Sentences with phrase «continental glaciation»
Continental glaciation refers to the process of large sheets of ice covering vast areas of land, like continents. It occurs when glaciers spread out and cover a substantial part of a continent, shaping the landforms and changing the environment around them. Full definition
However, this enhanced level of atmospheric CO2 does not seem to have been accompanied by unusually warm temperatures in the tropics, and in fact may have been contemporaneous with high - latitude continental glaciation on Gondwanaland9, 10.
nature.com
The Greenland ice sheet did not develop at all until the late Pliocene, but apparently developed very rapidly with the first continental glaciation.
That is, most of the period of polar bear existence has been during continental glaciations rather than inter-glacials.
The low - latitude λ 18O data are at variance with other climate data that show high - latitude warming and an absence of large - scale continental glaciation....
They find that periods of low CO2 correlate with long - lived, extensive continental glaciations while periods of high CO2 don't overlap with these glaciations.
That interglacial has also been estimated to have spanned 15,000 years before continental glaciation resumed.
However, the exact timing and extent of sea ice formation and continental glaciation in the Arctic during the Pliocene remains uncertain (Zachos et al., 2008).
Although there is limited evidence of ice - rafted debris in the Arctic from the Miocene and into the Eocene, suggesting some continental glaciation (Stickley et al., 2009; St. John and Krissek, 2002), empirical evidence suggests that widespread Northern Hemisphere glaciation did not occur until 2.75 Ma (Ravelo et al., 2004), which is substantiated by recent Pliocene paleotemperature SST estimates near Svalbard between 10 and 18 °C (Robinson, 2009).
This is corroborated by model simulations indicating that atmospheric CO2 levels must fall below 280 ppmv to promote widespread continental glaciation of the Northern Hemisphere (DeConto et al., 2008) and 250 ppmv to promote major continental glaciation on Greenland (Lunt et al., 2008), both of which are well below recent estimates of Pliocene atmospheric CO2 estimates of ∼ 390 ppmv (Pagani et al., 2010).
The continental glaciations of the Pleistocene left signatures on the landscape in the form of glacial deposits and landforms; however, the best knowledge of the magnitude and timing of the various glacial and interglacial periods comes from oxygen isotope records in ocean sediments.