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Ann Arbor, MI 48106 HARVARD UNIVERSITY THE GRADUATE SCHOOL OK ARTS AND SCIENCES THESIS ACCEPTANCE CERTIFICATE {To be placed in Original Copy) The undersigned, nppoiiucd hy the Division Department of Organismic and Evolutionary Biology Committee have examined a thesis entitled "Studies in Proterozoic paleobiology from Spitsbergen and arctic Canada" presented by Nicholas J. Butterfield candidate for the degree of Doctor of Philosophy and hereby certify that it is worthy_of acc^tanc Sif;m uurc' Typed name Andrew H,,.. K,no.l.l .... Signature / T / / / / Typed tiatne^. Ralph J Signature T y^ed name Dpnald H P o s t e r /( Raymond Siever Date January 23, 1992 STUDIES IN PROTEROZOIC PALEOBIOLOGY FROM SPITSBERGEN AND ARCTIC CANADA A thesis presented by Nicholas James Butterfield to The Department of Organismic and Evolutionary Biology in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the subject of Biology Harvard University Cambridge, Massachusetts January 1992 11 © 1992 by Nicholas James Butterfield All rights reserved Ill ABSTRACT Fossil assemblages from Spitsbergen, Baffin Island, and Somerset Island provide a much enhanced view of Proterozoic paleobiology. Shallow water shales, cherts, phosphorites, and carbonates in the 700-800 Ma Svanbergfjellet Formation, northeastern Spitsbergen, preserve 65 distinct fossil forms, including 4 species of multiceUular green algae (Siphonocladales and Chlorococcales), 3 multiceUular taxa of imknown taxonomic affiliation, 19 acritarch species, and numerous cyanobacteria and insertae sedis. An analysis of fossil taphonomy offers some useful taxonomic distinctions, but generally points to a pervasive 'over-splitting' of form taxa; several major taxonomic revisions are proposed. The SvanbergjQeUet fossils contribute significantly to the understanding of early multicellularity and to an increasingly detailed Neoproterozoic biostratigraphy. A shale sample from the Black Shale Member of the ca. 1250 Ma Agu Bay Formation (Fury and Hecla Group), northwestern Baffin Island, is dominated by small leiosphaerid acritarchs. Their very even distribution on bedding planes and a dearth of typical shallow-water forms (e.g., filaments, large and/or ornamented acritarchs) suggest an offshore deposition in water sufficiently deep to preclude a photosynthesizing benthos; a mid to outer shelf setting is supported by the local sedimentology. A review of Proterozoic fossil distribution permits the delineation of 5 depth-dependent paleoecological zones extending from restricted nearshore to basinal environments. Such recognition serves as a valuable measure of paleoenvironment and should substantiaUy refine any biostratigraphic signal. IV Silidfied peri tidal carbonates from the 1270-725 Ma Hunting Formation on Somerset Island (arctic Canada) contain fossils of a well preserved bangiophyte red alga, Bangiomorpha antigua n. gen., n. sp. Evidence of transverse intercalary cell division in unlseriate filaments, and a subsequent longitudinal division to yield multiseriate filaments of radially-arranged wedge-shaped cells, shows it to be dosely allied to modem Bangia. Together with the Svanbergfjellet chlorophytes, the Hunting fossils push the record of taxonomically resolved metaphytes well back into the Proterozoic. ACKNOWLEDGEMENTS I thank Andy Knoll for the inspiration and opportunity to pursue the study of early life, and Roger Buick, Stephen Grant and Julian Green for the enduring skepticism and collegiality necessary to carry it off. Keene Swett (University of Iowa) first introduced me to the business of systematic field work, and Jay Kaufman (then at the Biogeochemical Laboratories, Indiana University) that of stable isotope geochemistry. Fred Chandler (Geological Survey of Canada) provided sample materials of the Fury and Hecla Group and is largely responsible for its geological description (Chapter III); likewise, Andy Knoll, in the case of the Svanberg^ellet Formation (Chapter II). Rob Rainbird and Grant Young (University of Western Ontario) generously assisted with ongoing work on the Shaler Group, Victoria Island. I also thank Nikola Baumgarten, Steve Could, Don Pfister, Ralph Mitchell, Ray Siever, and sympathetic fellow graduate students for their encouragement, advice, and assistance. Financially, I was supported from 1986 through 1990 by a Natural Sciences and Engineering Research Council of Canada (NSERC) post-graduate scholarship. Research funds were provided by the National Geographic, the Department of Organismic and Evolutionary Biology (Harvard University), the Geological Society of America, Monsanto Inc., and various NSF, NASA, and DOE grants to Andy Knoll. VI TABLE OF CONTENTS A bstract........................................................................................................................ iü Acknowledgements ................................................................................................. v Table of Contents ................................................................................................... vi I. INTRODUCTION ............................................................................ 1 II. PALEOBIOLOGY OF THE NEOPROTEROZOIC SVANBERGFJELLET FORMATION, SPITSBERGEN ........................ 6 ABSTRACT .............................................................................................. 6 INTRODUCTION ................................................................................... 8 MATERIALS AND METHODS ........................................................... 9 GEOLOGICAL SETTING ....................................................................... 11 Paleoenvironments ......................................................................... 14 TAPHONOMY ....................................................................................... 17 Recalcitrance ..................................................................................... 19 Degradation ..................................................................................... 21 Preservation ..................................................................................... 22 Mineralization .............................................................................. 25 Fossil Analysis ............................................................................ 26 Thickness vs. opacity .................................................................. 27 Compression ................................................................................ 28 TAXONOMY ............................................................................................ 30 MULTICELLULARITY............................................................................ 32 Simple multicellularity ................................................................ 33 Filamentous Chlorophyta ........................................................... 34 vil MULTICELLULARITY (cont.) Complex multicellularity ........................................................... 36 Other Proterozoic Occurrences .................................................... 38 Evolutionary Implications ............................................................. 39 Metazoans(?) ............................................................................. 42 ACRITARCHS ......................................................................................... 43 Biostratigraphy ................................................................................ 44 SYSTEMATIC PALEONTOLOGY ...................................................... 46 nCURES ................................................................................................... 143 REFERENCES ........................................................................................... 199 APPENDIX