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Rulers of the Earth

Richard Bell’s Wild West Yorkshire nature diary, Sunday, 15th February 2009

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It’s difficult to get a grasp on millions or billions of years but at least you can get some sense of proportion. Preparing to lead a geology walk this afternoon I turned to Google Earth (new version just out, hope this one behaves better than the last on my computer!).

The walk starts alongside a playing field which Google Earth reveals to be 650 feet long. To use this distance as a time scale I worked out that if you take the length of the playing field to represent the 4.6 billion years of Earth’s history then 1.7 inches would represent a million years.

I’ve marked a ruler to illustrate this time scale: present day is on the left, the formation of the Earth on the right. The transition from the Carboniferous to the Permian period 290 million years ago - the rocks we’re looking at this afternoon - is represented by the red line on the left which on the ground would be just 40 feet from ‘present day’ while the dinosaurs were only three of my yard-long paces back in time.

Extinction of dinosaurs
65 million years ago

End of Carboniferous 290 million years ago

First complex cells
c. 2 billion years ago

Photosynthesis c. 3 billion years ago

First simple cells
c. 3.8 billion years ago

IF THE story of Earth, back to its birth 4,600 million years ago, was represented by the length of a football field then the extinction of the dinosaurs would be just two or three paces back in time.

I used a field sketch to explain the geological fault we encountered on the walk.

To familiarise myself with the rocks, paleo-environments and industrial history associated with the site I took a large (A2) layout pad and, starting in the middle, drew cartoons to remind myself of the key facts. This ‘Mind Map’ technique has been popularised by Tony Buzan and I’ve started using it again after reading his Mind Maps for Kids recently.

For more on Upton Cutting Regionally Important Geological Site, which we visited this afternoon, see my previous diary page from November 2007, Tracks through Time.