Sturtien

The Sturtian glaciation was a worldwide glaciation during the Cryogenian Period when the Earth experienced repeated large-scale glaciations. , the Sturtian glaciation is thought to have lasted from c. 717 Ma to c. 660 Ma, a time span of approximately 57 million years. It is hypothesised to have been be a Snowball Earth event, or contrastingly multiple regional glaciations, and is the longest and most severe known glacial event preserved in the geologic record. Ultimately, current usage of the term is in reference to the globally significant Sturt Formation (originally Sturtian Tillite) within the Adelaide Superbasin of Australia. The Sturt Formation is named after Sturt Gorge, South Australia; itself named after the Sturt River, which was given its name in April 1831 by British Military Officer Captain Collet Barker, after fellow officer and explorer Charles Sturt. The Sturtian glaciation is an informal, but commonly used name for the older of two worldwide glacial events (the other is known as the Marinoan/Elatina glaciation) preserved in Cryogenian rocks. The term Sturtian was originally defined as a chronostratigraphic unit (Series) and later proposed as an international chronostratigraphic division; however, this has been superseded by international nomenclature. 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. 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. According to Eyles and Young, "Glaciogenic rocks figure prominently in the Neoproterozoic stratigraphy of southeastern Australia and the northern Canadian Cordillera. The Sturtian glaciogenic succession (c. 740 Ma) unconformably overlies rocks of the Burra Group.