For this #ThinSectionThursday check out some nice pics from our recently published paper in Tectonics on the metamorphism of the Isua Supracrustal Belt. ( https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020TC006516)🧵

We have a nice range of garnet microstructures, some grains showing at least two grt generations.
For this #ThinSectionThursday check out some nice pics from our recently published paper in Tectonics on the metamorphism of the Isua Supracrustal Belt. ( https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020TC006516)We have a nice range of garnet microstructures, some grains showing at least two grt generations.
For this #ThinSectionThursday check out some nice pics from our recently published paper in Tectonics on the metamorphism of the Isua Supracrustal Belt. ( https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020TC006516)We have a nice range of garnet microstructures, some grains showing at least two grt generations.
For this #ThinSectionThursday check out some nice pics from our recently published paper in Tectonics on the metamorphism of the Isua Supracrustal Belt. ( https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020TC006516)We have a nice range of garnet microstructures, some grains showing at least two grt generations.
For this #ThinSectionThursday check out some nice pics from our recently published paper in Tectonics on the metamorphism of the Isua Supracrustal Belt. ( https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020TC006516)We have a nice range of garnet microstructures, some grains showing at least two grt generations.
Syn-tectonic inclusion-rich garnet is commonly overgrown by post-tectonic inclusion-poor garnet. Sometimes this post-tectonic garnet grows in calcite veins, like this beauty here:
Syn-tectonic inclusion-rich garnet is commonly overgrown by post-tectonic inclusion-poor garnet. Sometimes this post-tectonic garnet grows in calcite veins, like this beauty here:
Syn-tectonic inclusion-rich garnet is commonly overgrown by post-tectonic inclusion-poor garnet. Sometimes this post-tectonic garnet grows in calcite veins, like this beauty here:
Garnets also show compositional zoning, like this one right here of a nice spiral-like garnet from a metapelite.

Image processed using @XMapTools
But we can also find nice retrogression features.

Garnet pseudomorphism? Got it!

Chloritization of biotite? Yes! And it is stunning! <3

#ThinSectionThursday
But we can also find nice retrogression features. Garnet pseudomorphism? Got it!Chloritization of biotite? Yes! And it is stunning! <3 #ThinSectionThursday
But we can also find nice retrogression features. Garnet pseudomorphism? Got it!Chloritization of biotite? Yes! And it is stunning! <3 #ThinSectionThursday
But we can also find nice retrogression features. Garnet pseudomorphism? Got it!Chloritization of biotite? Yes! And it is stunning! <3 #ThinSectionThursday
These petrographic observations along with geothermobarometry allowed us to identify three metamorphic events in the Eoarchean Isua Supracrustal Belt.

#ArcheanTectonics #MetamorphicPetrology
But that’s not everything for #ThinSectionThursday, our sister paper by Zuo et al. ( https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020TC006514), also has some nice microstructures. Shear indicators, and a large set of #EBSD data, show that the Isua Supracrustal Belt records two opposite shear senses.
But that’s not everything for #ThinSectionThursday, our sister paper by Zuo et al. ( https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020TC006514), also has some nice microstructures. Shear indicators, and a large set of #EBSD data, show that the Isua Supracrustal Belt records two opposite shear senses.
But that’s not everything for #ThinSectionThursday, our sister paper by Zuo et al. ( https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020TC006514), also has some nice microstructures. Shear indicators, and a large set of #EBSD data, show that the Isua Supracrustal Belt records two opposite shear senses.
But that’s not everything for #ThinSectionThursday, our sister paper by Zuo et al. ( https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020TC006514), also has some nice microstructures. Shear indicators, and a large set of #EBSD data, show that the Isua Supracrustal Belt records two opposite shear senses.
Our results are consistent with the hypothesis that the Isua Supracrustal Belt evolved in a heat-pipe tectonic setting, contrary to the long-standing idea that it represents one of the earliest records of plate tectonics. ( https://pubs.geoscienceworld.org/gsa/lithosphere/article/12/1/166/580854/A-non-plate-tectonic-model-for-the-Eoarchean-Isua)

#ArcheanTectonics
These are Jiawei and mine first PhD papers and we hope they will bring something to the conversation about #ArcheanTectonics and the evolution of the Isua Supracrustal Belt.

@muellth @Webb_Tectonics @HarveyJasonDr @IGTLeeds @GzgPetro
You can follow @Anthnyy.
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