Original sentence: In a slushball scenario a band of ice-free, or ice-thin, waters remains around the equator, allowing for a continued hydrologic cycle.Many other features of the sedimentary record are easily explained by extensive glacial cover.Sedimentary features usually formed by glaciers, found in what may have been equatorial locations at the time of deposition, have been taken as evidence implying global ice cover.Snowball Earth remains controversial, and is contested by various scientists who dispute both the geophysical feasibility of a completely frozen ocean, or the geological evidence upon which the hypothesis is based.This appeals to scientists who believe that certain features of the sedimentary record can only be explained by rapidly moving ice, which would require somewhere ice free to move to, or that observed sedimentary structures could only form below open water.Whilst the presence of glaciers is not disputed, the idea that the entire planet was covered in ice is more contentious, leading some scientists to prefer a "slushball" to a "snowball"
Edited sentence: Certain forms of sedimentary deposit, such as banded iron formations and cap carbonates, are very unusual and are hard to explain without invoking an extreme glacial event.In a slushball scenario a band of ice-free, or ice-thin, waters remains around the equator allowing for a continued hydrologic cycle.Many other features of the sedimentary record are most easily explained by extensive glacial cover.Sedimentary features usually formed by glaciers, found in what were equatorial locations at the time of deposition, have been taken as evidence implying global ice cover.Snowball Earth remains controversial, and is contested by various scientists who dispute either the geophysical feasibility of a completely frozen ocean, or the geological evidence upon which the hypothesis is based.This appeals to scientists who believe that certain features of the sedimentary record can only be explained by rapidly moving ice, which would require ice-free space to flow to, or that observed sedimentary structures could only form below open water.Whilst extensive glacial cover is accepted, the idea that the entire planet was covered in ice is more contentious leading some scientists to prefer a "slushball" to a "snowball"