Eclogites and basement terrane tectonics in the northern arm of the Grenville orogen,NW Scotland  

作　　者：A.Bird M.Thirlwall R.A.Strachan I.L.Millar E.D.Dempsey K.Hardman 

机构地区：[1]School of Environmental Sciences,University of Hull,Cottingham Road,Hull HU67RX,United Kingdom [2]Department of Earth Sciences,Royal Holloway University of London,Egham,Surrey TW200EX,United Kingdom [3]School of the Environment,Geography and Geosciences,University of Portsmouth,Burnaby Rd,Portsmouth PO13QL,United Kingdom [4]Geochronology and Tracers,British Geological Survey,Keyworth,Nottinghamshire NG125GG,United Kingdom

出　　处：《Geoscience Frontiers》2023年第6期358-367,共10页地学前缘（英文版）

摘　　要：The presence of eclogites within continental crust is a key indicator of collisional orogenesis.Eclogites within the Eastern Glenelg basement inlier of the Northern Highland Terrane(NHT)have been redated in order to provide more accurate constraints on the timing of collision within the northern arm of the Grenville Orogen.The eclogites yield dates of ca.1200 Ma which are interpreted to record the onset of continent–continent interaction,and the NHT as a whole is thought to represent the lower plate in successive 1200–1000 Ma collision events.The Eastern Glenelg basement inlier is viewed as a fragment of the leading edge of the NHT continental basement that was partially subducted along a suture and then exhumed back up the subduction channel.Differences in ages of igneous protoliths and intrusive histories,and metamorphic events(this paper)between the NHT basement and the Laurentian foreland,suggests that they were separate crustal blocks until after ca.1600 Ma.We therefore suggest that:(1)the NHT represents a fragment of Archean–Paleoproterozoic crust that was reworked within the ca.1.7–1.6 Ga Labradorian-Gothian belt,although whether it was derived from Laurentia or Baltica is uncertain,and(2)amalgamation of the NHT with the Laurentian foreland did not occur until the terminal stages of the Grenville collision at ca.1000 Ma.

关 键 词：Geochronology ECLOGITES GRENVILLE RODINIA 

分 类 号：P542[天文地球—构造地质学] P597.3[天文地球—地质学]