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Glacial history of Minnesota; Glacial period – Interval of time within an ice age that is marked by colder temperatures and glacier advances; Ice age – Period of long-term reduction in temperature of Earth's surface and atmosphere; Last Glacial Period – Period of major glaciations of the Northern Hemisphere (115,000–12,000 years ago)
Knowledge of precise climatic events decreases as the record goes further back in time. The timeline of glaciation covers ice ages specifically, which tend to have their own names for phases, often with different names used for different parts of the world. The names for earlier periods and events come from geology and paleontology.
The stage names are part of the North American and the European Alpine subdivisions. The correlation between both subdivisions is tentative. Within the Quaternary, which started about 2.6 million years before present, there have been a number of glacials and interglacials. [5] At least eight glacial cycles have occurred in the last 740,000 ...
Ice ages, long periods of reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers.
Initially the glacial/interglacial cycle length was about 41,000 years, but following the Mid-Pleistocene Transition about 1 Ma, it slowed to about 100,000 years, as evidenced most clearly by ice cores for the past 800,000 years and marine sediment cores for the earlier period. Over the past 740,000 years there have been eight glacial cycles. [7]
These events are defined differently in different regions of the glacial range, which have their own glacial history depending on latitude, terrain and climate. There is a general correspondence between glacials in different regions. Investigators often interchange the names if the glacial geology of a region is in the process of being defined.
Ice streams are a type of glacier [5] and many of them have "glacier" in their name, e.g. Pine Island Glacier. Ice shelves are listed separately in the List of Antarctic ice shelves . For the purposes of these lists, the Antarctic is defined as any latitude further south than 60° (the continental limit according to the Antarctic Treaty System ).
The name of the geologic period refers to the very cold global climate of the Cryogenian. Characteristic glacial deposits indicate that Earth suffered the most severe ice ages in its history during this period (Sturtian and Marinoan). According to Eyles and Young, "Late Proterozoic glaciogenic deposits are known from all the continents.