Master Thesis, Department of Geosciences Late Smithian (Early Triassic) ammonoids from the uppermost Lusitaniadalen Member (Vikinghøgda Formation), Svalbard Veronica Piazza Late Smithian (Early Triassic) ammonoids from the uppermost Lusitaniadalen Member (Vikinghøgda Formation), Svalbard Veronica Piazza Master Thesis in Geosciences Discipline: Palaeontology Department of Geosciences Faculty of Mathematics and Natural Sciences University of Oslo 29.05.2015 i © Veronica Piazza, 2015 This work is published digitally through DUO – Digitale Utgivelser ved UiO http://www.duo.uio.no It is also catalogued in BIBSYS (http://www.bibsys.no/english) All rights reserved. No part of this publication may be reproduced or transmitted, in any form or by any means, without permission. ii Table of contents Acknowledgments ..................................................................................................................... 1 Abstract ..................................................................................................................................... 3 1. Introduction .......................................................................................................................... 5 2. Geological background ........................................................................................................ 6 2.1 Sedimentation and tectonics in the Early Mesozoic ......................................................... 7 2.2 Early and Middle Triassic deposits: the Sassendalen Group ............................................ 9 2.2.1 Nomenclature overview ........................................................................................... 10 2.3 The Vikinghøgda Formation .......................................................................................... 12 2.3.1 The Deltadalen Member .......................................................................................... 16 2.3.2 The Lusitaniadalen Member .................................................................................... 16 2.3.3 The Vendomdalen Member ..................................................................................... 17 3. Triassic palaeogeography: the faunal realms .................................................................. 18 3.1 Early Triassic ammonoid trends ..................................................................................... 20 3.2 Boreal ammonoid assemblages ...................................................................................... 22 4. Early Triassic ammonoid biostratigraphy ....................................................................... 23 4.1 The Boreal Early Triassic ............................................................................................... 23 4.1.1 The tardus Zone in the Boreal Realm ...................................................................... 24 4.1.2 Comparisons with the Tethyan Realm ..................................................................... 24 4.2 Smithian ammonoids from Svalbard .............................................................................. 27 4.2.1 Previous research ..................................................................................................... 27 4.2.2 Ammonoid faunal zonations .................................................................................... 28 5. Intraspecific variation and the Buckman’s law of covariation ...................................... 31 6. Data collection and methods .............................................................................................. 35 6.1 Working with the specimens: a group division as a start ............................................... 35 6.2 Measurements ................................................................................................................. 35 6.3 Preparation of the specimens .......................................................................................... 37 6.4 Photography .................................................................................................................... 37 6.4.1 Whitening ................................................................................................................. 38 iii 6.4.2 Photographic setup ................................................................................................... 39 6.5 Drawing the suture lines: the camera lucida ................................................................... 39 7. Terminology of ammonoid morphology: an overview .................................................... 41 7.1 Shell morphology ........................................................................................................... 41 7.2 Suture lines ..................................................................................................................... 43 7.3 Ornamentation ................................................................................................................ 44 8. Results ................................................................................................................................. 47 8.1 Systematic descriptions .................................................................................................. 48 Xenoceltites subevolutus Spath, 1930 ............................................................................... 48 Arctoprionites nodosus (Frebold, 1930) ........................................................................... 50 Arctoprionites resseri (Mathews, 1929) ........................................................................... 52 Anasibirites kingianus (Waagen, 1895) ............................................................................ 54 Wasatchites cf. distractus (Waagen, 1895) ....................................................................... 59 Wasatchites tridentinus Spath, 1934 ................................................................................. 61 Wasatchites spp. indet. ...................................................................................................... 64 Gen. et sp. nov. ................................................................................................................ 68 Arctoceras sp. nov. ........................................................................................................... 70 8.2 Statistical analyses .......................................................................................................... 74 8.2.1 Linear regressions (RMA) and histograms .............................................................. 74 8.2.2 Multivariate analyses: PCA vs. LDA ....................................................................... 85 9. Interpretations .................................................................................................................... 92 9.1 Taxonomy and biostratigraphy ....................................................................................... 92 9.2 Taphonomy ..................................................................................................................... 94 9.3 Ecology ........................................................................................................................... 95 9.4 Palaeobiogeography ........................................................................................................ 97 10. Conclusions ....................................................................................................................... 99 11. Bibliography ................................................................................................................... 101 Appendix 1 – Plates .............................................................................................................. 109 Plate I .................................................................................................................................. 110 Plate II................................................................................................................................. 112 Plate III ............................................................................................................................... 114 Plate IV ............................................................................................................................... 116 Plate V ................................................................................................................................ 118 iv Plate VI ............................................................................................................................... 120 Plate VII .............................................................................................................................. 122 Plate VIII ............................................................................................................................ 124 Appendix 2 – Measurements ............................................................................................... 126 Appendix 3 – Statistical values ............................................................................................ 130 Linear regressions (RMA) .................................................................................................. 130 Principal component analysis (PCA) .................................................................................. 132 Discriminant analysis (LDA).............................................................................................