Oligocene Sedimentation, Stratigraphy, Paleoecology and Paleoclimatology in the Big Badlands of South Dakota
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LIBRARY OF THE UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAICN K F4S£ ,. V4 GEOLOGY 1*w S a sponsfbTe g th,s material °for i?s S? ,s re " or LotestDotestamAdb:^ before the ° UNIVERSITY -u: 'V Univ -*V „ , „. ""V IUINOIS UBRJdP »t APR lo OCT^ DEC o 7 Mb© • ^ OLIGOCENE SEDIMENTATION, STRATIGRAPHY, PALEOECOLOGY AND PALEOCLIMATOLOGY IN THE BIG BADLANDS OF SOUTH DAKOTA JOHN CLARK JAMES R. BEERBOWER KENNETH K. KIETZKE 3en FIELDIANA: GEOLOGY MEMOIRS g WSfc* VOLUME 5 o f\ $*$ PubltsJied by J FIELD MUSEUM OF NATURAL HISTORY nr- U^ DECEMBER 29, 1967 GEOLOGY LIBRARY FIELDIANA: GEOLOGY MEMOIRS VOLUME 5 o/ *^ . ,'N\yNATURAL °V '"t HISTORY £" [> "|." ; JSLw .1^ FOUNDED Br I ^/cAgO FIELD MUSEUM OF NATURAL HISTORY CHICAGO, U.S.A. 1967 OLIGOCENE SEDIMENTATION, STRATIGRAPHY, PALEOECOLOGY AND PALEOCLIMATOLOGY IN THE BIG BADLANDS OF SOUTH DAKOTA OLIGOCENE SEDIMENTATION, STRATIGRAPHY, PALEOECOLOGY AND PALEOCLIMATOLOGY IN THE BIG BADLANDS OF SOUTH DAKOTA JOHN CLARK Associate Curator, Sedimentary Petrology, Field Museum JAMES R. BEERBOWER Department of Geology, McMaster University, Hamilton, Ontario KENNETH K. KIETZKE FIELDIANA: GEOLOGY MEMOIRS VOLUME 5 Published by FIELD MUSEUM OF NATURAL HISTORY DECEMBER 29, 1967 Edited by Edward G. Nash Patricia M. Williams Library of Congress Catalog Card Number: 67-31598 PRINTED IN THE UNITED STATES OF AMERICA BY FIELD MUSEUM PRESS CONTENTS I. Introduction 5 II. General Geography 8 III. General Geology 9 Stratigraphic Column 9 Regional Structural Setting 13 IV. The ? Slim Buttes Formation 16 V. Geology, Paleoecology, and Paleoclimatology of the Chadron Formation 21 Introduction 21 Acknowledgements 21 Structural Relationships 21 Lithology 22 Systematic Paleontology 25 Stratigraphic Paleontology 55 Paleogeography 59 Interpretation of Chadron Sedimentation 60 Paleoecology 67 Interpretative Summary 72 Conclusions 74 VI. Paleogeography of the Scenic Member of the Brule Formation 75 Introduction 75 Topography and General Stratigraphy 75 Lithology 77 Stratigraphic Relations of Sedimentary Lithotopes 85 Paleogeographic Interpretation of the Scenic Member 92 Relationship to Orellan Stratigfaphy and Sedimentation in Nebraska 102 VII. Paleoecology of the Lower Nodular Zone, Brule Formation, in the Big Badlands of South Dakota Ill Introduction Ill Acknowledgements Ill General Philosophy of Field Work Ill Pertinent Field Data for Individual Collections 112 Curating and Identification 114 Variables and Biases Affecting Interpretation of the Population Statistics 114 Analysis of Faunas 120 Ecologic Relationships of Particular Genera 123 VIII. Interpretative Summary 138 IX. Conclusions 141 References 144 Appendices 147 Index 156 VII LIST OF ILLUSTRATIONS TEXT FIGURES 1. Oligocene rocks of western South Dakota 6-7 2. Columnar section for the Big Badlands 9 3. Upper Chadron channel directions 10 4. The Slim Buttes Formation and the Ahearn Member 11 5A. View of Locality V 12 5B. Slim Buttes Formation 12 5C. Inherited Slim Buttes sediments 12 6. Structural axes in the Big Badlands 13 7. Cross section of Figure 6 14 8. Slim Buttes-Chadron contact zone 18 9. Rate of Deposition of the Chadron Formation 25 10. The genus Parictis 28 11. The genus Parictis 29 12. Measurements of Parictis (Campylocynodon) parvus 29 13. Posterior accessory cuspule on premolars of Daphoenus 30 14. The genus Daphoenocyon: mandibles 31 15. The genus Daphoenocyon: paratype 31 16. Comparative measurements of Daphoenocyon, Daphoenus, and Parictis 32 17. Measurements of Eusmilus sp 33 18. Measurements of Chadron Mesohippi 34^46 19. Type specimens of Daphoenocyon minor, mesohippus grandis and unnamed species of Merycoidodon .... 49 20. Measurements of Mesohippus grandis 49 21. Phylogeny of Chadron Mesohippi 49 22A. Type specimen of Merycoidodon lewisi 53 22B. Type specimen of Merycoidodon lewisi 53 23. Measurements of Merycoidodon lewisi 54 24. Suggested correlations of certain Oligocene formations 57 25. Ecology of the known Chadron fauna 58 26. Tertiary Paleogeographic data—sedimentary 62-63 27. Tertiary Paleogeographic data—vertebrate fossils 70-71 28. Chadronian paleoecology by genera 71 29. Chadronian paleoecology index 72 30. Location of numbered sections and places 76 31. Photograph of sample G 4077 78 32. Photograph of G 3743 78 33. Paleogeography of the Scenic Member 79 34. Riosome #3, near Cottonwood Pass 80 35. Riosome #3, near Cottonwood Pass 81 36. Drenajesome #4 82 37. Viscous flow marks on a skull of Archaeotherium 84 38. Layered concretions in a silty mudstone 85 39. Columnar sections, Scenic Member 87-90 40. Scenic member mudstones 91 41. NE - SW cross-section of the Scnic Member 93 42. Cross-sectional diagram of a stream in a depositional regimen 94 43. Components of an environment of fluvial sedimentation 95 44. Perthotaxy on temperate steppes 100 45. Archaeotherium skull in situ 101 46. Cross-section of Toadstool Park area 103 47. Photograph of "the Bench" 104 48. Laminated sediments, near Toadstool Park 105 49. View westward along fault, Toadstool Park 106 50. Fault-face cutting channel-fill sandstone 107 51. Diagrammatic interpretation of Figure 49 108 52. Probable miscorrelations of lithologic units 109 53. The relationship of a life population to a fossil collection 117 - 54. Graphs I XIII, population statistics 130-136 55. Internal consistency of Open Plains and Near Stream collections 137 56. Total fauna represented in collections used in Chapter VII 137 VIII Chapter I INTRODUCTION Successive faunas preserved in the classic Oligocene 4. What is the length of time represented by the sequence of western South Dakota offer clear evidence total sedimentary pile; what was the thickness of indi- that the Oligocene Period was a time of climatic change vidual increments; and what time is represented by the in western North America. The strata themselves have increments as opposed to the intervening episodes of long been recognized as "typical floodplain deposits." non-deposition? This to these two study attempts analyse critically gen- 5. What is the geomorphic pattern established eralities modern and to by applying techniques theory by a group of streams whose primary regimen is deposi- both the fossils and the sediments. The data resulting tion rather than erosion? from this analysis are used to reconstruct the Oligocene 6. Do fossil faunules reflect the local paleogeog- paleogeography of western South Dakota in detail. An raphy evidenced by the sediments? attempt is then made to reconstruct the successive The first question can be answered in advance with paleoclimates of the area. Finally, the interaction of a probable negative. Even the most positive advocates the physical environments upon the faunas is con- of various of continental drift seem to feel sidered. hypotheses that post-Oligocene movement of North America rela- of fossils has been the fact Study the complicated by tive to the poles of rotation has been slight. Abundant that the philosophy of collection, as well as the docu- paleobotanical and marine-paleontologic evidence tends of classic collections unsuit- mentation, the makes them to confirm this. The study has, therefore, been conducted able for analytical use. It has been necessary to make with the primary assumption that South Dakota occu- collections for this and col- specifically study, modern pied essentially the same position relative to the North in to certain lections the area are subject unpredictable Pole, and to the continents of North America and Eu- variables which need not have at the time the operated rasia, which it occupies today. older collections were made. The limited statistical treat- Chapters V, VI, and VII, which form the core of this ment justified has, nevertheless, revealed sufficient in- report, were originally written as separate papers, in- formation to merit its presentation here. tended for separate publication. The research was done aus- Study of the sediments has naturally devolved about at somewhat different times, under quite different several basic problems: pices. Each chapter retains its own acknowledgments in order to make clear the extent of assistance received. 1. Did the position of South Dakota relative to The senior author wishes to acknowledge here the un- the Earth's rotational poles differ materially from its stinted assistance of Dr. B. G. Woodland, who checked present position, or did it change significantly during most of the author's identifications of mineral species of Oligocene time? sand grains for various chapters. He also wishes to ex- press his appreciation of Dr. T. Perenyi's patient and 2. Which characteristics of the sediments are at- skillful art work on the charts, maps, and diagrams. tributable respectively to their ancestry, to their paleo- This study raises approximately as many new prob- graphic position, to the paleoclimate during deposition, lems, both local and fundamental, as it solves. I have and to epigenetic changes? attempted to indicate these in all cases where the prob- 3. What geomorphic controls determined that lem seems either to cast some doubt upon my favored Oligocene streams would deposit thick floodplain sedi- hypothesis, or to be fundamental enough to merit gen- ments within 30 miles of their headwaters? eral interest. gocene Rocks of Wester indicated. Note Fig. 1. Oligocene rocks of western South Dakota. The overlap of Oligocene sediments upon the Paleozoics is clearly also that elastics derived from the Laramide intrusive of the northern Black Hills are available to Box Elder and Elk Creeks at present. Laramide intrusives + + -t ±