Snowball Earth Theory Essay

As previously mentioned, the original purpose of the Snowball Earth theory was to explain the existence of glacial deposits at land masses which were found to be located at tropical latitudes at the time of deposition. According to (Eyles, 2004), the evidence of the validity of the theory must prove two main points which are:

1- The glacial deposits found in a sedimentary bed must have been created only by glacial activity (i.e. possibility of a non-glacial factor being responsible for the deposition is not accepted).

2- The sedimentary bed must be located within the tropics when it was deposited.

Eyles (2004) also mentions that during the period of glaciations, it must be proved that glaciers were the only active depositional factors at different global locations (i.e. no presence of non glacial deposits at the same age). Eyles (2004) continues that proving this point is very difficult due to the absence of bio-straitographic markers usually used to correlated rocks before the Ediacaran.

Several hypotheses were suggested to prove the Snow ball Earth theory, some of them are mentioned below:

3.1 Paleomagnetism

According to Butler (1992), Paleomagnetism refers to the study

For such formations to be deposited there would have to be anoxia in the ocean in order for dissolved iron to accumulate before it precipitates as ferric oxide after meeting an oxide. An ocean must have limited gas exchange with the oxygenated atmosphere in order to become anoxcic. It is worth of noting that limited oxygen levels in an ocean sealed or covered by ice offers suitable conditions for such formation deposition (Kirschvink, 1992). Proponents of the Snowball Earth theory argue that the existence of banded iron formations in the sedimentary record at tropical locations is due to the ice coverage of the