DOI: 10.1111/jmg.12521
论文题名: Complete metamorphic cycle and long-lived anatexis in the c. 2.1 Ga Mistinibi Complex, Canada
作者: Godet A. ; Guilmette C. ; Labrousse L. ; Davis D.W. ; Smit M.A. ; Cutts J.A. ; Vanier M.-A. ; Lafrance I. ; Charette B.
刊名: Journal of Metamorphic Geology
ISSN: 2634929
出版年: 2020
卷: 38, 期: 3 语种: 英语
英文关键词: granulite
; Lu–Hf garnet
; Paleoproterozoic
; Trans-Hudson Orogen
; U–Pb zircon
Scopus关键词: Gallium compounds
; Garnets
; Geochronology
; Monazite
; Phase equilibria
; Phosphate minerals
; Silicate minerals
; Structural geology
; Trace elements
; Zircon
; Driving mechanism
; Element chemistry
; granulite
; High grade metamorphism
; Metamorphic grade
; Metasedimentary rocks
; Paleoproterozoic
; Trans-Hudson orogen
; Metamorphic rocks
英文摘要: Secular changes in the architecture, thermal state, and metamorphic style of global orogens are thought to have occurred since the Archean; however, despite widespread research, the driving mechanisms for such changes remain unclear. The Paleoproterozoic may prove to be a key era for investigating secular changes in global orogens, as it marks the earliest stage of an eon that saw the onset of modern-style global tectonics. The 2.1 Ga granulite-facies Mistinibi-Raude Domain (MRD), located in the Southeastern Churchill Province, Canada, offers a rare exposure of Paleoproterozoic high metamorphic grade supracrustal sequences (Mistinibi Complex, MC). Rocks from this domain were subjected to petrochronological investigations to establish P–T–t–X evolutions and to provide first order thermal state, burial and exhumation rates, and metamorphic gradients for the transient Paleoproterozoic times. To obtain comprehensive insight into the P–T–t–X evolution of the MRD, we used multi-method geochronology—Lu–Hf on garnet and U–Pb on zircon and monazite—integrated with detailed petrography, trace element chemistry, and phase equilibria modelling. Despite the extensive use of zircon and monazite as geochronometers, their behaviour in anatectic conditions is complex, leading to substantial ambiguity in interpreting the timing of prograde metamorphism. Our results indicate a clockwise metamorphic path involving significant melt extraction from the metasedimentary rocks, followed by cooling from >815°C to ~770°C at ~0.8 GPa. The timing of prograde burial and cooling from supra- to subsolidus conditions is constrained through garnet, monazite, and zircon petrochronology at 2,150–2,120 Ma and at 2,070–2,080 Ma, respectively. These results highlight long-lived residence of the rocks at mid-crustal supra-solidus conditions (55–70 Ma), with preserved prograde and retrograde supra-solidus monazite and zircon. The rocks record extremely slow burial rates (0.25–0.30 km/Ma) along a high metamorphic gradient (900–1,000°C/GPa), which appears symptomatic of Paleoproterozoic orogens. The MC did not record any significant metamorphism after 2,067 Ma, despite having collided with terranes that record high-grade metamorphism during the major 1.9–1.8 Ga Trans-Hudson orogeny. The MC would therefore represent a remnant of a local early Paleoproterozoic metamorphic infrastructure, later preserved as superstructure in the large hot Trans-Hudson orogen. © 2020 John Wiley & Sons Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/158570
Appears in Collections: 气候变化与战略
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作者单位: E4m, Département de géologie et de génie géologique, Université Laval, Québec City, Canada; CNRS-INSU, Institut des Sciences de la Terre Paris, ISTeP, UMR 7193, Sorbonne Université, Paris, France; Department of Earth Sciences, University of Toronto, Toronto, ON, Canada; PCIGR, Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, BC, Canada; Bureau de la connaissance géoscientifique du Québec, Québec City, Canada
Recommended Citation:
Godet A.,Guilmette C.,Labrousse L.,et al. Complete metamorphic cycle and long-lived anatexis in the c. 2.1 Ga Mistinibi Complex, Canada[J]. Journal of Metamorphic Geology,2020-01-01,38(3)