fredag 19. desember 2014

Where on Google Earth #465

Matthew's WoGE #464 was tricky to find, I had eliminated all continents and was just about to start on the islands when a picture of a lemur pointed me straight to Madagascar and the threatened Lake Alaotra.

 There are many lakes in the world, and surprisingly many deserts. This time I have found a view with at least three interesting things, of which two are geology. One of them is related to my work, and so is the other but in a very different way.

If you want to have the honour of posting a Christmas WoGE, you should hurry up. :D

 As always, post a comment with latitude and longitude and write something about the (geologic/geographic/hydrographic) feature in the picture. If you win, you get to host the next one.

Previous WoGEs are collected by Felix on his blog and a KML file.

6 kommentarer:

  1. 31.8566°, -8.8803° Irhoud, Marocco. We are looking at a Cambrian lime stone area with carst and the Irhoud Mine. In the mine Hematite and Barite can be found. "Terrestrial Impact Structures A Bibliography 1965-68" describes all this as: "large amounts of berite have come from the Jebel Irhoud mine at the west end of the Paleozoic Jebilet massif. The barite occurs in veins and replacement bodies in Paleozic carbonate rocks near the margins fo foult blocks. The deposits are described as telethermal and post-Triassic in Age."

    This is only the first shot as I have to go to dinner in my favourite italian restaurant.

  2. Newer publications say the same as the old one from 1965, so besides the fact that we do have some 160.000 years old hominid fossils in the area, I have nothing more to say.

  3. I've just discovered, that you are looking for three things to be found. So the first one was the mine :
    The second the hominid fossils:

    By the way pretty often in a limestone carst area, we do find hominid fossils in caves. In my area we do have traces of 35.000 year old hominids.

    Your second geological thing is troubling me as I cannot find geological descriptions of the area and I have no geological map. On OpenGeology I do not find faults in the area. One could think there should be a fault at the contact zone of the light to the dark rock. I do assume that the light rocks are lime stones ( I could not find a proof for this assumption). The water flows in carst caves from the higher level to the dark lower level and feeds little springs. This is the same story with the lime stone hills in my area.

  4. You found the location, and the third thing is rather difficult to find out, you have to trawl through a lot of poor-resolution maps to figure it out!

    The light rocks in the southern part are indeed limestones, Cretaceous limestones. One of the crucial features in North Sea geology is the "BCU", or "Base Cretaceous Unconformity". In very many of our oil fields the marls and shales above the BCU are the caprock, without which we would have no oil fields! In this case, that means that the mountain of Ordovician(?) shales containing the barite was a mountain even before the Cretaceous, and that makes this angular unconformity even more spectacular in my view.

    I have been looking at this pretty unconformity for a long time, trying to find enough information to use it as a WoGE. I finally found some references last week, I will post links to them when I am back at work after holidays. :)

  5. I thought about something like this, but the many poor resolution maps did not tell me the fine print. I mean how could that be. If I could have figured all this out, why would we need all you geological educated scientists? ;-)
    So I am glad you are going to find some more oil until all the wind/solar-energy in Germany is enough to heat my living room.

    I think I am going to post my Christmas puzzle on the 23rd and wish everybody a save trip to his or her holiday location.

  6. The X-mas WOGE is ready for your pleasure: