MICROFAUNAL ASSEMBLAGES OF THE PLACID SHALE (MISSOURIAN, UPPER PENNSYLVANIAN), BRAZOS RIVER VALLEY, NORTH-CENTRAL TEXAS by BRITTANY E. MEAGHER Presented to the Faculty of the Graduate School of The University of Texas at Arlington in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE IN GEOLOGY THE UNIVERSITY OF TEXAS AT ARLINGTON August 2012 Copyright © by Brittany Meagher 2012 All Rights Reserved DEDICATION I would like to dedicate this thesis to my granddad Pope Meagher who as a geologist instilled in me, at a young age, my love for rocks. I don’t believe I would have gotten as far without this early love he planted and nurtured to grow within me. ACKNOWLEDGEMENTS There are many people that I would like to thank for their guidance and patience throughout this thesis project. Without these people, this thesis would not have been possible. I would like to thank Dr. Merlynd Nestell, Committee Chairman, for suggesting this project to me. His advice and assistance throughout this research project has helped me learn as much as possible about various types of microfauna. His review and editing of this manuscript is greatly appreciated. Dr. Galina Nestell, thesis committee member, for teaching me exactly what goes into taxonomically describing a microfossil. Her expertise on the identification of foraminifers contributed to the completion of this thesis. Dr. John Wickham, thesis committee member, for his guiding and teaching me various topics throughout my time at University of Texas Arlington. His time, in both reviewing this manuscript and serving on my committee, is invaluable and greatly appreciated. Dr. Andrew Hunt, for the 100+ hours spent taking SEM pictures for me. I really am very grateful that you had the patience and made the time to do this for me. Mike Lewis, with Hills Estates for allowing me access to the Hills Estates property to collect samples. iv The Dallas Paleontological Society who generously awarded the Frank Crane Memorial Scholarship, which helped me in the pursuit of this degree. To my field crew, you all rock for helping me measure my sections and collect samples. Last, but certainly not least, I would like to thank my family. My parents David and Anita Meagher, who continuously encouraged me to follow my dreams and to reach for the stars even when I cannot see them because of the clouds, thank you. To my siblings Ashley and Andrew, thank you for all the years you have listened to, asked about, and tolerated my babbling about rocks and “bugs”. Adam, thank you for your support and encouragement throughout this long process. May 9, 2012 v ABSTRACT MICROFAUNAL ASSEMBLAGES OF THE PLACID SHALE (MISSOURIAN, UPPER PENNSYLVANIAN), BRAZOS RIVER VALLEY, NORTH-CENTRAL TEXAS Brittany Meagher, M.S. The University of Texas at Arlington, 2012 Supervising Professor: Merlynd K. Nestell The Pennsylvanian and lowermost part of the Permian strata in North-Central Texas is assigned to the Strawn, Canyon, and Cisco Groups. The Canyon Group is approximately equivalent to the middle-upper part of the Missourian (Upper Pennsylvanian) and crops out in the Brazos River valley in a generally northeast- southwest strip across Palo Pinto and Jack counties. The Canyon Group is subdivided into seven formations that contain several cycles of well-known clastic and carbonate units. The Placid Shale, one of the clastic units within the Canyon Group, consists of two cycles of gray, brown, olive sandstone/siltstone/mudstone with few thin limestone beds. It is bounded below by the Winchell Limestone and above by the Ranger Limestone. In the Possum Kingdom Lake area in Palo Pinto County, three localities of the Placid Shale were chosen for study of their microfossil content. Closely spaced samples were taken vi from the two dominantly marine sequences of the two cycles, one in the lower part and one in the upper part of the formation. The dominant microfaunal elements present are holothurian sclerites, ostracodes, conodonts (Streptognathodus firmus and S. pawhuskaensis), fusulinids (which fall within the Triticites newelli zone) and a number of distinctive species of small foraminifers. The foraminifers are the main focus of the present study because of their diversity and biostratigraphic significance. The primary goal of this project is to describe and update the taxonomic assignments of the various microfaunal elements from two cycles of the Placid Shale. vii TABLE OF CONTENTS ACKNOWLEDGEMENTS ............................................................................................... iv ABSTRACT ....................................................................................................................... vi LIST OF FIGURES ......................................................................................................... xiii LIST OF TABLES ........................................................................................................... xiv Chapter Page 1. INTRODUCTION ……………………………………..………..….. ................1 Geologic Setting...........................................................................................1 Location .......................................................................................................4 History of Previous Research.......................................................................4 Methods........................................................................................................6 Purpose of Study ..........................................................................................7 2. PENNSYLVANIAN CYCLOTHEMS…………………………………..………..….. ..........................10 3. FORAMINIFERA..............................................................................................14 Introduction ................................................................................................14 Descriptions of Foraminifers .....................................................................15 Agglutinated Species .....................................................................15 Hyperammina bulbosa .......................................................16 Hyperammina clavata ........................................................17 viii Hyperammina glabra .........................................................18 Hyperammina sp. 1 ............................................................19 Hyperamminoides elegans .................................................20 Reophax arenatus...............................................................22 Reophax fittsi .....................................................................23 Ammobaculites magnigranulus ..........................................25 Ammobaculites parallelus ..................................................26 Ammobaculites spirans ......................................................27 Ammobaculites (?) sp. 1.. ...................................................27 Textularia (?) bucheri ........................................................29 Calcareous Species.........................................................................30 Tuberitina bulbacea ...........................................................31 Earlandia perparva ............................................................32 Pseudoammodiscus sp. 1 ...................................................34 Deckerella laheei ...............................................................35 Paleotextularia grahamensis .............................................37 Endothyra ovata .................................................................38 Endothyra rothrocki ...........................................................39 Endothyranella stormi .......................................................41 Endothyranella sp. 1 ..........................................................42 Pseudobradyina pulchra ....................................................43 Tetrataxis corona ...............................................................45 ix Planiinvoluta thompsoni ....................................................47 Foraminiferal Plates .......................................................................48 4. FUSULINACEANS……………………………………..………..….. .............60 Introduction ................................................................................................60 Descriptions of Fusulinaceans ...................................................................61 Kansanella sp. 1 .............................................................................61 Triticites newelli.............................................................................63 FUSULINACEAN PLATE .......................................................................65 5. OSTRACODES .................................................................................................67 Introduction ................................................................................................67 Descriptions of Ostracodes ........................................................................68 Kegelites dattonensis .....................................................................68 Healdia spinosa .............................................................................70 Cavellina nebrascensis ..................................................................72 Bairdia blakei.................................................................................74 Moorites minutus ...........................................................................75 Ostracode Plate ..........................................................................................77