Why Is Australia So Old and Flat? The Geological History Explained

At Hallett Cove, just south of Adelaide, the bare cliff-top rock is scored with long, straight scratches, all running the same way. In 1877 the geologist Ralph Tate worked out what had made them: a moving ice sheet, with stones frozen into its base. That ice passed over about 280 million years ago, so how did an ice sheet reach South Australia? This is the story of how Australia formed: some of the oldest rocks on Earth, three ancient blocks stitched into one, an eastern edge added piece by piece, ice and an inland sea, the parting from Antarctica, and a continent that set off north alone and is still moving. Earth Ages tells the story of the planet under your feet, one chapter at a time, using real reconstructions of the ancient Earth. CHAPTERS 0:00 Ice scratches at Hallett Cove 1:03 Where this story goes 1:42 Chapter 1: The old heart 2:57 Granite and greenstone 4:22 Chapter 2: Stitching a continent 5:58 Mountains in the middle 7:42 Chapter 3: Building the east 9:12 Tasmania's place 10:41 Chapter 4: Ice and an inland sea 12:06 The inland sea 13:57 Chapter 5: Letting go 15:36 The last link 17:12 Chapter 6: Drifting alone 18:55 Still moving 20:33 How we know 22:44 You can still see it 24:31 Australia on the Deep Time Clock SOURCES • Parks Australia: Uluṟu-Kata Tjuṯa geology, Tjukurpa and photography • Geoscience Australia: landforms, opal and the Great Artesian Basin • Hickman & Van Kranendonk (2012), Episodes: the Pilbara • Wilde et al. (2001), Froude et al. (1983) and Compston & Pidgeon (1986), Nature: Australia's oldest zircons • Blewett et al. (2012), Shaping a Nation: Australia in time and space • NASA/JPL: ASTER image releases • Myers et al. (1996), Tectonics; Cawood & Korsch (2008), Precambrian Research: assembling Australia • Nordsvan et al. (2018), Geology: Laurentian crust and Nuna; Li et al. (2008), Precambrian Research: Rodinia • Cawood (2005), Earth-Science Reviews: the Terra Australis orogen • Earth Resources Victoria: Victorian gold • University of Tasmania, Companion to Tasmanian History; Cayley (2011); GSA Today (2012): Tasmania's geology • National Parks and Wildlife Service SA: Hallett Cove and Ikara-Flinders Ranges • Kear et al. (2006), Biology Letters: Umoonasaurus; Rey (2013), Aust. J. Earth Sci.: opal; Mudd (2000), Environmental Geology: artesian water • Gibbons et al. (2013) and West et al. (1997), JGR: parting from Antarctica • Exon et al., ODP Leg 189: the Tasmanian Gateway • Davies et al. (2015), Nature: Earth's longest continental hotspot track • ICSM and Geoscience Australia: GDA2020 and the ATRF; National Geographic (2016) • Clarkson et al. (2017), Nature: the first Australians • Beck et al. (2008) and Gandolfo et al. (2011), PLoS ONE: early marsupials and eucalypts • Fujioka et al. (2009), Geology: Australia's dune fields • Parks and Wildlife Service WA: Karijini • Scotese & Wright (2018), PALEOMAP PaleoDEMs, Zenodo CREDITS Paleogeography: PALEOMAP PaleoDEMs, C.R. Scotese & N.M. Wright (2018), CC BY 4.0 Photos: • Glacial pavement, Hallett Cove: Vmenkov, CC BY-SA 3.0, via Wikimedia Commons • Hallett Cove panorama: Rok Krope, public domain • Kata Tjuta from the ISS: NASA / Soichi Noguchi (JAXA), ISS crew Earth observation, public domain • The Pilbara and Mount Whaleback: NASA/METI/AIST/Japan Space Systems, and U.S./Japan ASTER Science Team, public domain • The Jack Hills from orbit: NASA/GSFC/METI/ERSDAC/JAROS and U.S./Japan ASTER Science Team, public domain • Kalgoorlie-Boulder: NASA/JPL-Caltech, public domain • The Flinders Ranges, 1975: NASA/JSC, public domain • Wave Rock: Jonathan LaRocca, CC BY 2.0, via Wikimedia Commons • The Hazards, Freycinet: brewbooks, CC BY-SA 2.0, via Wikimedia Commons • Umoonasaurus ("Eric"): Geekgecko, CC0, via Wikimedia Commons • Puncak Jaya: NASA astronaut photograph via Gergyl, CC BY-SA 3.0, via Wikimedia Commons • Wilpena Pound: Cathcartw, CC BY-SA 4.0, via Wikimedia Commons • The Totem Pole and the Candlestick: Ed Dunens, CC BY 2.0, via Wikimedia Commons • Precious opal: Robert M. Lavinsky, CC BY-SA 3.0, via Wikimedia Commons • Banded iron, Dales Gorge: Graeme Churchard, CC BY 2.0, via Wikimedia Commons • Jack Hills zircons: Aaron Cavosie and John Valley, public domain • Glossopteris leaf: James St. John, CC BY 2.0, via Wikimedia Commons • Organ Pipes, kunanyi / Mount Wellington: Graeme Bartlett, CC BY-SA 3.0, via Wikimedia Commons • GPS station: Liz Westby, USGS, public domain • Ediacaran golden spike: Bahudhara, CC BY-SA 3.0, via Wikimedia Commons Maps of present-day relief from the PALEOMAP 0 Ma DEM. Animation, graphics and music: original, made for Earth Ages. Reconstructions and models are labelled as such. Narration: an AI voice (Google Gemini text-to-speech) reading an original script written and fact-checked for this channel. 🌍 Earth Ages: the 4.5-billion-year story of our planet, told in order. Subscribe for new episodes every two days: ‪@EarthAgesHistory‬ #EarthHistory #GeologicTime #EarthAges #Australia #Geology #EarthHistory