Australia on EARTH Magazine

Great Barrier Reef has died and recovered before

Fri, 03 Aug 2018 13:12:45 -0400

The Great Barrier Reef has rebounded from die-off events many times; however, it has never faced the combination of threats that it does today. Credit: NASA.

It’s hard to imagine Earth without the Great Barrier Reef, yet with the threats confronting it — including ocean warming and acidification — its demise is a possibility marine scientists are studying. A new study of how sea-level rise and sedimentation have impacted the reef over the last 30,000 years, however, shows it might be more resilient than previously thought.

Humans arrived Down Under earlier than thought

Wed, 18 Oct 2017 12:07:17 -0400

Chris Clarkson of the University of Queensland talks with Djurrubu Aboriginal Rangers at the Madjedbebe excavation site in Australia's Northern Territory. Credit: Dominic O'Brien, Gundjeihmi Aboriginal Corporation.

Analysis of sediments surrounding a trove of artifacts discovered in northern Australia suggests the first humans arrived on the continent about 10,000 years earlier than previously thought, a finding that has implications for the hypothesized role of humans in the extinctions of Australian megafauna.

Massive trove of dinosaur tracks cataloged in Australia

Mon, 17 Jul 2017 08:09:32 -0400

Anthony Romilio and Linda Pollard from the University of Queensland in Australia prepare to make a cast of a sauropod track in the Walmadany area on Dampier Peninsula in Western Australia. Credit: University of Queensland/Steven Salisbury, CC BY-ND 4.0.

In a remote region of Western Australia, paleontologists have documented the world’s most diverse assemblage of dinosaur tracks. The scientists found preserved in Early Cretaceous rocks thousands of tracks, 150 of which can be assigned to at least 11, and possibly as many as 21, different known track types representing theropods, sauropods, ornithopods and armored thyreophorans.

Down to Earth With: Paleoclimatologist Gifford H. Miller

Tue, 20 Jun 2017 21:40:06 -0400

Gifford H. Miller, a professor of geological sciences at the University of Colorado Boulder and associate director of the Institute for Arctic and Alpine Research, has spent years conducting paleoclimate fieldwork in the Arctic and Australia. Credit: Gifford H. Miller.

“Hope for the unexpected.” This motto has pulled paleoclimatologist Gifford H. Miller to remote corners of the world to conduct fieldwork for more than half a century. Miller, a professor of geological sciences at the University of Colorado Boulder (CU) and associate director of the Institute for Arctic and Alpine Research, thrives on the pursuit of knowledge, asking tough questions about the global climate system whose answers have far-reaching implications. But it’s the thrill of unexpected discoveries — of which he’s made many — that keep him returning for more. His discoveries, including the extinction timing of giant birds in Australia, the existence of “zombie mosses” that document the life-cycle of Arctic ice caps, and the finding of lake sediments that tell the story of Iceland’s deglaciation, have led to advances in our understanding of Earth’s climate history and the role humans have played in it.

Benchmarks: February 7, 2009: Deadliest day of fire ever recorded in Australia

Wed, 06 Jul 2016 12:53:24 -0400

A bush fire burns near Steels Creek in Victoria on Feb. 7, 2009. Credit: ©Daniel Cleaveley, Creative Commons Attribution 3.0 Unported.

Fires were still burning a week after they started on Black Saturday in the Australian state of Victoria. Credit: NASA.

On Friday, Feb. 6, 2009, John Brumby, premier of the Australian state of Victoria, warned the public of the high risk of wildfires that weekend: “It’s just as bad a day as you can imagine and on top of that the state is just tinder-dry. People need to exercise real common sense tomorrow.” He was right. The next day, more than a dozen major fires and hundreds of smaller ones tore across the region, fueled by record temperatures and high winds. The so-called Black Saturday fires released more energy than 1,500 Hiroshima bombs, according to one fire expert. Together, the fires cost billions in damage and killed 173 people — the deadliest day of fires recorded in Australia.

Fossil leaves provide clues to ancient Australian habitat

Tue, 19 Apr 2016 15:29:35 -0400

Heath and scrubland vegetation cover this part of Stirling Range National Park in southwestern Australia. In the Late Cretaceous, central Australia may have looked similar, with a mosaic of low-growing and open vegetation and woody thickets. Credit: Raymond Carpenter.

Researchers have long thought that the scrublands of Australia developed over the last 25 million to 30 million years as part of a global trend toward colder and drier climates in which rainforests yielded ground to more open, fire-prone environments.

Getting there and getting around the Whitsundays

Mon, 24 Aug 2015 11:26:55 -0400

Visitors to the Whitsundays often come through Cairns, which is also a gateway to the Great Barrier Reef. Credit: Terri Cook and Lon Abbott.

The gateway airports to the Whitsundays are on Hamilton Island and near Proserpine on the mainland. Neither hosts direct flights from the U.S., but both connect to Sydney and Brisbane, Australia’s primary international arrival points, as well as Cairns, the most popular access point to the Great Barrier Reef. From Proserpine, Whitsunday Transit can transport you to accommodations throughout the region.

Travels in Geology: Australia's Whitsunday Islands: Sun, sand and silicic volcanism

Mon, 24 Aug 2015 11:07:06 -0400

Whitehaven Beach on Whitsunday Island is perennially voted one of the top 10 beaches in the world. Credit: ©iStockphoto.com/Shane_Pedersen.

Whitehaven Beach is the only beach within all the Whitsunday Islands that has sand that is 99 percent pure quartz. Credit: Terri Cook and Lon Abbott.

In 2009, Tourism Queensland launched a campaign soliciting applications for what they billed as “the Best Job in the World”: “caretaker” of Australia’s Whitsunday Islands for six months. Benefits included transportation to Hamilton Island, the isles’ commercial hub, accommodation in a multimillion-dollar mansion and an extravagant salary. What responsibilities did the job entail? Mostly, it involved exploring the tropical paradise that is the Whitsunday Islands and documenting these explorations through photo diaries, blogs and web videos. Applications were only accepted by web video.

Great drying led to great dying down under

Tue, 16 Jun 2015 13:07:22 -0400

If not for the megafaunal extinctions that wiped out many large animals at the end of the Pleistocene, the world might be a very different place today — with humans coexisting alongside still-living saber-toothed tigers, woolly mammoths and 3-meter-tall birds. The agents of these mass extinctions have been debated for decades: Were shifting climates, or our spear-wielding ancestors mainly responsible? A new study of the receding shorelines of Australia’s largest lake has found that a substantial drying of the environment, more so than human pressure, is mostly to blame for the loss of megafauna down under.

Counting 'tree' rings in fish skulls provides climate clues

Fri, 29 May 2015 12:56:07 -0400

Most fish have little structures in their skulls that record growth patterns — periods of feast and famine — just like tree rings. Now, scientists are using these structures, called otoliths, to show how fish size may decrease as a result of a changing ocean.

Giant bolide hit South Africa 2.5 billion years ago

Thu, 14 May 2015 12:05:43 -0400

Tiny spherules, like those seen in this rock found in Western Australia, form when vaporized rock from a meteorite impact condenses into small, round particles. Credit: Oberlin College photo/Bruce M. Simonson.

Some of the oldest scraps of continental crust on Earth cling to the southern tip of Africa and the western edge of Australia. In both places, geologists have found rock layers rich in tiny particles called spherules. Scientists think spherules form when meteorites strike the planet, vaporizing surface rocks that then condense into small droplets, blanketing the surrounding landscape. Now, research published in Geology confirms the extraterrestrial origin of a 2.5-billion-year-old layer of spherules in South Africa, which scientists say was produced by a bolide at least as large as the one that doomed the dinosaurs.

Getting there and getting around in South Australia

Thu, 07 May 2015 14:45:34 -0400

Most vineyards in the South Australian wine region welcome visitors to "cellar door" tasting rooms. Credit: all: Terri Cook and Lon Abbott.

Adelaide, South Australia’s largest airport, doesn’t host direct flights to and from the U.S., but it is well connected to Sydney, Australia’s primary international arrival point, and other Australian cities. From the airport, you can take a taxi, a metro JetBus, or a Skylink minibus (www.skylinkadelaide.com) to get into town.

Travels in Geology: Glaciers and grapes in South Australia

Thu, 07 May 2015 10:58:17 -0400

Hallett Cove Conservation Park near Adelaide, Australia, exhibits evidence of a Permian glaciation that occurred when Australia lay at 70 degrees south latitude. Credit: Terri Cook and Lon Abbott.

Without an architecturally stunning opera house, an expansive colorful reef or an iconic redrock outcrop to boast, Adelaide is not usually considered one of Australia’s top travel destinations. But because we love Earth history as well as wine, this town on the southern coast was at the top of our Australian travel itinerary when we found ourselves on sabbatical near Sydney last year. Adelaide is a cosmopolitan city of manageable size, replete with stunning beaches and an especially accessible yet rugged corner of the Outback nearby. Best of all, visitors can observe the handiwork of successive glaciations — which covered the region between 700 million and 280 million years ago — while en route from one cellar door to the next as they tour a world-class South Australian wine region in the picturesque hills just minutes from the city.

Travels in Geology: Aussie Outback Adventure

Mon, 04 Aug 2014 11:33:54 -0400

Australia, having experienced little recent tectonic activity, is the world’s lowest and flattest continent on average. But don’t take that to mean it’s geologically boring. It is this very quiescence that has ensured the preservation of a remarkable record of early-Earth events on the continent: from mineral grains only slightly younger than the planet itself, to a glacial event so severe that geologists call it “Snowball Earth,” to an unparalleled record of life’s early evolution. To see the ancient rocks that hold this record, you must leave the comparatively lush coastal strip — home to 90 percent of Australia’s population — and venture into the vast, arid interior wilderness known as the Outback.

Ecosystem collapse in Pleistocene Australia

Wed, 30 May 2012 13:01:45 -0400

At Gnaraloo Warroora station and other places in Western Australia, winds have eroded several meters of sand, leaving behind heavier eggshells from the Late Quaternary. Gifford Miller and his colleagues detected these locations from high-resolution satellite images and then traveled to the locations to collect the eggshells. Courtesy of Gifford Miller

Between 50,000 and 45,000 years ago, in the Late Quaternary, Australia suffered a major loss of its megafauna. Sixty taxa of mammals, predominantly large leaf- and twig-eating animals called browsers, went extinct, including all 19 species exceeding 100 kilograms, like the half-ton Palorchestes azael, a marsupial similar to a ground sloth, and the rhinoceros-sized Diprotodon. Also lost were more than half of species weighing between 10 and 100 kilograms, such as the giant koala, Phascolarctos stirtoni, as well as three large reptiles and a flightless bird, Genyornis newtoni.

Voices: Harassment of scientists reaches a fever pitch

Fri, 20 Jan 2012 03:51:09 -0500

In recent years, climate scientists, particularly those involved in communicating the risks of anthropogenic climate change to the public, have faced increasing levels of vitriol from politicians, pundits and the public alike. The news earlier this year that leading Australian climate scientists were receiving death threats, in the midst of a fierce debate on the implementation of a carbon tax, is just the latest escalation. Other recent events include the legal harassment brought to bear on Penn State climatologist Michael Mann by the Attorney General of Virginia, and the baseless media firestorm over the hacked “Climategate” emails in late 2009, which also led to prominent British climate scientist Phil Jones receiving numerous death threats. And then there is this week's release of 5,000 more hacked emails. This has to stop, or we may start seeing a backlash where scientists refuse to explain their research findings at all. If that happens, society loses.

Travels in Geology: Australia's wonders, from ocean to desert

Thu, 05 Jan 2012 06:41:58 -0500

Ayers Rock at sunset. Why the world's largest monolith is in an otherwise flat terrain is a geological mystery. Jason Betzner

The Blue Mountains glow in the mid-morning sunlight. Jason Betzner

The Three Sisters are composed of sandstone carved by wind and rain. The Aborigines believe the Three Sisters were women turned to stone by a magician. Jason Betzner

A cable car carries tourists in the Blue Mountains across a valley thousands of meters below. Jason Betzner

In the dead center of Australia, Ayers Rock rises above the bush. Sunset brings an orange, red and purple glow to its walls. Jason Betzner

Ayers Rock displays many odd weathering patterns, such as honeycomb weathering. Although common in coastal and semi-arid environments, its cause is still disputed by geologists. Jason Betzner

Baffling weathering patterns on Ayers Rock: The large scour shape suggests the rock was powerfully carved by water. The alignment of the boulders in such an organized pattern is particularly strange. Jason Betzner

Aboriginal paintings on Ayers Rock. Jason Betzner

Cairns, on the Northeastern coast of Australia, is the gateway to the Great Barrier Reef. The reef (dark patch) is just visible in the shallow water. Jason Betzner

A parrot fish (blue) and an angel fish (black) hover over soft corals. The parrot fish use their hard "beak" to gnaw at the coral, which is their primary food source. (You can actually hear the gnawing while snorkeling.) Jason Betzner

Colorful soft corals (top half) are surrounded by bleached, dead corals (bottom half). Jason Betzner

Zebra fish and two different types of groupers on the Great Barrier Reef. Jason Betzner

A very friendly grouper on the Great Barrier Reef. Jason Betzner

Australia, both a country and a continent, has geological wonders as strange and unique as the furry marsupials that inhabit the Land Down Under.

Travels in Geology: Twin coral reefs separated in time in Western Australia

Thu, 05 Jan 2012 06:41:58 -0500

Geikie Gorge is one of the three national parks where visitors can see the Devonian Great Barrier Reef. Terri Cook and Lon Abbott

Turtle at Ningaloo Reef, one of the world's longest fringing reefs. s-ron mckellar, Creative Commons Attribution-NoDerivs 2.0 Generic

In Western Australia, you can visit two unusually accessible coral reefs. Although they look similar enough to be fraternal twins, these reefs were born nearly 400 million years apart. Ningaloo is a modern coral reef where you can snorkel amid spectacular reefbuilding organisms by wading just a few meters from the sandy, white shore. One of the longest fringing reefs on the planet, Ningaloo also boasts one of the planet’s healthiest reef environments, where 500 species of fish, 600 species of shellfish and more than 250 species of coral thrive.