About the Book
Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Pages: 53. Chapters: Snowball Earth, Neoproterozoic, Rodinia, Ediacaran, Paleoproterozoic, Microbial mat, Trans-Hudson orogeny, Anorthosite, Grenville orogeny, Ottawa-Bonnechere Graben, Midcontinent Rift System, Great Oxygenation Event, Wyoming craton, Columbia, Iapetus Ocean, Doushantuo Formation, Cryogenian, Hebridean Terrane, Gascoyne Complex, Ediacaran type preservation, End-Ediacaran extinction, Great Falls Tectonic Zone, Colorado orogeny, Atlantica, Pannotia, South China, Rhyacian, List of supercontinents, Francevillian Group Fossil, Baltica, Proto-Tethys Ocean, McArthur Basin, Ectasian, Huronian glaciation, Penokean orogeny, Statherian, Orosirian, Siderian, Calymmian, Centralian Superbasin, Stenian, Tonian, Georgina Basin, Grypania, Poseidon Ocean, Sauk sequence, East African Orogeny, Mesoproterozoic, Khanty Ocean, Spavinaw terrane, Nena, Arctica, Pan-African Ocean, Riphean, Southern Province, Nipigon Embayment, Pan-African orogeny, Fox River Belt, Thompson Belt. Excerpt: The Snowball Earth hypothesis posits that the Earth's surface became entirely or nearly entirely frozen at least once, some time earlier than 650 Ma (million years ago). The geological community generally accepts this hypothesis because it best explains sedimentary deposits generally regarded as of glacial origin at tropical paleolatitudes, and other otherwise enigmatic features in the geological record. Opponents of the hypothesis contested the implications of the geological evidence for global glaciation, the geophysical feasibility of an ice- or slush-covered ocean, and the difficulty of escaping an all-frozen condition. There are a number of unanswered questions, including whether the Earth was a full snowball, or a "slushball" with a thin equatorial band of open (or seasonally open) water. The geological time frames under consideration come before the sudde...
