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Coordinates: 63°56′23″N 51°40′29″W / 63.93972°N 51.67472°W / 63.93972; -51.67472
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{{Short description|Island in southwestern Greenland}}
{{TOCright}}
{{Infobox islands
'''Akilia Island''' is in West [[Greenland]], about 22 kilometers south of [[Nuuk]] (Godthåb), at {{coor d|63.933|N|51.667|W|type:isle}}. Akilia is the location of a controversial rock outcropping that some geologists believe contains the oldest known [[sedimentary rock]]s on Earth, and perhaps the oldest evidence of [[life on Earth]].
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| image_map_caption = Map of Akilia Island
| pushpin_map = Greenland
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| pushpin_map_caption = Location of the Akilia Island in Greenland
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| country_admin_divisions_title = [[Administrative divisions of Greenland|Municipality]]
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'''Akilia Island''' is an island in southwestern [[Greenland]], about 22 kilometers south of [[Nuuk]]. Akilia is the location of a rock formation that has been proposed to contain the oldest known [[sedimentary rock]]s on Earth,<ref>
McGregor, VR, Mason, B (1977 ''Petrogenesis and geochemistry of metabasaltic and metasedimentary enclaves in the Amîtsoq gneisses, West Greenland''. American Mineralogist, v. 62, p. 887-904</ref><ref>Nutman AP, Mojzsis, SJ, Friend, CRL (1997) ''Recognition of ≥3850 Ma water-lain sediments in West Greenland and their significance for the early Archaean Earth''. Geochimica et Cosmochimica Acta, v. 61, p. 2475-2484.
</ref> and perhaps the oldest evidence of [[life|life on Earth]].<ref name=mojzsis>Mojzsis, SJ, Arrhenius, G, McKeegan, KD, Harrison, TM, Nutman, AP, Friend, CRL (1996) ''Evidence for life on Earth before 3,800 million years ago''. Nature, v. 384, p. 55-59</ref>


==Geology==
==Geology==
The rocks in question are part of a [[metamorphism|metamorphosed]] [[supracrustal]] sequence located at the south-western tip of the island. The sequence has been dated as no younger than 3.8 billion years old, placing them in the [[Hadean]] eon, based on the age of an [[igneous]] band that cuts the rock (Manning et al., 2006). The supracrustal sequence contains layers of iron-rich rocks, variously interpreted as [[Banded iron formation]], chemical sediments from hot springs, or vein deposits. [[Carbon]] in the rock, present as [[graphite]], shows low levels of [[carbon-13]] (Mojzsis et al., 1996), which may suggest an origin as [[stable isotope|isotopically]] light organic matter derived from living organisms (Schidlowski, 1988). However, this interpretation is complicated because the Akilia rocks have undergone high-temperature [[metamorphism]]. The sedimentary origin, age and the carbon content of the rocks have been questioned (Myers and Crowley, 2000; Fedo and Whitehouse, 2002; Lepland et al, 2005).
The rocks in question are part of a [[metamorphism|metamorphosed]] [[supracrustal]] sequence located at the south-western tip of the island. The sequence has been dated as no younger than 3.85 billion years old - that is, in the [[Hadean]] eon - based on the age of an [[igneous]] band that cuts the rock.<ref>Manning, CE, Mojzsis, SJ, Harrison, TM (2006) ''Geology, age and origin of supracrustal rocks at Akilia, West Greenland''. American Journal of Science, v. 206, p. 303-366</ref> The supracrustal sequence contains layers rich in [[Iron(II) oxide|iron]] and [[Silicon dioxide|silica]], which are variously interpreted as [[banded iron formation]], chemical sediments from [[Black smoker|submarine hot springs]], or [[Hydrothermal circulation|hydrothermal]] vein deposits. [[Carbon]] in the rock, present as [[graphite]], shows low levels of [[carbon-13]],<ref name="mojzsis" /> which may suggest an origin as [[stable isotope|isotopically]] light organic matter derived from living organisms.<ref>Schidlowski, M (1988) ''A 3,850-Million-Year Isotopic Record of Life From Carbon in Sedimentary-Rocks''. Nature, v. 333, p. 313-318</ref>
However, this interpretation is complicated because of high-grade [[metamorphism]] that affected the Akilia rocks after their formation. The sedimentary origin, age and the carbon content of the rocks have been questioned.<ref>Myers, JS, Crowley, JL (2000) ''Vestiges of life in the oldest Greenland rocks? A review of early Archean geology in the Godthåbsfjord region, and reappraisal of field evidence for >3850 Ma life on Akilia''. Precambrian Research, v. 103, p. 101-124.</ref><ref>
Fedo, CM, Whitehouse, MJ (2002) ''Metasomatic origin of quartz-pyroxene rock, Akilia, Greenland, and implications for Earth's earliest life''. Science, v. 296, p. 1448-1452</ref><ref>Lepland, A, van Zuilen, M, Arrhenius, G, Whitehouse, M, Fedo, C (2005) ''Questioning the evidence for Earth's earliest life—Akilia revisited''. Geology, v. 33, p. 77-79</ref>


If the Akilia rocks do show evidence of life at 3.8 Ga, it would challenge models which suggest that Earth would not be hospitable to life at this time. Research is ongoing.
If the Akilia rocks do show evidence of life by 3.85 Ga, it would challenge models which suggest that Earth would not be hospitable to life at this time.


==See also==
==See also==
*[[List of islands of Greenland]]
*[[Origin of life]]
*[[Origin of life]]


==References==
==References==
<references/>
*Fedo, C. M., and Whitehouse M. J., 2002, Metasomatic origin of quartz-pyroxene rock, Akilia, Greenland, and implications for Earth's earliest life. "Science," v. 296, p. 1448-1452.
*Lepland, A., van Zuilen, M., Arrhenius, G., Whitehouse, M., and Fedo, C., 2005. Questioning the evidence for Earth's earliest life—Akilia revisited. ''Geology,'' v. 33, p. 77-79.
*Manning, C. E., Mojzsis, S. J., and Harrison, T. M., 2006. Geology, age and origin of supracrustal rocks at Akilia, West Greenland. ''American Journal of Science,'' v. 306, p. 303-366.
*Mojzsis, S. J., Arrhenius, G., McKeegan, K. D., Harrison, T. M., Nutman, A. P., and Friend, C. R. L., 1996. Evidence for life on Earth before 3,800 million years ago. ''Nature,'' v. 384, p. 55-59.
*Myers, J. S., and Crowley, J. L., 2000. Vestiges of life in the oldest Greenland rocks? A review of early Archean geology in the Godthåbsfjord region, and reappraisal of field evidence for >3850 Ma life on Akilia. ''Precambrian Research,'' v. 103, p. 101-124.
*Schidlowski, M., 1988. A 3,800-Million-Year Isotopic Record of Life From Carbon in Sedimentary-Rocks. ''Nature,'' v. 333, p. 313-318.


==External links==
==External links==
* [http://www.space.com/scienceastronomy/generalscience/oldest_life_021014.html Scientists Disagree over How, When Life Began on Earth]
* [https://web.archive.org/web/20050307112059/http://www.space.com/scienceastronomy/generalscience/oldest_life_021014.html Scientists Disagree over How, When Life Began on Earth]
* [http://www.explorenorth.com/library/communities/bl-nuuk.htm Information on Nuuk, Greenland]
* [https://web.archive.org/web/20050225061248/http://www.explorenorth.com/library/communities/bl-nuuk.htm Information on Nuuk, Greenland]
* [http://www.sciencedaily.com/releases/2004/12/041219171437.htm Study Resolves Doubt About Origin Of Earth’s Oldest Rocks, Possibility Of Finding Traces Of Ancient Life]
* [https://www.sciencedaily.com/releases/2004/12/041219171437.htm Study Resolves Doubt About Origin Of Earth’s Oldest Rocks, Possibility Of Finding Traces Of Ancient Life]
* [http://www.eurekalert.org/pub_releases/2006-07/uoc--uss072006.php ''UCLA scientists strengthen case for life more than 3.8 billion years ago'']
* [http://www.eurekalert.org/pub_releases/2006-07/uoc--uss072006.php ''UCLA scientists strengthen case for life more than 3.8 billion years ago'']


[[Category:Geology of Greenland]]
[[Category:Islands of Greenland]]
[[Category:Islands of Greenland]]
[[Category:Origin of life]]
[[Category:Origin of life]]
[[Category:Archaean]]
[[Category:Archean]]

Latest revision as of 12:31, 25 September 2023

Akilia Island
Map
Map of Akilia Island
Akilia Island is located in Greenland
Akilia Island
Akilia Island
Location of the Akilia Island in Greenland
Geography
Coordinates63°56′23″N 51°40′29″W / 63.93972°N 51.67472°W / 63.93972; -51.67472
Adjacent toDavis Strait
Area138 ha (340 acres)
Administration
MunicipalitySermersooq
Demographics
Population0 (2023)
Pop. density0/km2 (0/sq mi)

Akilia Island is an island in southwestern Greenland, about 22 kilometers south of Nuuk. Akilia is the location of a rock formation that has been proposed to contain the oldest known sedimentary rocks on Earth,[1][2] and perhaps the oldest evidence of life on Earth.[3]

Geology

[edit]

The rocks in question are part of a metamorphosed supracrustal sequence located at the south-western tip of the island. The sequence has been dated as no younger than 3.85 billion years old - that is, in the Hadean eon - based on the age of an igneous band that cuts the rock.[4] The supracrustal sequence contains layers rich in iron and silica, which are variously interpreted as banded iron formation, chemical sediments from submarine hot springs, or hydrothermal vein deposits. Carbon in the rock, present as graphite, shows low levels of carbon-13,[3] which may suggest an origin as isotopically light organic matter derived from living organisms.[5] However, this interpretation is complicated because of high-grade metamorphism that affected the Akilia rocks after their formation. The sedimentary origin, age and the carbon content of the rocks have been questioned.[6][7][8]

If the Akilia rocks do show evidence of life by 3.85 Ga, it would challenge models which suggest that Earth would not be hospitable to life at this time.

See also

[edit]

References

[edit]
  1. ^ McGregor, VR, Mason, B (1977 Petrogenesis and geochemistry of metabasaltic and metasedimentary enclaves in the Amîtsoq gneisses, West Greenland. American Mineralogist, v. 62, p. 887-904
  2. ^ Nutman AP, Mojzsis, SJ, Friend, CRL (1997) Recognition of ≥3850 Ma water-lain sediments in West Greenland and their significance for the early Archaean Earth. Geochimica et Cosmochimica Acta, v. 61, p. 2475-2484.
  3. ^ a b Mojzsis, SJ, Arrhenius, G, McKeegan, KD, Harrison, TM, Nutman, AP, Friend, CRL (1996) Evidence for life on Earth before 3,800 million years ago. Nature, v. 384, p. 55-59
  4. ^ Manning, CE, Mojzsis, SJ, Harrison, TM (2006) Geology, age and origin of supracrustal rocks at Akilia, West Greenland. American Journal of Science, v. 206, p. 303-366
  5. ^ Schidlowski, M (1988) A 3,850-Million-Year Isotopic Record of Life From Carbon in Sedimentary-Rocks. Nature, v. 333, p. 313-318
  6. ^ Myers, JS, Crowley, JL (2000) Vestiges of life in the oldest Greenland rocks? A review of early Archean geology in the Godthåbsfjord region, and reappraisal of field evidence for >3850 Ma life on Akilia. Precambrian Research, v. 103, p. 101-124.
  7. ^ Fedo, CM, Whitehouse, MJ (2002) Metasomatic origin of quartz-pyroxene rock, Akilia, Greenland, and implications for Earth's earliest life. Science, v. 296, p. 1448-1452
  8. ^ Lepland, A, van Zuilen, M, Arrhenius, G, Whitehouse, M, Fedo, C (2005) Questioning the evidence for Earth's earliest life—Akilia revisited. Geology, v. 33, p. 77-79
[edit]
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