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Late Paleozoic Glaciation and Ice Sheet University of Wisconsin Milwaukee UWM Digital Commons Theses and Dissertations May 2013 Late Paleozoic Glaciation and Ice Sheet Collapse Over Western and Eastern Gondwana: Sedimentology and Stratigraphy of Glacial to Post- Glacial Strata in Western Argentina and Tasmania, Australia Lindsey C. Henry University of Wisconsin-Milwaukee Follow this and additional works at: https://dc.uwm.edu/etd Part of the Geology Commons Recommended Citation Henry, Lindsey C., "Late Paleozoic Glaciation and Ice Sheet Collapse Over Western and Eastern Gondwana: Sedimentology and Stratigraphy of Glacial to Post-Glacial Strata in Western Argentina and Tasmania, Australia" (2013). Theses and Dissertations. 112. https://dc.uwm.edu/etd/112 This Dissertation is brought to you for free and open access by UWM Digital Commons. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of UWM Digital Commons. For more information, please contact [email protected]. LATE PALEOZOIC GLACIATION AND ICE SHEET COLLAPSE OVER WESTERN AND EASTERN GONDWANA: SEDIMENTOLOGY AND STRATIGRAPHY OF GLACIAL TO POST-GLACIAL STRATA IN WESTERN ARGENTINA AND TASMANIA, AUSTRALIA by Lindsey C. Henry A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Geosciences at The University of Wisconsin-Milwaukee May 2013 ABSTRACT LATE PALEOZOIC GLACIATION AND ICE SHEET COLLAPSE OVER WESTERN AND EASTERN GONDWANA: SEDIMENTOLOGY AND STRATIGRAPHY OF GLACIAL TO POST-GLACIAL STRATA IN WESTERN ARGENTINA AND TASMANIA, AUSTRALIA by Lindsey C. Henry The University of Wisconsin-Milwaukee, 2013 Under the supervision of Professors Margaret L. Fraiser and John L. Isbell The late Paleozoic ice age (LPIA; 345-280 million years ago) provides the last complete record of a major deglaciation on a vegetated Earth, and therefore can serve as a proxy for Earth’s inevitable transition out of its present glaciated state. This project analyzes climate change during and following the LPIA using two different approaches: 1) Detailed sedimentology analyses of five glacially-influenced formations in Argentina and Australia in order to determine the size and thermal regime of glaciers during the LPIA. 2) An investigation of massive volcanism along the Panthalassan margin of Gondwana as a source of CO2 that may have contributed to the end of the LPIA and to two ensuing extinction events. During the LPIA, glaciation occurred over the supercontinent Gondwana, and resulting glacial deposits are found in South America, Africa, Antarctica, India, and Australia. This project focuses on glacial and post-glacial outcrops in western Argentina and Tasmania, Australia that were deposited in western and eastern Gondwana, respectively. A study of outcrops from these two regions enables characterization and comparison of the early stages of the LPIA (when Argentina was glaciated) and when ii glaciation was at its peak (when Tasmania was glaciated). Glacial and post-glacial deposits are analyzed using sedimentologic field techniques to interpret depositional events, thin section analysis to determine the micromorphology of the deposits, and mineralogical (x-ray diffraction, or XRD) and elemental (x-ray fluorescence, or XRF) analysis to differentiate sediment sources and determine the oxygenation of the environments. Atmospheric CO2 fluctuations have been linked to ice volume fluctuations during the LPIA, and CO2 input from massive volcanism is considered a major driver of the Middle and Late Permian extinctions (261 and 250 million years ago, respectively). Although these events were previously considered as unrelated, volcanism along the subducting Panthalassan margin of Gondwana occurred throughout both the deglaciation of the LPIA and the Permian extinctions. Therefore, this study will also explore the hypothesis that Panthalassan margin volcanism influenced both deglaciation and the Permian extinctions. Ultimately this dissertation will improve the understanding of climate change during and following the LPIA and inform predictions for when and how Earth will experience deglaciation in the future. iii © Copyright by Lindsey C. Henry, 2013 All Rights Reserved iv To my little family, Chris and Heath v TABLE OF CONTENTS LIST OF FIGURES ......................................................................................................... xiii LIST OF TABLES ............................................................................................................ xx ACKNOWLEDGEMENTS ............................................................................................. xxi Chapter 1: Introduction ....................................................................................................... 1 The Far Field Record ...................................................................................................... 2 The Near Field Record .................................................................................................... 6 Causes of Gondwana Glaciation ..................................................................................... 7 The Dissertation Work .................................................................................................... 9 Dissertation Objectives ................................................................................................. 11 Significance of Research .............................................................................................. 13 Dissertation Structure ................................................................................................... 14 Figures .......................................................................................................................... 18 References ..................................................................................................................... 22 Chapter 2: Carboniferous glacigenic deposits of the Protoprecordillera of west-central Argentina........................................................................................................................... 30 Abstract ......................................................................................................................... 30 1. Introduction ............................................................................................................... 31 2. Geologic Setting ....................................................................................................... 32 3. Age ............................................................................................................................ 34 4. Glacigenic deposits of the Protoprecordillera ........................................................... 35 4.1. Paleovalleys ....................................................................................................... 35 4.1.1. Agua de Jagüel ............................................................................................ 36 4.1.2. Quebrada de las Lajas and Quebrada Grande ............................................. 39 vi 4.2. Calingasta-Uspallata Basin—Hoyada Verde ..................................................... 41 4.3. Paganzo Basin—Huaco Area ............................................................................. 43 4.4. Los Pozuelos Creek ............................................................................................ 43 4.5. Agua Hedionda Anticline................................................................................... 45 5. Ice-flow directions and ice-spreading centers .......................................................... 46 6. Postglacial transgression ........................................................................................... 48 7. Sequence stratigraphy ............................................................................................... 49 8. Conclusions ............................................................................................................... 52 Acknowledgments ........................................................................................................ 53 Figures .......................................................................................................................... 55 References ..................................................................................................................... 58 Chapter 3: Mid-Carboniferous deglaciation of the Protoprecordillera, Argentina recorded in the Agua de Jagüel paleovalley .................................................................................... 63 Abstract ......................................................................................................................... 63 1. Introduction ............................................................................................................... 64 2. Geologic Setting and Stratigraphy ............................................................................ 67 3. Study Area and Methodology ................................................................................... 70 4. Facies Analysis ......................................................................................................... 71 4.1. Diamictite Facies ............................................................................................... 71 4.1.1. Diamictite Facies Description ..................................................................... 71 4.1.2. Diamictite Facies Interpretation .................................................................
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