page_title: Eoarchean geology
section_title: Occurrence of Eoarchean rocks
hierarchical_section_title: Eoarchean geology / Occurrence of Eoarchean rocks
caption_attribution_description: English: Eoarchean World occurrence
context_page_description: Eoarchean geology is the study of the oldest preserved crustal fragments of Earth during the Eoarchean era from 4 to 3.6 billion years ago. Major well-preserved rock units dated Eoarchean are known from three localities, the Isua Greenstone Belt in Southwest Greenland, the Acasta Gneiss in the Slave Craton in Canada, and the Nuvvuagittuq Greenstone Belt in the eastern coast of Hudson Bay in Quebec. From the dating of rocks in these three regions scientists suggest that plate tectonics could go back as early as Eoarchean.
  All 3 regions contain an abundance of Archean felsic volcanic rocks, including tonalite, trondhjemite and granodiorite series rocks, with minor granulite to amphibolite facies gneiss complexes, which means that the original characters of the rocks has been disturbed by at least one ductile deformation at deep crustal conditions.
  Eoarchean geology is important in investigating earth's tectonic history. It is because the earth had just undergone an transformation to the present-day-similar convective mode and lithosphere from a magma ocean in Hadean Eon, to either a protoplate tectonics or an unstable stagnant lithosphere lid at its infant stages.
context_section_description: Eoarchean geology is dominated by:
  (1) Mafic to ultramafic volcanics
  (2) Tonalite-Trondhjemite-Granodiorite (TTG)
  (3) Chemical sedimentary rocks such as chert and Banded-Iron-Formations (BIF)
  (4) Subordinate clastic sedimentary rocks.
  There are some zircon dated back to eoarchean, but not necessarily indicate the host rock was formed in Eoarchean, in
  (1) Anshan Area in North China Craton
  (2) Sebakwe Protocraton in Zimbabwe Craton
caption: World Map showing the location of the most prominent well-preserved Eoarchean geology 1.Acasta Gneiss 2.Nuvvuagittuq Supracrustal Belt 3.Saglek-Hebron Block 4.Itsaq Gneiss Complex 5.Napier Complex a.Sebakwe protocraton b.Anshan
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