The Pennsylvania State University The Graduate School College of Earth and Mineral Sciences ORGANIZATION AND DISTRIBUTION OF MIDDLE DEVONIAN BIOFACIES WITHIN A SEQUENCE STRATIGRAPHIC FRAMEWORK, HUNTINGDON COUNTY, PENNSYLVANIA, USA A Thesis in Geosciences by Travis J. Deptola © 2012 Travis J. Deptola Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science December 2012 The thesis of Travis J. Deptola was reviewed and approved* by the following: Mark E. Patzkowsky Associate Professor of Geosciences Thesis Advisor Rudy L. Slingerland Professor of Geology Peter D. Wilf Associate Professor of Geosciences Lee R. Kump Professor of Geosciences Department Head of Geosciences *Signatures are on file in the Graduate School. ii ABSTRACT Understanding the controls on the distribution of fossils in time and space is a fundamental aspect of paleontological research, because it underlies studies of ecosystem change through time, patterns of origination and extinction, and the geographic distribution of diversity. In the marine fossil record many studies have investigated onshore-offshore gradients and how they change through time, whereas little is known about how these ecological gradients vary spatially within and between depositional basins. For example, the temporal stability of biofacies gradients in the Middle Devonian Hamilton Group of New York state has been studied extensively using both qualitative and quantitative methodologies, yet no studies have been conducted in other regions of the Appalachian Basin to assess the spatial variability of these gradients. Field collection from an extensive outcrop of Mahantango Formation (Hamilton Group) in Huntingdon, Pennsylvania was conducted to characterize ecological gradients and to identify biofacies. Cluster analysis and detrended correspondence analysis reveal seven biofacies in the Hamilton Group of Central Pennsylvania that are distributed primarily by factors associated with water depth. Four biofacies identified in Pennsylvania (Tropidoleptus, Tropidoleptus- Devonochonetes, Devonochonetes, Ambocoelia) are qualitatively similar to biofacies identified in New York. Three novel biofacies have been identified in Pennsylvania (Pustulatia-Longispina, Rhipidomella, Rhipidomella-Devonochonetes), suggesting that additional undiscovered biofacies may exist in this basin. Quantitative comparison between Pennsylvania and New York study sites reveal that biofacies distribution throughout the Appalachian basin is governed by environmental differences associated with distance from the delta front, such as turbidity, sediment flux, or nutrient supply. For taxa shared between Pennsylvania and New York preferred environment (PE) is strongly correlated between study sites, while environmental tolerance and peak abundance are only weakly correlated. iii TABLE OF CONTENTS List of Tables.....................................................................................................................................v List of Figures..................................................................................................................................vi Chapter 1. INTRODUCTION...........................................................................................................1 Chapter 2. GEOLOGIC SETTING…………………………………………...……………………3 Chapter 3. METHODOLOGY……………………………………………………………………10 Section Measurement and Correlation…………………………………………………...10 Field Collection…………………………………………………………………..………11 Quantitative Analysis…………………………………………………………………….12 Gradient Comparison with Middle Devonian of New York……………………………..14 Analysis of Niche Parameters…………………………………………………………...15 Chapter 4. RESULTS……………………………………………………………………………..18 Facies Analysis…………………………………………………………………………...18 Vertical Facies Succession……………………………………………………………….29 Sequence Stratigraphy……………………………………………………………….......31 Cluster Analysis Results………………………………………………………………....32 Q-Mode Cluster Results…………………………………………………………32 R-Mode Cluster Results…………………………………………………………36 Cluster Analysis Summary…………………………………………………...….37 Ordination Results……………………………………………………………………….38 DCA Axis 1 Sample Scores……………………………………………………..38 DCA Axis 2 Sample Scores……………………………………………………..41 Chapter 5. DISCUSSION………………………………………………………………………...44 I. a. Biofacies Gradients…....…………….……………………………………………...44 I. b. Ecology of Biofacies..………………………………………………………………46 I. c. Oxygenation and Stratification of the Appalachian Basin………………………….48 II. Qualitative Comparison of Pennsylvania and New York Biofacies…………………..50 III. Quantitative Comparison of Pennsylvania and New York Biofacies..……………....54 Chapter 6. CONCLUSIONS……………………………………………………………………...65 References………………………………………………………………………………………...67 Appendix A: Latitude and Longitude Data……………………………………………………….73 Appendix B: Raw API Gamma Ray Data………………………………………………………...74 Appendix C: Biofacies Composition and Life History Traits…………………………………….76 Appendix D: Collection-based Rarefaction Analysis…………………………………………….81 Appendix E: Raw Data Matrix of Collection…………………………………………………….82 iv LIST OF TABLES Table 1...............................................................................................................................16 Differences between Pennsylvania data set and New York data set Table 2……………………………………………………………………………………20 Summary table of four facies identified in the Mahantango Formation in Huntingdon County, Pennsylvania, USA Table 3…………………………………………………………………………………....57 Overall Hamilton Group generic diversity differences between central Pennsylvania and New York State Table 4……………………………………………………………………………………62 Genera list for Huntingdon, Pennsylvania and New York State v LIST OF FIGURES Figure 1……………………………………………………………………………………4 Paleogeography of Laurentia during the Middle Devonian period Figure 2…………………………………………………………………………………....5 Correlation table of the Middle Devonian Hamilton Group showing relationship between New York units and Pennsylvania units Figure 3…………………………………………………………………………………....8 Proposed paleogeography of the Mahantango delta complex in central Pennsylvania, USA Figure 4…………………………………………………………………………………..19 Measured stratigraphic section of the Mahantango Formation in Huntingdon County, Pennsylvania, USA Figure 5…………………………………………………………………………………..21 Silty Sandstone facies of the Middle Devonian Hamilton Group in Huntingdon County, Pennsylvania, USA Figure 6…………………………………………………………………………………..22 Zoophycos traces within the Silty Sandstone facies of the Donation Member at Huntingdon Figure 7…………………………………………………………………………………..24 Sandy Siltstone facies of the Middle Devonian Hamilton Group in Huntingdon County, Pennsylvania, USA Figure 8…………………………………………………………………………………..26 Silty Mudstone facies of the Middle Devonian Hamilton Group in Huntingdon County, Pennsylvania, USA Figure 9………………………………………………………………………………......28 Calcareous Silty Mudstone facies of the Middle Devonian Hamilton Group in Huntingdon County, Pennsylvania, USA Figure 10…..……………………………………………………………………………..30 Dip-oriented cross-section correlation of the Mahantango Formation in central Pennsylvania Figure 11…………………………………………………………………………………33 Two-Way Cluster Analysis of Q-Mode (sample) clusters and R-Mode (species) clusters vi Figure 12…………………………………………………………………………………39 Q-Mode DCA Axis 1 vs. Axis 2 scores Figure 13…………………………………………………………………………………43 Q-Mode DCA Axis 1 score plotted against stratigraphic height of the measured section in Huntingdon Figure 14…………………………………………………………………………………52 Distribution of Middle Devonian Hamilton biofacies in New York and Pennsylvania along a bathymetric gradient Figure 15…………………………………………………………………………………55 DCA Analysis comparing Pennsylvania samples with New York samples Figure 16…………………………………………………………………………………59 DCA Analysis showing shared onshore-offshore gradient between the Pennsylvania samples and New York samples Figure 17…………………………………………………………………………………61 Correlation of preferred environment (PE), environmental tolerance (ET), and peak abundance (PA) for all shared taxa between Pennsylvania and New York State vii INTRODUCTION Understanding the spatial and temporal variability in the distribution of fossils is essential for investigating ecosystem change through time (Brett and Baird, 1995; Patzkowsky and Holland, 1999; Holland and Patzkowsky, 2007), patterns of origination and extinction (Sepkoski and Miller, 1985; Sepkoski, 1987; Patzkowsky and Holland, 1997), and partitioning of diversity among local, regional, and continental scales (Valentine and Moores, 1970; Sepkoski, 1988; Patzkowsky and Holland, 2007). One approach to characterizing the distribution of fossil taxa is to quantify ecological gradients and the occurrence and abundance of individual taxa along the gradient. For example, based on detrended correspondence analysis of two Ordovician data sets of different age, Holland and Patzkowsky (2004) compared the preferred environment (PE), environmental tolerance (ET), and peak abundance (PA) for the shared taxa. Both PE and PA were generally similar for the two data sets suggesting little change in these aspects of distribution however ET was not similar suggesting change in this niche parameter. This same approach can be used to study the spatial change in ecological gradients, although no studies have attempted this kind of comparison. The Middle Devonian Hamilton Group in New York state is an ideal geologic setting to examine because of its purported paleoecological stability and the wealth of paleoecological data. Despite the plethora of paleoecological studies conducted