{"id":25715,"date":"2022-09-19T15:12:07","date_gmt":"2022-09-19T07:12:07","guid":{"rendered":"https:\/\/stuif.com\/blog\/?p=25715"},"modified":"2023-10-02T18:35:04","modified_gmt":"2023-10-02T10:35:04","slug":"the-paleomap-project","status":"publish","type":"post","link":"https:\/\/stuif.com\/blog\/?p=25715","title":{"rendered":"The Paleomap Project"},"content":{"rendered":"\n

INTRODUCTION<\/em><\/strong><\/p>\n\n\n\n

Twenty years ago I started my own website. Although now in hibernation, this Stuif Site<\/a> is still online. It has a Science -> Earth category<\/a>, here is a screenshot of that page. I was quite interested in plate tectonics and continental drift and was planning to write more webpages about it. This never happened, the Earth page remained a “stub”.<\/p>\n\n\n\n

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But finally I have now decided to write a blog.<\/p>\n\n\n\n

Recently I came across an article The Lost Continent of Kumari Kandam<\/a> in which I found this map: I had never heard about Kumari Kandam and had to check Wikipedia: Kumari Kandam<\/a>, “a mythical continent, believed to be lost with an ancient Tamil civilization<\/em>” <\/p>\n\n\n\n

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\"This<\/a><\/figure>\n<\/figure>\n\n\n\n

Apparently some Tamil revivalists still think that this continent really existed and actually was the cradle of civilisation, not Mesopotamia . The continent was submerged after the last Ice Age, when sea levels rose, forcing the Tamil people to migrate to other parts of the world. And yes, the sea levels rose after the last Ice Age, more than 120 meters. But have a look at the Google Earth nap of the Indian Ocean, where I have outlined Kumari Kandam. Mean sea depth is ~ 4 km! <\/p>\n\n\n\n

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So the Kumari Kandam continent never existed. A few months ago I have written a separate blog about this myth: Kumari Kandam & Lemuria<\/a> .In that post I announced a post about continental drift and plate tectonics. Here it is. <\/p>\n\n\n\n

THE STRUCTURE OF EARTH<\/em><\/strong><\/p>\n\n\n\n

When Earth was formed, 4.55 billion year ago, it was in a completely molten state. The heavier elements sank to the center, the lighter elements rose to the surface. Because of cooling soon a crust developed. Here are two images of present Earth , showing its structure. Basically there are three main layers, the Crust, the Mantle and the Core. <\/p>\n\n\n\n

The Core consists mainly of iron and nickel. In the Outer Core they are liquid (high temperature) and are the source of Earth’s magnetic field. The Inner Core is solid, the temperature is even higher, (about 6000 \u00b0C) but the pressure is gigantic.<\/p>\n\n\n\n

The mantle is basically solid, but the upper mantle is already so hot, that it behaves as a fluid on a timescale of many millions of years. This upper part is called the Asthenosphere. .<\/p>\n\n\n\n

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The right image gives more details about the size of the various layers. The crust of Earth is very thin, especially under the oceans (~6-7 km). The continental crust is much thicker , 30-70 km and less dense than the oceanic crust. Compare the Earth crust with the shell of a chicken egg, or the skin of an apple<\/p>\n\n\n\n

The crust of Earth is not one whole, it is broken in many separate parts, called tectonic plates. Below you see the main tectonic plates at present. They “float” on the mantle, very slowly, about a few cm\/year. Red arrows indicate the direction in which they move.<\/p>\n\n\n\n

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A few comments on this map<\/p>\n\n\n\n