Why Form 2220 Circular 2023-2024

There's no more Earth hypothesis proposes that Earth's surface became almost entirely frozen during the Cryogenian period from about 850 to 630 million years ago. In 1964, Brian Harlan proposed that a global scale glaciation had occurred before the Cambrian period. He based his conclusion on paleomagnetic data showing that glaciers had existed in tropical latitudes. The petrified glacial sediments on opposite sides of the South Atlantic Ocean provided early evidence for continental drift and also supported the Precambrian snowball Earth glaciation hypothesis. In 1969, Mikhail Bedico, a Russian climatologist, published an energy balance model to calculate the effect of ice cover on global climate. Bedico's model predicted that if the ice sheets advanced far enough out of the polar regions, the increased reflectiveness of the ice led to further cooling until the entire Earth was covered with ice. The physical evidence and the computational model firmly established the snowball Earth hypothesis. The world was very different during the time of the snowball Earth. The supercontinent Rodinia formed about 1,100 million years ago and was the dominant landmass for about 350 million years. Geologists generally agree that the east coast of present-day North America, Laurentia, was adjacent to western South America, which then consisted of the Rio de la Plata and ian cratons. The west coast of North America lay next to what is today Australia and Antarctica. Rodinia broke apart during the Cryogenian period from about 750 to 600 million years ago to form the Pan-African mountains and a new supercontinent called Pangea. The Cryogenian period from 850 to 630 million years ago included the breakup of Rodinia. The snowball Earth freezing event caused the mass extinction of 70% of the dominant algae-like sea plants. 650 million years ago, the Cryogenian was followed by the Ediacaran period, during which the supercontinent...