• Uncovering new understanding of Earth's

    From ScienceDaily@1337:3/111 to All on Wed Sep 23 21:30:46 2020
    Uncovering new understanding of Earth's carbon cycle

    Date:
    September 23, 2020
    Source:
    University of Alberta
    Summary:
    A new study is examining the Earth's carbon cycle in new depth,
    using diamonds as breadcrumbs of insight into some of Earth's
    deepest geologic mechanisms.



    FULL STORY ==========================================================================
    A new study led by a University of Alberta PhD student -- and published
    in Nature -- is examining the Earth's carbon cycle in new depth, using
    diamonds as breadcrumbs of insight into some of Earth's deepest geologic mechanisms.


    ========================================================================== "Geologists have recently come to the realization that some of the
    largest, most valuable diamonds are from the deepest portions of our
    planet," said Margo Regier, PhD student in the Department of Earth
    and Atmospheric Sciences under the supervision of Graham Pearson and
    Thomas Stachel. "While we are not yet certain why diamonds can grow to
    larger sizes at these depths, we propose a model where these 'superdeep' diamonds crystallize from carbon-rich magmas, which may be critical for
    them to grow to their large sizes." Beyond their beauty and industrial applications, diamonds provide unique windows into the deep Earth,
    allowing scientists to examine the transport of carbon through the mantle.

    "The vast majority of Earth's carbon is actually stored in its silicate
    mantle, not in the atmosphere," Regier explained. "If we are to fully understand Earth's whole carbon cycle then we need to understand this
    vast reservoir of carbon deep underground." The study revealed that the carbon-rich oceanic crust that sinks into the deep mantle releases most of
    its carbon before it gets to the deepest portion of the mantle. This means
    that most carbon is recycled back to the surface and only small amounts of carbon will be stored in the deep mantle -- with significant implications
    for how scientists understand the Earth's carbon cycle. The mechanism
    is important to understand for a number of reasons, as Regier explained.

    "The movement of carbon between the surface and mantle affects Earth's
    climate, the composition of its atmosphere, and the production of magma
    from volcanoes," said Regier. "We do not yet understand if this carbon
    cycle has changed over time, nor do we know how much carbon is stored in
    the deepest parts of our planet. If we want to understand why our planet
    has evolved into its habitable state it is today and how the surfaces and atmospheres of other planets may be shaped by their interior processes,
    we need to better understand these variables."

    ========================================================================== Story Source: Materials provided by University_of_Alberta. Original
    written by Andrew Lyle.

    Note: Content may be edited for style and length.


    ========================================================================== Journal Reference:
    1. M. E. Regier, D. G. Pearson, T. Stachel, R. W. Luth, R. A. Stern,
    J. W.

    Harris. The lithospheric-to-lower-mantle carbon cycle recorded
    in superdeep diamonds. Nature, 2020; 585 (7824): 234 DOI:
    10.1038/s41586- 020-2676-z ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2020/09/200923124730.htm

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