DOI: 10.1016/j.earscirev.2020.103375
论文题名: Arclogites and their role in continental evolution; part 1: Background, locations, petrography, geochemistry, chronology and thermobarometry
作者: Ducea M.N. ; Chapman A.D. ; Bowman E. ; Triantafyllou A.
刊名: Earth Science Reviews
ISSN: 00128252
出版年: 2021
卷: 214 语种: 英语
中文关键词: Arc roots
; Arclogite
; Cumulates
; Residues
; Restites
; Thermobarometry
; U-Pb zircon geochemistry
英文关键词: andesite
; barometry
; chronology
; clinopyroxene
; cumulate
; eclogite
; geochemistry
; granite
; petrography
; restite
; uranium-lead dating
; xenolith
; zircon
英文摘要: Arclogites, or clinopyroxene-, garnet-, amphibole-, and Fe[sbnd]Ti oxide-bearing cumulates and restites (collectively representing residues) to andesitic continental arc magmas, are reviewed here and in a companion paper (Ducea et al., 2020). Experimental petrology and petrologic observations suggest that these eclogite facies rocks form magmatically in deep crustal hot zones beneath arcs with crustal thicknesses exceeding 35–40 km. Volcanic and plutonic products of thinner arcs may instead be entirely extracted from amphibolite to granulite facies and garnet-free pyroxenite residues. Arclogites are perhaps best known as xenoliths, with notable examples from young (Sierra Nevada and Central Arizona) and modern (Colombia) sub-arc environments. We suspect that arclogite occurs more commonly than currently recognized in the xenolith record from orogenic and cratonic domains. Arclogite is also found as discrete intervals in the deepest exposures of the Kohistan arc and as small volume inclusions in tectonically exposed peridotite massifs (e.g., Beni Bousera, Morocco). Geochemically, these rocks are low silica (SiO2 < 50%) assemblages with low Nb/Ta and Sr/Y ratios and enrichments in heavy REEs such that they represent the complement to the andesitic-dacitic liquids that make up the surface volcanics and batholiths of most arcs. Virtually all rock-forming minerals in arclogites are of similar or greater density than the underlying mantle, making them ideal candidates for foundering. Arclogites are formed in the lowermost crust of arcs at 35–70 km depth and record high temperatures (~800–1000 °C) at the time of formation which then cool and metamorphose at ~650–750 °C if they remain attached to the crust for an extended period of time. Ages of these rocks are obtainable by Sm[sbnd]Nd and Lu[sbnd]Hf garnet isochron geochronology as well as titanite or rutile U[sbnd]Pb geochronology, although these ages can be reset through long-term storage in hot lower crustal environments. Recent discovery of zircon accessory minerals in arclogites makes these rocks datable with greater precision and greater chance of preserving crystallization ages by U[sbnd]Pb chronology. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/166382
Appears in Collections: 气候变化与战略
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作者单位: University of Arizona, Tucson, AZ 85721, United States; Faculty of Geology and Geophysics, University of Bucharest, Bucharest, 010041, Romania; Geology Department, Macalester College, St. Paul, MN 55105, United States; Department of Geology, University of Liège, Liège, Belgium; Laboratoire de géologie de Lyon, Université de Lyon, Université Lyon 1, ENS de Lyon, CNRS, UMR 5276 LGL-TPE, Villeurbanne, F-69622, France
Recommended Citation:
Ducea M.N.,Chapman A.D.,Bowman E.,et al. Arclogites and their role in continental evolution; part 1: Background, locations, petrography, geochemistry, chronology and thermobarometry[J]. Earth Science Reviews,2021-01-01,214