Huronian glaciation

Artist's impression of the "snowball Earth" interpretation of the Huronian glaciation, with ice covering the whole planet.

The Huronian glaciation (or Makganyene glaciation) refers to the period encompassing three ice ages which occurred on the ancient Earth, during the deposition of the eponymous Huronian Supergroup. This largely sedimentary succession was laid down from around 2.4 to 2.1 billion years ago, during the Siderian and Rhyacian periods of the Paleoproterozoic era. Evidence for glaciation is mainly derived from the presence of diamictites within the sequence, a rock that is understood to be of glacial origin. The Huronian glaciation broadly coincides with the Great Oxygenation Event, with changes in atmospheric composition under the fainter, younger sun likely leading to the cooler global climate which allowed ice to form.

Discovery and name

In 1907, Arthur Coleman first inferred a "lower Huronian ice age" from analysis of a geological formation near Lake Huron in Ontario. In his honour, the lower (glacial) member of the Gowganda Formation is referred to as the Coleman member. These rocks have been studied in detail by numerous geologists and are considered to represent the type example of a Paleoproterozoic glaciation.

The glacial period is also known as the Makganyene glaciation, named after the Makganyene Formation in South Africa which exhibits some similarities, most notably in the deposition of numerous diamictites.

The confusion of the terms glaciation and ice age has led to the more recent impression that the entire time period represents a single glacial event with continuous ice coverage. The term "Huronian" was used to describe a lithostratigraphic supergroup and according to The North American Stratigraphic Code should not be used to describe glacial cycles. Diachronic or geochronometric units should be used according to the code.

Geological context

The three glacial diamictite-bearing units of the Huronian are, from the oldest to youngest, the Ramsay Lake, Bruce, and Gowganda formations. The Huronian is named after the region north of Lake Huron, between Sault Ste. Marie, Ontario, and Rouyn-Noranda, Quebec. The Gowganda Formation (2.3 Bya) contains "the most widespread and most convincing glaciogenic deposits of this era", according to Eyles and Young. In North America, similar-age deposits are exposed in Michigan, the Medicine Bow Mountains, Wyoming, Chibougamau, Quebec, and central Nunavut. Globally, glacial deposits of a roughly comparable age occur in the Makganyene Formation of the Griquatown Basin in South Africa, as well as India and Australia.

Due to the global distribution of these deposits, it was theorized that one or more of the glaciations may have been snowball Earth events, when all or most of Earth's surface was covered in ice. This theory went on to shape public perception of the period, however determining the original location of these rocks so far back in time is extremely difficult. The palaeomagnetic evidence which could suggest ice sheets were present at low latitudes is contested, and the glacial sediments (diamictites) are discontinuous, alternating with carbonate and other sedimentary rocks indicating temperate climates, providing scant evidence for global glaciation.

Relationship to the Great Oxidation Event

Before the Huronian glaciation and the Great Oxidation Event, most organisms were anaerobic microbes, relying on chemosynthesis and retinal-based anoxygenic photosynthesis for production of biological energy and biocompounds. This changed once cyanobacteria evolved porphyrin-based oxygenic photosynthesis, which produced dioxygen as a waste product. At first, most of this oxygen was dissolved in the ocean and absorbed through the oxidation of reduced surface ferrous compounds, atmospheric methane and hydrogen sulfide. Eventually though, these sinks were saturated and free oxygen accumulated in the atmosphere, leading to a permanent change in the atmospheric chemistry of the Earth.

This atmospheric shift led to changes in the Earth's energy balance. Now-abundant oxygen reacted with methane to form carbon dioxide and water, both much weaker greenhouse gases, greatly reducing the potency of the greenhouse effect, especially as water vapor readily precipitated out of the air with dropping temperature. This caused an icehouse state, compounded by the lower solar irradiation at the time as well as potentially reduced geothermal activity.[citation needed] Extensive ice coverage led to the deposition of glacial rocks in multiple sequences across the globe, including what would become the Huronian Supergroup. The combination of increasing free oxygen (which causes oxidative damage to organic compounds) and climate change may have caused an extinction event, which would have wiped out most of the anaerobe-dominated microbial mats both on the Earth's surface and in shallow seas.

See also

References

  1. ↑ Tang, Haoshu; Chen, Yanjing (1 September 2013). "Global glaciations and atmospheric change at ca. 2.3 Ga". Geoscience Frontiers. 4 (5): 583–596. Bibcode:2013GeoFr...4..583T. doi:10.1016/j.gsf.2013.02.003.
  2. ↑ Coleman, A. P. (1 March 1907). "A lower Huronian ice age". American Journal of Science. s4-23 (135): 187–192. Bibcode:1907AmJS...23..187C. doi:10.2475/ajs.s4-23.135.187. ISSN 0002-9599.
  3. ↑ Bekker, Andrey (2014). "Huronian Glaciation". Encyclopedia of Astrobiology. pp. 1–8. doi:10.1007/978-3-642-27833-4_742-4. ISBN 978-3-642-27833-4.
  4. ↑ Young, Grant M. (April 1970). "An extensive early proterozoic glaciation in North America?". Palaeogeography, Palaeoclimatology, Palaeoecology. 7 (2): 85–101. Bibcode:1970PPP.....7...85Y. doi:10.1016/0031-0182(70)90070-2.
  5. ↑ Nesbitt, H. W.; Young, G. M. (October 1982). "Early Proterozoic climates and plate motions inferred from major element chemistry of lutites". Nature. 299 (5885): 715–717. Bibcode:1982Natur.299..715N. doi:10.1038/299715a0. ISSN 0028-0836. S2CID 4339149.
  6. ↑ Heron, D.; Busfield, M.; Smith, A.; Wimmer, S. (28 September 2022). "A grounding zone wedge origin for the Palaeoproterozoic Makganyene Formation of South Africa". Frontiers in Earth Science. 10.
  7. 1 2 3 Kopp, Robert (14 June 2005). "The Paleoproterozoic snowball Earth: A climate disaster triggered by the evolution of oxygenic photosynthesis". PNAS. 102 (32): 11131–11136. Bibcode:2005PNAS..10211131K. doi:10.1073/pnas.0504878102. PMC 1183582. PMID 16061801.
  8. ↑ "NORTH AMERICAN STRATIGRAPHIC CODE: North American Commission on Stratigraphic Nomenclature" (PDF). AAPG Bulletin. 89 (11): 1547–1591. November 2005. doi:10.1306/07050504129. ISSN 0149-1423.
  9. ↑ Bekker, Andrey (2020), "Huronian Glaciation", in Gargaud, Muriel; Irvine, William M.; Amils, Ricardo; Claeys, Philippe (eds.), Encyclopedia of Astrobiology, Berlin, Heidelberg: Springer, pp. 1–9, doi:10.1007/978-3-642-27833-4_742-5, ISBN 978-3-642-27833-4, S2CID 245528915
  10. 1 2 Eyles, Nicholas; Young, Grant (1994). Deynoux, M.; Miller, J.M.G.; Domack, E.W.; Eyles, N.; Fairchild, I.J.; Young, G.M. (eds.). Geodynamic controls on glaciation in Earth history, in Earth's Glacial Record. Cambridge: Cambridge University Press. pp. 3–5. ISBN 978-0-521-54803-8.
  11. ↑ Rasmussen, Birger; et al. (5 November 2013). "Correlation of Paleoproterozoic glaciations based on U–Pb zircon ages for tuff beds in the Transvaal and Huronian Supergroups". Earth and Planetary Science Letters. 382: 173–180. Bibcode:2013E&PSL.382..173R. doi:10.1016/j.epsl.2013.08.037.
  12. ↑ Kurucz, Sophie; et al. (October 2021). "Earth's first snowball event: Evidence from the early Paleoproterozoic Huronian Supergroup". Precambrian Research. 365 106408. Bibcode:2021PreR..36506408K. doi:10.1016/j.precamres.2021.106408. S2CID 244217078.
  13. ↑ Danishevska, Kateryna. "Nearly killing all life and freezing Earth: When oxygen almost destroyed planet". RBC Ukraine. Retrieved 22 October 2026.
  14. ↑ Williams, George E.; Schmidt, Phillip W. (2 December 1997). "Paleomagnetism of the Paleoproterozoic Gowganda and Lorrain formations, Ontario: low paleolatitude for Huronian glaciation". Earth and Planetary Science Letters. 153 (3): 157–169. Bibcode:1997E&PSL.153..157W. doi:10.1016/S0012-821X(97)00181-7. ISSN 0012-821X.
  15. ↑ Kopp, Robert E.; Kirschvink, Joseph L.; Hilburn, Isaac A.; Nash, Cody Z. (9 August 2005). "The Paleoproterozoic snowball Earth: A climate disaster triggered by the evolution of oxygenic photosynthesis". Proceedings of the National Academy of Sciences. 102 (32): 11131–11136. Bibcode:2005PNAS..10211131K. doi:10.1073/pnas.0504878102. ISSN 0027-8424. PMC 1183582. PMID 16061801.
  16. ↑ EPA.gov page "Understanding Global Warming Potentials"
  17. ↑ "Geologists uncover ancient mass extinction from 2 billion years ago". 5 September 2019.
  18. ↑ Plait, Phil (28 July 2014). "When a Species Poisons an Entire Planet". Slate Magazine. Retrieved 16 March 2022.