Marinoan glaciation

The name is derived from the stratigraphic terminology of the Adelaide Superbasin (Adelaide Rift Complex) in South Australia and is taken from the Adelaide suburb of Marino. The term Marinoan Series was first used in a 1950 paper by Douglas Mawson and Reg Sprigg to subdivide the Neoproterozoic rocks of the Adelaide area, and encompassed all strata from the top of the Brighton Limestone to the base of the Cambrian. The corresponding time period, referred to as the Marinoan Epoch, spanned from the middle Cryogenian to the top of the Ediacaran in modern terminology. Mawson recognised a glacial episode within the Marinoan Epoch which he referred to as the Elatina glaciation after the Elatina Tillite (now Elatina Formation) where he found the evidence. Recently, there has been a move to return to the term Elatina glaciation in South Australia because of uncertainties regarding global correlation and because an Ediacaran glacial episode (Gaskiers) also occurs within the wide-ranging Marinoan Epoch.{{cite journal == Cryogenian Snowball Earth ==

Emerging evidence suggests that the Earth underwent a number of glaciations during the Neoproterozoic era. The Earth may not have been fully covered in ice, as some computer simulations show an extreme slowdown of the hydrological cycle that inhibited new glacial formation before the Earth was fully ice-covered. The melting of the Snowball Earth is associated with greenhouse warming due to the accumulation of high levels of carbon dioxide in the atmosphere. Deglaciation likely started in the mid-latitudes, as in the tropics, the intense hydrological cycle replenished snow rapidly. As the mid-latitudes became ice free, dust was blown from them into other regions, lowering albedo and speeding up deglaciation. == Evidence ==

GSSP site in the Flinders Ranges NP, South Australia. A$1 coin for scale. of the Neoproterozoic Pocatello Formation, a 'Snowball Earth'—type deposit Even though much evidence has been lost through geological changes, field investigations show evidence of the Marinoan glaciation in China, Svalbard archipelago and South Australia. In Guizhou Province, China, glacial rocks were found to be underlying and overlying a layer of volcanic ashes which contained zircon minerals, which could be dated through radioisotopes. Glacial deposits in South Australia are approximately the same age (about 630 Ma), confirmed by similar stable carbon isotopes, mineral deposits (including sedimentary baryte), and other unusual sedimentary structures. In Uruguay, evidence of the Marinoan glaciation is known from dropstones, diamictites, rhythmites, clast layers, and varve-like deposits. == Effects on life ==

The survival of benthic macroalgae indicates that there remained areas of suitable habitat for them in the photic zone along the coasts of mid-latitude continents during the Marinoan glaciation. == See also ==