Akia terrane

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The Akia terrane is a tectonostratigraphic terrane located in the North Atlantic Craton in southern West Greenland. [1] The Akia terrane is bounded to the Southeast by the Eo- to Neo-archaean tectonostratigraphic terranes of the Nuuk region, [2] and to the North by the recently recognised Alanngua Complex, which separates the Akia terrane from the Neoarchaean Tuno terrane. [3] The crust in the Akia terrane formed in two major pulses. The first at ~3.2 Ga, predominantly comprises dioritic gneisses, whereas the second, at ~3.0 Ga comprises a more diverse mix of TTG and dioritic gneisses with enclaves of supracrustal rocks and mafic-ultramafic intrusions. [3] [4] [5] [6] Supracrustal rocks are largely tholeiitic and calc-alkaline amphibolites formed at ~3.07 Ga. [7] The mafic-ultramafic intrusions include peridotite cumulates [8] and a belt of noritic intrusions formed at the same time as the TTG gneisses, the Maniitsoq Norite Belt. [9] Various tectonic settings have been proposed for the 3.0 Ga crust forming event, including subduction related magmatism, [4] stagnant lid tectonic processes, [10] and crust and mantle melting in an ultra-hot orogeny. [9]

The terrane underwent high grade granulite facies metamorphism at ~3.0 Ga, immediately after or simultaneous with the second major crust forming event. [9] [10] Further high temperature metamorphism followed at ~2.7 Ga and ~2.5 Ga. [3] [11] The earlier event is marked by widespread formation of pegmatite granite dykes [6] and may be associated with the juxtaposition of the Akia and Tuno terranes. [3] [11]

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References

  1. ↑ C. R. L. Friend, A. P. Nutman, V. R. McGregor (1988). "Late Archaean terrane accretion in the Godthåb region, southern West Greenland". Nature . 335 (6190): 535–538. Bibcode:1988Natur.335..535F. doi:10.1038/335535a0. S2CID   4254354.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  2. ↑ C. R. L. Friend, A. P. Nutman (2005). "New pieces to the Archaean terrane jigsaw puzzle in the Nuuk region, southern West Greenland: steps in transforming a simple insight into a complex regional tectonothermal model". Journal of the Geological Society . 162 (1): 147–162. Bibcode:2005JGSoc.162..147F. doi:10.1144/0016-764903-161. S2CID   52855189 – via Lyell Collection.
  3. 1 2 3 4 A. Steenfelt, J. Hollis, C. L. Kirkland, A. Sandrin, N. J. Gardiner, H. K. H. Olierook, K. Szilas, P. Waterton, C. Yakymchuk (2021). "The Mesoarchaean Akia terrane, West Greenland, revisited: New insights based on spatial integration of geophysics, field observation, geochemistry and geochronology". Precambrian Research . 352: 105958. Bibcode:2021PreR..352j5958S. doi:10.1016/j.precamres.2020.105958. hdl: 10023/21175 . S2CID   225111824 – via Elsevier Science Direct.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  4. 1 2 A. A. Garde, C. R. L. Friend, A. P. Nutman, M. Marker (2000). "Rapid maturation and stabilisation of middle Archaean continental crust: the Akia terrane, southern West Greenland". Bulletin of the Geological Society of Denmark. 47: 1–27. doi: 10.37570/bgsd-2000-47-01 .{{cite journal}}: CS1 maint: multiple names: authors list (link)
  5. ↑ A. A. Garde (1997). "Accretion and evolution of an Archaean high-grade grey gneiss – amphibolite complex: the Fiskefjord area, southern West Greenland". Geology of Greenland Survey Bulletin . 177: 1–115. doi: 10.34194/ggub.v179.5075 .
  6. 1 2 N. J. Gardiner, C. L. Kirkland, J. Hollis, K. Szilas, A. Steenfelt, C. Yakymchuk, H. Heide‑Jørgensen (2019). "Building Mesoarchaean crust upon Eoarchaean roots: the Akia Terrane, West Greenland". Contributions to Mineralogy and Petrology . 174 (3): 20. Bibcode:2019CoMP..174...20G. doi: 10.1007/s00410-019-1554-x . hdl: 10023/18486 . S2CID   134027320.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. ↑ K. Szilas, J. Tusch, J. E. Hoffmann, A. A. Garde, C. Münker (2017). "Hafnium isotope constraints on the origin of Mesoarchaean andesites in southern West Greenland, North Atlantic Craton". Geological Society, London, Special Publications . 449 (1): 19–38. Bibcode:2017GSLSP.449...19S. doi:10.1144/SP449.2. S2CID   132614766 – via Lyell Collection.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  8. ↑ K. Szilas, V. van Hinsberg, I. McDonald, T.Næraa, H. Rollinson, J. Adetunjie, D. Bird (2018). "Highly refractory Archaean peridotite cumulates: Petrology and geochemistry of the Seqi Ultramafic Complex, SW Greenland". Geoscience Frontiers. 9 (3): 689–714. doi: 10.1016/j.gsf.2017.05.003 . ISSN   1674-9871.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. 1 2 3 Waterton, Pedro; Hyde, William R.; Tusch, Jonas; Hollis, Julie A.; Kirkland, Christopher L.; Kinney, Carson; Yakymchuk, Chris; Gardiner, Nicholas J.; Zakharov, David; Olierook, Hugo K. H.; Münker, Carsten (2020). "Geodynamic Implications of Synchronous Norite and TTG Formation in the 3 Ga Maniitsoq Norite Belt, West Greenland". Frontiers in Earth Science . 8: 406. Bibcode:2020FrEaS...8..406W. doi: 10.3389/feart.2020.562062 . hdl: 10023/20744 . ISSN   2296-6463.
  10. 1 2 C. Yakymchuk, C. L. Kirkland, J. A. Hollis, J. Kendrick, N. J. Gardiner, K. Szilas (2020-04-01). "Mesoarchean partial melting of mafic crust and tonalite production during high-T–low-P stagnant tectonism, Akia Terrane, West Greenland". Precambrian Research. 339: 105615. Bibcode:2020PreR..339j5615Y. doi: 10.1016/j.precamres.2020.105615 . hdl: 10023/19439 . ISSN   0301-9268.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  11. 1 2 C. L. Kirkland, C. Yakymchuk, J. Hollisd, H. Heide-Jørgensen, M. Danišík (2018-09-01). "Mesoarchean exhumation of the Akia terrane and a common Neoarchean tectonothermal history for West Greenland". Precambrian Research. 314: 129–144. Bibcode:2018PreR..314..129K. doi: 10.1016/j.precamres.2018.06.004 . ISSN   0301-9268.{{cite journal}}: CS1 maint: multiple names: authors list (link)
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