HYDROGEOLOGY, HYDROCHEMISTRY AND ISOTOPE HYDROLOGY OF PALM VALLEY, CENTRAL AUSTRALIA. John David Henry Wischusen BSc, Grad. Dip. Appl. Geol., MSc Submitted as a requirement in full for the degree of Doctor of Philosophy at the THE UNIVERSITY OF NEW SOUTH WALES SCHOOL OF BIOLOGICAL, EARTH AND ENVIRONMENTAL SCIENCES FACULTY OF SCIENCE AUGUST 2005 TABLE OF CONTENTS 1. INTRODUCTION.............................................................................................................................. 1 1.1. BACKGROUND............................................................................................................................... 1 1.2. OBJECTIVES .................................................................................................................................. 4 2. SAMPLING AND METHODOLOGY............................................................................................. 6 2.1. INTRODUCTION ............................................................................................................................. 6 2.2. NTG DATABASE............................................................................................................................ 7 2.3. SURVEY DATA............................................................................................................................... 8 2.4. GEOLOGY...................................................................................................................................... 8 2.5. PUMP TESTS ................................................................................................................................10 2.6. HYDROCHEMISTRY ..................................................................................................................... 10 2.7. CHLORIDE BROMIDE RATIOS ....................................................................................................... 11 2.8. TRACE ELEMENTS. ...................................................................................................................... 11 2.9. STABLE ISOTOPES........................................................................................................................ 12 2.10. CARBON 13 AND 14................................................................................................................. 12 2.11. CHLORINE 36 .......................................................................................................................... 13 3. ENVIRONMENTAL SETTING..................................................................................................... 17 3.1. INTRODUCTION ........................................................................................................................... 17 3.2. CLIMATE ..................................................................................................................................... 17 3.2.1. Rainfall............................................................................................................................... 17 3.2.2. Temperature and Evaporation ........................................................................................... 23 3.2.3. Summary............................................................................................................................. 23 3.3. TOPOGRAPHY.............................................................................................................................. 25 3.4. LAND SYSTEMS........................................................................................................................... 25 3.5. FLORA......................................................................................................................................... 27 3.5.1. Introduction........................................................................................................................ 27 3.5.2. Livistonia mariae................................................................................................................ 30 3.5.3. Genetic evidence of isolation.............................................................................................. 31 3.5.3.1. Livistona species............................................................................................................................31 3.5.3.2. Cycads ...........................................................................................................................................33 3.5.3.3. Discussion......................................................................................................................................33 3.5.3.4. Conclusion .....................................................................................................................................34 3.5.4. Water Requirements ........................................................................................................... 34 3.6. ABORIGINAL CONNECTION.......................................................................................................... 36 4. HYDROGEOLOGY ........................................................................................................................ 42 4.1. GEOLOGY.................................................................................................................................... 42 4.1.1. Introduction........................................................................................................................ 42 4.1.2. Mapping ............................................................................................................................. 42 4.1.3. Stratigraphy........................................................................................................................ 45 4.1.4. Lithology ............................................................................................................................ 49 4.1.5. Structure............................................................................................................................. 49 4.2. BACKGROUND -AQUIFER CHARACTERISTICS.............................................................................. 52 4.2.1. Introduction........................................................................................................................ 52 4.2.2. Fractured aquifers.............................................................................................................. 53 4.3. HERMANNSBURG SANDSTONE –REGIONAL DATA ...................................................................... 57 4.3.1. Introduction........................................................................................................................ 57 4.3.2. Test pumping ...................................................................................................................... 58 4.3.3. Previous assessments ......................................................................................................... 61 i 4.3.4. Hermannsburg Sandstone - aquifer characteristics ........................................................... 62 4.3.5. Groundwater flow .............................................................................................................. 64 4.4. LOCAL HYDROGEOLOGY............................................................................................................. 66 4.4.1. Previous work..................................................................................................................... 66 4.4.2. Groundwater features......................................................................................................... 69 4.4.2.1. Introduction....................................................................................................................................69 4.4.2.2. Discharge sites...............................................................................................................................69 4.4.3. Aquifer type ........................................................................................................................ 73 4.5. SUMMARY................................................................................................................................... 74 5. HYDROCHEMISTRY .................................................................................................................... 80 5.1. INTRODUCTION ........................................................................................................................... 80 5.2. PREVIOUS WORK ......................................................................................................................... 81 5.3. PALM VALLEY AREA................................................................................................................... 82 5.3.1. Major ion chemistry ........................................................................................................... 82 5.3.2. Hydrochemical processes...................................................................................................85 5.3.2.1. Saturation Indices ..........................................................................................................................85 5.3.2.2. Dissolution / Precipitation reactions ..............................................................................................87 5.4. REGIONAL DATA SET................................................................................................................... 89