Sunday, June 14, 2009


[During the Carboniferous Era swamps had little oxygen in the water. So the plants decayed to ooze but were not oxidized to CO2. The ooze, compressed by layer upon layer above it, became coal and oil.]

Harvey's friend and neighbor (whose name Harvey will no doubt soon supply) is a professor of geology at Chico State. I have long wanted to learn geology since it occurred to me that I have spent all my life crawling around on the surface of the earth and figure to spend the rest of it doing the same, but have no clue what it is, how it works, how it got this way, and yada yada yada. So I jumped on the man for the name of a decent geology textbook.

I had read one before but it was for community college students. It was 'Mr. Wizard Explains Rocks to Dick and Jane' with lots of pictures in color.

Harvey's friend recommended "New Views on an Old Planet" by Tjeerd H. van Andel. I got it on ABEbooks (Advanced Book Exchange which is one of the best websites on the web. It consolidates the inventories of hundreds of used bookstores across the US, Canada, UK, and Australia, and provides a great search engine for finding things by title, author, subject, or keyword. One can find whatever one wants and for cheap.

Van Andel writes in a somewhat condensed form and though the book is short, it requires some paying attention to stay with him. Mostly it is on account of the things he is relating are so large, and in some cases literally earth-shattering, that it sometimes takes a second reading to get one's imagination around what he is saying. He also assumes you remember what he just told you so you will understand what he is telling you now. No Dick and Jane condescension.

As in, oh by the way, all earth's climate is primarily driven by the abyssal (sea bottom) cold water current flowing north from Antarctica. And oh by the way, that current has to squeeze through two narrow gateways, one off Samoa and the other east of the Falklands. If either or both of those gateways is either closed or widened by the effects of the seafloor spreading that drives plate tectonics, then the climate of the whole planet will change abruptly and permanently. Did I say "if"? I meant "when".

Van Andel bombards the hapless reader with bombshells like that one after another. Also, you know how plate tectonics has finally given us a comprehensive understanding of geology and it is all a nice tidy package? 'Tain't so. There are gaping holes in geology. For instance, even after allowing for discontinuities and this and that, most of the geological record that should be there, isn't. Also, given some well-understood and reliable processes, the ocean should be far saltier than it is. Where did the salt go? He gives a speculation about that based on seabed geothermal springs but in 1985 when he was writing it was still just a promising guess.

Most of all he makes a persuasive case that while we invariably focus on plate tectonics and continental drift, this is only because we are land animals. He makes the case, without specifically saying it, that the effects of plate tectonics on the currents and temperatures of the oceans is more important.

In the Mesozoic, loosely the Age of Dinosaurs, temperatures on earth were warm and much more uniform than today. Rainfall was high. There were no deserts. There were no ice caps. There were palm trees at the poles. 25 million years ago the landbridge between South America and Antarctica sank making the circum-Antarctic current possible. The Isthmus of Panama rose 6 million years ago and shut off the remainder of the warm equatorial current between the Atlantic and Pacific. The two together led to the current series of ice ages.

During much of the late Palaeozoic, loosely, very loosely, the Age of Fishes, there was a lot less land than today. Sea level was higher and much of what are now continents were archipelagoes in vast warm shallow seas full of reefs, plankton, and sargassum. We have scant examples of such seas in our world today. Which is why coal and oil formed then and are not forming now.

Van Andel is as always unwilling to sweep difficulties under the rug. Where did the additional water come from/where did it go? Today's polar ice caps, mountain glaciers, lakes, and rivers do not come even close to making up the difference.

My constant reaction when reading "New Views on an Old Planet" is, "This is huge! Why didn't I know this before?!" It is an important book.

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