University of Montana ScholarWorks at University of Montana Graduate Student Theses, Dissertations, & Professional Papers Graduate School 2013 NEARING THE END: REEF BUILDING CORALS AND BIVALVES IN THE LATE TRIASSIC AND COMPARING CORALS AND BIVALVES BEFORE AND AFTER THE END-TRIASSIC MASS EXTINCTION USING A TAXONOMIC DATABASE Hannah Morgan Elliott Shepherd The University of Montana Follow this and additional works at: https://scholarworks.umt.edu/etd Let us know how access to this document benefits ou.y Recommended Citation Shepherd, Hannah Morgan Elliott, "NEARING THE END: REEF BUILDING CORALS AND BIVALVES IN THE LATE TRIASSIC AND COMPARING CORALS AND BIVALVES BEFORE AND AFTER THE END-TRIASSIC MASS EXTINCTION USING A TAXONOMIC DATABASE" (2013). Graduate Student Theses, Dissertations, & Professional Papers. 1403. https://scholarworks.umt.edu/etd/1403 This Thesis is brought to you for free and open access by the Graduate School at ScholarWorks at University of Montana. It has been accepted for inclusion in Graduate Student Theses, Dissertations, & Professional Papers by an authorized administrator of ScholarWorks at University of Montana. For more information, please contact [email protected]. NEARING THE END: REEF BUILDING CORALS AND BIVALVES IN THE LATE TRIASSIC AND COMPARING CORALS AND BIVALVES BEFORE AND AFTER THE END-TRIASSIC MASS EXTINCTION USING A TAXONOMIC DATABASE By HANNAH MORGAN ELLIOTT SHEPHERD Bachelors of Arts, University of Montana, Missoula, MT, 2006 Thesis presented in partial fulfillment of the requirements for the degree of Master of Science in Geosciences, Paleontology The University of Montana Missoula, MT August 2013 Approved by: Sandy Ross, Dean of The Graduate School Graduate School George D. Stanley, Jr., Chair Geoscience James Sears Geoscience Bonnie Ellis Division of Biological Sciences ii Shepherd, Hannah M.E., Masters of Science, Spring 2013 Geoscience Nearing the End: Reef Building Corals and Bivalves in the Late Triassic and Comparing Corals and Bivalves before and after the end-Triassic Mass Extinction Using a Taxonomic Database Chairperson: George D. Stanley, Jr. One of the most important tenants in geology is that the present is the key to the past, but it can also be said that the past is the key to the present. The five great extinction events are some of the key events that can help us to understand how changes in climate and sea chemistry can cause great changes in the ecology of our planet. Today the increase in atmospheric CO2 is causing ocean acidification, which has also been proposed as part of the system that caused the end-Triassic mass extinction. Ocean acidification can be greatly detrimental to the skeletal structures of marine invertebrate such as reef building corals and bivalves. During the Norian and Rhaetian (Late Triassic), corals and bivalves had high diversity and abundance, but like many organisms involved in the mass extinction, quickly disappeared at the end of the Triassic. In the early Jurassic, very few surviving species of corals can be found, and almost no reefs. If this ‘reef gap’ was caused by a change in ocean chemistry, then how did these few species of corals survive? Were bivalves also affected by the changes? On Vancouver Island, rock units containing corals and bivalves can be found that represent both Norian and Rhaetian time intervals, but early Jurassic sedimentary units are found rarely, if ever. This creates a difficulty in looking for patterns in changes that happened after the mass extinction, but does allow for analysis of what reef communities looked like shortly before the end of the Triassic. In addition, by building upon data from the Paleobiology Database, changes in the global reef communities after the end-Triassic mass extinction can be examined. iii TABLE OF CONTENTS Title Page……………………………………………………………………….. i Abstract…………………………………………………………………………. ii Table of Contents……………………………………………………………….. iii List of Figures…………………………………………………………………… vi List of Tables and List of Equations……………………………………………. vii List of Plates…………………………………………………………………….. viii Part I: Nearing the End: Reef Building Corals and Bivalves in the Late Triassic 1 Chapter 1: Introduction…………………………………………………… 1 (1) The big 5 mass extinctions………………………………. 1 (2) Setting the scene: Late Triassic………………………….. 1 (3) Geologic Setting…………………………………………. 3 (a) Tectonostratigraphic Terranes…………………… 3 (b) Wrangellia and Vancouver Island……………….. 6 (c) Northern Vancouver Island……………………… 10 (d) Previous Research on Northern Vancouver Island. 11 (e) Statement of problem……………………………. 13 Chapter 2: Methods………………………………………………………. 18 (1) Field Methods…………………………………………… 18 (2) Lab Methods…………………………………………….. 20 (3) Statistical Methods……………………………………… 20 (4) Locality Descriptions……………………………………. 22 iv Chapter 3: Results………………………………………………………… 23 (1) Faunal Assemblage……………………………………… 23 (2) Lithology………………………………………………... 23 (a) Parson Bay Formation…………………………… 23 (b) Volcaniclastic-Sedimentary Unit or upper Parson Bay Formation……………………………………….. 24 Chapter 4: Discussion……………………………………………………. 25 Chapter 5: Conclusions…………………………………………………... 27 Part 2: Comparing Corals and Bivalves before and after the end-Triassic Mass Extinction Using a Taxonomic Database Chapter 1: Introduction…………………………………………………… 29 (1) The big 5 mass extinctions………………………………. 29 (2) Value of Database Applications in Paleontology………... 32 (3) Databases Developed for Scleractinian Corals……………. 38 (a) Background on coral morphology……………….. 38 (i) Definition of Scleractinia and explanation of morphology………………………………. 38 (ii) Coral colony integration…………………. 39 (iii) Photosymbiosis in Scleractinia…………… 43 (b) History of scleractinian coral databases………….. 43 (c) Development of a new database for scleractinian corals……………………………………………… 45 v (4) Databases of bivalves……………………………………... 46 Chapter 2: Methods……………………………………………………….. 47 (1) Database methods…………………………………………. 47 (2) Statistical methods………………………………………… 48 Chapter 3: Results…………………………………………………………. 51 (1) Corals and Bivalves……………………………………….. 51 (2) Coral Morphology………………………………………… 51 Chapter 4: Discussion…………………………………………………….. 54 Chapter 5: Conclusions……………………………………………………. 56 Acknowledgements……………………………………………………………….. 57 Bibliography………………………………………………………………………. 58 Plates………………………………………………………………………………. 73 Appendix: Database of Triassic Scleractinian Corals.……………………………… 79 vi LIST OF FIGURES Part 1: Nearing the End: Reef Building Corals and Bivalves in the Late Triassic Figure 1: Terrane maps of North America with major terranes and Wrangellia 5 Figure 2: Geology of Vancouver Island 7 Figure 3: Stratigraphic section of Vancouver Island formations 9 Figure 4: Outline map and satellite image of Vancouver Island 10 Figure 5: Satellite image of area near Port Alice, British Columbia, showing general localities 15 Figure 6: Geologic map of area near Port Alice, British Columbia 16-17 Figure 7: Correlated stratigraphic columns of measured sections at Yreka-1 and Pulp Mill Hill localities 19 Figure 8: Stratigraphic column of measured section at Yreka-3 21 Part 2: Comparing Corals and Bivalves before and after the end-Triassic Mass Extinction Using a Taxonomic Database Figure 9: Time scale of the middle Triassic through the early Jurassic with paleogeographic maps 31 Figure 10: General diagram of coral morphologic features 39 Figure 11: Illustrations of coral colony integration types 40 Figure 12: Diversity of corals and bivalves from Middle Triassic to Early Jurassic 49 Figure 13: Number of coral species by integration type from middle Triassic to early Jurassic 50 Figure 14: Boxplots of coral survival of the end-Triassic mass extinction by integration 56 vii LIST OF TABLES Part 1: Nearing the End: Reef Building Corals and Bivalves in the Late Triassic Table 1: Previous research on Northern Vancouver Island Geology 12 Table 2: Locality descriptions near Port Alice, BC on Vancouver Island 22 Table 3: Fossils found near Port Alice, BC with Plate and Locality information 23 Part 2: Comparing Corals and Bivalves before and after the end-Triassic Mass Extinction Using a Taxonomic Database Table 4: Comparison of select coral databases 37 Table 5: Coral integration types with definitions and examples 41 Table 6: Diversity of bivalves and corals from Middle Triassic to Early Jurassic 51 Table 7: Diversity of corals by integration type 53 LIST OF EQUATIONS Part 1: Nearing the End: Reef Building Corals and Bivalves in the Late Triassic Equation 1: Shannon’s H diversity index 20 Part 2: Comparing Corals and Bivalves before and after the end-Triassic Mass Extinction Using a Taxonomic Database Equation 2: Pearson’s product moment correlation coefficient 48 viii LIST OF PLATES Part 1: Nearing the End: Reef Building Corals and Bivalves in the Late Triassic Plate 1: Corals 73-74 Plate 2: Bivalves 75-76 Plate 3: Myophorigonia ?paucicostata 77 Plate 4: Wallowaconcha raylenea 78 1 Part 1: Nearing the End: Reef Building Corals and Bivalves in the Late Triassic Chapter 1: Introduction (1) The Big 5 Mass Extinctions One of the most important tenants in geology is that the present is the key to the past, but it can also be said that the past is the key to the present. Over the course of geologic history, there have been five events which are considered major mass extinctions, Late Ordovician (440 Ma), Late Devonian (370–350 Ma), End-Permian (250 Ma), End-Triassic (201 Ma) and End- Cretaceous (65 Ma) (Raup and Sepkoski, 1982, 1984). Although it is likely that these events have different causes, such as bolide impacts and