EXCEPTIONAL FOSSIL PRESERVATION: A Unique View on the Evolution of Marine Life Edited by DAVID J. BOTTJER COLUMBIA UNIVERSITY PRESS Bottjer_00FM 5/16/02 1:23 PM Page i EXCEPTIONAL FOSSIL PRESERVATION Critical Moments and Perspectives in Earth History and Paleobiology DAVID J. BOTTJER RICHARD K. BAMBACH Editors Bottjer_00FM 5/16/02 1:23 PM Page ii Critical Moments and Perspectives in Earth History and Paleobiology David J. Bottjer and Richard K. Bambach, Editors The Emergence of Animals: The Cambrian Breakthrough Mark A. S. McMenamin and Dianna L. S. McMenamin Phanerozoic Sea-Level Changes Anthony Hallam The Great Paleozoic Crisis: Life and Death in the Permian Douglas H. Erwin Tracing the History of Eukaryotic Cells: The Enigmatic Smile Betsey Dexter Dyer and Robert Alan Obar The Eocene-Oligocene Transition: Paradise Lost Donald R. Prothero The Late Devonian Mass Extinction: The Frasnian/Famennian Crisis George R. McGhee Jr. Dinosaur Extinction and the End of an Era: What the Fossils Say J. David Archibald One Long Experiment: Scale and Process in Earth History Ronald E. Martin Interpreting Pre-Quaternary Climate from the Geologic Record Judith Totman Parrish Theoretical Morphology: The Concept and Its Applications George R. McGhee Jr. Principles of Paleoclimatology Thomas M. Cronin The Ecology of the Cambrian Radiation Andrey Yu. Zhuravlev and Robert Riding, Editors Plants Invade the Land: Evolutionary and Environmental Perspectives Patricia G. Gensel and Dianne Edwards, Editors Bottjer_00FM 5/16/02 1:23 PM Page iii EXCEPTIONAL FOSSIL PRESERVATION A Unique View on the Evolution of Marine Life Edited by DAVID J. BOTTJER, WALTER ETTER, JAMES W. HAGADORN, AND CAROL M. TANG COLUMBIA UNIVERSITY PRESS New York Bottjer_00FM 5/16/02 1:23 PM Page iv Columbia University Press Publishers Since 1893 New York Chichester, West Sussex Copyright © 2002 Columbia University Press All rights reserved Library of Congress Cataloging-in-Publication Data Exceptional fossil preservation: a unique view on the evolution of marine life / edited by David J. Bottjer . [et al.]. p. cm. — (Critical moments and perspectives in Earth history and paleobiology) Includes bibliographical references and index. ISBN 0-231-10254-2 (cloth : acid-free paper) ISBN 0-231-10255-0 (pbk. : acid-free paper) 1. Marine animals, Fossil. 2. Taphonomy. I. Bottjer, David J. II. Critical moments in earth history and paleobiology series. QE766.E93 2001 560Ј.457–dc21 2001042434 ∞ Columbia University Press books are printed on permanent and durable acid-free paper. Printed in the United States of America c 10 9 8 7 6 5 4 3 2 1 p 10 9 8 7 6 5 4 3 2 1 Bottjer_00FM 5/16/02 1:23 PM Page v CONTENTS Foreword ix Acknowledgments xiii 1 FOSSIL-LAGERSTÄTTEN: JEWELS OF THE FOSSIL RECORD • 1 David J. Bottjer, Walter Etter, James W. Hagadorn, and Carol M. Tang 2 ENIGMATIC EDIACARA FOSSILS: ANCESTORS OR ALIENS? • 11 David J. Bottjer 3 CHENGJIANG: EARLY RECORD OF THE CAMBRIAN EXPLOSION • 35 James W. Hagadorn 4 BURGESS SHALE: CAMBRIAN EXPLOSION IN FULL BLOOM • 61 James W. Hagadorn 5 BURGESS SHALE–TYPE LOCALITIES: THE GLOBAL PICTURE • 91 James W. Hagadorn 6 ORSTEN DEPOSITS FROM SWEDEN: MINIATURE LATE CAMBRIAN ARTHROPODS • 117 Carol M. Tang Bottjer_00FM 5/16/02 1:23 PM Page vi vi • Contents 7 BEECHER’S TRILOBITE BED: ORDOVICIAN PYRITIZATION FOR THE OTHER HALF OF THE TRILOBITE • 131 Walter Etter 8 HUNSRÜCK SLATE: WIDESPREAD PYRITIZATION OF A DEVONIAN FAUNA • 143 Walter Etter 9 BEAR GULCH: AN EXCEPTIONAL UPPER CARBONIFEROUS PLATTENKALK • 167 James W. Hagadorn 10 MAZON CREEK: PRESERVATION IN LATE PALEOZOIC DELTAIC AND MARGINAL MARINE ENVIRONMENTS • 185 Stephen A. Schellenberg 11 GRÈS À VOLTZIA: PRESERVATION IN EARLY MESOZOIC DELTAIC AND MARGINAL MARINE ENVIRONMENTS • 205 Walter Etter 12 MONTE SAN GIORGIO: REMARKABLE TRIASSIC MARINE VERTEBRATES • 221 Walter Etter 13 BERLIN-ICHTHYOSAUR: PRESERVING SOME OF THE EARTH’S LARGEST MARINE VERTEBRATES • 243 David J. Bottjer 14 OSTENO: JURASSIC PRESERVATION TO THE CELLULAR LEVEL • 251 Carol M. Tang 15 POSIDONIA SHALE: GERMANY’S JURASSIC MARINE PARK • 265 Walter Etter and Carol M. Tang 16 LA VOULTE-SUR-RHÔNE: EXQUISITE CEPHALOPOD PRESERVATION • 293 Walter Etter Bottjer_00FM 5/16/02 1:23 PM Page vii Contents • vii 17 OXFORD CLAY: ENGLAND’S JURASSIC MARINE PARK • 307 Carol M. Tang 18 SOLNHOFEN: PLATTENKALK PRESERVATION WITH ARCHAEOPTERYX • 327 Walter Etter 19 SMOKY HILL CHALK: SPECTACULAR CRETACEOUS MARINE FAUNA • 353 David J. Bottjer 20 MONTE BOLCA: AN EOCENE FISHBOWL • 365 Carol M. Tang Contributors 379 Index 383 Bottjer_02 5/16/02 1:24 PM Page 11 2 Enigmatic Ediacara Fossils: Ancestors or Aliens? David J. Bottjer he ediacara fossils, of late precambrian (vendian) through Cambrian age, are among the most remarkable fossil bio- Ttas known from the stratigraphic record. This stems from the fact that this biota is thought to include fossils of some of the earliest larger organisms, whose nature has been much debated: Are they ancient rep- resentatives of still extant metazoan phyla, do they represent phyla or a kingdom now extinct on Earth, or could they even be colonial procary- otes or fossil lichens? Furthermore, when compared with younger de- posits, this biota is in general a taphonomic anomaly. The Ediacara fos- sils represent remains of completely soft-bodied organisms, and yet they are commonly preserved in coarser-grained siliciclastics deposited in rel- atively well oxygenated marine environments, a seemingly improbable phenomenon not known elsewhere from the marine fossil record. Be- cause Ediacara fossil preservation is commonly associated with some sort of event bed, varying from tidal sandstones to storm beds, to turbidites and subaqueous ash falls, their taphonomic context is best thought of as obrution deposits. Fossils we now recognize as Ediacara were discovered as early as the nineteenth century in England at the Charnwood Forest locality (Hill and Bonney 1877) and in the early twentieth century in Namibia (Gürich 1930). However, their importance was not internationally rec- ognized until the 1940s when R. C. Sprigg, an assistant government ge- ologist of South Australia, discovered fossils of late Precambrian soft- bodied organisms in the Ediacara Hills of the Flinders Range, 600 km north of Adelaide. Sprigg’s (1947, 1949) discoveries led to the extensive work of Glaessner (1961, 1969, 1983, 1984; Glaessner and Wade 1966) and Bottjer_02 5/16/02 1:24 PM Page 12 12 • Enigmatic Ediacara Fossils figure 2.1 Global location, marked by dots, of the Ediacara biota; see text for in- dicated sites. Wade (1972a, 1972b), who systematically documented this fauna and its preservation. This work in South Australia led to the appellation “Edi- acara fauna” and fostered recognition that these fossils of soft- bodied organisms correspond to those in Charnwood Forest and Namibia and have a worldwide distribution, with other occurrences in- cluding the United States (California, Nevada, North Carolina), Canada (British Columbia, Yukon, Northwest Territories, Newfoundland), South America, Wales, Ireland, Sardinia, Norway, Finnmark, Russia (White Sea area, Urals, Siberia), Ukraine, central Australia, and China (Liao-Dun Peninsula, Heilongjiang Province, Yangtze Gorges) (Fedonkin 1992; Waggoner 1999) (Figure 2.1). The entire Ediacara biota was once thought to have become extinct well before the beginning of the Cam- brian, but recent research indicates that at least portions of this biota survived into the Cambrian (Conway Morris 1993; Crimes, Insole, and Williams 1995; Grotzinger et al. 1995; Jensen, Gehling, and Droser 1998; Hagadorn, Fedo, and Waggoner 2000). Geological Context Among the numerous localities where Ediacara fossils are found, paleo- environmental reconstructions indicate that these organisms lived in a variety of shallow- to deep-marine environments (Conway Morris 1990; Narbonne and Aitken 1990; Runnegar 1992; Seilacher 1992; Crimes, In- Bottjer_02 5/16/02 1:24 PM Page 13 Ancestors or Aliens? • 13 sole, and Williams 1995; Narbonne 1998). Detailed accounts in this chap- ter will concentrate on two examples: the Flinders Ranges fauna, which is interpreted to have lived in nearshore to shallow shelf environments, and the fauna found on the Avalon Peninsula of Newfoundland, which has been interpreted as deep marine in origin (Gehling 1999; Narbonne, Dalrymple, and Gehling 2001; Wood et al. 2001). Folded and faulted outcrops of upper Proterozoic strata occur discontinuously in the Flinders Ranges (Figure 2.2). Ediacara fossils are found in the Ediacara Member of the Rawnsley Quartzite (Pound Subgroup), which occurs in a thick sequence of sedimentary rocks of late Proterozoic age (Figure 2.3). The Pound Subgroup is overlain by Cambrian strata with definite Cambrian trace fossils, although the exact figure 2.2 Generalized geologic map of the Flinders Ranges in South Australia il- lustrating the distribution of the upper Proterozoic Pound Subgroup (stippled). (Modified from Mount 1989) Bottjer_02 5/16/02 1:24 PM Page 14 14 • Enigmatic Ediacara Fossils relationships at the contact are of considerable controversy (Mount 1989, 1991; Nedin and Jenkins 1991). Upper Proterozoic rocks are a prominent component of the Avalon Peninsula in Newfoundland, and the Mistaken Point area represents a classic locality for Ediacara fossils (Figure 2.4). Ediacara fossils from the Avalon Peninsula are found in the upper part of the Conception Group (Briscal and Mistaken Point Formations) and the overlying lower part of the St. John’s Group (Trepassey and Fermeuse Formations)