DOI: 10.1016/j.epsl.2020.116421
论文题名: Strain localization and fluid-assisted deformation in apatite and its influence on trace elements and U–Pb systematics
作者: Ribeiro B.V. ; Lagoeiro L. ; Faleiros F.M. ; Hunter N.J.R. ; Queiroga G. ; Raveggi M. ; Cawood P.A. ; Finch M. ; Campanha G.A.C.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 545 语种: 英语
中文关键词: apatite recrystallization
; dynamic recrystallization
; EBSD
; fluid-assisted recrystallization
; microstructures
; trace elements and U–Pb system
英文关键词: Creep
; Dynamic recrystallization
; Flow of fluids
; Mica
; Microstructure
; Quartz
; Structural geology
; Trace elements
; Crystal plastic deformations
; Crystallographic preferred orientations
; Dislocation densities
; Dissolution precipitations
; Electron back scatter diffraction
; Fluid assisted deformation
; Strain localizations
; Stretching lineations
; Apatite
; apatite
; backscatter
; deformation
; granite
; microstructure
; mylonite
; recrystallization
; strain
; thermometry
; trace element
; uranium-lead dating
; Brazil
英文摘要: This paper presents electron backscatter diffraction (EBSD), trace element and U–Pb data of apatite grains from a granitic mylonite from the Taxaquara Shear Zone (SE Brazil). The mylonite recrystallized under upper-greenschist facies and presents two types of apatite with distinct microstructures. Type-1 apatite appears in quartz-rich layers and does not exhibit any microstructural, crystallographic, or chemical evidence of deformation/recrystallization, and resembles the original igneous apatite. Type-2 apatite appears in mica-rich layers and exhibits core-and-mantle microstructures, and intragranular subgrain development, suggesting that they have undergone dynamic recrystallization. Recrystallized tails of type-2 apatite grains exhibit a strong c-axis crystallographic preferred orientation parallel to the X-direction (stretching lineation), and lack evidence of dislocation density. This evidence from type-2 apatite grains, combined with REE depletion, high La and a negative Ce anomaly compared to type-1 grains, suggests that type-2 apatite tails underwent recrystallization via dissolution-precipitation creep, whereas parental grains underwent crystal-plastic deformation and subgrain formation through dynamic recrystallization. Phase-equilibrium modelling and quartz CPO opening-angle thermometry are consistent with recrystallization at ∼480 – 530°C and 2.2 – 5.0 kbar. We were not able to determine precise deformation ages from type-2 apatite because fluid-assisted recrystallization appears to have substantially decreased the U/Pb ratio. We find that preferential fluid flow along high-strain, biotite-rich layers in the mylonite caused type-2 apatite to recrystallise, whereas type-1 apatite in low strain layers was unaffected and retained the characteristics of the protolith. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165234
Appears in Collections: 气候变化与战略
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作者单位: School of Earth, Atmosphere and Environment Science, Monash University, Clayton, Victoria 3800, Australia; Federal University of Paraná, Geology Department, 100 Francisco Heráclito dos Santos Street, Bloco VI, Curitiba, 35400000, Brazil; Department of Mineralogy and Geotectonics, University of São Paulo, Rua do Lago 562, São Paulo, 05508-900, Brazil; DEGEO/EM/UFOP, Morro do Cruzeiro, Ouro Preto, MG 35400-000, Brazil
Recommended Citation:
Ribeiro B.V.,Lagoeiro L.,Faleiros F.M.,et al. Strain localization and fluid-assisted deformation in apatite and its influence on trace elements and U–Pb systematics[J]. Earth and Planetary Science Letters,2020-01-01,545