University of Connecticut OpenCommons@UConn Master's Theses University of Connecticut Graduate School 12-12-2013 Raindrop Imprints and Their seU in the Retrodeformation of Carboniferous Trace Fossils Meredith Fichman [email protected] Recommended Citation Fichman, Meredith, "Raindrop Imprints and Their sU e in the Retrodeformation of Carboniferous Trace Fossils" (2013). Master's Theses. 518. https://opencommons.uconn.edu/gs_theses/518 This work is brought to you for free and open access by the University of Connecticut Graduate School at OpenCommons@UConn. It has been accepted for inclusion in Master's Theses by an authorized administrator of OpenCommons@UConn. For more information, please contact [email protected]. Raindrop Imprints and Their Use in the Retrodeformation of Carboniferous Trace Fossils Meredith Elizabeth Fichman B.A., University of Connecticut, 2011 A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science At the University of Connecticut 2013 APPROVAL PAGE Masters of Science Thesis Raindrop Imprints and Their Use in the Retrodeformation of Carboniferous Trace Fossils Presented by Meredith Elizabeth Fichman, B.A. Major Advisor___________________________________________________________ Dr. Jean M. Crespi Associate Advisor_________________________________________________________ Dr. Andrew M. Bush Associate Advisor_________________________________________________________ Dr. Timothy B. Byrne University of Connecticut 2013 i ACKNOWLEDGEMENTS I’d like to thank all those who have helped me during my time at UConn and that have helped make the completion of this thesis possible. First and foremost, I’d like to thank my advisor, Dr. Jean Crespi, for her continued support through both my undergraduate and graduate careers. Jean was the first person I met when I starting to consider a Geoscience major. She welcomed me with open arms, and working with her has helped mold me into a stronger student, scientist and person. I can never thank her enough for all of the time she spent working with me. Her knowledge and skill set played critical roles in the completion of this work, and without her, this thesis would not have been possible. I’d like to thank my other committee members, Dr. Andrew Bush and Dr. Timothy Byrne. Andy was one of the first professors to peak my educational interests and introduce me to the realm of research (I hope that project gets finished one day). I’ll always appreciate his time, sense of humor and moral support throughout my years at UConn, and I cannot thank him enough for being an integral part of my undergraduate and graduate careers. Tim has helped so much with understanding the geological history of my study area. Early on, he challenged me to truly understand my work and pushed me to think and reason at higher levels. I’d like to thank Patrick Getty for initially approaching me with this project and supporting me every step of the way. His prior work, knowledge and skill set were hugely important to this project, and I can’t even begin to thank him for all of his moral support. He is not only a colleague, but also a dear friend. ii I’d like to thank UConn and the Center for Integrative Geosciences for providing me with a strong education and funding over the last few years. I’ve had a wonderful experience being a part of the Geoscience program and have thoroughly enjoyed having the opportunity to teach a number of different courses as part of my assistantship. I’d like to thank Bob Sproule for providing us with a number of samples for this project. Without his extensive collection, we would not have been able to collect as much data as we did. I’d also like to thank Yale Peabody Museum for allowing us to gather and analyze data from slabs within their invertebrate paleontology collection. Last, but certainly not least, I would like to take the time to thank my friends and family. To all of my geoscience friends – spending time with you, sharing stories and bouncing around ideas has made this experience incredibly rewarding. I love our tight- knit group and little geoscience family. To all of my non-geoscience friends – thanks for putting up with me over these last few years. You have all been there when I have needed a breather and I’m so thankful that you have embraced the “rock nerd” in me. To my family – there aren’t enough words to describe how truly thankful I am for all of your time, patience, love and support. Without you, I would not be who I am today, and without your encouragement, I would not have been able to accomplish as much as I have. I thank you all very much for the love and support over these last few years. iii TABLE OF CONTENTS Acknowledgments.............................................................................................................. ii List of Figures .................................................................................................................... v Abstract ..............................................................................................................................vi Introduction ........................................................................................................................1 Geological Setting ..............................................................................................................3 Raindrop Imprints ..............................................................................................................4 Materials .............................................................................................................................7 Strain Analysis of Raindrop Imprints................................................................................10 Retrodeformation Using Raindrop Imprints......................................................................18 Retrodeformation Without Raindrop Imprints...................................................................27 Conclusion.........................................................................................................................42 References..........................................................................................................................44 Appendix............................................................................................................................55 iv LIST OF FIGURES FIGURE 1 − Geologic setting. 9 FIGURE 2 − Polar Rf/Φ plots of deformed raindrop imprints 14 and associated FInt Lin. FIGURE 3 − Correlation between FInt Lin and Rs. 16 FIGURE 4 − Fossil reptilomorph manus from quarry in 21 Plainville, Massachusetts. FIGURE 5 − Fossil amphibian trackway from quarry in 24 Plainville, Massachusetts. FIGURE 6 − Body imprint of archaeognathan insect from 31 quarry in Plainville, Massachusetts (YPM227991). FIGURE 7 −Body imprints of archaeognathan insects from 33 quarry in Plainville, Massachusetts (YPM236969-72). FIGURE 8 − Fossil amphibian trackway from quarry in 38 Plainville, Massachusetts. FIGURE 9 − Fossil amphibian trackway from quarry in 40 Plainville, Massachusetts. FIGURE 10 − Fossil amphibian trackway from quarry in 41 Plainville, Massachusetts. v ABSTRACT The Narragansett Basin of Massachusetts and Rhode Island is a Carboniferous terrestrial basin and is the only location within New England that preserves fossil evidence of early amphibians and reptilomorphs. Footprints and trackways constitute the only record of these early tetrapods, but deformation during the Alleghanian orogeny has distorted the traces. To improve identification, description, and comparison with non- distorted material, tracks from Plainville, Massachusetts were retrodeformed using raindrop imprints as strain markers. The axial ratios of 354 raindrop imprints found on 12 slabs were analyzed using the Rf/Φ technique. Strain ratios for slabs ranged from 1.33 to 1.93, with individual raindrop imprints ranging from 1.14 to 2.51. Although weakly expressed, cleavage exhibits an anastomosing characteristic and is visible on bedding surfaces in the form of a bedding-cleavage intersection lineation. The fluctuation of the bedding-cleavage intersection lineation varies between 10° and 33° among the raindrop-imprint—bearing slabs. This fluctuation is strongly correlated to the strain ratio of a slab, and this correlation was used to obtain strain ratios for slabs lacking raindrop imprints. Vertebrate tracks appeared less distorted following retrodeformation, and the accuracy of the methods was successfully tested by retrodeforming insect traces that were originally bilaterally symmetrical. Deformed raindrop imprints and bedding-cleavage intersection lineation provide a useful new way of retrodeforming fossils, as well as a more complete understanding of the fossil record of early tetrapods in New England. vi INTRODUCTION The appearance of fully terrestrial animals marks a major event in vertebrate evolution. Evidence for the existence of early amphibians and reptilomorphs, the group of animals that gave rise to all modern amniotes, comes from skeletal remains found in Carboniferous rocks from around the world (Caroll, 1988). However, in New England, the only record of these early tetrapods consists of footprints and trackways preserved in sedimentary rocks of the Narragansett Basin (Woodworth, 1900; Lull, 1920; Willard and Cleaves, 1929). Although these trace fossils are relatively common, they have been tectonically deformed and require retrodeformation in order to be properly described, identified and compared with