Sentences with word «glaciation»
Glaciation refers to the process of when large masses of ice, known as glaciers, form and spread over a land area. It occurs due to long periods of cold temperatures where snow accumulates and compacts into ice. Full definition
Linked by a single root system, Pando consists of tens of thousands of genetically identical trees, cloned from a sprout that emerged after the last glaciation in southern Utah, roughly 13,000 years ago.
discovermagazine.com
The closing of the Central American Seaway initially may have warmed Earth's climate, but then set the stage for glaciation in the Northern Hemisphere at 2.7 million years ago.
The second clue is that Northern Hemisphere glaciation intensified between 3.1 and 2.5 million years ago, thanks to all the moisture delivered to the far north via evaporation from a more vigorous Gulf Stream.
There are no sites in the hypothetical Ice - Free Corridor, (between the Laurentine and the Cordilleran glaciers) to provide convincing evidence of human activity prior to the last major glaciation, nor are any known from the Alaska and British Columbia coasts (Wilson and Burns 1999:235).
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.
Timing and depositional environments of a Middle Pleistocene glaciation of northeast England: New evidence from Warren House Gill, County Durham.
A similar low and high arsenic content accompanied the coming and going of global glaciations at around 0.7 billion years ago, which is when Earth first saw the appearance of complex life.
They suggest that the two raven types may have been geographically isolated, possibly by glaciation, and are now remerging.
The real interesting thing of all this, is how fast earth changes from glaciation to warm.
Although there was widespread glaciation about 2.3 billion years ago, the oceans seem to have been liquid since 4 billion years ago and life has existed for at least the past 3.5 billion years.
Ruddiman has also recently published the intercomparison of many interglacials in defense of his hypothesis claiming that we have avoided entering into glaciation already thousands of years ago.
And finally our current Quaternary glaciation began a brief 2.58 mya.
Given that a CO2 doubling or halving is equivalent to a 2 % change in solar irradiance [66] and the estimate that solar irradiance was approximately 6 % lower 600 Ma at the most recent snowball Earth occurrence [113], figure 7 implies that about 300 ppm CO2 or less was sufficiently small to initiate glaciation at that time.
During a period of glaciation about 660,000 years ago, Himalayan brown bears were one of the first groups to branch off and become distinct from other brown bears, the data suggest.
That would make Mars's giant mid-latitude mountains — Ascraeus Mons, Pavonis Mons and Arsia Mons — prime locations for glaciation around 210 million years ago.
Subsequently, large Northern Hemisphere glaciations began to occur when pCO2 dropped below about 300 ppm in the middle Pliocene.
Coming closer to the present we have learned from Antarctic ice cores that for the past 800,000 years there have been regular periods of major glaciation followed by interglacial periods in 100,000 year - cycles.
Glacial troughs, excavated throughout maximum glaciations over the last 2 million years, provide a major route for Circumpolar Deep Water to access the ice shelves11.
Hopefully, eventually fusion in the ice age glaciation time scale or at least advanced fission.
So it would seem a bit surprising if land use forcing were enough to itself initiate glaciation.
They have not had the remaking influences of fairly recent glaciation and sedimentation, followed by the biological colonization typical of many rich lands in more temperate zones.
And I'm pretty sure none of these papers takes the view that preventing glaciation is the right thing to do and thinking otherwise is «callous».
The closing of the Isthmus of Panama about 3 million years ago may have ushered in the present period of strong glaciation over North America by ending the exchange of water between the tropical Atlantic and Pacific Oceans.
They were a cold adapted people and endured severe climate fluctuations, including several periods of increased glaciation throughout their existence.
If environmental changes as substantial as continent - wide glaciations do not force evolutionary change, then what does?