Author: Neville

  • Election driving Tarkine mines: Greens

    Election driving Tarkine mines: Greens

    AAPUpdated August 5, 2013, 2:40 pm

    Conservationists are calling the approval of a second mine in as many weeks in Tasmania’s Tarkine blatant ALP electioneering.

    Green groups have been dealt a second blow with federal environment minister Mark Butler giving the go-ahead to a Venture Minerals iron ore proposal at Riley Creek in the contentious northwest region.

    The approval comes despite a challenge to the state government’s approval still pending in Tasmania’s Resource Management and Planning Appeals Tribunal.

    Just last week Mr Butler gave the green light to a $20 million Shree Minerals’ iron ore mine at Nelson Bay River in the Tarkine.

    Environmentalists say the decisions are attempts by federal Labor to hang on to the vulnerable seat of Braddon.

    “The minister has raced to rush this out for a perceived electoral gain,” Save the Tarkine spokesman Scott Jordan said in a statement.

    “This is a shameful decision that further compromises the integrity of Tarkine.”

    Mr Jordan’s group is behind the planning tribunal appeal and the federal court action that temporarily halted work on the Shree project last month.

    Tasmanian Greens senator Peter Whish-Wilson said mining was not a long-term solution to Tasmania’s nation-high unemployment rate of 8.1 per cent.

    “It’s a short-term political decision, made on the first day of the election, to prop up a Labor MP in a marginal seat,” he said.

    But the Tasmanian government said the Riley Creek project would inject $40 million into the struggling northwest’s economy.

    “The northwest and west coasts have some of the most highly mineralised and prospective areas in the world and I am confident we will see more new mines in the region,” Deputy Premier Bryan Green said.

    The Tarkine is home to one of the last populations of Tasmanian devils free of the facial tumour disease which has wiped out up to 80 per cent of the species, and to the largest temperate rainforest in the southern hemisphere.

    Minister Butler said Venture, which is also proposing two other mines in the area, would be subject to 37 environmental conditions.

    They include $144,000 to help fight the tumour disease.

    Tasmania’s Liberal opposition said the conditions meant too much “green tape” for investors.

  • Australia’s future: solar energy Download transcript for Australia’s future: solar energy Share on facebook Share on twitter Share on email Share on print Over the past five years a quiet energy revolution has been taking place in Australia. It’s built on the growth of solar power, especially rooftop photvoltaic (PV) solar sytems. In just five years the number of Australian solar PV systems went from 8,000 to 1,000,000 with ordinary Australians driving the change. It’s a revolution that nobody saw coming. Download The Critical Decade: Australia’s future – solar energy. Download the images and infographics. Related content What is the difference between solar PV and solar hot water systems? Does solar energy influence electricity prices? How is solar electricity integrated in the existing electricity grid infrastructure? How affordable is solar PV? What are the payback periods for installing solar PV? Obama and Shenzhen: International action continues to build on climate change China and the US step up on climate Three months in the Climate Commission Greening your outdoor living Solar systems soar Author: Climate Commission Tags: renewables, solar, solar PV, Tim Flannery, Veena Sahajwalla

     

    Australia’s future: solar energy

    Download transcript for Australia’s future: solar energy

    Over the past five years a quiet energy revolution has been taking place in Australia. It’s built on the growth of solar power, especially rooftop photvoltaic (PV) solar sytems. In just five years the number of Australian solar PV systems went from 8,000 to 1,000,000 with ordinary Australians driving the change. It’s a revolution that nobody saw coming.

    Download The Critical Decade: Australia’s future – solar energy.
    Download the images and infographics.

    Related content

     

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    Download transcript for Australia’s future: solar energy

    Over the past five years a quiet energy revolution has been taking place in Australia. It’s built on the growth of solar power, especially rooftop photvoltaic (PV) solar sytems. In just five years the number of Australian solar PV systems went from 8,000 to 1,000,000 with ordinary Australians driving the change. It’s a revolution that nobody saw coming.

    Download The Critical Decade: Australia’s future – solar energy.
    Download the images and infographics.

    Related content

     

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  • Federal approval for second mine in Tasmania’s Tarkine region

    Federal approval for second mine in Tasmania’s Tarkine region

    ABCAugust 5, 2013, 9:11 am

    Federal approval has been given for another iron ore mine in Tasmania’s Tarkine region.

    Venture Minerals’ Riley Creek mine gained state approval in May and now has been given the go ahead by Federal Environment Minister Mark Butler.

    The west coast mine will operate for two years.

    Venture wants to build it to help finance the company’s flagship Mount Lindsay tin and tungsten project nearby.

    Mining has been a key focus in the Braddon electorate in recent months as workers deal with a downturn in the forestry sector and high unemployment rates.

    Shree Minerals’ open cut iron more mine gained a second federal approval last week after the first one was successfully challenged by environmentalists.

    That action was brought by the Tarkine National Coalition which is also challenging Venture’s Riley Creek mine in the state planning appeals tribunal.

    The group is arguing the Environmental Protection Authority did not fully consider the mine’s impact on rare plants and the endangered Tasmanian devil.

  • Historical sea level changes

    Figures marked “CSIRO”, are copyright CSIRO, but please feel free to use them, conditional on the figures not being altered, and their source being acknowledged, and with a link to this site where possible.

    All other figures are copyright. Please do not copy without the owner’s permission.

     

    Historical sea level changes

    Last two decades

    High quality measurements of (near)-global sea level have been made since late 1992 by satellite altimeters, in particular, TOPEX/Poseidon (launched August, 1992), Jason-1 (launched December, 2001) and Jason-2 (launched June, 2008). This data has shown a more-or-less steady increase in Global Mean Sea Level (GMSL) of around 3.2 ± 0.4 mm/year over that period. This is more than 50% larger than the average value over the 20th century. Whether or not this represents a further increase in the rate of sea level rise is not yet certain.

    The two plots below show the GMSL measured from TOPEX/Poseidon, Jason-1 and Jason-2.

    This one shows it with the seasonal signal removed:

    Plot of global sea level from 1993 to 2012

    And this shows it with the seasonal signal left in:


    Sea level and El Niño

    Plot of global sea level vs the SOI index from 1993 to 2012

    There are a number of changes of slope over short periods in the GMSL record. This variability is at least partly related to El Niño and La Niña (sea level rises during El Niño and falls during La Niña) and associated changes in the hydrological cycle.

    The above graph shows detrended GMSL (from the top graph) versus the Southern Oscillation (SOI) index, which is one of the common indexes of the El Niño/La Niña cycle.

    Clearly (see, e.g. 1997/1998) sea level is higher during an El Niño event (SOI -ve) and lower (see, e.g. 1999/2000 and 2010/2011) during La Niña (SOI +ve).

    SOI data is from the Australian Bureau of Meteorology and data and graphs can be downloaded and seen at the Bureau of Meterology’s web site.


    Regional trends

    Sea level does not rise (or fall) uniformly over the oceans. This is illustrated by the map (below) showing sea-level trends from 1993 to 2012. There is a clear pattern of sea-level change that is also reflected in patterns of ocean heat storage.

    Plot of sea level trends from 1993 to 2009

    This pattern reflects interannual climate variability associated with the El Niño/La Niña cycle and the Indian Ocean Dipole, but also longer term changes such as the increase in sea levels in the Western Tropical Pacific due to changes in the Trade Winds. During El Niño years sea level rises in the eastern Pacific and falls in the western Pacific, whereas in La Niña years the opposite is true.

    Plot of sea level trends from 1993 to 2001 and 2001 to 2009


    Movie of sea-level changes (2.8MB animated gif) over the last 20 years – this version has had the seasonal (annual+semi-annual) signal removed at each point. This is comparable to the top figure (above).

    Click on the map below to see a movie of monthly-mean sea-surface height from January 1993 to April 2013 with the seasonal signal removed. The plot at the top of the page shows the time series of the means of these fields.

    The data that is displayed here can be downloaded from the “Sea level data>Data downloads” page on this site.

    Note the 1997/98 El Niño event!

    Sea surface height 1993-2010


    Another movie of sea-level changes (2.9MB animated gif) over the last 20 years

    Click on the map below to see a movie of monthly-mean sea-surface height from January 1993 to April 2013. The seasonal signal has not been removed from this, so you should see the pumping as the water in each hemisphere warms and expands in Spring and Summer and cools and shrinks in Autumn and Winter. The second plot (above) shows the time series of the means of these fields.

    The data that is displayed here can be downloaded from the “Sea level data>Data downloads” page on this site.

    Note especially the 1997/98 El Niño event!

  • Newly discovered flux in the Earth may solve missing-mantle mystery

    Newly discovered flux in the Earth may solve missing-mantle mystery

    Research points to large reservoirs of material deep in the mantle that may help to explain Earth’s origins.
    Jennifer Chu, MIT News Office

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    Newly discovered flux in the Earth may solve missing-mantle mystery

    This artist’s rendering shows a solar system that is a much younger version of our own. Dusty disks, like the one shown here circling the star, are thought to be the breeding grounds of planets, including rocky ones like Earth.
    Image: NASA/JPL-Caltech
    It’s widely thought that the Earth arose from violent origins: Some 4.5 billion years ago, a maelstrom of gas and dust circled in a massive disc around the sun, gathering in rocky clumps to form asteroids. These asteroids, gaining momentum, whirled around a fledgling solar system, repeatedly smashing into each other to create larger bodies of rubble — the largest of which eventually cooled to form the planets.

    Countless theories, simulations and geologic observations support such a scenario. But there remains one lingering mystery: If the Earth arose from the collision of asteroids, its composition should resemble that of meteoroids, the small particles that break off from asteroids.

    But to date, scientists have found that, quite literally, something doesn’t add up: Namely, the Earth’s mantle — the layer between the planet’s crust and core — is missing an amount of lead found in meteorites whose composition has been analyzed following impact with the Earth.

    Much of the Earth is composed of rocks with a high ratio of uranium to lead (uranium naturally decays to lead over time). However, according to standard theories of planetary evolution, the Earth should harbor a reservoir of mantle somewhere in its interior that has a low ratio of uranium to lead, to match the composition of meteorites. But such a reservoir has yet to be discovered — a detail that leaves Earth’s origins hazy.

    Now researchers in MIT’s Department of Earth, Atmospheric and Planetary Sciences have identified a “hidden flux” of material in the Earth’s mantle that would make the planet’s overall composition much more similar to that of meteorites. This reservoir likely takes the form of extremely dense, lead-laden rocks that crystallize beneath island arcs, strings of volcanoes that rise up at the boundary of tectonic plates.

    As two massive plates push against each other, one plate subducts, or slides, under the other, pushing material from the crust down into the mantle. At the same time, molten material from the mantle rises up to the crust, and is ejected via volcanoes onto the Earth’s surface.

    According to the MIT researchers’ observations and calculations, however, up to 70 percent of this rising magma crystallizes into dense rock — dropping, leadlike, back into the mantle, where it remains relatively undisturbed. The lead-heavy flux, they say, puts the composition of the Earth’s mantle on a par with that of meteorites.

    “Now that we know the composition of this flux, we can calculate that there’s tons of this stuff dropping down from the base of the crust into the mantle, so it is likely an important reservoir,” says Oliver Jagoutz, an assistant professor of geology at MIT. “This has a lot of implications for understanding how the Earth evolved through history.”

    Jagoutz and his colleague Max Schmidt, of the Swiss Federal Institute of Technology in Zurich, have detailed their results in a paper published in Earth and Planetary Science Letters.

    A mantle exposed

    Measuring the composition of material that has dropped into the mantle is a nearly impossible task. Jagoutz estimates that such dense rocks would form at a depth of 40 to 50 kilometers below the surface, beyond the reach of conventional sampling techniques.

    There is, however, one place on earth where such a depth of the crust and mantle is exposed: a region of northern Pakistan called the Kohistan arc. Forty million years ago, this island arc was crushed between India and Asia as the two plates collided.

    “When India came in, it slammed into the arc, and the arc extended and rotated itself,” Jagoutz says. “Because of that, we now have a cross-section of the mantle-to-crust transition. This is the only place on Earth where this exists.”

    On various trips from 2000 to 2007, Jagoutz trekked through the Kohistan arc region, collecting rocks from various parts of the arc’s crust and mantle. Bringing them back to the lab, he analyzed the rocks’ density and composition, discovering that some were “density-unstable” — much denser than the mantle. These denser rocks could potentially sink into the mantle, creating a hidden reservoir.

    Adding up to an asteroid origin

    The researchers measured the rocks’ composition, and found that the denser rocks contained much more lead than uranium — exactly the ratio predicted for the missing reservoir of material. Jagoutz then performed a mass balance (a simple conservation-of-mass calculation) to determine how much dense rock drops into the mantle, based on the composition of the region’s crust, rocks and mantle: Essentially, the mass of the Kohistan arc, minus whatever material drops into the mantle, should equal the material that comes out of the mantle.

    Jagoutz and Schmidt solved the equation for 10 common elements. From their calculations, they found that 70 percent of the magma that rises from the mantle must ultimately drop back down, relatively heavy with lead. Applying this statistic to other island arcs in the world — such as the Andean volcanic belt and the Cascade Range — they found that the amount of material dropped into the mantle globally equals the composition and quantity of the so-called missing reservoir — a finding that suggests that Earth did indeed form from the collision of meteorites.

    Bruce Buffett, a professor of earth and planetary science at the University of California at Berkeley, says a hidden reservoir in the mantle made of dense rocks is “interesting and plausible,” though he points out that there are other competing theories. For example, the subduction of oceanic crust into the mantle may contribute unknown material. Likewise, material may form from the cooling and solidifying of a large magma ocean.

    “There are a large variety of options on the table to explain the complex structure we detect seismically at the bottom of the mantle,” says Buffett, who was not involved in the study. “The attractive aspect of [Jagoutz’s] idea is that it has testable consequences. This is how progress is made.”

    “If we are right, one of the questions we have is: Why is the Earth capable of hiding something from us? Why is there never a volcano that brings up these rocks?” Jagoutz adds. “You’d think it’d come back up, but it doesn’t. It’s actually interesting.”

  • Fast Rising Magma Triggered Some Volcano Eruptions

    Fast Rising Magma Triggered Some Volcano Eruptions
    Submitted by Manjinder Singh on Sat, 08/03/2013 – 13:03

    VolcanoScientists have figured out that magma triggered the eruption of the Irazu volcano in the 1960s. Magma rose 22 miles in just two months.

    The 1963 Eruption of Costa Rica’s Irazu volcano has been re-examined by scientists. They have found something surprising and bit unsettling.

    Their findings suggested that some eruptions may happen in a much shorter time than previously thought. Scientists used to think that the rise of magma from the earth’s surface takes thousands of years.

    But they are surprised with what they have found now. Some volcanoes have the ability to recharge their magma supply in a manner of months to blow their tops relatively quickly. The findings were published in the journal Nature on Wednesday.

    The short fuse of the 10,000-foot-tall, 200-square mile-wide Costa Rican volcano Irazu has been described in the paper by a pair of researchers from Columbia University’s Lamont-Doherty Earth Observatory.

    “There’s definitely already evidence for fast-rising magmas in smaller volcanoes, but our new observation was that even `full-grown’ large volcanoes can also operate very fast”, lead author Philipp Ruprecht said in a phone interview.

    Icelandic volcanoes are directly connected to the earth’s mantle because of the location’s geology. Volcano in Costa Rica, according to the research, may have a direct connection to the mantle too, despite the fact of lying on a much thicker part.