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Tuesday, 17 January 2017

Pangea

Pangea's name is derived from the Greek pangaia, meaning “all the Earth". Pangea’s existence was first proposed in 1912 by German meteorologist Alfred Wegener as a part of his theory of continental drift. When you look at any world map, it's hard to miss that the continents appear to fit like a puzzle. (eg, Britannica, Live Science, Wiki)

The supercontinent of Pangea existed some 300 million years ago. It broke up around 180 million years ago, again at 140 million years ago (Africa's separation from South America), and the final split occurred about 80 million years ago (North America separated from Europe, and Australia from Antarctica). Some 50 million years ago, India collided with Eurasia, forming the Himalayas.

Within the next 250 million years, Africa and the Americas will merge with Eurasia to form a supercontinent that approaches Pangean proportions. (Britannica) In my view, we should thus differentiate climate change from climate shift. Climate shift is one of the many explanations of climate change (eg, BGS).

Today, we live in an interglacial period following the Last Glacial Maximum (? - 24,500 BCE) of the Quaternary Ice Age (2.58 million years ago-onwards). The period of deglaciation (aka global warming) started some 22,000 years ago and is still ongoing. The global melting of ice caused an extreme sea level rise (aka the Great Flood) of some 120-140 meters between 17,000 BCE to 5,000 BCE. Its global destruction must have been beyond imagination (my 31 December 2016 blog).

Until 22,000 years ago, there was some kind of a mini Pangea between Africa, Arabia and Asia as the Persian Gulf (avg. depth 50m; max. 90m) and the Mandeb Strait (avg. depth 186m) at Djibouti did not exist.

On average the global sea levels were some 120m or 400 feet lower which would turn seas into rivers at most.

An exodus from East Africa to the Iran-Iraq border (eg, Babylon, Sumer) did not require boats. The black-headed Sumerians may just have travelled from Africa by foot.

The Supercontinent cycle (a.k.a. Wegenerian cycle) is driven by Earth's plate tectonics and lasts some 500 million years. It must thus have happened several times in the past 4.5 billion years. Given such timeframes, it's hard to blame humans for living in the Now. The Now is the only constant in a sea of Change. 

Cool Change (1979) by Little River Band - artists, lyrics, video, Wiki-1, Wiki-2