7 Canada e-mail: flongsta@julian.uwo.ca Berthierine Isotopic Methods in Sedimentology Donald R. Lowe Department of Geol./Environmental Sci. Stanford University, Bldg 320 Stanford CA 94305-2115 USA e-mail: lowe@pangea.stanford.edu Dish Structure Eluid Escape Structures Pillar Structure Tim K. Lowenstein Department of Geological Sciences State University of New York Binghamton NY 13901 USA e-mail: lowenst@binghamton.edu Evaporites Hans G. Machel Department of Earth and Atmospheric Sciences University of Alberta Edmonton AB T6G 2E3 Canada e-mail: hans.machel@ualberta.ca Dolomites and Dolomitization

CONTRIBUTORS

Ian G. Maclntyre Natl. Museum of Natural History MRC 125 Smithsonian Institution Washington DC 20560 USA e-mail: macintyre.ian@nmnh.si.edu Micritization Greg H. Mack Geological Sciences Department 3AB, P.O. Box 30001 Las Cruces NM 88003-8001 USA e-mail: gmack@nmsu.edu Climatic Control of Sedimentation Tectonic Control of Sedimentation Fred T. Mackenzie Department of Oceanography University of Hawaii 1000 Pope Road Honolulu HI 96822 USA e-mail: fredm@soest.hawaii.edu Carbonate Mineralogy and Geochemistry Jon J. Major USGS Cascades Volcano Obs. 5400 Macarthur Blvd Vancouver WA 98661-7049 USA e-mail: jjmajor@usgs.gov Debris Elow Hindered Settling Slurry Prakash B. Malla Manager, Paper research & Application Lab. P.O. Box 1056, 520 Kaolin Road Thiele Kaolin Company Sandersville GA 31082 USA e-mail: prakash.malla@thielekaolin.com Vermiculite Ole J. Martinsen Norsk Hydro Research Centre Bergen N-5020 Norway e-mail: ole.martinsen@hydro.com Slide and Slump Structures Earle F. McBride Department of Geological Sciences University of Texas Austin TX 78713-7909 USA e-mail: efmcbride@mail.utexas.edu Sedimentologists: Robert L Eolk Sedimentologists: Johan August Udden

Nicholas I. McCave Department of Earth Sciences, Downing St University of Cambridge Cambridge CB2 3EQ England, UK e-mail: mccave@esc.cam.ac.uk Nepheloid Layer, Sediment Cheryl Z. McKenna-Neuman Department of Geography Trent University 1600 West Bank Drive Peterborough ON K9J 7B8 Canada e-mail: cmckneuman@trentu.ca Eolian Transport and Deposition Daniel F. Merriam Kansas Geol. Survey University of Kansas Lawrence KS 66047 USA e-mail: dmerriam@kgs.ukans.edu Geothermic Characteristics of Sedimentary Rocks Sedimentologists: William C. Krumbein Statistics Analysis of Sediments and Sedimentary Rocks John Merzies Department of Earth Sciences Brock University St. Catherine's, ON L2S 3A1 Canada e-mail: jmenzies@spartan.ac.brocku.ca 77//.? and Tillites Andrew D. Miall Department of Geology University of Toronto Toronto ON M5S 3B1 Canada e-mail: miall@quartz.geology.utoronto.ca Sands, Gravels and their Lithified Equivalents Paleocurrent Analysis Gerard V. Middleton School of Geography and Geology McMaster University 1280 Main St West Hamilton ON L8S 4K1 Canada e-mail: middleto@mcmaster.ca Convolute Lamination Eabric, Porosity, Permeability Elame Structure Sedimentary Geology Sedimentology: History Sedimentologists: Robin G. C. Bathurst Sedimentologists: Amanz Gressly Sedimentologists: Paul D. Krynine Sedimentologists: Philip H. Kuenen Sedimentologists: John Murray and the Challenger Expedition Sedimentologists: Henry Clifton Sorby Submarine Eans and Channels Tool Marks

CONTRIBUTORS

Robert Millar Department of Civil Engineering, 2324 Main Mall University of British Columbia Vancouver BC V6T 1Z4 Canada e-mail: millar@civil.ubc.ca Elow Resistance Kitty L. Miliiken Department of Geological Sciences University of Texas at Austin Austin TX 78712 USA e-mail: kittym@mail.utexas.edu Diagenesis Geodes Andrew Moore Disaster Control Research Center Graduate School of Engineering Tohoku University Aramaki, Aoba 06, Sendai 980-8579 Japan e-mail: moore@tsumani2.civil.tohoku.ac.jp Tsunami Deposits Sadoon Morad Institute of Earth Sciences Uppsala University Uppsala S 752 36 Sweden e-mail: sadoon.morad@geo.uu.se Eeldspars in Sedimentary Rocks Andrew C. Morton HM Research Associates 100 Main Street Woodhouse Eaves Leics LEI2 8RZ England, UK e-mail: a.c.morton@heavyminerals.fsnet.co.uk Heavy Minerals Peter Moziey Department of Barth and Environmental Sciences New Mexico Tech Socorro NM 87801 USA e-mail: mozley@nmt.edu Diagenetic Structures Raymond C. Murray 106 Ironwood Place Missoula Montana 59803 USA e-mail: rcm@selway.umt.edu Eorensic Sedimentology Paul M. Myrow Department of Geology Colorado College Colorado Springs CO 80903 USA e-mail: pmyrow@cc.colorado.edu Colors of Sedimentary Rocks Gutter and Gutter Casts Storm Deposits

Gerald C. Nanson School of Geosciences University of Wollongong Wollongong NSW 2522 Australia e-mail: gerald_nanson@uow.edu.au Anabranching Rivers Rivers and Alluvial Eans H. Wayne Nesbitt Department of Earth Sci. University of Western Ontario London ON N6A 5B7 Canada e-mail: hwn@uwo.ca Seawater: Temporal Changes in the Major Solutes Nora Noffke Department of Ocean, Earth, Atmospheric Sciences Old Dominion University 4600 Elkhorn Ave Norfolk VA 23529 USA e-mail: nnoffke@odu.edu Bacteria in Sediments Microbially Induced Sedimentary Structures Hakuyu Okada Oyo Corporation Kyushu Office 2-21-36 ljiri, Minami-ku Fukuoka 811-1302 Japan e-mail: hokada@bb.mbn.or.jp Sedimentology: History in Japan Geraint Owen Department of Geography University of Wales, Swansea Singleton Park, Swansea SA2 8PP Wales, UK e-mail: g.owen@swansea.ac.uk Ball-and-Pillow (Pillow) Structure Pseudonodules Henry M. Pantin School of Earth Sciences University of Leeds Leeds LS5 9JT England, UK e-mail: h.m.pantin@earth.leeds.ac.uk Autosuspension Roger L. Parfitt Landcare Research PB 11052 Palmerston North New Zealand e-mail: ParfittR@landcare.cri.nz Allophane and Imogolite

CONTRIBUTORS

H. Martyn Pedley Research Institute of Environmental Science University of Hull Cottingham Rd. Hull East Yorkshire England, UK e-mail: H.M.Pedley@geo.hull.ac.uk Tufas and Travertines Morten Pejrup Institute of Geography, University of Copenhagen Oster Voldgade 10 Copenhagen K DK-1350 Denmark e-mail: mp@geogr.ku.dk Elocculation George S. Pemberton Department of Earth and Atmospheric Sciences University of Alberta Edmonton AB T6G 2E3 Canada e-mail: gpembert@gpu.srv.ualberta.ca Biogenic Sedimentary Structures Sedimentologists: Rudolf Richter and the Senckenberg Laboratory Substrate-Controlled Ichnofacies George Postma Department of Geology, Faculty of Earth Sci. Utecht University, P.O. Box 80.021 Utrecht 3508 TA The Netherlands e-mail: gpostma@geo.uu.nl Ean Delta Paul E. Potter Geosciencias/UFRGS Campus Do Vale Sala 302B Porto Allegre 91509-900 Brazil Mudrocks Sedimentologists: Erancis J. Pettijohn Brian R. Pratt Department of Geol. Sci., 114 Science Place University of Saskatchewan Saskatoon SK S7N 5E2 Canada e-mail: brian.pratt@usask.ca Stromatolites Bruce Railsback Department of Geology University of Georgia Athens GA 30602-2501 USA e-mail: rlsbk@gly.uga.edu Stylolites Harold G. Reading Department of Earth Sciences University of Oxford Parks Road Oxford 0X1 3PR United Kingdom Eacies Models

R. Pamela Reid RSMAS-MGG University of Miami 4600 Rickenbacker Causeway Miami, FL 33149 USA Micritization Wolf Uwe Reimold Department of Geology University of Witwatersrand Private Bag 3, P.O. Wits 2000 Johannesburg South Africa e-mail: 065wur@cosmos.wits.ac.za Eeatures indicating Impact and Shock Metamorphism Renard LGIT Universite Joseph Fourier BP53 Grenoble 38041 France e-mail: Francois.Renard@obs.ujf-grenoble.fr Pressure Solution Robin W. Renaut Department of Geological Sci., 114 Science Place University of Saskatchewan Saskatoon SK S7N 5E2 Canada e-mail: robin.renaut@sask.usask.ca Magadiite Gregory J. Retallack Department of Geological Sciences University of Oregon Eugene OR 97403-1272 USA e-mail: gregr@darkwing.uoregon.edu Weathering. Soils, and Paleosols Franco Ricci Lucchi Instituto di Geologia, Universita di Bologna Via Zamboni 67 40127 Bologna Italy e-mail: riccil@geomin.unibo.it Bedding and Internal Structures Robert Riding Department of Earth Seences, Cardiff University Park Place, P.O. Box 914 Cardiff CFIO 3YE Wales, UK e-mail: riding@cardiff.ac.uk Algal and Bacterial Carbonate Sediments

CONTRIBUTORS

David M. Rubin USGS Pacific Science Center University of California 1156 High Street Santa Cruz CA 95064 USA e-mail: drubin@usgs.gov Cross- Stratification Juergen Schieber Department of Geology University of Texas Arlington Box 19049 Arlington TX 76019-0049 USA e-mail: schieber@uta.edu Black Shales Depositional Eabric of Mudstones Peter A. Scholle New Mexico Bureau of Mines and Mineral Resources New Mexico Institute of Mining and Technology 801 Leroy Place Socorro, NM 87801 USA e-mail: pscholle@gis.nmt.edu Cements and Cementation Andrew C. Scott Department of Geology Royal Holloway College, University London Egham Surrey TW20 OEX England, UK e-mail: scott@gl.rhul.ac.uk Charcoal in Sediments Coal Balls E. Seibold Richard Wagner Strasse 56 Freiburg D-7106 Germany e-mail: Seibold-Freiburg@t-online.de Sedimentologists: Johannes Walther I. Seibold Richard Wagner Strasse 56 Freiburg D-7106 Germany e-mail: Seibold-Freiburg@t-online.de Sedimentologists: Johannes Walther Graham Shimmield Dunstaffhage Marine Lab. P.O. Box 3 Oban Argyll PA34 4AD Scotland, UK e-mail: gbs@dml.ac.uk Upwelling Duncan F. Sibley Center for Integrative Studies Michigan State University 100 North Kedzie Lab East Lansing MI 48824 USA e-mail: sibley@pilot.msu.edu Dolomite Textures

Fredrick D. Siewers Department of Geography and Geology Western Kentucky University Bowling Green, KY 42101 USA e-mail: fred.siewers@wku.edu Oolite and Coated Grains Bruce M. Simonson Department of Geology Carnegie Bldg, Oberlin College 52 West Lorain St Oberlin OH 44074-1044 USA e-mail: bruce.simonson@oberlin.edu Ironstones and Iron Eormations Balwant Singh Department of Agricultural Chemistry & Soil Science University of Sydney Sydney NSW 2006 Australia e-mail: b.singh@acss.usyd.edu.au Cation Exchange Rudy L. Slingerland 303 Deike Bldg Pennsylvania State University 262 East Hamilton Ave University Park PA 16801 USA e-mail: sling@ustar.geosc.psu.edu Numerical Models and Simulation Sedimentologists: Grove Karl Gilbert Norman D. Smith Department of Geosciences, U. Nebraska 214 Bessey Hall Lincoln NE 68588-0340 USA e-mail: nsmith3@unl.edu Avulsion Joseph P. Smoot U.S. Geological Survey National Center MS 955 Reston VA 20192 USA e-mail: jpsmoot@usgs.gov Desert Sedimentary Environments John B. Southard EAPS, Bldg. 54-1026, Massachsetts Institute of Technology 77 Massachusetts Ave Cambridge MA 02139 USA e-mail: southard@mit.edu Surface Eorms D.A. Spears Environmental and Geological Sciences Dainton Bldg., University of Sheffield Sheffield S3 7HF England, UK e-mail: d.a.spears@sheffield.ac.uk Bentonites and Tonsteins

CONTRIBUTORS

Jan Srodoii Institute of Geol. Sciences, PAN Senacka I Krakow 31-002 Poland e-mail: ndsrodon@cyf-kr.edu.pl Iliite Group Clay Minerals Mixed-Layer Clays Robert F. Stallard US Geological Survey, Campus Box 458 3215 Marine St, Room El46 Boulder CO 80303-1066 USA e-mail: stallard@colorado.edu Erosion and Sediment Yield Helge Stanjek Lehrstuhl fiir Bodenkunde Technische Universitiit Munchen 85350 Freising Germany e-mail: stanjek@wzm.tum.de Hydroxides and Oxyhydroxide Minerals Donald J.P. Swift Department of Oceanography Old Dominion University Norfolk VA 23529-0276 USA e-mail: dswift@odu.edu Relict and Palimpset Sediments Zoltan Sylvester Shell International Exploration and Production, Inc. P.O. Box 481 Houston, TX 77001-0481 USA e-mail: zoltan.sylvester@shell.com Dish Structure Fluid Escape Structures Pillar Structure James P. Syvitski Institute of Arctic and Alpine Research University of Colorado, Campus Box 450 1560 30th St Boulder CO 80309-0450 USA e-mail: syvitski@stripe.colorado.edu Sediment Fluxes and Rates of Sedimentation P.W. Geoff Tanner Div. of Earth Sci., Gregory Bldg. University of Glasgow, Lilybank Gardens Glasgow GI2 8QQ Scotland, UK e-mail: G.Tanner@earthsci.gla.ac.uk Structures (Mudcracks, etc.) Syneresis

Yves Tardy Institute National Polytechnique de Toulouse Montegeard Nailloux 31560 France Laterites Colin R. Thorne Department of Geography University of Nottingham Nottingham NG7 2RD England, UK e-mail: Colin.Thorne@nottingham.ac.uk Physics of Sediment Transport: The Contributions of R.A. Bagnold Sedimentologists: Reginald A. Bagnold B.R. Turner School of Earth Sciences University of Birmingham, Birmingham England, UK e-mail: p.turner@bham.ac.uk Red Beds Dana Ulmer-Scholle Department of Earth and Environmental Sciences New Mexico Institute of Mining and Technology 801 Leroy Place Socorro, NM 87801 USA e-mail: dulmer@nmt.edu Cements and Cementation John W. Waldron Department of Earth & Atmospheric Sci. University of Alberta Edmonton AB T6G 2E3 Canada e-mail: john.waldron@ualberta.ca Melange: Melange Karl Hans Wedepohl Geochemische Institut Universitat Gottingen Goldschmidtstrasse I D-21011 Gottingen Germany e-mail: Hans.Wedepohl@geo.uni-goettingen.de Sedimentologists: Carl Wilhelm Correns Barry G. Warner Wetland Research Centre University of Waterloo Waterloo ON N2L3G1 Canada e-mail: bwarner@watserv 1 .uwaterloo.caPeat

Brian W. Whalley School of Geosciences The Queen's College Belfast BT7 INN Northern Ireland e-mail: B.Whalley@Queens-Belfast.ac.uk Surface Textures

CONTRIBUTORS

Daryl M. Wightman AEC East 3900 421-7th Avenue SW Calgary AB T2P 4K9 Canada e-mail: DarylWightman@aec.ca Oil Sands Rick T. Wilkin U.S. EPA, Natl. Risk Management Res. Lab P.O. Box 1198 Ada OK 74820 USA e-mail: wilkin.rick@epa.gov Sulfide minerals in Sediments Sherwood W. Wise Department of Geol. Sci. 4100, Florida State University 100 Antarctic Circle Tallahassee FL 32306-4100 USA e-mail: wise@gly.fsu.edu Calcite Compensation Depth Lepisphere

V. Paul Wright Dept of Earth Sciences Cardiff University Cardiff Wales CFl 3YE UK e-mail: WrightVP@cardiff.ac.uk Caliche - Calcrete Raphael A.J. Wlist Department Earth and Ocean Sciences University of British Columbia 6270 University Blvd Vancouver BC V6T 1Z4 Canada e-mail: rwuest@interchange.ubc.ca Kerogen Maturation, Organic Ellis L. Yoehelson Department of Paleobiology, National Museum of Nat. History Smithsonian Institution, 10th St & Constitution Ave NW Washington DC 20560-0121 USA e-mail: yochelson.ellis@NMNH.SI.edu Sedimentologists: T. Wayland Vaughan

Preface

The study of natural sediments and sedimentary rocks has been called sedimentology. This encyclopedia is a thorough revision of the original Encyclopedia of Sedimentology, published by Dowden, Hutchinson and Ross in 1978: The field has advanced so fast, however, that all the articles in the present volume are new, and this is recognized by a new title. The present encyclopedia interprets sedimentology, both more narrowly and more broadly than is often the case (see Sedimentary Geologyan entry in this encyclopediafor further discussion). More narrowly, because the encyclopedia contains relatively little information about stratigraphy, the science concerned with stratified rocks. Stratigraphy and sedimentology overlap, particularly in the area of faeies analysis and sequence stratigraphy. In general, however, stratigraphic topics have been reserved for full treatment in a companion Encyclopedia of Stratigraphy, which is now in preparation. More broadly, this encyclopedia includes topics that some sedimentologists tend to exclude, for examples: the mineralogy of clays and other minerals common in sediments; geochemistry of sediments (sediments are included in the Encyclopedia of Geochemistry); some features of sediments interesting to the general public but somewhat neglected by sedimentologists (e.g., clathrates, coal balls, geodes, resin and amber, speieothems, toxicity of sediments); contributions of engineering studies to sediment transport and soil mechanics; studies on the geophysical and petrophysical properties of sediments; and studies by physicists on granular matter.

Three other disciplines that are represented by separate encyclopedias also have overlapping interests in sediments: hydrology and hydrogeology (represented by Encyclopedia of Hydrology and Water Resources); geomorphology (represented by Encyctopedia of Geomorphology and Lanforms, and also by Encyclopedia of Coastal Science); and environmental studies (represented by Encyclopedia of Environmental Science). A final word about the selection of topics: there is always a subjective element in the choice of topics, but if the reader does not see an entry for the particular topic that interests him, then he or she should look in the index. The topic may be covered (perhaps in more than one article) under a different name. The editors have tried to make the coverage comprehensive, but we are aware of some partial omissions: unfortunately, willing contributors cannot always be found for all the topics that might be suggested. Encyclopedias are not generally places to look for extended acknowledgments. This is a tradition dating back to the days when contributors were anonymous, or only identified by their initials (and imagine the space that would be taken up by acknowledgments from every author: the Academy Awards would pale by comparison!). On behalf of all the editors and contributors, therefore, we extend thanks to those colleagues who have assisted us by providing data, figures, critical reviews, and sustaining personal and financial encouragement. Thank you allwe hope you realize that your generosity is not forgotten, even if your contribution remains anonymous.

Guide to the Reader

This eneyelopedia is devoted to the seienee of sediments and sedimentary rocks, a seienee generally ealled sedimentology. It does not address those broader aspeets of stratified roeks eoncerned with the naming of rocks units, their correlation from one place to another, and their dating in geological time. Those aspects belong to stratigraphy, the subject of another encyclopedia in this series. Sediments and sedimentary rocks ean be approached from three main points-of-view: 1. Like other roeks, they have a mineral and chemical composition, physical properties, and struetures and textures, all of which need description and interpretation in order that we may understand their origin. These are the geochemical, mineralogical, petrological and petrophysical (geophysical) aspeets of sediments and sedimentary rocks. 2. Sediments are first laid down in sedimentary environments. The (primary) aspects of sedimentary rocks that were formed at the time of deposition (particularly, but not exelusively, their structures), are generally ealled their sedimentary faeies. Faeies analysis is concerned with using primary aspects of sediments to determine the environment in which they were deposited: and, in a complementary way, with understanding how modern sedimentary environments control, or are determined by, the characteristics ofthe sediments deposited in them. Sediments interact with many other aspects of the environment, including their biology. 3. Many sedimentologists try to understand the basic physical, chemical and biological processes that form sediments, transport and deposit them, and later convert them into sedimentary rocks. Such studies may be carried out in the laboratory, in the field (particularly by studying processes active in modern environments), and by theoretical and numerical analysis and simulation. For those readers not already familiar with sedimentology. Table I indicates the major introductory articles in eaeh of these three categories (there is, of course, some overlap in the approaches used in most of the articles). Besides these there are also introductory articles on Sedimentary Geology; SedimentologyOrganizations, Meetings, Publications; SedimentologyHistory; and Sedimentologists (brief biographic sketeiies).

Table 1 Major articles, classified by methodology: starred topics are general introductionsGeochemistry, Mineralogy, Petrology 'Bedding and tnternal Structures Biogenic Sedimentary Structures Carbonate Mineralogy and Geochemistry Cements and Cementation Classification of Sediments and Sedimentary Rocks *Clay Mineralogy Compaction (Consolidation) of Sediments * Diagenesis Diagenetic Structures Dolomites and Dolomitization Evaporites Fabric, Porosity, and Permeability Geophysical Properties of Sediments Grain Size and Shape Ironstones and Iron Formations Isotopic Methods in Sedimentology Magnetic Properties of Sediments Mudrocks Offshore Sands Paleocurrent Analysis Phosphorites Provenance Sands, Gravels and their Lithified Equivalents Siliceous Sediments Surface Forms Surface Textures Weathering, Soils, and Paleosols Sedimentary Environments and Faeies Climatic Control of Sedimentation Coastal Sedimentary Faeies Cyclic Sedimentation Deltas and Estuaries Desert Sedimentary Environments Erosion and Sediment Yield Faeies Models Floods and Other Catastrophic Events Glacial Sediments: Processes, Environments and Faeies Lacustrine Sedimentation Neritic Carbonate Depositional Environments Oceanic Sediments Rivers and Alluvial Fans Slope Sediments Submarine Fan and Channels

CUIDE TO THE READER Table 1 Continued Taphonomy: Sedimentological Implications of Fossil Preservation Tectonic Controls of Sedimentation Tidal Flats Tidal Inlets and Deltas Turbidites Upwelling Sedimentary Processes Debris Flow Eolian Transport and Deposition Features Indicating Impact and Shock Metamorphism Grain Settling Grain Threshold Gravity-Driven Mass Flows Numerical Models and Simulation of Sediment Transport and Deposition Sediment Fluxes and Rates of Sedimentation Sediment Transport by Tides Sediment Transport by Unidirectional Water Flows Sediment Transport by Waves

A good approach for readers unfamiliar with the subject is to begin with a general article, then follow the crossreferences listed at the end of the article to tind related topics. For example, one might begin to learn something about Sands, Gravels and their Lithified Equivalents, go on to Bedding and Internal Struetures, then Paleocurrent Analysis, then Cross-Stratification, or some other specific topic. A reader with more knowledge, might begin searching for a speeific topic, for example, concretions. As it happens, there is no article with that name, but reference to Diagenesis, or Diagenetic Structures (or to the Index) would soon lead to articles that describe concretions of various types. If the reader needs more than he ean find in the encyclopedia, most articles give copious bibliographic references, to both general texts and research articles.

RED ALGAE

ALGAL AND BACTERIAL CARBONATE SEDIMENTS

Corallinaceae Peyssonneliaceae Charophyta Dasydadales Halimedaceae Gynfinocodiaceae phylloid algae Solenoporaceae r-.,^,,^u^^^A^

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Calcified algae and bacteriaOnly a few algae and bacteria calcify (Figure Al), but their abundance and wide distribution make them important in limestones of many ages and environments (Figure A2). Microbial carbonates appeared in the Archaean and are significant in Proterozoic carbonate platforms. Calcified cyanobacteria became important in the Cambrian, and calcified green and red algae in the Ordovician. Additional extinct organisms have been regarded as calcified algae or bacteria, but are still of uncertain affinity. These problems of affinity hamper paleocological and phylogenetic interpretations.

UNCERTAIN AFFINITY

GREEN ALGAE

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mannecalc

^

CalcificationEnvironmental range and variations in cellular site and mineralogy of calcification refiect the organism's control over calcification. With decreasing control, calcification site moves from intra- to extra-cellular, mineralogy shifts toward that of ambient abiotic carbonate precipitates, and environmental distribution becomes restricted to locations where inorganic precipitation is favored (e.g., warmer water in marine environments). Strong control (e.g., coralline red algae) allows wide environmental distribution of calcification and is linked to intraeellular sites of CaCO3 nucleation. Weak control (e.g., halimedaceans and cyanobacteria) limits the environmental distribution of calcification, and is linked to an extracellular site of CaC03 nucleation and a polymorph in equilibrium with the ambient environment. Consequently, calcified algae and bacteria have potential to reflect past fluctuations in environmental controls over carbonate precipitation. Cyanobacteria, for example, calcify only when environmental conditions are favorable (Arp etal., 2001). At present, this is only widespread in freshwater, but took place extensively in marine environments in the Paleozoic and Mesozoic.

Figure Al Principal groups of calcified benthic algae and cyanobacteria. Calcified red algae include corallines that are marine, calcitic, occur at all latitudes, and are important reef builders. In contrast, calcified marine green dasycladaleans and halimedaceans are aragonitic and mainly tropical. They mainly produce particulate sediment, although Halimeda creates reefs with its disarticulated segments. Charophyte green algae also produce bioclastic sediment, but are essentially freshwater, calcitic, and prefer temperate climates. Gymnocodiaceans and phylloids are certainly algae, but lack the distinctive features necessary to either subdivide or classify them. Solenoporaceans are a heterogeneous grouping.

Microbial carbonatesMicrobes (bacteria, small algae, fungi) are widespread on wetted substrates. Carbonate precipitation, locally augmented by grain trapping, results in their accretion and preservation as microbial carbonates. Extracellular polymeric substances (EPS), produced by microbes for attachment and protection, provide nucleation sites and facilitate grain trapping. Precipitation is stimulated by photosynthetic uptake of CO2 and/or HCO^ by algae and cyanobacteria, and by ammonification, denitrification, sulfate reduction and other metabolic processes in other bacteria.

ALGAL AND BACTERIAL CARBONATE SEDIMENTS

phylloid reef

rhodolith

; NODULESoncoid

fu

coralline reef REEFS Halimeda , . segments

z o o

MUD-SAND-GRAVELwhiting

microbiai reef MORE

COMPONENT IN-PLACE

Figure A2 Algal-bacterial carbonate sediment. Variations in particle/ component size and degree of movement. Sizes are for basic components in reefs (mud-grade to millimetric fabrics and calcified sheaths in microbial reefs, crustose thalli in coralline red algal reefs, and leaflike algal skeletons in phylloid reefs), and mud-sand-gravel. Internally, microbial domes may have stromatolitic, thrombolitic, dendrolitic, or leiolitic mesofabricsor combinations of these. In nodules, size indicates overall rhodolith or oncoid size. Whereas components in microbial, coralline and phylloid reefs are essentially in place, segments ofthe green alga Halimeda in segment reefs are parauthochtonous. Centimetric nodules, built by red algae (rhodoliths) and calcified microbes (oneoids) are also commonly parautochtonous. Halimeda segment reefs typically accumulate at depths of 20-50 m on low angle shelves and atoll lagoon floors. In contrast, on slopes and in shallower water, carbonate mud-sand-gravel produced by disaggregation of Halimeda and Pen ici 11 us green algae is commonly transported. In addition, numerous other freshwater and marine algae, such as green charophytes and red articulated corallines, produce particulate sediment. Whiting crystals form in surface waters and settle out of suspension.

macrofabrics. Nodules also form, usually with stromatolitic coats (oneoids). Stromatolites probably appeared at 3540 Ma and contributed significantly to Paleo-Mesoproterozoic (2500-1000 Ma) carbonate platforms. Their Neoproterozoie decline has been attributed to eukaryote competition and/or reduced lithification. However, thrombolites and dendrolites were major Cambrian and Late Devonian reef-builders. In addition to domes and columns, less conspicuous but volumetrically significant microbial masses and layers are widespread in Phanerozoie algal-invertebrate reefs. Modern marine examples at Shark Bay, Western Australia, and Lee Stocking Island, Bahamas, are coarse-grained agglutinated columns with crudely layered macrofabrics built by cyanobacterial-algal mats on wave-swept hypersaline shorelines (Shark Bay) or in normal salinity tidal channels (Lee Stocking). Thick fine-grained microbial crusts also form on Neogene coral-coralline reefs, and mats and biofilms calcify heavily in present-day calcareous streams and lakes. Temporal variation in abundance of marine microbial carbonate has been attributed to dependence on supersaturation state of seawater facilitating synsedimentary calcification. Cyanobacterialcalcification, in which the protective mucopolysaccharide sheath is impregnated with CaCO3, creates distinctive mierofossils that contribute to dendrolites, some thrombolites, and skeletal stromatolites. Patterns of cyanobacterial calcification and microbial dome formation through time could retlect fluctuations in seawater chemistry (Riding 2000).

ReefsMicrobial. In the Paleo-Mesoproterozoic and Paleozoic, stromatolite and other microbial reefs are major components of carbonate platforms. Some of the largest examples, hundreds of meters in extent and with tens of meters of relief, formed in deepwater. Dendrolites and thrombolites built by millimetric calcified microbes, most likely cyanobacteria, such as Angusticellularia, Epiphyton, and Renalcis, are locally important as rigid microframes. In Cambrian reefs, (e.g., Siberia) they are often much more abundant than archaeocyath sponges, and can rival stromatoporoids in Late Devonian reefs (e.g.. Canning Basin). Phylloid algae. Carboniferous-Triassic phylloid algae are united by leaflike form more than affinity. Erect blades with internal medulla and cortex (e.g., Anchicodium, Eugonophyllum, Ivanovia) resemble halimedaeean green algae. Prostrate crusts with internal cellular tissue and conceptacles (e.g., Archaeolithophyllum) resemble red algae, particularly peyssonneliaceans. Both forms build self-supporting skeletal frame reefs with substantial shelter cavities and abundant localized fine sediment that are common in the Late Carboniferous-Early Permian of the southwestern USA, Arctic Canada, and Russia. Coralline algae. Cell-wall calcification and encrusting growth allow crustose coralline red algae (Cretaceous-Recent) to build reefs in wave-swept environments. Present-day coralline laminar frames are characteristic of Pacific algal ridges and Atlantic cup and boiler reefs. Corallines (e.g., Lithoporella, Lithothamnion, Sporolithon) have calcitic, often magnesiumrich, skeletons and range from tropical to cold and deep water. In mid-latitudes, for example, the Mediterranean, they form thick ledges (trottoir) close to sea-level, and reefs (coralligene) in deeper water. Branched forms create interlocking frameworks in high latitudes. Crustose corallines also form rhodolith nodules. Related articulated corallines disaggregate to sand.

Biofilms are very thin layers, usually only a few hundreds of microns in thickness, of heterotrophic bacterial cells >r] silty clay and sandy clay

j.! ^ 11 bedrock

Figure A4 Textural lacifS model ofthe upper Columbia River (British Cdlumbi.!, Canada!, a ra|iidiy aggr^iding (Anastomosing syslem in J temperate humid montane setting. Scale is approximately 2 km in width and alluvial thickness ^-lOm (atter Makaske, 2001).

effectively as a systetn of multiple channels separated by vegetated lioodplain islands. Gerald C, Nanson and Martin R, Gibling

Nanson, G,C,. and Knighton. A,D., 1996, Anabranehing rivers: their cause, charaeler and classification. Eiirih Surfiue f'roces.se.s amil.amlforms. 2 t : 217 239.

BibliographyChurch, M,, 19^3. Anastotnosed fltivi:il deposits: modern examples from Western Catiada. In Cdllinson. J,D,, and Lcwin, J, (eds,). Moilcrn ami .iiicicnt Fluvial Sysicni\. liilcrnulional Association of Scdimt:iitologists, Special Ptiblicalion 6. pp, 15.5 168, I riend, P,K,. 198.1, Towards the licki eJassification of ;illuvial architecture or sequence. In Collinson, J,D,, and Lcwiti, J, (eds,), Motlcrii iiiul .Aiicicnr Fliniul SysWiiis. International Association of SedlI1lcntologist^, .Special Ptiblicalion, 6, pp, 345 354. (libling, M.R,, Nanson, G,C,, and Maroulis. J,C,. 1998, Anastomosing river sedimentation in tlie Cliannel Country of central Aiislralia. 5t'(//(fH/^j/()^'i. 45; 595 619. Hickin, E.J,, 1^93, fluvla! facies models: a review of Caiuidian research, Pnif-rcssin PliysiciilCeof^ni/iliy. t7: 205-222, Knigliton, A.D,. and Nanson, G . C . 199.'^, Anastomosis ;tnd the continuum of channel piittern, Eiirtli Surface PfiHes.se.\ andLaiuiJorim, 18: 613-625. Maka.ske. B,, 2001, Anastomosing rivers: a review of iheir elassilie;i\\o\\. origin and sedimentary prodiiets, Earih-Scieiicc Reviews. 53: 149 I9f), Nanson, G,C., and Huang, H,Q,. I9*>9. .Anabiiincliing rivers: divided el'ticieney leading lo lluvial diversity. In Miller. A.J,, and Gupta. A, (eds.). VarietiesiijFiu\iulh'arnt. Chichester: Wiie>. pp, 219 248,

Smitli, D,G,, 1973, Aggradation ofthe Alexandria-North Saskatchewan River, Banff Park, Alberta, In Morisawa, M, (ed,), Fluvieil (ieaiiKirpliol'igy. Binghamton, NY: Publications in Geomorphology, New York State L'niversity, pp, 201 219, Smith, D,G,. and Smith, N,D,, 1980, Seduiientation in anastomosed river systems: examples from alluvial vallevs near Banff, Alberta, .hnirnalof SeilimeiUary Relnilogy, 50: 157 164,

Cross-referencesBraided t lianneU Meandering Channels Rivers and Alltivial Fans

ANCIENT KARST IntroductionKaist is characterized by spectacular surlace topographies, caves, and subterranean drainage systetns that have developed in soluble limestone, dolostone. or gypsum bedrocks (e.g., Jennings. 1971, 1985: Sweeting. 1973: Bogli, 1980; Trudgill, !9S5). Karst is geologically complex because it represents the

12

ANCIENT KARST

balance between the diametrically opposed processes of dissolution and precipitation which are mediated by groundwater that flows over and through the bedroek. Thus, from a geological perspective karst is a subaerial diagenetic terrain. Esteban and Klappa (1983) defined karst as " , , . a diagenetie faeies. an overprint in subaerially exposed carbonate bodies, produced and controlled by dissolution and migration of calcium carbonate in meteoric waters, occurring in a wide variety ofclitnatic and tectonic settings, and generating a recognizable landscape." Similarly. Choquette and James (1988) defined karst to " , . , inelude all oi" the diagenetie features maeroseopie and microscopic, surface and subterraneanthat are produced during the chemical dissolution and associated modification of a earbonate sequence." Ancient karst (or paleokarst) includes relict paleokarst (present landscapes formed in the past) and buried paleokarst (karst landscape buried under younger seditiients) as defined by Jennings (1971), Sweeting (197.1), and Choquette and James (1988), Ancient karst is charaeterized by an unconformity that represents the original erosional landform and the underlying "karsted"" rocks, which are characterized by diagenetic fabrics fonned by dissolution and precipitation. Recognition of ancient karst is important because the karst surface repre.sents a break in deposition that commonly constitutes a sequettee boundary, and the diagenetically modified rocks beneath the karst surface may be superb reservoir rocks for hydrocarbons or hosts for various economically important ores.

Features of ancient karstAn ancient karst surface may be eharaeterized by (1) stratigraphie geomorphic features, (2) maeroseopie surface and subsurfaee karst features, and (3) microseopic features (Choquette and James, 1988).

Figure A5 General view of the Cayman Unconformity (U/C) that separates the Cayman Formation (CF) from the Pedro Castle Forma, at which point the grains begin to flow, reducing the overall slope to the true angle of repose, the slope after avalanching has ceased. In a similar fashion, when piled to form a cone, the grains accumulate to the angle didui- orchickeu wiirfabrics nol, on its own. sufficient evidence lo c/.v.v/tj;; a sabkha origin lo the host .sedimentary rorks. This follows because anhydrite nodules ean form under a variety of conditions, the most unusual being the nodules of anhydrite found in cores of sealloor sediments under 2 km of water in the Atlantis II Deep of the Red Sea, a site ofupwelling hydrothermal brines (Degens and Ross, 1969, pp. .366 367). Clearly, modern nodular anhydrite is not unique to sabkha settings. Instead, the common factor is the process of replacement of gypsum by anhydrite, that is. single erystals of gypsum are altered to a mass of tiny anhydrite laths plus liquid water, a rather eohesionless mixture easily deformed by the

weight of the enclosing sediment. The observed tendency is for the anhydrite mass to change toward a spherieal or ovoid shape. Dehydration of clusters of gypsum crystals or layers of crystalline (or detrital) gypsum would yield "chicken wire" anhydrite. The tinjing of the formation of the nodular anhydrite would depend on the P. Tand activity of H^O of the pore fluids. Anhydritization could have taken place at the surface contemporaneously with sedimentation or much later during burial. Nodular and "chicken wire"" gypsum is likely to have had a more complex history, one in which primary gypsum crystals were first replaced by a felted aggregate of anhydrite laths which in turn were later rehydrated to a mass of small gypsum crystals. In this regard, Murray (1964) has pointed out that gypsum formed at the surface will inevitably dehydrate to anhydrite on burial (depth of conversion dependent on the pre\ailing T, P and groundwater salinity). In turn, on uplift and contact with dilute groundwaters, anhydrite uill rehydrate to gypsum. In conclusion, gypsum and anhydrite nodular fabrics are at best ambiguous eriteria for determining depositiona! environment. Nodules composed of other minerals such as calcite, chert or other non-sulfate mineral presumed to be pseudomorphous replacements of anhydrite or gypsum must carry even less weight. Instead, reliance can only be placed on the vertical succession of subfacies and their internal primary sedimentary is structures and fabrics, fossils assemblages, ete.. in diagnosing the depositional settings of ancient gypsum/anhydrite deposits (e.g.. Figure A8) Lawrenee A. Hardie

BibliographyAli, Y.A.. and West, I.M., 198.'(, Relationships of modem gypsum nodules in sabkhas of loess to compositions of brines and sL'dinu-nti. in northern Egypt. Journal of Sedimenlarv Pelroiogr. 53: ILM Il(i8.

ANKBRITE (IN SEDlMFNTSi Bchoui. D.Ci.. and Maiklom. W.R,. 1973, Ancicnl aniiydrile lacics ami replaced calcitc. Ankcrite Is more stable ihan both calcite and cinironniL-nts. Middle Devonian Elk Point Basin, AlbcrUi. Biil/ciiii dolomite in many iron-rich fluids, even if they have relatively of Ctiiuiiliiin Pclrolciiiii (Jcoloi^y. 21: 287 343. highCa-VMg'^ ratios. Builcr. Ci.P.. 1970. Holoccnc gypstim atid anhydrite of llic .4bu Dhabi Chemical analysis is usually required to distinguish ankerite SiibkliLi: an allcrnalive explanation of origin, [n R:ILI, J.L.. and Dellwlg. L.F. (cds.). Proceedings of the Third Salt Sympiisitini. from fcrroan dolomite, although aiikerile may be discrimiCleveland: Norihern Ohio Geologiail Society, pp. 120 152. nated from pure dolomite by X-ray diffractonictry. It Is idenDcgens. E.T., and Ross. D.A. (cds.). 1%9. Hot Brims ami Recent MCKII tical to dolomite in thin section, and gives a turquoise color Dc/'osit.s in the RetlSea. Springer-Vcrlag. with alizarin red-S and potassium fcrricyanide mixed stain (see Demieeo, R.V.. and Hardic. L.A.. 1994. Seclimenlary Structures ciinl "Stains"). Ankerite is black in cathodoluminescence. but may hiirly Didnenctic Fetitiire.s of Shallow Marine Carbonate Depo.sit.s. display complex compositional zonation when imaged with SEPM Alias Scries Number I, 265pp. Garbcr. R.A., i.cvy. Y.. and Friedman. G.M.. 19S7, Ihc scditiicniolbackscatter scanning electron microscopy. It sometimes has ogv of ihf Dead Sea. Onhonnte.sancl livapiirite.s. 2; 43 57. curved crystal faces comparable the high-temperature "baroHardie. L.A.. 1967. The gypsum-aiihydrile eciuilihrium al one almoque" form of dolomite (e.g.. SpotI eiaL, 1996). splicre pressure. .American Miiieralniiisl. 52: 171 201). Ankerite in sedimentary rocks is commonly investigated I lardie. L.A.. and tiugsier, H.P.. 1971. The" depositional environments using stable isotope geochemistry. However. O isotope fractioof marine evaporites: a case for shallow clastic accumulation. nation between water and ankerite at diagenetic temperatures Si'ilimentohgy. 16: 187-220. 1 laritie. L.A.. and Shinn. IZ.A.. 19S6. Carbonate depositional environ- is poorly constrained. Many studies extrapolate e.\perittiental ments modern and aneient. part 3: tidal Hats. Colonulo Schimlof high temperature fractionation factors, or assume an "averMines Qiuirtcrly. 81: 1-74. age" 4 3 percent difference between cogeiietic calcite and lmla>. R.W., 1940. Lower Crelaceoiis and Jurassic tbrmalions ot" dolomite/ankerite (e.g., Dutton and Land. 1988). Theoretical southern Arkansas and their oil and gas possibilites. Inrormation considerations based on crystal structure, chemical comCireiilcir 12. .-irkan.'His Re.soiirce.^ and Developiiicni Commissiini. Little position and cation-oxygen bond strengths suggest that the Rock. M pp. .lung. W.. 195S. Zur Feinslraligralie de Werraanhydrite (Zechstein 1) ankerite-calcite fractionation may actually be less than 3 perini Beieich dcr Satigerhauser und Mansfelder Mtilde. Geohn^ie. cent In low-temperature situations (Zheng. 1999). Valid interBeiheflc. 24: }\2 .325. pretations of ankeriie geochemistry critically require Mmray. R.( .. 1964. Origin and diagenesis of gypsum and anhydrite.Journalo/ Sedimentary Petniloi;y. 3 4 : 512 523.

Neev. D.. and Emery. K.O.. 1967. The Dead Sea: deposilional processes and environments of evaporiies. Geolofiical Survey of l.sriu-l Bulletin. 41: 147 pp. Parea. G.C, and Ricchi Lucchi, F.. 1972. Resedimented evaporites in ihe Periadrialie trough. IsriielJinirnalo/Earth Science. 21: 125 141. Riley. C M . , and Byrne. J.V., 1961. Genesis of primary struetures in anhydrite. Joiirnalof Sedimentary Petrology. 31: 553 559. Warren. J.K.. 1984. Evaporiic Scdinfcntohigy. Prentice Hall.

evaluation of its replacive or pore-filling nature, which can be difficult in sandstones. Occurrence of ankerite in sedimentary rocks

Cross-referencesEivaponies Sabkha. Sail Flal. Salina

ANKERITE (IN SEDIMENTS)

Ankcritc is a frequent but usually mitior burial diagcnctic phase in sandstones. It can also be present in early diagenetic niudrock-hosted coneretions. and rarely as a replacive or void filling bui'ial precipitate iti limestones, Ankcrite precipitation may result from kical (bed-scale) to regional mass transfer, particularly during interaction of composilionally and thermally distinct subsurface fluids. Mineralogy and chemistry Ankerite has a general formula Ca (Mg, F"c^'. Mn) (COi): and is part of a solid solution series resulting from substitution of l^c"' ( +subordinate M n " ) for Mg"' in the dolomite lattice. It is usually defined as having a Mg" ' : Fe"^ * ratio of 1() percent of the mineral assemblage. Ankerite commonly overgrows earlier dolomite and/or replaces bioclastic or authigenic calcite. Quartz grains enveloped by ankerite cements are corroded, and partial to complete replacement of feldspars is also common. Many exatiiples are described from the Mesozoic North Sea (e.g.. Kantorowicz, 1985), (iulf Coast and Eastern Te.xas (e.g.. Land and Fisher. 1987) and Alberta Basin. Ankerite is also recorded from Pernto-Triassic continental sandstones in a variety of locations, and from a number of Paleozoic sandstones, notably in the southern USA. Pervasive cementation by ankerite is rare, although m-dm sized concretions have been described from deeply buried (>5km) Jurassie sandstones of the Centra! North Sea (Ilendry I'laL. 2000). Ankerite in sandstones tends to be paragenetically lale, strongly depleted In '*^0 and variably depleted in '"'C. This suggests formation at elevated temperatures (deep burial) with a proportion of the carbon derived by thermal decarboxylation of organic matter and the remainder remobllized from bioclasts and early cements or from adjacent limestones. Radiogenic ^''Srl^^Sr values commonly indicate ankerite formation after a substantial amount of silicate diagenesis. Mudrocks are commonly believed to be principal sources of Mg~' and Fe"^. and ankerite formation has been causally related to mobilization of these cations fbllovving illitization of smectite and thermal reduction of ferric oxides (e.g.. Boles. 1978). This interpretation has been questioned beeause Cenozoie strata in the Gulf Coast contain very little ankerite despite laree volumes of illitized mudrock. and becatise much of the Fe''

20

ANKFRITE ilN SEDIMENlSt

Figure A9 I ligh contrast backscatter eleclron pholomicro^taph of compositionally zoned tinkcritet'crroan dolomite in Upper lurassic sandstones, Central Craben, North Sea, Quart? j^rains and (lorosity appear black, K-feldspars arc bright.

and as concretionary cement. Stable isotopie data suggest that it formed at shallow to intermediate burial depths (lO's lOO's m) with carbon soiirced by bacterial fermentation or thermal deearboxylation of organic matter and Fe"' from redtiction of detrital ferric oxides (e.g.. Irwin. 1980). A limited supply of Mg"" from residtial seawater might explain why such ankerite is tisually calcian. Ankerite does not typically form in the shallower sullate reduction zone because pyrite is a more effective sink tor Fe"^'. Ankerite is less common than siderite and calcite in nonmarine mudrocks because of a paucity of Mg""^. Nevertheless, it can be a significant diagenetic precipitate in siltstones and mudrocks of coal measures as well as replacing authigcnic siderite in coal seams. High concentrations of ferric oxides and hydroxides were eroded from latcritic soils and deposited in anaerobic coastal plain lagoons and swamps. Pore lltiid mixing during marine inundation and/or between intercalated brackish and marine faeies during shallow burial introduced Mg"' and Fe"* into the non-marine strata allowing ankerite to form (Matsumoto and lijima. 1981),

Summaryand Mg produced in mudrocks can be consumed bv in.situ mineral authigenesis. An alternative source of Fc"' and Mg'' tnay be volcaniclastic materials within sandstones (Morad et al.. 1996). However, mudrocks appear to be the only viable Fe"^ and Mg"''' source for ankerite formation in many sandstones. A variety of models have been proposed for lluid and mass transfer related to ankerite formation in sandstones. Variable ankerite eompositions and/or concentration in close proximity to intercalated mudroeks suggest local solute transfer in stagnant pore fluids (e,g,. Macaulay etal., 1993). Other ankerites yield isotopie and fluid inclusion data that require long distanee and/or cross-formational fluid flow. Ankerite associated with sulfate-sultide mineralization in sandstones has been linked to mixing of hypersaline lluids derived IVom juxtaposed evaporites and metalilerous hot tluids transmitted tip faults from source rocks deeper in the basin (Burley etal.. 1989). Ankerite exists in sedimentary rocks as a late diagenetic cement or replacement of pre-existing carbonate, li can be formed in a number of ways, provided an adequate supply of Fe''' and Mg^" relative to Ca"'. The iron is mostly derived from ferric oxides deposited in mudrocks. but sources of Mg'"^ are more varied and can be difficult to constrain in individual cases, Ankerite can be formed as a response to basin-scale fluid flow or by localized tnass transfer between juxtaposed porous sediments and mudrocks. Ankerite cements may also precipitate during early diagenesis given suffieient Mg^' in pore lluids and provided that pyrite formation did not exhaust the local supply of labile iron. James P. Hendry

BibliographyBoles. J.R.. 1978. Active ankerite cetnentation in the stibsurfaee Eocene of Soulhwest Texas. OinirihtiiiniiMo MiiicralngviiinlPelrdl(>i:y. 68: 13 22. Barley. S,D,, Miillis. J,. and Maiter. A,. \9H9. Timing diagenesis in the Tiirtiin Reservoir (LJ. K, North Sea): consfraliils from combined cathodoliimincsecnce microscopy and Huid incltision sttidies. A//% clay, and measures soil plasticity normalized by clay content. Activity values are strongly correlated with clay mineral type. Values above 2 indicate expanding montmorillonite clays; values closer to 0,5 are typical of kaolinite clay soils. High IA values generally indicate soils of low strength, high plasticity and high swell-shrink potential, thus indicating potential slope stability and foundation engineering problems. Table Al summarizes typical values of Atterberg Limits and associated indices for a range of soil materials. The very large ranges in values emphasize the importance of both clay mineral species and clay content as controls. Of particular note is the contrast between very high plasticity, montmorillonite clay soils (e,g,, Mexico City volcanogenie lacustrine clay and Pierre Shale marine clay-shale), in comparison with very low plasticity silts and silty-clay soils (e,g,, glaciolacustrine silts and glaciomarine Leda Clay), In the latter two deposits, much of the clay-sized fraction typically is not true phyllosilieate but

2435

ATTRITION (ABRASION), FLUVIAL Liquefaction and Fluidization Mass Movement Mudrocks Slurry Smectite Group Weathering, Soils, and Paleosols

25

20 -0.02 / 15

ATTRITION (ABRASION), FLUVIAL

DO 1 0

-1

I

L_

0

20

40

60

80

100

120

Plasticity Index, /p (%)

Figure A10 Relation between plasticity index and residual angle of shearing resistance. Data points are derived from Voight (1973), Kanji (1974) and the author's files.

instead quartz-feldspar rock flour derived from glacial abrasion. Average values of residual friction angle are also given for each soil type. Residual strength refers to the lowest value obtainable from large-displacement, drained shear tests. Strong inverse relations exist between and Ip (Figure AlO) Ir and IA, as previously noted by Voight (1973), Kanji (1974), and Wroth and Wood (1979), Michael J, Bovis

Fluvial attrition is generally understood to refer to any process of mechanical grain wear leading to grain size reduction in the course of sediment transport through rivers. Fluvial abrasion is generally accepted as an equivalent term, though it might also be interpreted to mean modification of the stream bed or banks, Mikos (1993) has presented a modern treatise on the subject of fluvial attrition of clastic grains, "Abrasion" in the present context specitically implies surface wear caused by the relative motion of two surfaces in frictional contact, especially when one surface is harder than the other ("grinding", when one of the grains is at rest, is sometimes distinguished). Additional processes that have been invoked as contributing to fluvial "abrasion" include impact or percussive effects (e,g,, chipping, splitting and sandblasting), and crushing, when the impact of a larger rock causes a small grain to disintegrate. Weathering and solution have also been invoked, but this appears to confuse preparatory processes with mechanical destructive mechanisms. In rivers, abrasion appears mainly to affect pebble and larger sizes. The characteristic downstream reduction in size, hence weight, of fluvial gravels was formulated by Sternberg (1875) into a "law" of weight loss"the wear of a grain is proportional to its submerged weight (W) and the distance (L) it has travelled". Mathematically, dlVldL = -oi.W, in which a is the weight loss rate coefficient. The statement integrates to the familiar result

BibliographyCraig, R,F,, 1997, Soil Mechanics, 6th edn, London: Spon Press, Higgins, J,D,, and Modeer, V,A,, 1996, Loess, In Turner, A,K,, and Schuster, R,L, (eds,). Landslides: Investigation and Mitigation. Washington, DC: National Acadetny Press, pp, 585-606, Kanji, M,A,, 1974, The relationship between drained friction angles and Atterberg limits of natural soils, Geotechnique, 24: 671-674, Kenney, C , 1984, Properties and behaviours of soils relevant to slope stability. In Brunsden, D,, and Prior, D,B, (eds,). Slope Instability. New York: J, Wiley & Sons, pp, 27-66, Lambe, T,W,, and Whitman, R,V,, 1969, Soil Mechanics. New York: J, Wiley & Sons, Lefebvre, G,, 1996, Soft sensitive clays. In Turner, A,K,, and Schuster, R,L, (eds,). Landslides: Investigation and Mitigation. Washington, DC: National Academy Press, pp, 607-619, Selby, M,J,, 1993, Hillslope Materials and Processes, 2nd edn, Oxford: Oxford University Press, Voight, B,, 1973, Correlation between Atterberg plasticity limits and residual strength of natural soils, Geotechnique, 23: 265-267, Wroth, C,P,, and Wood, D,M,, 1979, The correlation of index properties with some basic engineering properties of soils, Canadian Geotechnical Journal, 15: 137-145,

Cross-referencesBentonites and Tonsteins Colloidal Properties of Sediments Grain Size and Shape Gravity-Driven Mass Flows

in which WQ is the initial grain weight before travel. Since W oc D^, grain diameter, the rule can be interpreted as a size reduction rule, in which oi.o = aiyB. Sternberg's result has been abundantly confirmed empirically and, since river engineers supposed for a long time that abrasion was the chief source of the effect, it became known as the law of fluvial abrasion. However, experimental measurements of abrasion nearly always return rate coefficients much smaller than ones inferred from field data (Adams, 1978 provides a list of experimentally derived abrasion coefficients for a wide range of lithologies). It has consequently been recognized that size-selective transport (e,g,, Plumley, 1948; Bradley etal., 1972) and weathering of grains during storage in bars and floodplains (Bradley, 1970) represent additional mechanisms for gravel size reduction along rivers, Adams (1979) investigated the wear of weathered grains recruited into river headwaters. He found that the size reduction coefficient (a) itself changes with distance downstream, at a declining rate, so that the rate of change of grain size with distance follows a power law, rather than the exponential rule of Sternberg, He also showed convincingly that the result was due to wear and interpreted it to reflect the rapid destruction of weathered material. Farther downstream, the Sternberg rule applies to the remaining, competent material. However, Jones

ATTRITION (ABRASION), MARINE

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and Humphrey (1997) demonstrated rapid changes in the wearing coefficient of material liberated from long-term storage in fluvial deposits, where substantial weathering again occurs. At the other extreme, Rice and Church (1998) demonstrated dramatic changes in grain size over reach-scale distances far too short for appreciable particle wear to occur, indicating the efficacy of size-selective transport. Both processes occur simultaneously, particularly in the presence of multiple lithologies, when less resistant lithologies may be consumed by abrasion whilst the size of the more resistant ones varies mainly by selective transport. Recent work has sought to examine the relative significance of and interaction between abrasion and selective transport of grains (e.g., Parker, 1991a,b). There remain significant complexities in the problem of determining wear and its