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A less severe cold period or ice age is shown during the Jurassic-Cretaceous (150 Ma). There have been five or six major ice ages in the history of Earth over the past 3 billion years. The Late Cenozoic Ice Age began 34 million years ago, its latest phase being the Quaternary glaciation, in progress since 2.58 million years ago.
Areas of study within glaciology include glacial history and the reconstruction of past glaciation. A glaciologist is a person who studies glaciers. A glacial geologist studies glacial deposits and glacial erosive features on the landscape. Glaciology and glacial geology are key areas of polar research.
Andean-Saharan glaciation: 360–260: Karoo Ice Age: 305: Cooler climate causes Carboniferous rainforest collapse: 251.9: Permian–Triassic extinction event: 199.6: Triassic–Jurassic extinction event, causes as yet unclear 66: Perhaps 30,000 years of volcanic activity form the Deccan Traps in India, or a large meteor impact. 66
Glaciation has been a rare event in Earth's history, [44] but there is evidence of widespread glaciation during the late Paleozoic Era (300 to 200 Ma) and the late Precambrian (i.e., the Neoproterozoic Era, 800 to 600 Ma). [45] Before the current ice age, which began 2 to 3 Ma, Earth's climate was typically mild and uniform for long periods of ...
The Sturtian glaciation persisted from 720 to 660 million years ago, and the Marinoan glaciation which ended approximately 635 Ma, at the end of the Cryogenian. [12] The deposits of glacial tillite also occur in places that were at low latitudes during the Cryogenian, a phenomenon which led to the hypothesis of deeply frozen planetary oceans ...
Reconstruction of the past 5 million years of climate history, based on oxygen isotope fractionation in deep sea sediment cores (serving as a proxy for the total global mass of glacial ice sheets), fitted to a model of orbital forcing (Lisiecki and Raymo 2005) [2] and to the temperature scale derived from Vostok ice cores following Petit et al. (1999).
The National Science Board's Patterns and Perspectives in Environmental Science report of 1972 discussed the cyclical behavior of climate, and the understanding at the time that the planet was entering a phase of cooling after a warm period. "Judging from the record of the past interglacial ages, the present time of high temperatures should be ...
The Quaternary glaciation is the current glaciation period and began 2.58 million years ago. In 2020 scientists published a continuous, high-fidelity record of variations in Earth's climate during the past 66 million years and identified four climate states , separated by transitions that include changing greenhouse gas levels and polar ice ...