Detrital garnet petrology challenges Paleoproterozoic ultrahigh-pressure metamorphism in western Greenland

Abstract. Modern-style plate tectonics is characterised by the global operation of cold and deep subduction involving blueschist facies ultrahigh-pressure metamorphism. This has been a common process since Neoproterozoic, but couple studies indicate similar processes were active in Paleoproterozoic, at least on local scale. Particularly conspicuous are extreme conditions ∼ 7 GPa thermal gradients < 150 ∘C GPa−1 proposed for metamorphic rocks Nordre Strømfjord shear zone western part Paleoproterozoic Nagssugtoqidian Orogen Greenland. By acquiring large dataset heavy minerals (n = 52 130) garnet major-element composition integrated with mineral inclusion analysis (n=2669) from modern sands representing fresh naturally mixed erosional material rocks, we here intensely screened area potential occurrences put constraints evolution. Apart absence any indications pointing to low-temperature–high-pressure metamorphism, results well accordance subduction–collision evolution along Barrovian-type intermediate temperature pressure gradient peak amphibolite–granulite–eclogite-facies transition medium- high-pressure granulite-facies conditions. In addition, discuss that all “evidence” metamorphism literature this equivocal. Accordingly, not an example modern-style or very low general.