Records of Prior Glaciation
Main article: Timeline of glaciation See also: Ice age and paleoclimatologyGlaciation has been a rare event in Earth's history, but there is evidence of widespread glaciation during the late Paleozoic Era (200 to 300 Ma) and during late Precambrian (i.e. in the Neoproterozoic Era, 600 to 800 Ma). Before the current ice age, which began 2 to 3 Ma, Earth's climate was typically mild and uniform for long periods of time. This climatic history is implied by the types of fossil plants and animals and by the characteristics of sediments preserved in the stratigraphic record. There are, however, widespread glacial deposits, recording several major periods of ancient glaciation in various parts of the geologic record. Such evidence suggests major periods of glaciation prior to the current Quaternary glaciation.
The best documented record of pre-Quaternary glaciation, called the Karoo Ice Age, is found in the late Paleozoic rocks in South Africa, India, South America, Antarctica, and Australia. Exposures of ancient glacial deposits are numerous in these areas. Deposits of even older glacial sediment exist on every continent except South America. These indicate that two other periods of widespread glaciation occurred during the late Precambrian, producing the Snowball Earth during the Cryogenian Period.
Read more about this topic: Quaternary Glaciation
Famous quotes containing the words records of, records and/or prior:
“What a wonderful faculty is memory!the most mysterious and inexplicable in the great riddle of life; that plastic tablet on which the Almighty registers with unerring fidelity the records of being, making it the depository of all our words, thoughts and deedsthis faithful witness against us for good or evil.”
—Susanna Moodie (18031885)
“Philosophy, astronomy, and politics were marked at zero, I remember. Botany variable, geology profound as regards the mud stains from any region within fifty miles of town, chemistry eccentric, anatomy unsystematic, sensational literature and crime records unique, violin player, boxer, swordsman, lawyer, and self-poisoner by cocaine and tobacco.”
—Sir Arthur Conan Doyle (18591930)
“As humans have a prior right to existence over dogs by virtue of being more highly evolved and having a superior consciousness, so women have a prior right to existence over men. The elimination of any male is, therefore, a righteous and good act, an act highly beneficial to women as well as an act of mercy.”
—Valerie Solanas (b. 1940)