Editing Snowball Earth (section)

===Open-water deposits===
It appears that some deposits formed during the snowball period could only have formed in the presence of an active [[Water cycle|hydrological cycle]]. Bands of glacial deposits up to 5,500 meters thick, separated by small (meters) bands of non-glacial sediments, demonstrate that glaciers melted and re-formed repeatedly for tens of millions of years; solid oceans would not permit this scale of deposition.<ref name=Condon2002>{{cite journal
| author = Condon, D.J.
|author2=Prave, A.R. |author3=Benn, D.I. 
| date = 1 January 2002
| title = Neoproterozoic glacial-rainout intervals: Observations and implications
| journal = Geology
| volume = 30
| issue = 1
| pages = 35–38
| doi = 10.1130/0091-7613(2002)030<0035:NGRIOA>2.0.CO;2
|bibcode = 2002Geo....30...35C
}}</ref> It is considered{{by whom|date=June 2015}} possible that [[ice stream]]s such as seen in [[Antarctica]] today could have caused these sequences.
Further, sedimentary features that could only form in open water (for example: [[wave-formed ripples]], far-traveled [[ice-rafted debris]] and indicators of [[Photosynthesis|photosynthetic]] activity) can be found throughout sediments dating from the snowball-Earth periods. While these may represent "[[Oasis|oases]]" of [[meltwater]] on a completely frozen Earth,<ref name=Halverson2004>{{cite journal
| author = Halverson, G.P.
|author2=Maloof, A.C. |author3=Hoffman, P.F. 
| year = 2004
| title = The Marinoan glaciation (Neoproterozoic) in northeast Svalbard
| journal = Basin Research
| volume = 16
| issue = 3
| pages = 297–324
| doi = 10.1111/j.1365-2117.2004.00234.x
| bibcode = 2004BasR...16..297H
|citeseerx=10.1.1.368.2815 |s2cid=53588955 }}</ref> computer modelling suggests that large areas of the ocean must have remained ice-free, arguing that a "hard" snowball is not plausible in terms of energy balance and general circulation models.<ref name="Peltier">
{{cite book
| last= Peltier
| first= W.R.
| editor= Jenkins, G.S.
| editor2= McMenamin, M.A.S.
| editor3= McKey, C.P.
| editor4= Sohl, L.
| title= The Extreme Proterozoic: Geology, Geochemistry, and Climate
| year= 2004 |publisher=American Geophysical union |pages=107–124
| chapter= Climate dynamics in deep time: modeling the "snowball bifurcation" and assessing the plausibility of its occurrence
}}
</ref>