Geological and geomorphological features with OUV in the GBRWHA GEOLOGICAL AND GEOMORPHOLOGICAL FEATURES OF OUTSTANDING UNIVERSAL VALUE IN THE GREAT BARRIER REEF WORLD HERITAGE AREA February 2013 Technical Report Prepared for the Department of Sustainability, Environment, Water, Population and Communities Compiled by Geoscience Australia and James Cook University 1 Geological and geomorphological features with OUV in the GBRWHA Geological and Geomorphological features of Outstanding Universal Value in the Great Barrier Reef World Heritatge Area. February 2013 Authors: Tanya Whiteway1, Scott Smithers2, Anna Potter1 and Brendan Brooke1 1Coastal Marine and Climate Change Group, Geoscience Australia, Canberra 2School of Earth and Environmental Sciences, James Cook University, Townsville 2 Geological and geomorphological features with OUV in the GBRWHA 1 INTRODUCTION ................................................................................................. 5 2 GREAT BARRIER REEF WORLD HERITAGE AREA ............................................... 6 3 IDENTIFICATION OF FEATURES OF OUV ........................................................... 7 4 GEOLOGICAL EVOLUTION OF THE GREAT BARRIER REEF ................................ 8 5 GEOLOGICAL AND GEOMORPHOLOGICAL FEATURES WITH OUV ................. 10 5.1 Fringing Reefs ......................................................................................................... 11 5.1.1 Description ......................................................................................................... 11 5.1.2 Description of OUV ............................................................................................ 14 5.2 Inshore Turbid Reefs .............................................................................................. 23 5.2.1 Description ......................................................................................................... 23 5.2.2 Description of OUV ............................................................................................ 25 5.3 Shelf Reefs (Excluding Fringing, Ribbon and Inshore Turbid Reefs) ...................... 30 5.3.1 Description ......................................................................................................... 30 5.3.2 Description of OUV ............................................................................................ 32 5.4 Ribbon Reefs .......................................................................................................... 41 5.4.1 Description ......................................................................................................... 41 5.4.2 Description of OUV ............................................................................................ 42 5.5 Deltaic Reefs........................................................................................................... 46 5.5.1 Description ......................................................................................................... 46 5.5.2 Description of OUV ............................................................................................ 46 5.6 Northern Detached Reefs ...................................................................................... 49 5.6.1 Description ......................................................................................................... 49 5.6.2 Description of OUV ............................................................................................ 49 5.7 Submerged Coral Reefs and Banks (Mesophotic Coral Ecosystems) ..................... 52 5.7.1 Description ......................................................................................................... 52 5.7.2 Description of OUV ............................................................................................ 55 5.8 Carbonate Reef Islands (excluding Low Wooded Islands and Mangrove Islands) . 58 5.8.1 Description ......................................................................................................... 58 1.8.2 Description of OUV ............................................................................................ 63 5.9 Gravel and Shingle Ridges ...................................................................................... 68 5.9.1 Description ......................................................................................................... 68 5.9.2 Description of OUV ............................................................................................ 69 5.10 Mangrove Shorelines, Mangrove Islands and Low Wooded Islands ..................... 72 5.10.1 Description .................................................................................................... 72 5.10.2 Description of OUV ........................................................................................ 75 5.11 Halimeda (Banks, Bioherms and Meadows) .......................................................... 80 5.11.1 Description .................................................................................................... 80 5.11.2 Description of OUV ........................................................................................ 81 5.12 Seagrass Beds ......................................................................................................... 83 5.12.1 Description .................................................................................................... 83 5.12.2 Description of OUV ........................................................................................ 84 5.13 Karstic Channels and Blue Holes ............................................................................ 86 5.13.1 Description .................................................................................................... 86 5.13.2 Description of OUV ........................................................................................ 89 5.14 Palaeochannels ...................................................................................................... 92 5.14.1 Description .................................................................................................... 92 5.14.2 Description of OUV ........................................................................................ 92 5.15 Continental Islands ................................................................................................. 95 5.15.1 Description .................................................................................................... 95 5.15.2 Description of OUV ........................................................................................ 98 5.16 River Deltas .......................................................................................................... 104 3 Geological and geomorphological features with OUV in the GBRWHA 5.16.1 Description .................................................................................................. 104 5.16.2 Description of OUV ...................................................................................... 105 5.17 Dune Systems ....................................................................................................... 107 5.17.1 Description .................................................................................................. 107 5.17.2 Description of OUV ...................................................................................... 109 5.18 Submarine Canyons and Turbidite Deposits ........................................................ 113 5.18.1 Description .................................................................................................. 113 5.18.2 Description of OUV ...................................................................................... 116 6 PRESSURES ON FEATURES WITH OUV – AN OVERVIEW ..................................... 119 6.1 Climate change ..................................................................................................... 120 6.1.1 Sea level rise .................................................................................................... 120 6.1.2 Rising sea temperatures .................................................................................. 121 6.1.3 Increased tropical cyclone activity / changed rainfall patterns ....................... 121 6.1.4 Ocean Acidification .......................................................................................... 122 6.2 Catchment runoff ................................................................................................. 122 6.3 Coastal and Marine Development ....................................................................... 123 6.3.1 Sediment transport pathways ......................................................................... 123 6.3.2 Dredging and spoil disposal ............................................................................. 124 6.4 Direct Use ............................................................................................................. 124 6.4.1 Trawling ........................................................................................................... 124 6.4.2 Shipping ........................................................................................................... 125 6.4.3 Mining .............................................................................................................. 126 6.4.4 Grazing ............................................................................................................