The Late Middle Devonian (Givetian) Global Taghanic Biocrisis in Its
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The Late Middle Devonian (Givetian) Global Taghanic Biocrisis in its Type Region (Northern Appalachian Basin): Geologically Rapid Faunal Transitions Driven by Global and Local Environmental Changes A dissertation submitted to the Graduate School University of Cincinnati In partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Geology McMicken College of Arts and Sciences August 9th, 2011 by James Joseph Zambito IV M.S., University at Buffalo, 2006 B.S., SUNY College at Brockport, 2004 Dissertation Committee Dr. Carlton E. Brett, Chair Dr. Arnold I. Miller Dr. David L. Meyer Dr. Thomas J. Algeo Dr. Gordon C. Baird Dr. Alex J. Bartholomew Abstract The late Middle Devonian Global Taghanic Biocrisis marks the onset of extinction and a loss of faunal endemism that culminated in the subsequent Frasnian-Famennian extinction. Global environmental changes recognized at this time include increased warming and aridity, as well as rapid eustatic sea level fluctuations. In the type region, the northern Appalachian Basin, the biocrisis is recorded within the deposits of the uppermost Hamilton, Tully, and lowermost Genesee Groups over an interval of ~0.5 million years. A high-resolution stratigraphic framework reconstructed along a complete onshore through offshore gradient has resulted in the recognition of three main pulses (bioevents) of faunal transition in the type region: 1) the incursion of the tropical Tully Fauna into eastern Laurentia and temporary loss of the endemic Hamilton Fauna; 2) Tully Fauna extermination and replacement by a recurrent Hamilton Fauna; and, ultimately, 3) extinction of large portions of the Hamilton Fauna and the beginning of cosmopolitan Genesee Fauna. Similar faunal patterns of incursion, recurrence, and cosmopolitanism have also been noted for other regions, albeit with somewhat different regional characteristics. Global environmental changes during the biocrisis are recognized in the type region through reconstruction of δ18O(conodont apatite) and δ13C(carbonate) records. However, regional faunal incursion, replacement, and recurrence patterns during the first and second bioevents, as well as corresponding sedimentological observations, are best explained by basinal-scale water mass changes in response to the global environmental changes. During the third bioevent, eustatic sea- level rise was accentuated regionally by renewed Acadian tectonic activity. Quantitative paleoecological analysis demonstrates that Hamilton Fauna survivors of this bioevent were those taxa adapted to nearshore, siliciclastic-dominated settings. Persistence of these taxa was a direct ii result of the persistence of their preferred habitat through the biocrisis and subsequent tectonically-driven expansion of this facies. Similar, multi-disciplined studies of the Taghanic Biocrisis in other regions will increase our understanding of regional response to global change on geologic timescales. iii iv Acknowledgements Thanks to Dr. Carl Brett for his guidance in the field and classroom, the many research opportunities he has included me in beyond my dissertation, and the freedom to take my research in unexpected directions. I am grateful to Dr. Arnie Miller 'due to' his advice on my dissertation and life itself, his encouragement throughout my time at UC, and for helping me to find out the hard way that brightly colored liquors don't mix well... I would like to thank Dr. Dave Meyer for sharing with me his excitement for all things paleontological, guidance in fossil preparation techniques, and reminding me of the importance of the work done by my predecessors. Thank you to Dr. Tom Algeo for teaching me geochemical techniques and for very helpful discussion of my dissertation. I am very much indebted to Dr. Gordon Baird for all of his assistance and instruction in the field, for sharing his tremendous wealth of locality and stratigraphic knowledge with me, and for great discussions. Thanks to Dr. Alex Bartholomew for assisting with fieldwork in the early phases of my dissertation. Thank you to Dr. Michael Joachimski and Daniele Lutz for training me in the oxygen isotopic analysis of conodont apatite, discussion of my research, and for taking me to the Bergkirchweih. I am also grateful to Dr. Jed Day, Dr. Jeff Over, Dr. Ted Williams Jr., Dr. Charles Thayer, and especially Dr. Bill Kirchgasser for helpful discussion and sharing of samples and data. Thanks to Dr. Susan Butts and the staff at the Yale Peabody Museum for providing access to, and assistance in working with, the Thayer collections. Fieldwork was assisted, at various times, by Nick Bose, Sara Oser, Ian VanDonkelaar, and Joe Sullivan. I am extremely grateful for all of the financial support and opportunities provided to me by the UC Department of Geology. Thanks to my family, and in-laws, for all of their support throughout graduate school. v I am eternally indebted to Sarah, my amazing wife and best friend, for helping with fieldwork, discussion of my research, assistance with data analysis, and putting up with me these past four years. I could not have done this without you. Funding for this dissertation was provided by the National Science Foundation, Deutscher Akademischer Austauschdienst (German Academic Exchange Service), the American Museum of Natural History (Theodore Roosevelt Memorial Fund), the American Association of Petroleum Geologists, the Evolving Earth Foundation, the Geological Society of America, the Paleontological Society, the Schuchert and Dunbar Grants in Aid Program (Yale Peabody Museum), the Paleontological Research Institute, the Society for Sedimentary Geology, Sigma Xi, the Mid-America Paleontology Society, the UC Department of Geology, the UC Graduate Student Governance Association, the UC University Research Council, and the UC Graduate School. vi Table of Contents: Chapter 1: Introduction (p. 1-16) Chapter 2: Depositional Sequences and Paleontology of the Middle – Upper Devonian Transition (Genesee Group) at Ithaca, New York: A Revised Lithostratigraphy for the Northern Appalachian Basin (p. 17-76) Chapter 3: The Late Middle Devonian (Givetian) Global Taghanic Biocrisis in its Type Area (Northern Appalachian Basin): Geologically Rapid Faunal Transitions Driven by Global and Local Environmental Changes (p. 77-151) Chapter 4: Reconstruction of Isotopic Changes for the Late Givetian (Middle Devonian) Global Taghanic Biocrisis in its Type Region (Northern Appalachian Basin) (p. 152-192) Chapter 5: Quantitative Paleoecological Analysis of the Post-Taghanic Genesee Fauna and its Relationship to the Pre-Biocrisis Hamilton Fauna (p. 193-230) Chpater 6: Conclusions (p. 231) vii Chapter 1 Introduction During the Global Taghanic Biocrisis (GTB), approximately 385 million years ago, Middle Devonian faunas worldwide underwent a major extinction in apparent conjunction with global warming and aridity, eustatic sea level rise (known as the Taghanic Onlap), and decreased oxygenation of epicontinental seas (Johnson, 1970; House, 2002; Aboussalam, 2003; Joachimski et al., 2004, 2009; Aboussalam and Becker, 2011; and Marshall et al., 2011). In fact, the Middle-Upper Devonian Boundary was originally defined at this stratigraphic level because of the abrupt faunal changes observed in a number of taxonomic groups globally (Klapper et al., 1987). Studies of marine invertebrate global biodiversity trends at various taxonomic scales through the Phanerozoic recognize the GTB interval as the beginning of a period of protracted extinction lasting to at least the Frasnian-Famennian extinction, the prolonged duration of which has likely prevented this biocrisis from being recognized as a major mass extinction (Raup and Sepkoski, 1982; Alroy et al., 2008). A growing body of work suggests, however, that these lesser studied and more frequent events that involve in faunal restructuring and replacement at regional to global scales may have a greater aggregate effect on the evolution of life (Walliser, 1990; Brett and Baird, 1995; Brett et al., 1996; Miller, 1998). Johnson (1970) and Boucot (1988) describe this time as the end of a period of established Devonian faunal provinciality related to latitudinal climatic (temperature) gradients, resulting in a world-wide cosmopolitan fauna that persists until the late Frasnian extinction (McGhee, 1996, and references therein; and Sandberg et al., 2002). Indeed, global analyses of sea-surface temperature variation before and after the GTB interval based on oxygen isotopic composition of apatite in conodonts and carbonate in brachiopods have shown a period of global warming, but, 1 the stratigraphic resolution of these analyses is too coarse to compare with the faunal changes observed in the type-area during the biocrisis, and, furthermore, samples from the type-area have never been isotopically examined (Joachimski et al., 2004, 2009). In the type-area of the GTB, the New York Appalachian Basin, a high-resolution stratigraphic framework has allowed detailed qualitative and quantitative paleoecological study of the pulsed faunal migrations, replacements, recurrence, and extinctions comprising this biocrisis (Heckel, 1973; Baird and Brett, 2003, 2008; reviewed in Zambito et al., in press). Comparatively, the only paleoenvironmental reconstructions using geochemical proxies in the type-area to date lack the stratigraphic resolution for which paleoecological changes have been described, as the studies were conducted on successions in which a majority of the strata recording the faunal transitions was