DOI: 10.1016/j.tecto.2021.228863
论文题名: Exhumation history of the Variscan orogen in western Iberia as inferred from new K-Ar and 40Ar/39Ar data on granites from Portugal
作者: Hildenbrand A. ; Marques F.O. ; Quidelleur X. ; Noronha F.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2021
卷: 812 语种: 英语
中文关键词: 40Ar/39Ar and K-Ar dating
; 40Ar/39Ar thermochronology
; Collapse stage
; Long-term exhumation
; Multi-diffusion domain approach (MDD)
; Variscan orogeny
; Western Iberia
英文关键词: Argon
; Binary alloys
; Biotite
; Deposits
; Feldspar
; Granite
; Lead alloys
; Mica
; Quartz
; Structural geology
; Tectonics
; Tin deposits
; Tungsten deposits
; Uranium alloys
; Zircon
; Ductile stretching
; Orogenic collapse
; Orogenic cycles
; Shallow intrusions
; Tectonic exhumation
; Tectonic uplift
; Variscan Orogen
; Variscan orogenies
; Potassium compounds
; argon-argon dating
; deformation
; exhumation
; granite
; Hercynian orogeny
; potassium-argon dating
; thermochronology
; uranium-lead dating
; Iberian Peninsula
; Portugal
英文摘要: Exhumation of the roots of collapsing orogens is a key process in the evolution of mountain belts, which is critical for the understanding of orogenic cycles. From new structural analyses, K-Ar and 40Ar/39Ar on muscovite, biotite and K-feldspar, and available U-Pb ages, we constrain the cooling and exhumation history of granitic batholiths from the main structural zones of the Variscan orogen in Iberia. We show that: (1) the oldest Ar dated granites (ca. 335 Ma on biotite) record exhumation of gneisses crystallized much earlier (up to ca. 530‐510 Ma U-Pb age); (2) granitoids crystallized at ca. 330 Ma record mostly ductile stretching (L-tectonites striking around N-S), consistent with N-S extension (Variscan intra-orogenic collapse); (3) most granites crystallized between ca. 320 and 305 Ma record ductile stretching consistent with deformation along NW-SE to ENE-WSW shear zones during the late-Variscan compression (C3); (4) granites crystallized after 305 Ma record mostly isotropic strain (no visible ductile foliation or lineation), consistent with their emplacement during/after the final collapse of the Variscan orogeny (E2); (5) comparison between Ar ages on micas and zircon U-Pb ages shows two contrasting situations: (i) similar ages, reflecting crystallization and fast cooling, which can be explained by relatively shallow intrusion and/or fast tectonic uplift; (ii) significant difference between U-Pb and Ar ages, supporting crystallization of deeper seated intrusions and their subsequent uplift for several Ma to tens of Ma; (6) thermochronological modelling on K-feldspar supports significant tectonic exhumation in the core of the chain between ca. 315 and 285 Ma, followed by late-stage passive denudation; 7) Late Carboniferous to early Permian tectonic exhumation was accompanied by significant formation of ore-deposits. Tin deposits occur in pegmatites and/or quartz veins associated with muscovite-rich syn-C3 granites and those of tungsten in quartz veins, breccia pipes and skarns associated with the E2 biotite-rich granites. © 2021 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170820
Appears in Collections: 气候变化与战略
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作者单位: Université Paris-Saclay, CNRS, GEOPS, Orsay, 91405, France; Universidade de Lisboa, Lisboa, Portugal; Universidade do Porto, ICT, Porto, 4169-007, Portugal
Recommended Citation:
Hildenbrand A.,Marques F.O.,Quidelleur X.,et al. Exhumation history of the Variscan orogen in western Iberia as inferred from new K-Ar and 40Ar/39Ar data on granites from Portugal[J]. Tectonophysics,2021-01-01,812