Comment on “Tectonics of the Isua Supracrustal Belt 1: P-T-X-d Constraints of a Poly-Metamorphic Terrane” by A. Ramírez-Salazar et al. and “Tectonics of the Isua Supracrustal Belt 2: Microstructures Reveal Distributed Strain in the Absence of Major Fault Structures” by J. Zuo et al.

Publication Name



The two Isua supracrustal belt area (Greenland) papers by Zuo et al. (2021, and Ramírez-Salazar et al. (2021, contain no evidence supporting an Eoarchean “heat-pipe” geodynamic regime and yet no evidence negating a mobile lid one. From quartz micro-fabric studies, Zuo et al. (2021, argued for Eoarchean “relatively equal strain distributed across the belt.” This contradicts clear meso- and macro-scale evidence for strongly heterogeneous Eoarchean deformation before the later deformed and metamorphosed ∼3,500 to 2,750 Ma Ameralik dykes were intruded. The Zuo et al. strain indicators relate to syn-amphibolite facies Neoarchean basin and dome formation throughout the ∼250 km extent of the Eoarchean gneiss complex. Ramírez-Salazar et al. (2021, argued the Isua area's metamorphic signature reflects a uniform Eoarchan “heat-pipe” geodynamic regime. However, observed Eoarchean tectonothermal conditions are more diverse, including ultra-high-pressure relicts in peridotite lenses with supra-subduction zone attributes, and are incompatible with a “heat-pipe” regime.





Article Number


Funding Number


Funding Sponsor

Australian Research Council



Link to publisher version (DOI)