Recovery from the end-Triassic mass extinction in European shelf seas: body size changes in marine invertebrates and the role of temperature and anoxia Jed William Atkinson Submitted in accordance with the requirements of the degree of Doctor of Philosophy The University of Leeds Earth Surface Science Institute School of Earth and Environment August, 2019 ii The candidate confirms that the work submitted is his own, except where work which has formed part of jointly-authored publications has been included. The contribution of the candidate and the other authors to this work has been explicitly indicated below. The candidate confirms that appropriate credit has been given within the thesis where reference has been made to the work of others. Contributions of the candidate and the other authors: In all chapters the candidate (J.W. Atkinson) was the primary data gatherer and processor. All chapters were primarily written by the candidate with comments and suggested edits to the manuscripts provided by P.B. Wignall (all chapters) and T. Aze (Chapter 2). Contribution to data gathered for Chapter 2 was provided by J.D Morton and Chapter 4 by P.B. Wignall. Ammonite identifications and short related paragraph provided by K.N. Page also in Chapter 4. This copy has been supplied on the understanding that it is copyright material and that no quotation from the thesis may be published without proper acknowledgement. © 2019 The University of Leeds and Jed William Atkinson iii iv Acknowledgements A hearty thanks goes to all those who permitted me to take a hammer to a SSSI: Tom Sunderland, Bob Corns, Tom Charman, and Hugh Luttrell. Also thanks to all those museum staff who granted me access to their collections: Caroline Buttler, Lucy McCobb, Deborah Hutchinson, Jon Radley, Matt Williams, Sarah King, Stuart Ogilvy, Roger Osborne, Tim Burnhill and especially to Peter Hodges whose meticulous and extensive collections greatly improved my own work. Mike Simms and Mick Oates, thank you to you both for showing us field locations and additionally, Mick for allowing me to trawl through your collections. A thanks to temporary field assistants Karolina Zarzyczny and Ovye Yohanna and most crucially to long suffering field assistant and valued friend Jacob Morton – who I have lead off many ridiculous cliffs, made to carry twice his own body weight in stone and subjected to the aromas of rotting badger flesh – there could have been no better ‘Watson’ to have in the field at my side. For technical help I wish to thank Duncan Hedges and Harri Wyn Williams. Everyone in the basement offices – past and present: Autumn Pugh, Tom Fletcher, James Witts, Luke Faggetter, Kathy Doyle, James Woodman, Andy Cooke, Sam Parsons, Connor O’Keeffe, Dot Drayton, Delia Cangelosi, Beth Allen, Adam Woodhouse, Andy Mair, Carl Spence-Jones and anyone I missed. Thank you to you all for making the time here so enjoyable. Of course my deepest gratitude to my supervisors Tracy Aze, Rob Newton and most of all Paul Wignall – whose guidance and occasional company in the field has been quite capital. My Parents I thank for their support, especially to my Father to whom I owe a great mechanical debt. The Mustard King (Acey) and Doc Shaw (Alex) for keeping me insane whenever sanity threatened to take grasp, for keeping me in the wrong century and reminding me that in life three is company, two is none. And lastly an apology to the dear ladies in the reception who have, over the last four years, had a menagerie of the dead pass through their office in all manner of unsavoury conditions. v vi Abstract Fossil communities in the wake of mass extinction are often characterised by small sized individuals, this is often ascribed to the Lilliput Effect (a transient body size reduction within a surviving species). During periods of biotic recovery body size should increase, this, and its relationship with other recovery parameters are seldom documented. In order to explore the relationships between size, diversity and environments bivalve taxonomic richness and body size are recorded from the latest Triassic and Lower Jurassic of the British Isles. This interval encompasses the end-Triassic mass extinction event and its subsequent recovery. During the post-extinction interval oxygen depleted marine waters are reported to have become widespread and allegedly delayed onset of biotic recovery. During the Lower Jurassic three phases of size change are noted: an initial size increase from the extinction event through the Hettangian Stage (Lower Jurassic); a phase of size decrease characterises the next Stage, the Sinemurian; another phase of size increase then followed during the Pliensbachian Stage. These trends are reported for whole communities as well as among- and within- species. The latter is well exemplified by the dramatic size increase seen in Plagiostoma giganteum J. Sowerby which increases in size by 179% over the Hettangian. It is here proposed that within-species size increase in newly originating taxa following mass extinction be termed the Brobdingnag Effect, in honour of the giants in Gulliver’s Travels. Such patterns in body size act independent of other recovery metrics and appear unrelated to marine oxygenation which, for the Hettangian and lowermost Sinemurian, was oxic-dysoxic interspersed by comparably brief, localised bouts of anoxia. Temperature often exerts a control on the body size with creatures in cooler climates often being larger sized (i.e. Bergmann’s Rule). Temperature appears unrelated to body size patterns in the Lower Jurassic, however there are gaps at critical intervals. vii viii Table of contents Acknowledgements ……………………………...………………………………….v Abstract …………………………………………………...…………………………vii Table of contents…………………………………………………………………….ix List of tables………………………………………………………………………....xv List of figures……………………………………………………………………….xvii Abbreviations………………………………………………...…………………...xxiii Chapter 1: Introduction……………………………………………………………...1 1.1 Extinction losses……………………………………...……………………1 1.2 Extinction mechanism……………………………………………………..3 1.3 Biotic recovery from mass extinction……………………………...……..6 1.4 Recovery from the end-Triassic mass extinctions……………………..9 1.5 Body size……………………………………………………………...…..11 1.6 Aims…………………………………………………………………...…..15 1.7 Rationale for work…………………………………………………...…...16 1.8 Geological overview…………………………………………………...…16 1.8.1 The Rhaetian………………………………………………………...…17 1.8.2 The Hettangian……………………………………………………...….19 1.8.3 The Sinemurian……………………………………………………...…20 1.8.4 The Pliensbachian…………………………………………………......20 1.9 Thesis outline……………………………………………………………..21 References………………………………………………...………………….22 Chapter 2: Body size changes in bivalves of the family Limidae in the aftermath of the end-Triassic mass extinction: the Brobdingnag Effect……………………………………………………………………………...…..39 2.1 Abstract……………………………………………………………………………41 2.2 Introduction…………………...…………………………………………………..42 2.3 Geological setting……………………………………...…………………………44 2.4 Materials and Methods………………………………………...………………...47 2.4.1 Species studied………………………………………...………47 2.4.2 Sampling…………………………………………...…………...48 2.4.3 Growth lines………………………………………………...…..54 ix 2.5 Results……………………………………………..……………………..55 2.5.1 Body size……………………………………………………….55 2.5.1.1 Plagiostoma giganteum……………...……………..55 2.5.1.2 Plagiostoma punctatum…………………...………...60 2.5.1.3 Antiquilima succincta…………………………...…...63 2.5.1.4 Pseudolimea pectinoides……………………………64 2.5.1.5 Ctenostreon philocles…………………………...…..66 2.5.2 Growth patterns………………………………...………………67 2.5.3 Museum versus field collections………...……………………69 2.6 Discussion………………………………………………...………………71 2.6.1 Body size………………………………………………………..71 2.6.2 Growth patterns………………………………...………………72 2.6.3 Contemporary Early Jurassic size increase……………...….73 2.6.4 Causes of body size and growth rate changes………………73 2.6.4.1 Water depth and body size………...………………..73 2.6.4.2 Oxygen availability………………...………………...74 2.6.4.3 Temperature and body size…………………………76 2.6.4.4 Food availability……………...………………………77 2.6.5 Lilliputians and Brobdingnagians……………………………..78 2.7 Conclusions………………………...………………………………….....81 References…………………...……………………………………….82 Chapter 3: How quick was marine recovery after the end-Triassic mass extinction and what role did anoxia play?.....................................................93 3.1 Abstract……………………………………………………………………95 3.2 Introduction………………...……………………………………………..96 3.3 Geological setting……………………...…………………………………98 3.4 Materials and methods…………………...…………………………….102 3.5 Results…………………..………………………………………………104 3.5.1 Pyrite framboids…………………...………………………….104 3.5.1.1 Lithological variability……………...……………….104 3.5.1.2 Regional variability……………...………………….112 3.5.1.3 Temporal variability……………...…………………120 3.5.2 Faunas……………………………………...…………………121 x 3.5.2.1 Field collections………………...…………………..121 3.5.2.2 Museum collections………...……………………...128 3.6 Discussion……………………………………………………………….128 3.6.1 Recovery………………………………………………..…….128 3.6.2 Duration of recovery…………………………………...……..134 3.6.3 Role of anoxia in recovery……………………………………135 3.7 Conclusions………………………………...…………………………...137 References…………………………………………………………………..138 Chapter 4: The Hettangian-Sinemurian strata of Redcar, Cleveland Basin, NE England: facies and palaeoecology………………………………………..145 4.1 Abstract……………………………………………………...…………..147 4.2 Introduction………………………………………...……………………148 4.3 Geological setting……………………………………………………….149 4.4 Materials and methods………………………………………...……….151 4.5 Results…………………………………………..………………………152 4.5.1 Sedimentology………………...……………………………...152