气候变化领域集成服务门户(CCPortal): Radiometric Temperature Determination in Nongray Bridgmanite: Applications to Melting Curve and Post-Perovskite Transition Boundary in the Lower Mantle

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DOI	10.1029/2021JB021723
	Radiometric Temperature Determination in Nongray Bridgmanite: Applications to Melting Curve and Post-Perovskite Transition Boundary in the Lower Mantle
	Lobanov S.S.; Speziale S.; Lin J.-F.; Schifferle L.; Schreiber A.
发表日期	2021
ISSN	21699313
卷号	126 期号:5
英文摘要	Experiments in laser-heated diamond anvil cells (LH DACs) are conducted to assess phase diagrams of planetary materials at high pressure-temperature (P-T) conditions; thus, reliable determination of temperature in LH DAC experiments is essential. Radiometric temperature determination in LH DACs relies on the assumption of sample's wavelength-independent optical properties (graybody assumption), which is not justified for major lower mantle materials. The result is that experimental phase diagrams contain systematic unconstrained errors. Here we estimate the systematic error in radiometric temperature of nongray polycrystalline bridgmanite (Bgm; Mg0.96Fe2+0.036Fe3+0.014Si0.99O3) in a LH DAC by modeling emission and absorption of thermal radiation in a sample with experimentally-constrained optical properties. A comparison to experimental data validates the models and reveals that thermal spectra measured in LH DAC experiments record the interaction of radiation with the hot nongray sample. The graybody assumption in the experiments on translucent Bgm (light extinction coefficient, k < ∼250 cm-1 at 500–900 nm) yields temperatures ∼5% higher than the maximum temperature in the sample heated to ∼1900 K. In contrast, the graybody temperature of dark Bgm (k > ∼1500 cm−1), such as that produced upon melt quenching in LH DACs, underestimates the maximum temperature by ∼10%. Our experimental results pose quantitative constraints on the effect of nongray optical properties on the uncertainty of radiometric temperature determination in Bgm in the LH DACs. Evaluating nongray temperature in the future would enable a revision of the Bgm to post-perovskite phase transition and the high-pressure melting curve of Bgm. © 2021. The Authors.
英文关键词	bridgmanite; diamond anvil cell; graybody assumption; laser heating; melting curve; optical absorption spectra
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187144
作者单位	GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, Germany; Insitute of Geosciences, University of Potsdam, Karl-Liebknecht-Straße, Potsdam, Germany; Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, United States
推荐引用方式 GB/T 7714	Lobanov S.S.,Speziale S.,Lin J.-F.,et al. Radiometric Temperature Determination in Nongray Bridgmanite: Applications to Melting Curve and Post-Perovskite Transition Boundary in the Lower Mantle[J],2021,126(5).
APA	Lobanov S.S.,Speziale S.,Lin J.-F.,Schifferle L.,&Schreiber A..(2021).Radiometric Temperature Determination in Nongray Bridgmanite: Applications to Melting Curve and Post-Perovskite Transition Boundary in the Lower Mantle.Journal of Geophysical Research: Solid Earth,126(5).
MLA	Lobanov S.S.,et al."Radiometric Temperature Determination in Nongray Bridgmanite: Applications to Melting Curve and Post-Perovskite Transition Boundary in the Lower Mantle".Journal of Geophysical Research: Solid Earth 126.5(2021).