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Meyer MB D 2013.Pdf (6.128Mb) Contributions to late Ediacaran geobiology in South China and southern Namibia Michael Bruce Meyer Dissertation submitted to the faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy In Geosciences Shuhai Xiao Michal J. Kowalewski James D. Schiffbauer Benjamin Gill Ken Eriksson April 29th 2013 Blacksburg, VA Keywords: Taphonomy, Ediacara, South China, Namibia, Geobiology Copyright 2013 © Michael B. Meyer Contributions to late Ediacaran geobiology in South China and southern Namibia Michael Bruce Meyer ABSTRACT The Ediacaran, particularly the late Ediacaran-Cambrian (E-Є) boundary (551-541 Ma), has been noted as a major time of biological and biochemical transition, including: the rise of predators, the emergence of skeletons, the radiation of bioturbators, and large fluctuations in oceanic chemical conditions (e.g. anoxia/euxinia/ferruginia) with emerging data suggesting that it is not until the late Ediacaran Period (551-542 Ma) when pervasive oxidation of the deep oceans occurred. In addition, the study of Ediacaran paleobiology involves numerous factors, including but not limited to, restricted amount of outcrops, taphonomic biases, metamorphism, enigmatic phylogenetic affinities, non-actualistic atmospheric and oceanic conditions, and unusual taphonomic windows, making it difficult to assign order to the myriad types of fossils (both body and trace) found during this time . It is with these problems in mind that my dissertation focuses on taphonomic questions in the late Ediacaran. We observe fossil through the taphonomic window and thereby colors all aspects of the study of that organism. By understanding how an organism was preserved we can learn about other factors affecting it, such as their taxonomic affinities, paleoecology, and morphology. All of these factors were examined through taphonomic investigations and this can be seen in the analytical path through my chapters. In chapter two I examined the preservation of trace fossils in the late Ediacaran. In chapter three I analyzed the taphonomy of an exceptionally preserved Ediacaran fossil to solve its affinity, tubular trace or tubular soft-bodied fossil. In chapter four, understanding the nature of exceptional preservation, I investigated the taphonomy of an Ediacara fossil in coarse grained sediments. In chapter five, I combined the findings of the previous chapters and applied that knowledge to analyze the in situ three dimensional morphology of an Ediacara fossil. Each of the projects presented pairs new technologic methodologies (SEM, BSE-Z, EDS, Raman, microCT) with traditional paleontological and petrologic investigations (field work, hand sample, and petrographic thin-section analysis). The result of this union of Old and New are findings that expand our understanding of these earliest multicellular organisms, their modes of life, and their biological affinities. DEDICATION I dedicate this work to my family and friends. Without their love and support I could not have accomplished any of this. iii ACKNOWLEDGEMENTS There are too many people to thank for their part in helping me complete this work, both personally and professionally. They are, in no particular order: my parents, Bruce and Susan Meyer, for boundless support and advice, my brothers, Matt and Steve Meyer, for being the best sounding boards, the whole of the Meyer and Lamonte families for always believing in me, the Sliko clan, better in laws I could not have, my friends, from Sundling to Fremd to USF and Virginia Tech, you all inspire me and I look forward to more good times, all of my teachers, Mr. B, Linda Bragg, Peter Konecki, my Masters advisor, Dr. Peter Harries, for showing me how to balance life, my PhD committee for their advice and guidance, my PhD advisor, Shuhai Xiao, who has shown me how to be a better person and scientist, and finally my wonderful wife, whose patience, support, and love has allowed me to achieve my dreams, I love you so much. iv ATTRIBUTIONS Chapter Two is in the final stages of preparation for submission to Palaeogeography Palaeoclimatology Palaeoecology as “Meyer, M., Xiao, S., Gill, B.C., Schiffbauer, J.D., Chen, Z., Zhou, C., Yuan, X. Interactions between Ediacaran animals and microbial mats: insights from Lamonte trevallis, a new trace fossil from the Dengying Formation of South China”. M. Meyer and S. Xiao conceived of the project and collected the material with Z. Chen, C. Zhou, and X. Yuan. M. Meyer collected isotope samples and analyzed them with assistance from B.C. Gill. M. Meyer and J.D. Schiffbauer collected elemental maps and point analyses. Chapter Three was published as “Meyer, M., Schiffbauer, J.D., Xiao, S., Cai, Y., Hua, H., 2012. Taphonomy of the upper Ediacaran enigmatic ribbon-like fossil Shaanxilithes. Palaios 27, 354-372”. It is reprinted here with permission from M. Meyer. M. Meyer and S. Xiao conceived of the project and collected the material with Y. Cai and H. Hua. M. Meyer and J.D. Schiffbauer collected elemental maps and point analyses. Chapter Four is in review at Journal of Paleontology as “Meyer, M., Elliott, D.A., Schiffbauer, J.D., Vickers-Rich, P., Xiao, S., Hoffmann, K.H., Hall, M., and Schneider, G., Taphonomy of the Ediacaran fossil Pteridinium simplex preserved three-dimensionally in mass flow deposits in the Nama group of Namibia”. It is reprinted here with permission from M. Meyer. M. Meyer, D. Elliott, P. Vickers-Rich, and S. Xiao conceived of the project and collected the material. M. Hall and P. Vickers-Rich provided stratigraphic background. K. H. Hoffman and G. Schneider allowed access to the fossil locality and access to museum specimens. M. Meyer, D. Elliott, and J.D. Schiffbauer made thin section material and collected elemental maps and point analyses. Chapter five is in the final stages of preparation for submission to Proceedings of the National Academy of Sciences as “Meyer, M., Elliott, D.A., Wood, A. D., Polys, N.F., Colbert, M., Maisano, J. A., Hall, M., Hoffmann, K.H., Hall, M., Schneider, G., Vickers-Rich, P., and Xiao, S. Three dimensional microCT analysis of the Ediacara fossil Pteridinium simplex sheds new light on its ecology and phylogenetic affinity”. M. Meyer, D. Elliott, P. Vickers-Rich, and S. Xiao conceived of the project and collected the material. M. Hall and P. Vickers-Rich provided stratigraphic background. K. H. Hoffman and G. Schneider allowed access to the fossil locality and access to museum specimens. M. Meyer, D. Elliott, and J.D. Schiffbauer made thin section material and collected elemental maps and point analyses. M. Colbert and J.A. Maisano processed the samples using microCT scans. M. Meyer, A.D. Wood, and N.F. Polys post- processed and segmented the microCT data. v TABLE OF CONTENTS Abstract……………………………………………………………………………………..….…ii Dedication…………………………………………………………………………………..……iii Acknowledgements………………………………………………………………………..……..iv Attributions……….………………………………………………………………………..……...v Table of Contents…………………………………………………………………………………vi List of Figures……………………………………………………………………………….…….x List of Tables…………………………………………………………………….……………...xiii Grant Information……………………………………………………………………….………xiv Chapter 1: OVERVIEW……………..……………………………………………………………1 1.1 Introduction…………………………………………………………………………………....2 1.2 Summary of Research………………………………………………………………………....3 1.3 Geologic Setting………………………………………………………………………….….3 1.3.1 South China…………………………………………………………………….…...5 1.3.2 Southern Namibia…………………………………………..……………………….7 1.4 References……………………………………………………………………………………..9 Chapter 2: INTERACTIONS BETWEEN EDIACARAN ANIMALS AND MICROBIAL MATS: INSIGHTS FROM LAMONTE TREVALLIS, A NEW TRACE FOSSIL FROM THE DENGYING FORMATION OF SOUTH CHINA…………………………………….………..11 2.1 Abstract………………………………………………………………………………………12 2.2 Introduction………………………………………………………………………….……….13 2.3 Geological Setting……………………………………………………………………………15 2.4 Materials and Methods…………………………………………………………………….…17 2.5 Systematic Ichnology………………………………………………………………..………19 2.5.1 Ichnogenus Lamonte Description………………………………………...…….…20 vi 2.5.2 Ichnospecies Lamonte trevallis Description………………………………………20 2.6 Analytical Results……………………………………………………………………………23 2.7 Taphonomic and Paleoecological Discussion…………………………………………….…24 2.8 Conclusions………………………………………………………………………………….29 2.9 Acknowledgements…………………………………………………………………….…….30 2.10 Table and Table Captions…………………………………………………………….…….31 2.11 Figure and Figure Captions…………………………………………………………….…...39 2.12 References……………………………………………………………………………….….50 Chapter 3: TAPHONOMY OF THE LATE EDIACARAN ENIGMATIC RIBBON-LIKE FOSSIL SHAANXILITHES………………………………………………………………….…55 3.1 Abstract……………………………………………………………………..……………..…56 3.2 Introduction………………………………………………………………………………..…56 3.3 Geological and Stratigraphic Background…………………………………..…………….…59 3.4 Materials and Methods.……………………………………………………..…………..……60 3.5 Results………………………………………………………………………….……….……62 3.6 Discussion………………………………………………………………...…………….……66 3.6.1 Clay Association ……………………………………………………….…….……66 3.6.2 Possible Pyrite Association ………………………………………….……….……70 3.6.3 Body vs. Trace Fossil Affinity…………………………….……….………….……71 3.9 Conclusions …………………………………………………………………………….……73 3.10 Systematic Paleontology …………………………………………………………….…..…73 3.10.1 Description ………………………………………………………………….……74 3.10.2 Discussion ……………………………………………………………….….……75 3.11 Acknowledgements…………………………………………………………………………75 3.12 Table and Table Captions……………………………………………………………..……76 3.13 Figure and Figure Captions…………………………………………………………………80
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