气候变化领域集成服务门户(CCPortal): Rates of Olivine Grain Growth During Dynamic Recrystallization and Postdeformation Annealing

CCPortal

DOI	10.1029/2020JB020415
	Rates of Olivine Grain Growth During Dynamic Recrystallization and Postdeformation Annealing
	Speciale P.A.; Behr W.M.; Hirth G.; Tokle L.
发表日期	2020
ISSN	21699313
卷号	125 期号:11
英文摘要	We performed deformation and grain growth experiments on natural olivine aggregates with olivine water contents (COH = 600 ± 300 H/106 Si) similar to upper mantle olivine, at 1000–1200°C and 1,400 ± 100 MPa confining pressure. Our experiments differ from published grain growth studies in that most were (1) conducted on natural olivine cores rather than hot-pressed aggregates and (2) dynamically recrystallized prior to or during grain growth. We combine our results with similar experiments performed at 1200–1300°C and fit the data to a grain growth relationship, yielding a growth exponent (p) of 3.2, activation energy (EG) 620 ± 145 kJ mol−1 (570 ± 145 kJ mol−1 when accounting for the role of temperature on water content), activation volume (VG) ~5 × 10−6 m3 mol−1, and rate constant (k0) 1.8 × 103 mp s−1. Our EG is within uncertainty of that predicted for dislocation creep of wet olivine (E* = 480 ± 40 kJ mol−1). Grain size in strain rate-stepping samples adjusted to the olivine piezometer within 1.3–7.9% strain. The active grain boundary migration processes during deformation and dynamic recrystallization affect the kinetics of postdeformation grain growth, as grain boundary migration driven by strain energy density (ρGBM) may delay the onset of grain growth driven by interfacial energy (γGBM). We compared our postdeformation grain growth rates with data from previously published hydrostatic annealing experiments on synthetic olivine. At geologic timescales, the growth rates are much slower than predicted by the existing wet olivine grain growth law. ©2020. The Authors.
英文关键词	dynamic recrystallization; grain growth; olivine; postdeformation; strain localization; upper mantle
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/187522
作者单位	Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, United States; Geological Institute, Department of Earth Sciences, ETH Zürich (Swiss Federal Institute of Technology), Zürich, Switzerland; Department of Earth, Environmental, and Planetary Sciences, Brown University, Providence, RI, United States
推荐引用方式 GB/T 7714	Speciale P.A.,Behr W.M.,Hirth G.,et al. Rates of Olivine Grain Growth During Dynamic Recrystallization and Postdeformation Annealing[J],2020,125(11).
APA	Speciale P.A.,Behr W.M.,Hirth G.,&Tokle L..(2020).Rates of Olivine Grain Growth During Dynamic Recrystallization and Postdeformation Annealing.Journal of Geophysical Research: Solid Earth,125(11).
MLA	Speciale P.A.,et al."Rates of Olivine Grain Growth During Dynamic Recrystallization and Postdeformation Annealing".Journal of Geophysical Research: Solid Earth 125.11(2020).