Paleobiology and Paleoenvironments of Eocene Rocks: McMurdo Sound, East Antarctica (Antarctic Research Series)

Published by the American Geophysical Union as part of the __Antarctic Research Series__. Michael K. Brett-Surman, George Washington University, observed that, "being a paleontologist is like being a coroner except all the witnesses are dead and all the evidence has been left out in the rain for 65 million years." In the study of paleontology in Antarctica it could also be added that, if not left out in the rain, most of the evidence remains buried beneath several thousand feet of ice. Elucidating the geologic history of the Antarctic continent will always be plagued with this problem. Nonetheless, numerous clever means have been used to extract as much information as is possible, and as presented in this volume. In this light, one of the most intriguing time intervals in Antarctic history is the Eocene Epoch. During this time, the climatic conditions deteriorated rapidly from the so-called "Greenhouse" conditions that dominated Earth's conditions from mid-Mesozoic time through the early Cenozoic to the "Icehouse" conditions that have dominated the climate since that time. Unfortunately, the record of Eocene rocks on the continent is sparse. On the Antarctic Peninsula, specifically on Seymour Island, a robust record of Eocene rocks and fossils has provided virtually all the information we possess about this time interval. Thus the discovery and description of Eocene erratic boulders in morainal deposits in the McMurdo Sound region provides only the second site on the entire continent where we can study the paleontology of this time interval. In all likelihood, the description of erratics containing fossils from any other place in the world would warrant little study and would attract even less attention. However, when most of the vast area of Antarctica lies beneath ice and when clues to the nature of the crust of that part of the continent can be extracted only from study of erratics, the discovery carries with it some excitement.Content: Title page 6 Copyright 7 Contents 8 Preface 10 THE McMURDO ERRATICS: INTRODUCTION AND OVERVIEW 11 APPROACH TO UNCOVER ANTARCTICA'S HIDDEN GEOLOGY AND PALEONTOLOGY 11 PRE-GLACIAL TO GLACIAL TRANSITION IN ANTARCTICA 12 THE McMURDO ERRATICS 16 FIELDWORK 17 LOCATION OF THE McMURDO ERRATICS 18 LOCATION AND INDEX OF ERRATIC SAMPLES 18 HISTORY OF RESEARCH ON THE McMURDO ERRATICS 18 RECONSTRUCTION OF THE EOCENE-OLIGOCENE COASTLINE,PALEOENVIRONMENT AND PALEOCLIMATE OF EAST ANTARCTICA 21 McMURDO ERRATICS AS MARKERS OF EOCENE-QUATERNARY GLACIAL HISTORY OF McMURDO SOUND 22 CONCLUSIONS 23 REFERENCES 23 GLACIAL GEOLOGY AND ORIGIN OF FOSSILIFEROUS-ERRATIC-BEARING MORAINES, SOUTHERN MCMURDO SOUND, ANTARCTICA AN ALTERNATIVE ICE SHEET HYPOTHESIS 29 INTRODUCTION 29 METHODS 30 RESULTS 33 DISCUSSION 42 CONCLUSIONS 45 REFERENCES 46 SEDIMENTARY LITHOFACIES OF THE MCMURDO SOUND ERRATICS 48 INTRODUCTION 48 PREVIOUS WORK 49 METHODS 49 RESULTS 49 DISCUSSION 67 CONCLUSION 69 REFERENCES 69 CLAY MINERAL COMPOSITION OF GLACIAL ERRATICS, MCMURDO SOUND 71 INTRODUCTION 71 METHODS 72 RESULTS 73 DISCUSSION 74 CONCLUSIONS 78 REFERENCES 79 MARINE DIATOM ASSEMBLAGES FROM EOCENE AND YOUNGER ERRATICS, McMURD0 SOUND, ANTARCTICA 81 INTRODUCTION 81 EOCENE DIATOM BIOSTRATIGRAPHIC REFERENCE SECTIONS 83 METHODS 84 DIATOM ASSEMBLAGES 84 SYNOPSIS OF DIATOM FLORAS 87 COMMENTS 98 CONCLUSIONS 99 TAXONOMIC LIST 99 CHRYSOPHCEAN CYST 102 REFERENCES 102 EBRIDIAN AND SILICOFLAGELLATE BIOSTRATIGRAPHY FROM EOCENE McMURDO ERRATICS AND THE SOUTHERN OCEAN 107 INTRODUCTION 107 EBRIDIANS 109 PALEOGENE RECORDS FROM THE SOUTHERN HIGH LATITUDES 110 METHODS AND MATERIALS 113 RESULTS 116 PROPOSED EBRIDIAN ZONATION FROM HOLE 748B 119 EBRIDIAN AGE ASSIGNMENT FOR EOCENE McMURDO ERRATICS 123 SILICEOUS MICROFOSSIL OCCURRENCE IN ROSS SEA DRILLCORES 125 DISCUSSION 126 BASIS FOR FUTURE WORK 126 CONCLUSION 126 SYSTEMATIC PALEONTOLOGY 127 REFERENCES 159 SPORES AND POLLEN FROM THE MCMURDO SOUND ERRATICS, ANTARCTICA 168 INTRODUCTION 168 RESULTS 170 TAXONOMIC NOTES 175 REFERENCES 186 TERTIARY MARINE PALYNOMORPHS FROM THE MCMURDO SOUND ERRATICS, ANTARCTICA 189 INTRODUCTION 189 THIS STUDY 195 METHODS 195 AGE OF THE MCMURDO ERRATICS 204 CONCLUSION 207 REFERENCES 241 EOCENE PLANT MACROFOSSILS FROM ERRATICS, MCMURDO SOUND, ANTARCTICA 249 INTRODUCTION 249 METHODS 249 LOCALITIES 249 RESULTS 250 DISCUSSION 253 REFERENCES 256 FOSSIL WOOD FROM EOCENE HIGH LATITUDE FORESTS MCMURDO SOUND, ANTARCTICA 258 INTRODUCTION 258 FOSSIL MATERIAL 258 DISCUSSION 263 SUMMARY 264 REFERENCES 264 EOCENE MOLLUSCA BIVALVIA, GASTROPODA AND SCAPHOPODA FROM MCMURDO SOUND: SYSTEMATICS AND PALEOECOLOGIC SIGNIFICANCE 266 INTRODUCTION 266 PREVIOUS INVESTIGATIONS ON EOCENE MOLLUSCA OF ANTARCTICA 266 AGE 268 PALEOECOLOGY 268 SYSTEMATIC PALEONTOLOGY 269 REFERENCES 316 BRYOZOAN FRAGMENTS FROM EOCENE GLACIAL ERRATICS OF MCMURDO SOUND, EAST ANTARCTICA 326 INTRODUCTION 326 SYSTEMATIC NOTE 326 FINAL REMARKS 327 REFERENCES 328 RHYNCHONELLIDE BRACHIOPODS FROM EOCENE TO EARLIEST OLIGOCENE ERRATICS IN THE MCMURDO SOUND REGION, ANTARCTICA 329 INTRODUCTION 329 SYSTEMATIC PALEONTOLOGY 329 REFERENCES 331 A NEW SPECIES OF Austrobalanus CIRRIPEDIA, THORACICA FROM EOCENE ERRATICS, MOUNT DISCOVERY, MCMURDO SOUND, EAST ANTARCTICA 332 INTRODUCTION 332 SYSTEMATICS 332 BIOGEOGRAPHY 334 CONCLUSION 335 REFERENCES 335 CALLICHIRUS? SYMMETRICUS DECAPODA: THALASSINOIDEA AND ASSOCIATED BURROWS, EOCENE, ANTARCTICA 337 INTRODUCTION 337 LITHOLOGIC DESCRIPTION 338 SYSTEMATIC PALEONTOLOGY 338 ASSOCIATED BURROWS 342 OTHER ICHNOFOSSILS 347 DISCUSSION 348 REFERENCES 348 FISH REMAINS FROM THE EOCENE OF MOUNT DISCOVERY, EAST ANTARCTICA 350 INTRODUCTION 350 SYSTEMATIC PALEONTOLOGY 350 DISCUSSION 352 REFERENCES 353 A PROBABLE PISCIVOROUS CROCODILE FROM EOCENE DEPOSITS OF MCMURDO SOUND, EAST ANTARCTICA 355 INTRODUCTION 355 AGE AND ASSOCIATED FAUNA 355 DESCRIPTION 356 IDENTIFICATION 356 POSSIBLE AFFINITIES 357 REFERENCES 357 THE FIRST RECORD OF A FOSSIL BIRD FROM EAST ANTARCTICA 359 INTRODUCTION 359 DESCRIPTION 360 DISCUSSION 361 REFERENCES 362 PALEOBIOGEOGRAPHIC SYNTHESIS OF THE EOCENE MACROFAUNA FROM MCMURDO SOUND, ANTARCTICA 365 INTRODUCTION 365 EOCENE PALEOGEOGRAPHY AND PALEOCEANOGRAPHY OF ANTARCTICA 365 PALEOBIOGEOGRAPHY OF EOCENE FAUNA 368 REFERENCES 370 Title page ......Page 6 Copyright ......Page 7 Contents ......Page 8 Preface ......Page 10 APPROACH TO UNCOVER ANTARCTICA'S HIDDEN GEOLOGY AND PALEONTOLOGY......Page 11 PRE-GLACIAL TO GLACIAL TRANSITION IN ANTARCTICA......Page 12 THE McMURDO ERRATICS......Page 16 FIELDWORK......Page 17 HISTORY OF RESEARCH ON THE McMURDO ERRATICS......Page 18 RECONSTRUCTION OF THE EOCENE-OLIGOCENE COASTLINE,PALEOENVIRONMENT AND PALEOCLIMATE OF EAST ANTARCTICA......Page 21 McMURDO ERRATICS AS MARKERS OF EOCENE-QUATERNARY GLACIAL HISTORY OF McMURDO SOUND......Page 22 REFERENCES......Page 23 INTRODUCTION......Page 29 METHODS......Page 30 RESULTS......Page 33 DISCUSSION......Page 42 CONCLUSIONS......Page 45 REFERENCES......Page 46 INTRODUCTION......Page 48 RESULTS......Page 49 DISCUSSION......Page 67 REFERENCES......Page 69 INTRODUCTION......Page 71 METHODS......Page 72 RESULTS......Page 73 DISCUSSION......Page 74 CONCLUSIONS......Page 78 REFERENCES......Page 79 INTRODUCTION......Page 81 EOCENE DIATOM BIOSTRATIGRAPHIC REFERENCE SECTIONS......Page 83 DIATOM ASSEMBLAGES......Page 84 SYNOPSIS OF DIATOM FLORAS......Page 87 COMMENTS......Page 98 TAXONOMIC LIST......Page 99 REFERENCES......Page 102 INTRODUCTION......Page 107 EBRIDIANS......Page 109 PALEOGENE RECORDS FROM THE SOUTHERN HIGH LATITUDES......Page 110 METHODS AND MATERIALS......Page 113 RESULTS......Page 116 PROPOSED EBRIDIAN ZONATION FROM HOLE 748B......Page 119 EBRIDIAN AGE ASSIGNMENT FOR EOCENE McMURDO ERRATICS......Page 123 SILICEOUS MICROFOSSIL OCCURRENCE IN ROSS SEA DRILLCORES......Page 125 CONCLUSION......Page 126 SYSTEMATIC PALEONTOLOGY......Page 127 REFERENCES......Page 159 INTRODUCTION......Page 168 RESULTS......Page 170 TAXONOMIC NOTES......Page 175 REFERENCES......Page 186 INTRODUCTION......Page 189 METHODS......Page 195 AGE OF THE MCMURDO ERRATICS......Page 204 CONCLUSION......Page 207 REFERENCES......Page 241 LOCALITIES......Page 249 RESULTS......Page 250 DISCUSSION......Page 253 REFERENCES......Page 256 FOSSIL MATERIAL......Page 258 DISCUSSION......Page 263 REFERENCES......Page 264 PREVIOUS INVESTIGATIONS ON EOCENE MOLLUSCA OF ANTARCTICA......Page 266 PALEOECOLOGY......Page 268 SYSTEMATIC PALEONTOLOGY......Page 269 REFERENCES......Page 316 SYSTEMATIC NOTE......Page 326 FINAL REMARKS......Page 327 REFERENCES......Page 328 SYSTEMATIC PALEONTOLOGY......Page 329 REFERENCES......Page 331 SYSTEMATICS......Page 332 BIOGEOGRAPHY......Page 334 REFERENCES......Page 335 INTRODUCTION......Page 337 SYSTEMATIC PALEONTOLOGY......Page 338 ASSOCIATED BURROWS......Page 342 OTHER ICHNOFOSSILS......Page 347 REFERENCES......Page 348 SYSTEMATIC PALEONTOLOGY......Page 350 DISCUSSION......Page 352 REFERENCES......Page 353 AGE AND ASSOCIATED FAUNA......Page 355 IDENTIFICATION......Page 356 REFERENCES......Page 357 INTRODUCTION......Page 359 DESCRIPTION......Page 360 DISCUSSION......Page 361 REFERENCES......Page 362 EOCENE PALEOGEOGRAPHY AND PALEOCEANOGRAPHY OF ANTARCTICA......Page 365 PALEOBIOGEOGRAPHY OF EOCENE FAUNA......Page 368 REFERENCES......Page 370 Michael K. Brett-Surman, George Washington University, observed that, "being a paleontologist is like being a coroner except all the witnesses are dead and all the evidence has been left out in the rain for 65 million years." In the study of paleontology in Antarctica it could also be added that, if not left out in the rain, most of the evidence remains buried beneath several thousand feet of ice. Elucidating the geologic history of the Antarctic continent will always be plagued with this problem. Nonetheless, numerous clever means have been used to extract as much information as is possible, and as presented in this volume.

In this light, one of the most intriguing time intervals in Antarctic history is the Eocene Epoch. During this time, the climatic conditions deteriorated rapidly from the so-called "Greenhouse" conditions that dominated Earth's conditions from mid-Mesozoic time through the early Cenozoic to the "Icehouse" conditions that have dominated the climate since that time. Unfortunately, the record of Eocene rocks on the continent is sparse. On the Antarctic Peninsula, specifically on Seymour Island, a robust record of Eocene rocks and fossils has provided virtually all the information we possess about this time interval. Thus the discovery and description of Eocene erratic boulders in morainal deposits in the McMurdo Sound region provides only the second site on the entire continent where we can study the paleontology of this time interval. In all likelihood, the description of erratics containing fossils from any other place in the world would warrant little study and would attract even less attention. However, when most of the vast area of Antarctica lies beneath ice and when clues to the nature of the crust of that part of the continent can be extracted only from study of erratics, the discovery carries with it some excitement.