KeywordsPaleoproterozoic Ice ages Snowball earth Rise of atmospheric oxygen
The Huronian glaciation is the oldest series of protracted climatic refrigeration events that extensively affected Earth. It occurred between 2.45 and 2.22 Ga in association with the rise of atmospheric oxygen. Three glaciations of that series, the classical Huronian ice ages, are bracketed in time between ~2.45 and 2.32 Ga; the fourth event, recognized so far only in South Africa, is ~2.22 Ga in age. During these events, glaciers covered continents, extended to low latitudes, and reached to sea level. The ice ages were followed by a protracted time interval with greenhouse (warm and humid) conditions. The name is derived from the Huronian Supergroup exposed on the north shore of Lake Huron in Ontario, Canada, between Sault Ste. Marie, Sudbury, and Cobalt.
The Huronian glacial deposits were first recognized by Coleman (1907) in the northeastern part of the Huronian Basin in Ontario, Canada; just a year after a poorly sorted conglomerate with scattered pebbles and cobbles, some striated and faceted, was described in the Northern Cape Province of South Africa by Rogers (1906), who interpreted it to be glacial in origin. Almost 40 years later, Pettijohn (1943) described tillite in a correlative to the Huronian Supergroup succession of Michigan, USA. Young (1970) inferred glacial influence on Paleoproterozoic successions in Wyoming, Michigan, Quebec, and Nunavut. Shortly thereafter, Paleoproterozoic glacial deposits were for the first time recognized in Western Australia (Trendall 1976) and described in more details in South Africa (Visser 1971). Although the presence of Paleoproterozoic glacial deposits in Fennoscandia was originally discussed by Eskola (1919), they were not described and documented in detail until recently (Marmo and Ojakangas 1984; Strand and Laajoki 1993). In Antarctica, the 2.45–2.5 Ga Ruker Series contains diamictite above thick banded iron formation associated with mafic volcanics (Mikhalsky et al. 2006; Phillips et al. 2006), offering a comparison with the Meteorite Bore Member of the Turee Creek Group in the Hamersley Province of Western Australia (see below). All other reported cases of Paleoproterozoic glacial deposits were either not confirmed by subsequent sedimentologic studies or turned out to be significantly younger and not correlative with the Huronian glaciation.
Large igneous provinces were extensively emplaced before (2.5–2.45 Ga) and after (ca. 2.22 Ga) the Huronian glaciation, but with the exception of the ca. 2.32 Ga superplume event, the 2.45–2.22 Ga time interval is largely devoid of magmatic activity (cf. Partin et al. 2014). Tuff beds dated in the Huronian Supergroup, Canada, and the Pretoria Group, South Africa (Rasmussen et al. 2013), have finally bracketed the age of the Paleoproterozoic ice ages (Fig. 3). Three Huronian glaciations are all between ca. 2.45 and 2.32 Ga in age, whereas the youngest glaciation recorded by the upper Pretoria Group is ca. 2.22 Ga in age. These data allow two tantalizing implications: (1) The Huronian ice ages lasted long; (2) there was a glacial event at ca. 2.22 Ga in South Africa, which has not yet been recognized anywhere else in the world. The Makganyene Diamictite of the Postmasburg Group of the Griqualand West basin (paleomagnetically pinned to low paleolatitudes; Evans et al. 1997) was recently geochronologically bracketed between ~2.46 and 2.43 Ga in age (see Fig. 3; Gumsley et al. 2015), potentially providing the best age constraint for the beginning of the GOE. Correlation of the glacial diamictite of the Meteorite Bore Member of the Turee Creek Group with the Huronian glacials remains uncertain; considering that the retro-arc setting of the Turee Creek Group evolved from a conformably underlying back-arc basin containing 2.5–2.45 Ga banded iron formations (e.g., Krapež 1996), the most parsimonious interpretation is that it represents the oldest Huronian ice age.
References and Further Reading
- Eskola PE (1919) Hufvuddragen av Onega-Karelens geology: Helsingin Geol. Yhd. Tiedonantoja 1917 u. 1918, pp 13–18, and Teknikern, vol 29, pp 37–39Google Scholar
- Gumsley AP, Chamberlain K, Bleeker W, Söderlund U, de Kock MO, Kampmann TC, Larsson E (2015) U-Pb TIMS and in-situ SIMS dating of baddeleyite and zircon from sub-volcanic sills of the Ongeluk Formation (Transvaal Supergroup) in the Griqualand West sub-basin, Kaapvaal Craton, with implications for Snowball Earth and the Great Oxygenation Event. AGU-GAC-MAC-CGU Joint Assembly 2015 Program with Abstracts.Google Scholar
- Rogers AW (1906) The glacial beds in the Griqua Town Series. Rep S Afr Assoc Adv Sci 4:261–265Google Scholar
- Trendall AF (1976) Striated and faceted boulders from the Turee Creek Formation – evidence for a possible Huronian glaciation on the Australian continent. Geol Surv West Aust Annu Rep 1975:88–92Google Scholar
- Visser JNJ (1971) The deposition of the Griquatown glacial member in the Transvaal Supergroup. Trans Geol Soc S Afr 74:187–199Google Scholar
- Young GM (2004) Earth’s earliest glaciations: tectonic setting and stratigraphic context of Paleoproterozoic glaciogenic deposits. In: Jenkins GS, McMenamin MAS, McKay CP, Sohl L (eds) The extreme Proterozoic: geology, geochemistry, and climate, AGU geophysical monograph series. American Geophysical Union, Washington, DC, 146, pp 161–181Google Scholar