A Palaeoenvironmental History of the Paroo and Warrego Regions, Australia: a Multi-Proxy, Multi-Site Approach
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A Palaeoenvironmental History of the Paroo and Warrego Regions, Australia: a Multi-proxy, Multi-site Approach Lucyna M. Gayler BA (Hons) A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy (Environmental Science), University of Newcastle. January 2008 This work contains no material which has been accepted for the award of any other degree or diploma in any university or other tertiary institution and, to the best of my knowledge and belief, contains no material previously published or written by another person, except where due reference has been made in the text. I give consent to this copy of my thesis, when deposited in the University Library, being made available for loan and photocopying subject to the provisions of the Copyright Act 1968. I hereby certify that the work embodied in this Thesis is the result of original research, the greater part of which was completed subsequent to admission to candidature for the degree. Acknowledgements The completion of this research would not have been possible without support from many people and organisations. Thus I would like to extend my sincere thanks to: My family and friends for the unwavering support and patience as well as bravely lending a hand with fieldwork under the blazing desert sun, My husband Maciek for help with the re-development of the pollen database and setting up the digital herbarium, My supervisors Dr Stuart Pearson and A/Prof Tina Offler for loads of encouragement and always ready assistance, Prof Brian Timms for passionate introduction to the Paroo lakes, assistance with trips to the fieldwork sites, and sharing his immense knowledge about the Paroo/Warrego Region, David O’Brian for many fruitful discussions and editorial support, Prof Eric Colhoun for valuable comments on the manustript, Dr Tim Rolph for introduction to the field of mineral magnetic susceptibility and assistance with its measurements as well as the laser particle size analysis, and Prof Greg Skilbeck for assistance with magnetic susceptibility measurements by the Multi-sensor Core Logger, A/Prof Bob Loughran for assistance with 137Caesium analysis and interpretation, Dr Matt Cupper and Dr Jeff Parr for inspiration in the development of new pollen/phytolith processing protocol, Prof Patrick DeDeckker, Dr Adriana Garcia, Dr Doreen Bowdery, Prof Geoff Hope, Dr Mike Macphail, Dr John Magee, Dr Peter Gell, and Joan Powling for their keen interest in this project and help with identifications of different fossils, The Royal Botanic Garden Herbarium, Sydney, and Don McNair for assistance with plant identifications, Ed Rhodes for assistance with OSL dating of the Paroo/Warrego sediments, The technical officers: Chris Dever, Peter Loughran, and Richard Bale for assistance with laboratory work, Olivier Rey-Lescure for tips on image editing, The School of Environmental and Life Sciences and the Department of Geography, University of Newcastle, for financial contribution towards fieldwork and laboratory analysis, Jenny and Mark Handley and Danny MacKellar of Queensland Parks and Wildlife Service, Robin and Rhonda Davis (the managers) and John and Heather Buster (the owners) of Rockwell-Blue Lakes Station, Ray and Wilga Bremner of Muella Station, Garth and Mary Lou Davis of Yandaroo Station, James and Cheryl Hatch of Wombah Station, Bruce Sharp of Comeroo Sation, and Reg and Claudia Collins of Bloodwood Station for their hospitality and access to the lakes. iii Table of Contents Acknowledgements iii Table of Contents iv List of Tables xi List of Figures xii Abstract xvii Chapter 1 Introduction 1 1.1 Palaeoenvironmental research in arid and semi-arid inland lakes 1 1.1.1 The beginnings of the arid and semi-arid palaeoenvironmental studies in Australia: large lake research 2 1.1.2 Benefits of records from smaller lakes 2 1.1.3 Benefits of a holistic, multi-proxy, multi-site approach 3 1.2 The Paroo/Warrego Region: an attractive study area 3 1.3 The research objectives 5 1.4 Content overview 5 Chapter 2 The Paroo/Warrego Region: Background information 9 2.1 Introduction 9 2.2 Location of the study area 9 2.3 Climate 11 2.3.1 General outline 11 2.3.2 Historical rainfall patterns 11 2.4 Geology and soils 14 2.5 Geomorphology and hydrology 15 2.5.1 The Paroo and Warrego Rivers 15 2.5.2 Wetlands 17 2.5.3 Erosion 18 2.5.4 The erosion-deposition cycles in a saline lake/playa-lunette system 19 2.6 Vegetation 23 2.6.1 Modern vegetation 23 2.6.1.1 Mulga dominated shrublands and woodlands 23 2.6.1.2 Shrubby and grassy semi-arid woodlands 24 2.6.1.3 Arid riverine chenopod shrubland 24 2.6.1.4 Saline and freshwater wetlands 25 2.6.1.5 Woody shrubs 26 2.6.2 Vegetation history 26 2.7 Fire history 28 2.8 Human impact 29 2.8.1 Aboriginal occupation 29 2.8.2 European settlement 29 Chapter 3 Methods 33 3.1 Introduction 33 3.2 Site selection 33 3.3 Field methods and sample collection 34 3.3.1 Lake and dune cores 34 3.3.2 Surveying 35 3.3.3 Vegetation and modern pollen 35 3.4 Laboratory processing of the samples and cores - summary 36 3.5 Sediment description 37 iv 3.5.1 Colour 37 3.5.2 Stratification and sharpness of boundary 38 3.5.3 Bioturbation 38 3.5.4 Abundance/content 38 3.6 Sediment texture and particle size analysis 38 3.6.1 Sediment texture 38 3.6.2 Particle size analysis 38 3.7 Mineral Magnetic Susceptibility 38 3.7.1 Multi-Sensor Core Logger (MSCL) 39 3.7.2 Bartington MS2B sensor 39 3.7.3 Frequency dependent susceptibility 39 3.8 Organic matter content 40 3.9 Carbonates 40 3.9.1 Hydrochloric acid (HCl) test 40 3.9.2 Loss on ignition 40 3.10 Sediment salinity and pH 40 3.10.1 Electrical conductivity and salinity 40 3.10.2 pH 41 3.11 Gypsum 41 3.11.1 Visual description 41 3.11.2 Drying at 105oC 41 3.11.3 Portable Infrared Mineral Analyser (PIMA) 42 3.12 Mineral composition 42 3.13 Plant identification 42 3.14 Pollen 43 3.14.1 Sampling 43 3.14.2 Pollen extraction from sediment 43 3.14.3 Reference pollen 46 3.14.4 Pollen analysis 46 3.14.5 Pollen diagrams 47 3.15 Biogenic silica: phytoliths, sponge spicules, and diatoms 47 3.15.1 Phytolith analysis 48 3.15.2 Additional phytolith extraction 48 3.15.3 Sponge spicules 48 3.15.4 Diatoms 48 3.16 Other fossils 49 3.16.1 Charophytes, macrophytes, and invertebrates 49 3.16.2 Charcoal 49 3.17 Dating 49 3.17.1 137Caesium 49 3.17.2 Radiocarbon 50 3.17.3 Optically Stimulated Luminescence 50 Chapter 4 Proxies and methods: discussion 51 4.1 Introduction 51 4.2 Sediment colour 51 4.3 Bioturbation 53 4.4 Sediment texture and particle size analysis 53 4.5 Mineral Magnetic Susceptibility 54 4.5.1 Palaeoenvironmental significance 54 4.5.2 Comparability of the results from the Multi-Sensor Core Logger (MSCL) and Bartington MS2B sensor 56 4.5.3 Future directions 57 4.6 Organic matter 57 4.6.1 Selected palaeoenvironmental implications 57 4.6.2 Loss on ignition estimation 58 4.7 Carbonates 59 4.7.1 Palaeoenvironmental significance 59 4.7.2 Comparison of quantification methods 59 v 4.8 Sediment salinity and pH 61 4.8.1 General comments 61 4.8.2 Sediment permeability (relationship with pH and salinity changes) 61 4.8.3 Salinity (electrical conductivity): impacts of gypsum and particle size 62 4.9 Gypsum 62 4.9.1 Habit, location, and orientation within the matrix and their palaeoenvironmental implications 62 4.9.2 Content quantification 64 4.10 Sulphides 65 4.11 Mineral composition 66 4.11.1 Clay minerals 66 4.11.2 Short-Wave Infrared Reflectance (SWIR) 66 4.12 Multi-fossil studies 67 4.12.1 Vegetation proxies: pollen and phytoliths – general comments 67 4.12.2 ‘Unknown type 1’ pollen/spore 70 4.12.3 Pollen: comments on selected aspects of extraction methodology, recovery/preservation trends, and analysis 72 4.12.4 Phytoliths: selected comments on the extraction methodology and analysis 73 4.12.5 Sponge spicules 75 4.12.6 Diatoms 77 4.12.7 Fossil 1 79 4.12.8 Macrophytes (seeds) and charophytes (oospores) 81 4.12.9 Invertebrates: gastropods, ostracods, cladocerans, and chironomids 82 4.12.10 Fossil extraction methods: summary and future progress 84 4.12.10.1 Microfossils including pollen and biogenic silica 84 4.12.10.2 Other micro- and macro-fossils 84 4.13 Charcoal 85 4.14 Continuity of records, accumulation/deflation rates, and dating 86 4.14.1 Accumulation and deflation processes 86 4.14.2 Dating 87 4.14.2.1 137Caesium 87 4.14.2.2 Radiocarbon 88 4.14.2.3 Optically Stimulated Luminescence 88 Chapter 5 Lake Bindegolly 89 5.1 Lake Bindegolly 89 5.1.1 Site and lake overview 89 5.1.2 Results 92 5.1.2.1 Dating: 137Caesium 92 5.1.2.2 Pollen 94 5.1.2.3 Phytoliths 94 5.1.2.4 Other biogenic silica 94 5.1.2.5 Other signs of plant and animal life 96 5.1.2.6 Organic matter and carbonate content 97 5.1.2.7 Magnetic susceptibility 97 5.1.2.8 Gypsum 99 5.1.2.9 Mineral composition: clay content 100 5.1.3 Palaeoenvironmental reconstruction of events 100 Chapter 6 Currawinya Wetlands: Lake Wyara and Lake Numalla 103 6.1 Currawinya Wetlands 103 6.2 Lake Wyara 103 6.2.1 Site and lake overview 103 6.2.2 Results 107 6.2.2.1 Gypsum 108 6.2.2.2 Pollen 109 6.2.2.3 Phytoliths 109 6.2.2.4 Other biogenic silica 109 vi 6.2.2.5 Other signs of plant and animal life 109 6.2.2.6 Magnetic susceptibility 113 6.2.2.7 Mineral composition: clay content 113 6.2.3 Palaeoenvironmental reconstruction of events 113 6.3 Lake Numalla 116 6.3.1 Site and lake overview 116 6.3.2 Results 119 6.3.2.1 Dating: 137Caesium 120 6.3.2.2 Pollen 120 6.3.2.3 Phytoliths 122 6.3.2.4 Other biogenic silica 122 6.3.2.5 Other signs of plant and animal life 122 6.3.2.6 Magnetic susceptibility 123 6.3.2.7 Mineral