King Helen E, Plümper Oliver, Putnis Christine V, O'Neill Hugh St C, Klemme Stephan, Putnis Andrew
Institut für Mineralogie, University of Münster, Corrensstrasse 24, 48149 Münster, Germany.
Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, Connecticut 06511, United States.
ACS Earth Space Chem. 2017 Apr 20;1(2):113-121. doi: 10.1021/acsearthspacechem.6b00016. Epub 2017 Mar 31.
Mineral surfaces play a critical role in the solar nebula as a catalytic surface for chemical reactions and potentially acted as a source of water during Earth's accretion by the adsorption of water molecules to the surface of interplanetary dust particles. However, nothing is known about how mineral surfaces respond to short-lived thermal fluctuations that are below the melting temperature of the mineral. Here we show that mineral surfaces react and rearrange within minutes to changes in their local environment despite being far below their melting temperature. Polished surfaces of the rock and planetary dust-forming silicate mineral olivine ((Mg,Fe)SiO) show significant surface reorganization textures upon rapid heating resulting in surface features up to 40 nm in height observed after annealing at 1200 °C. Thus, high-temperature fluctuations should provide new and highly reactive sites for chemical reactions on nebula mineral particles. Our results also may help to explain discrepancies between short and long diffusion profiles in experiments where diffusion length scales are of the order of 100 nm or less.
矿物表面在太阳星云 中起着关键作用，它是化学反应的催化表面，并且在地球吸积过程中，通过水分子吸附到行星际尘埃颗粒表面，可能充当了水的来源。然而，对于矿物表面如何响应低于矿物熔点的短暂热波动，我们却一无所知。在此，我们表明，尽管远低于熔点温度，矿物表面在几分钟内就能对其局部环境的变化做出反应并重新排列。岩石和形成行星尘埃的硅酸盐矿物橄榄石（(Mg,Fe)SiO）的抛光表面在快速加热时会呈现出显著的表面重组纹理，在1200℃退火后可观察到高达40纳米的表面特征。因此，高温波动应为星云矿物颗粒上的化学反应提供新的高活性位点。我们的结果或许还有助于解释在扩散长度尺度约为100纳米或更小的实验中，短扩散剖面与长扩散剖面之间的差异。
