The earliest Neoproterozoic magmatic record of the Pearya terrane, Canadian high Arctic: Implications for Caledonian terrane reconstructions

摘要: Abstract Succession I of the exotic Pearya terrane, northernmost Ellesmere Island, includes voluminous granitoid orthogneiss units that form presumptive basement to this displaced crustal fragment. Previous whole rock Rb/Sr and multigrain zircon U/Pb geochronology revealed ages in a range from latest Mesoproterozoic earliest Neoproterozoic. This study presents new single grain geochronolgy suite 7 samples defines relatively narrow Neoproterozoic ages, 964 ± 6 Ma 974 ± 8 Ma. Whole trace element geochemistry reveals LILE enrichment decoupled low depleted HFSE values, suggestive subduction zone origin. Nd Hf isotope supports input both juvenile evolved materials, with eNd (i) values between −1 −4.6, similar for eHf microsampled age domains consistent crystallization protolith. Documentation abundant magmatic reinforces correlations areas North Atlantic-Arctic Caledonides containing tectonothermal record magmatism. The Northwestern, Northeastern, Southwestern terranes Svalbard events c. 965 Ma–920 Ma range. Likewise, lower Kalak Nappes Norway East Greenland preserve slightly older younger magmatism metamorphism, respectively. Slightly occur south central Brooks Range Farewell Alaska. geochemical isotopic data terrane support links these regions terms subchrondritic Paleoproterozoic mantle model ages. dispersed Arctic are interpreted have originated near or on northeastern margin Greenland, continental arc later carried out Caledonide orogen into Circum-Arctic realm. These permit models an origin as part strike-slip orogenic system.