Estimate ofProterozoic glacial periods.[1][2][a] Vertical axis: millions of years ago
TheSturtian glaciation, also known as theSturt glaciation, was a worldwideglaciation during theCryogenianPeriod when the Earth experienced repeated large-scale glaciations. The Sturtian glaciation is thought to have lasted from c. 717Ma to c. 660 Ma, a time span of approximately 57 million years. It is hypothesised to have been aSnowball Earth event, or contrastingly multiple regional glaciations, and is the longest and most severe known glacial event preserved in thegeologic record after the much earlierHuronian glaciation.
Ultimately, current usage of the term is in reference to the globally significant Sturt Formation (originally Sturtian Tillite)[3] within theAdelaide Superbasin of Australia. The Sturt Formation is named afterSturt Gorge,South Australia;[4][5] itself named after theSturt River, which was given its name in April 1831 by British Military OfficerCaptain Collet Barker,[6] after fellow officer and explorerCharles Sturt.[7]
The Sturtian glaciation, also known as Sturt glaciation,[8] is an informal, but commonly used name for the older of two worldwide glacial events (the other is known as theMarinoan/Elatina glaciation) preserved in Cryogenian rocks.[4][9][10] The term Sturtian was originally defined byDouglas Mawson andReg Sprigg in 1950 as achronostratigraphic unit (Series),[11] and later proposed as aninternational chronostratigraphic division;[12] however, this has been superseded by international nomenclature.[further explanation needed] The suggestion of the glacial nature of the Sturt Formation during the early 20th century resulted in discussion about Neoproterozoic glaciations (thought to be Cambrian at the time) and encouraged the research that eventually resulted in the Snowball Earth hypothesis.[4][13]
Rocks preserving evidence for the Sturtian Glaciation are found on every continent. Notable sections are found in Australia, Canada, China, Ethiopia, Namibia, Siberia, and Svalbard.[citation needed]
According to Eyles and Young, "Glaciogenic rocks figure prominently in theNeoproterozoicstratigraphy of southeastern Australia and the northernCanadian Cordillera. The Sturtian glaciogenic succession (c. 740Ma)unconformably overlies rocks of the Burra Group." The Sturtian succession includes two majordiamictite-mudstone sequences which represent glacial advance and retreat cycles. It is stratigraphically correlated with the Rapitan Group of North America.[14]
Reusch's Moraine in northern Norway may have been deposited during this period.[15]
In 2024 researchers at the University of Adelaide and University of Sydney, using a combination of known geological formations from the Cryogenian Period and plate tectonic modelling, usingEarthByte computer models, proposed the low temperature was the result of low levels of CO2 degassing along mid-ocean ridges, the result of the break-up of the supercontinentRodinia.[16]
The duration of the ice sheet advance at the start of the Sturtian glaciation lasted for less than a million years.[17]
^Dating of pre-Gaskiers glaciations is uncertain. As for theKaigas, its very existence is doubted by some. TheHuronian glaciation is not shown; there is a lack of any significant evidence for a Snowball Earth during the time period.
^Arnaud, Emmanuelle; Halverson, Galen P.; Shields-Zhou, Graham Anthony (30 November 2011). "Chapter 1: The geological record of Neoproterozoic ice ages".Geological Society, London, Memoirs.36 (1):1–16.doi:10.1144/M36.1.
^Mawson, Douglas; Sprigg, Reginald (1950). "Subdivision of the Adelaide System".Australian Journal of Science.13 (3):69–72.
