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Palynomorph and Palynofacies Assemblages of Neutral-Alkaline and Acid Lakes South of Norseman, Southern Western Australia

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Palynomorph and Palynofacies Assemblages of Neutral-Alkaline and Acid Lakes South of Norseman, Southern Western Australia Scholars' Mine Masters Theses Student Theses and Dissertations Summer 2012 Palynomorph and palynofacies assemblages of neutral-alkaline and acid lakes south of Norseman, Southern Western Australia Lutfia Grabel Follow this and additional works at: https://scholarsmine.mst.edu/masters_theses Part of the Geology Commons Department: Recommended Citation Grabel, Lutfia, "Palynomorph and palynofacies assemblages of neutral-alkaline and acid lakes south of Norseman, Southern Western Australia" (2012). Masters Theses. 5209. https://scholarsmine.mst.edu/masters_theses/5209 This thesis is brought to you by Scholars' Mine, a service of the Missouri S&T Library and Learning Resources. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact [email protected]. PALYNOMORPH AND PALYNOFACIES ASSEMBLAGES OF NEUTRAL- ALKALINE AND ACID LAKES SOUTH OF NORSEMAN, SOUTHERN WESTERN AUSTRALIA by LUTFIA GRABEL A THESIS Presented to the Faculty of the Graduate School of the MISSOURI UNIVERSITY OF SCIENCE AND TECHNOLOGY In Partial Fulfillment of the Requirements for the Degree MASTER OF SCIENCE IN GEOLOGY 2012 Approved by Francisca E. Oboh-Ikuenobe, Advisor Wan Yang Melanie R. Mormile iii ABSTRACT The Yilgarn Craton in Western Australia hosts hundreds of shallow ephemeral hypersaline lakes, the majority of which have acid to neutral pH values. As part of a multidisciplinary study of the evolution of hypersalinity and acidity in the region, three drill cores were studied for their palynofacies and palynomorph contents in order to characterize palynofloral response to environmental changes. Drill cores from two acid lakes, Prado Lake (PL1-09 and PL2-09) and Twin Lake West (TLW1-09), and the neutral-alkaline Gastropod Lake (GLE1-09) south of Norseman recovered Miocene to Holocene sediments of the Revenge and Polar Bear formations. Transmitted light microscopy was used to identify the dispersed organic matter (DOM) as well as palynomorphs. Statistical analyses were performed only for palynofacies since the palynomorph abundances were low. The palynofacies study revealed that the comminuted phytoclasts are the dominant components in the four drill cores; however; there are subtle differences in DOM distributions, even in drill cores from the same lake due to the dynamic nature of the environment. Lake dynamics appear to be controlled by flooding, evapoconcentration, desiccation, and reworking and eolian erosion. Modern observations indicate the possibility of a lake undergoing more than one process at the same time, resulting in different depositional mechanisms. Palynomorph analysis revealed that: 1) an open woodland vegetation with shrubs and herbs (Chenopodiaceae and Myrtaceae) had succeeded the much wetter climate of the Paleogene; 2) reworking has been a part of lake history as evidenced by the recovery of late Eocene palynomorphs (Nothofagidites and Aglaoreidia cyclops) at almost all depths; 3) the first record of a salt tolerant alga, Dunaliella, in the drill cores is likely be an indicator of the onset of salinity in the region; and 4) the apparent absence of Dunaliella in the most recent sediments in the neutral-alkaline Gastropod Lake may be related to either predation by the gastropod Coxiella or the possibility that this Dunaliella species is acidophilic. Both probabilities suggest that Gastropod Lake has become more neutral-alkaline with time. iv ACKNOWLEDGMENTS First of all, I would like to sincerely thank Allah, my God, the Most Gracious and Most Merciful, for blessing me and guiding me through out my life and my study, and for enabling me to complete my M.S. degree by placing good people who have helped me along the way. “If you should count the favors of Allah, you could not enumerate them.” (14:34) “The more you thank Me (Allah), the more I (Allah) give you” (14:7). My sincere thanks and deep gratitude are expressed to my wonderful advisor Dr. Francisca Oboh-Ikuenobe who has been more than an advisor to me. Thanks to her for accepting me as one of her students, for her guidance, for her support not only academic but also socially, especially during the 2011 Libyan crisis. Without her I would not have reached my goal and received my M.S. degree. I also gratefully thank Drs. Wan Yang and Melanie Mormile for serving on my committee, and for their help and cooperation. Sincere thanks also to the U.S. National Science Foundation for funding this project, and to all the other researchers involved in this project, who helped me during my studies. Special thanks to my fellow students Carlos Sanchez Botero, who has taught me and helped me a lot, Robert Haselwander who always offered his advise and help, Kate Schlarman for her contribution to analysis of Twin Lake sediments, and Marissa Spencer for being such a good friend. Last but not least, no words can express my everlasting gratitude, thanks and appreciation to my beloved parents and grandparents for their love, care, and sincere prayers especially during my time in the U.S.A. Their support and encouragement were my motivation toward accomplishing my dream. Thanks to my beloved sisters and brothers, in particular my brother Emad who accompanied me during my study journey. Without him accompanying me I would not have succeeded in the U.S.A. v TABLE OF CONTENTS Page ABSTRACT………………………...……………………………………………………iii ACKNOWLEDGMENTS…………..……………………………………………………iv LIST OF ILLUSTRATIONS………………………………………………………….....vii LIST OF TABLES……………………………………………………………………..viii SECTION 1. INTRODUCTION…………………...…………..……………………………..…..1 2. GEOLOGICAL SETTING……………..........……………………………………..3 2.1. INTRODUCTION ………………………....………….……………………..3 2.2. STRATIGRAPHY……………………………………………………… …...4 2.3. LAKE CHARACTERISTICS ………………………………………… ……5 3. LITERATURE REVIEW……………………………………………………..……9 4. METHODS……………………………………………….…..…………………...12 4.1. CORING………………………………………………………………….…12 4.2. SAMPLE PROCESSING AND ANALYSIS…………………….…………14 5. RESULTS…………………………………………………………………………16 5.1. LITHOLOGY……………………………………………………………….16 5.2. DISPERSED ORGANIC MATTER………………………………………..16 5.3. PALYNOMORPHS…………………………………………………………27 5.3.1. GLE1-09 and PL1-09……………………………..……………….27 5.3.2. TLW1-09…………………………………………………………..32 vi 6. DISCUSSION…………………..…………………………………………………41 6.1. LAKE DYNAMICS AND PALEOENVIRONMENTS…………………....41 6.2. PALYNOFLORAS …………………………………..….………………….43 6.3. PALYNOSTRATIGRAPHY………………………………………………..47 6.4. DUNALIELLA AS A SALINITY PROXY………………………………….47 6.5. NEUTRAL-ALKALINE VS. ACID LAKES……………………………….49 6.6. EVIDENCES OF REWORKING…………………..………….……………50 7. CONCLUSION………………………………………..…….……………….……51 APPENDICES A. PHOTOGRAPHS OF COREHOLES TRAYS………………………….……53 B. SAMPLE INVENTORY AND QUANTITATIVE PALYNOMPRPH RECORD…………….…………………………………...58 C. AVERAGE LINKAGE CLUSTER ANALYSIS FOR EACH INDIVIDUAL DRILL CORE………..................................................................................…..61 BIBLIOGRAPHY…………………………….………………………………………….64 VITA………………………………………………..……………………………………71 vii LIST OF ILLUSTRATIONS Figure Page 1.1. Map of the study area in southern Western Australia………………..……..………..2 2.1. Lithostratigraphy of Lefroy and Cowan Paleodrainages ………….…………………6 2.2. Geological settings of saline lakes in southern Western Australia. ……….…………7 4.1. Rotosonic drill rig coring at the four sites studied ………………..…………..….…13 5.1. Idealized lithologic column shows the main deposits occurring in the coreholes ….17 5.2. Lithologic columns and scanned cores of some horizons in the Prado Lake coreholes…………………………………………………….………………………18 5.3. Photomicrographs of DOM in the four drill cores ………………………………….20 5.4. Distribution graphs of relative abundances of DOM……………………….……….24 5.5. Dendrograms for average linkage cluster analysis of the entire palynological samples from the four drill cores……....…………………………..………………...26 5.6. Photomicrographs of reworked trilete spores in GLE1-09 and PL1-09………..…...29 5.7. Photomicrographs of reworked gymnosperms in GLE1-09 and PL1-09…………...30 5.8. Photomicrographs of reworked angiosperms in GLE1-09 and PL1-09……………..31 5.9. Photomicrographs of contemporaneous pollen in GLE1-09, PL1-09 and TLW1-09……………………………………………………………………………33 5.10 Photomicrographs of contemporaneous pollen in GLE1-09, PL1-09 and TLW1-09……………….……………………..………………………………..34 5.11. Photomicrographs of selected algae and fungi in GLE1-09, PL1-09 and TLW1-09…………………………………………...……………………..…....35 5.12. Palynomorph abundance distribution graphs………………………………………39 6.1. Core scans of TLW1-09 sediment at 25-36 cm interval show oxidation …………..46 viii LIST OF TABLES Table Page 5.1. Description of dispersed organic matter identified in the four drill cores ….………19 5.2. Relative abundances (in percent) of dispersed organic matter in the four drillcores..21 5.3. Principal component loadings for the dataset of the four drill cores. ………………22 5.4. Palynomorph abundances ………………………….…………………………..…...36 6.1 Radiocarbon dating of shallow sediments from the three lakes……………....……..50 1. INTRODUCTION Vast numbers of ephemeral hypersaline lakes prevail over much of the Australian landscape, where many of them exist in arid and semi arid regions (Van De Graaff et al., 1977; Timms, 2005). These lakes align in chains following the traces of the paleodrainage systems or occupying the deepest depressions in the region (Van De Graaff et al., 1977). Commonly, they range in area and shape from small rounded to large elongated bodies with shallow water depths, even during flooding periods (Benison et
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