Marine Science 2016 Edition

Page 22 Chapter 1 E LORD HOW RISE LAND LAND ANTARCTICA INDIA What Australia looked like Depth of sea Shallow (< 200 m) Variable depth (0 - 2 km) Deep (> 2 km) Volcanic action Subducting Ancient reefs Figure 22.2 The islands of the Buccaneer Archipelago, located in Western Australia, contain rich silver and iron ore deposits Figure 22.6 Shallow seas contained plant life which decomposed to form coal basins in Eastern Australia . Figure 22.5 Australia 400 mya (Illustration Bob Moffatt after Perspectives of the Earth AustralianAcademy of Science) Figure 22.1 Sediment run off Sediments Sediments ran off and covered areas in a deep trench which was later to be uplifted out of the sea to form coastal zones east of what now is the Great Dividing Range. The shallow sea had ancient reefs now found in the Kimberly (Figures 22.1 and 22.5) This shallow seas also contained paleozoic animal and plant life which can be seen in road cuttings at many places in Eastern Australia (Figure 22.3) and formed the rich coal deposits of eastern Australia Figure 22.6. The old craytons rich in minerals were deformed into the rich mining deposits of Western Australia (Figure 22.2) Figure 22.3 Geological time as seen in a road cutting Paleozoic (Illustration Queensland Museum) MiningAustralia) Figure 22.4 Cliffs of the Great Australia Bight which were once joined with Antarctica Bob Moffatt Bob Moffatt Ian Morris