Monday, 29 November 2010

Where on Google Earth #229

I was lucky enough that Felix posted his hint (WoGE #228) just before my lunch-hour, which stopped my futile search for diamond mines (don't ask me why).

Find the location of the picture on GoogleEarth (latitude/longitude) and describe the geology of the place (I have a particular feature in mind). There is no Schott rule, as I think it may be hard to find, but I'm prepared to be proved wrong...

If you do not know what this is all about read this.

Felix has won!
My take on the Geology below.

The ghostly wiggly lines are called roddons (see Wikipedia entry). They are indeed silt/mud surrounded by darker peat and represent an old (but not very old) set of drainage channels over the area.

Since they were formed, the area has been drained (hence the regular shaped fields and drainage ditches). Through a process of drying out and other things the peat has shrunk but the silt channels have not. This means they remain as raised areas and are sometimes the site of villages or roads. The whole area is now below sea-level.

Note the regular fields: these areas were 'enclosed' c. 0.3ka which forms a landscape more like the Netherlands than the rest of England. Also note that the range of photos in the bottom left don't show them; they are subtle features not visible under a healthy crop of vegetation.

A final whimsical note, a less interesting section in Wikipedia debates whether roddon should be spelt rodham, which is the US Secretary of State's middle name (or is it maiden name?). Given her daughter has the same name as a part of London, I wonder if there is a traditional of geographical names in her family.


  1. Simon: you found a really interesting spot. Do you want to tell us where North is?

  2. Simon, I am sorry. I couldn't resist. That's not nice of me... Finding the spot was not difficult as the Copyright note "Infoterra" clearly idendified Britain. And your spot is exactly at the border of a more colourish map to a more greyisch map. And there are not many "colour borders" on the map.
    But the geology was not so easy, as I found different things, old ones, new ones..

    52°30'N, 0°22'O
    Great Britain, village Southery

    The image shows pleistocene river valleys, scoured away by the Anglian Stage (cold period), covered and preserved by glacial soil deposits. (beautiful!!)

    There can two stories be found about this spot.
    First a so called Bytham river (c. 450.000 years) running from around Stratford upon Avon - Leicester- BuryStdEdmunds into the North Sea. According
    to a map , this river was running exactly over our picture.
    As the "Bytham river" should be running from west to east, and our river in the picture flows from east to west, I am in favour of story two:

    According to new findings, the location we are looking at, was identified as a glacial meltwater delta, dating from a Wolstonian-age glaciation (c. 160 000 old) (Wikipedia) .

  3. Hi Felix,

    You've found it, no need to apologise.
    In your Geological descriptions you cover some nice things about the area, but not quite exactly what I had in mind.

    I'm still happy to declare you winner, but I'll post some more tomorrow on what I think is going on. I'll talk about the ghostly channels, which have a particular name.

    If anyone wants to tell us what they are in the meantime, I'd be delighted...

  4. Simon: so I have to try again. The area is also called Fen Area or The Fens. A low area within the sea level. A Fen is some kind of marsh-, or wetland. In order to get farmland, the marshes have been artificially drained. Now comes my speculation. The channels look like if they would be the cannels for drying the marshes. As far as I can see, the cannels lead to still existing rivers, so the direction of the water flow for the drainage would be correct. As the water was out of the marshes, one had to fill the dry channels up in order to get an even farming land. So the channels have been filled with soil/sand/mud from the nearby see. The light grey colour of the cannels looks like the german "Watt" or mudflats. We see the light color of the former dry channels agains the dark soil of the marshes.

    If anyone finds a better/correct/not-speculation geology and want to host the next WOGE, please tell us your interpretation of the area.

  5. Let's draw this to a close. Felix has all but got it and I'm sure we'd all like a new picture from Felix to work on. I've put my take on the Geology in the main article.
    Over to Felix!

  6. Simon: pretty interesting stuff, you've found here. The pattern looks like the fractal Mandelbrot Set. There should be more of these patterns somewhere. On my picture at WOGE230 we have a dendritic flow pattern, on you picture a dendritic shrink pattern. Two different processes but similar result.