Sentences with phrase «glaciation around»

«In particular, this mechanism may have contributed to Earth's entry into a long period of global glaciation around 700 million years ago, a theory known as the Snowball Earth hypothesis.»

Current interpretation of Y - chromosome and mtDNA data suggests that modern - day Portuguese trace a significant amount of these lineages to the paleolithic peoples who began settling the European continent between the end of the last glaciation around 45,000 years ago.

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.

Not exact matches

While the first of the glaciations that the team studied was probably triggered by nonvascular plants such as mosses and liverworts, the second ice age — the one that began around 445 million years ago — may have been brought on by the rise and spread of vascular plants.

Around this time and afterwards, we started having glaciations — ice ages — over and over again, and it's not clear why that started to happen.

The first Ediacaran to begin crawling around would have discovered a world devoid of predatory animals, with a seafloor covered either in thick bacterial mats or toxic sediment and, possibly, a climate thawing from a worldwide glaciation event known as «Snowball Earth.»

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.

A few million years after the sponges were around a glaciation extended to the equator, wiping out large swathes of life.

Around 720 - 640 million years ago, much of the Earth's surface was covered in ice during a glaciation that lasted millions of years.

As astronomical cycles they are predictable into the future and will cause another ice age probably in around 50,000 years (that depends on where the threshold for glaciation is, and what future CO2 levels will be at that time), but there is no way the Milankovich cycles could explain the current global warming.

The encroachment of increases in desert terrain around the fringes of the equatorial region is expected to show increases as the warming process reaches its «peak», before the «turn» back to a «glaciation dip».

If he's worried about ice ages, perhaps he should ponder the selfishness of squandering what could have been a useful geoengineering resource to future generations faced with an imminent glaciation; carefully burning fossil fuels to enhance the greenhouse effect just enough to maintain temperatures in the face of declining northern - hemisphere insolation due to the Milankovich cycles may well be the most cost - effective method for them to do so, if those resources are still around at the time.

I just found this info on the Gaskiers Glaciation and the 90 km diameter meteorite impact at around the same time (about 590 Mya)(I am interested in this because I worked in the area in 1967 - 68).

If these plumes of warm air operated in the same way during the last glaciation as they do know then they would make short work of ice sheets that were hanging around because of the albedo effect, this is possible because not all the northern hemisphere mid latitude land surface was covered with ice throughout the period of glaciation and might explain why glaciations terminate quickly

Opening with a biographical sketch of Broecker — who, we learn, was born to an Evangelical suburban Chicago family, and initially drifted into his scientific vocation via a summer job in a radiocarbon dating lab — the book explains the currently - accepted Milankovitch theory of Ice Age glaciation; proceeds to an account of the Dr. David Keeling's measurements atmospheric CO2; continues with a summary of research work on glacial ice cores, sediments, and fossil pollen from around the world showing startlingly abrupt prehistoric climate changes; and moves on to the possible consequences of continued warming, closing with an account of the prospects of removing carbon dioxide from the atmosphere.

The last of these so - called «Snowball Earth» glaciations ended around 635 million years ago when complex life was just starting to develop.

Then, around 1 million years ago, glaciations got longer, with cycles lasting for about 100,000 years.

The LIA was intended by the originator of the phrase Francis Matthes to mean the last 4000 years of renewed glaciation following the warmest part of the Holocene some 6000 years ago not merely a 500 year epoch commencing around 1300.

Indeed, they note that about 800,000 years ago, orbital alignments were similar but carbon dioxide concentrations were around 240 parts per million, and glaciation did indeed occur.